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Sample records for goby neogobius melanostomus

  1. Effectiveness of piscicides for controlling round gobies (Neogobius melanostomus)

    USGS Publications Warehouse

    Schreier, T.M.; Dawson, V.K.; Larson, W.

    2008-01-01

    Round gobies (Neogobius melanostomus) were introduced to the Great Lakes presumably as a result of ballast water releases from seagoing freighters returning from European water bodies. These unwelcome fish have become established in the Great Lakes region and are expanding their range to suitable portions of other interior drainage basins including the Mississippi River traversing the central United States and the Trent-Severn waterway spanning south-central Ontario. If the invasion continues, use of chemical toxicants as a control measure may be necessary. Toxicity tests of the currently registered piscicides antimycin, rotenone, 3-trifluoromethyl-4-nitrophenol (TFM), and Bayluscide?? were conducted with three fish species native to the Great Lakes and round gobies collected from the Illinois Waterway. Tests indicated that round gobies are sensitive to all of the piscicides, however, the level of sensitivity is similar to that of the native fish species tested. Therefore, currently registered piscicides have limited potential to selectively remove round gobies. Bottom-release formulations of Bayluscide?? and antimycin were also evaluated as control agents for the normally bottom-dwelling round goby. Avoidance behavior tests demonstrated that the round goby did not react to the presence of either chemical. Therefore, the bottom-release formulations may have some application for the selective removal of round gobies, and may be one of the few tools presently available to fishery managers to help limit the range expansion of this invasive fish.

  2. Hearing and the round goby: Understanding the auditory system of the round goby (Neogobius melanostomus)

    NASA Astrophysics Data System (ADS)

    Belanger, Andrea J.; Higgs, Dennis M.

    2005-04-01

    The round goby (Neogobius melanostomus), is an invasive species in the Great Lakes watershed. Adult round gobies show behavioral responses to conspecific vocalizations but physiological investigations have not yet been conducted to quantify their hearing abilities. We have been examining the physiological and morphological development of the auditory system in the round goby. Various frequencies (100 Hz to 800 Hz and conspecific sounds), at various intensities (120 dB to 170 dB re 1 Pa) were presented to juveniles and adults and their auditory brain-stem responses (ABR) were recorded. Round gobies only respond physiologically to tones from 100-600 Hz, with threshold varying between 145 to 155 dB re 1 Pa. The response threshold to conspecific sounds was 140 dB re 1 Pa. There was no significant difference in auditory threshold between sizes of fish for either tones or conspecific sounds. Saccular epithelia were stained using phalloidin and there was a trend towards an increase in both hair cell number and density with an increase in fish size. These results represent a first attempt to quantify auditory abilities in this invasive species. This is an important step in understanding their reproductive physiology, which could potentially aid in their population control. [Funded by NSERC.

  3. Twenty years of invasion: a review of round goby Neogobius melanostomus biology, spread and ecological implications.

    PubMed

    Kornis, M S; Mercado-Silva, N; Vander Zanden, M J

    2012-02-01

    The round goby Neogobius melanostomus is one of the most wide-ranging invasive fish on earth, with substantial introduced populations within the Laurentian Great Lakes watershed, the Baltic Sea and several major European rivers. Rapid expansion and deleterious ecosystem effects have motivated extensive research on this species; here this research is synthesized. Maps of the global distribution are provided and the invasion history of N. melanostomus, which spread more rapidly at first in North America, but has undergone substantial expansion over the past decade in the Baltic Sea, is summarized. Meta-analyses comparing their size at age, diet, competitors and predators in North American and European ecosystems are provided. Size at age is region specific, with saline habitats typically supporting larger and faster growing individuals than fresh water. Neogobius melanostomus prey differs substantially between regions, demonstrating a capacity to adapt to locally abundant food sources. Neogobius melanostomus comprise at least 50% of the diet of eight taxa in at least one site or life stage; in total, 16 predator taxa are documented from the Laurentian Great Lakes v. five from Eurasia. Invasive N. melanostomus are the only common forage fish to heavily exploit mussels in the Laurentian Great Lakes and the Baltic Sea, facilitating the transfer of energy from mussels to higher trophic levels in both systems. Neogobius melanostomus morphology, life history, reproduction, habitat preferences, environmental tolerances, parasites, environmental effects, sampling strategies and management are also discussed. Neogobius melanostomus inhabit a wide range of temperate freshwater and brackish-water ecosystems and will probably continue to spread via ballast water, accidental bait release and natural dispersal worldwide. Climate change will probably enhance N. melanostomus expansion by elevating water temperatures closer to its energetic optimum of 26° C. Future research needs

  4. The impact of introduced round gobies (Neogobius melanostomus) on phosphorus cycling in central Lake Erie

    USGS Publications Warehouse

    Bunnell, D.B.; Johnson, T.B.; Knight, C.T.

    2005-01-01

    We used an individual-based bioenergetic model to simulate the phosphorus flux of the round goby (Neogobius melanostomus) population in central Lake Erie during 1995-2002. Estimates of round goby diet composition, growth rates, and population abundance were derived from field sampling. As an abundant introduced fish, we predicted that round gobies would influence phosphorus cycling both directly, through excretion, and indirectly, through consumption of dreissenid mussels, whose high mass-specific phosphorus excretion enhances recycling. In 1999, when age-1+ round gobies reached peak abundance near 350 million (2.4 kg??ha-1), annual phosphorus excretion was estimated at 7 t (1.4 ?? 10-3 mg P??m-2??day -1). From an ecosystem perspective, however, round gobies excreted only 0.4% of the phosphorus needed by the benthic community for primary production. Indirectly, round gobies consumed <0.2% of dreissenid population biomass, indicating that round gobies did not reduce nutrient availability by consuming dreissenids. Compared with previous studies that have revealed introduced species to influence phosphorus cycling, round gobies likely did not attain a sufficiently high biomass density to influence phosphorus cycling in Lake Erie. ?? 2005 NRC Canada.

  5. Divergent life histories of invasive round gobies (Neogobius melanostomus) in Lake Michigan and its tributaries

    USGS Publications Warehouse

    Kornis, Matthew; Weidel, Brian C.; Vander Zanden, M. Jake

    2016-01-01

    Round gobies (Neogobius melanostomus) have invaded benthic habitats of the Laurentian Great Lakes and connected tributary streams. Although connected, these two systems generally differ in temperature (Great Lakes are typically colder), food availability (Dreissenid mussels are more prevalent in Great Lakes), and system size and openness. Here, we compare round goby life histories from inshore Lake Michigan and adjacent tributary systems—an uncommon case study of life-history differences between connected systems. Tributary round gobies grew much faster (average length-at-age of 122.3 vs. 65.7 mm for Age 2 +  round gobies), appeared to have shorter life spans (maximum observed age of 2 vs. 5) and had lower age-at-50% maturity (1.6 vs. 2.4 years; females only) compared to gobies from Lake Michigan. In addition, tributary gobies had greater fecundity at Ages 1–2 than lake gobies, but had fewer eggs for a given body size prior to the first spawning event of the summer. We were not able to determine the cause of the observed life-history differences. Nonetheless, the observed differences in growth, maturation and longevity were consistent with known effects of water temperature, as well as predictions of life-history theory for animals at invasion fronts exposed to novel environmental conditions. The high degree of phenotypic plasticity in connected populations of this invasive species has implications for our understanding of invasive species impacts in different habitats.

  6. Sound localization and auditory response capabilities in round goby (Neogobius melanostomus)

    NASA Astrophysics Data System (ADS)

    Rollo, Audrey K.; Higgs, Dennis M.

    2005-04-01

    A fundamental role in vertebrate auditory systems is determining the direction of a sound source. While fish show directional responses to sound, sound localization remains in dispute. The species used in the current study, Neogobius melanostomus (round goby) uses sound in reproductive contexts, with both male and female gobies showing directed movement towards a calling male. The two-choice laboratory experiment was used (active versus quiet speaker) to analyze behavior of gobies in response to sound stimuli. When conspecific male spawning sounds were played, gobies moved in a direct path to the active speaker, suggesting true localization to sound. Of the animals that responded to conspecific sounds, 85% of the females and 66% of the males moved directly to the sound source. Auditory playback of natural and synthetic sounds showed differential behavioral specificity. Of gobies that responded, 89% were attracted to the speaker playing Padogobius martensii sounds, 87% to 100 Hz tone, 62% to white noise, and 56% to Gobius niger sounds. Swimming speed, as well as mean path angle to the speaker, will be presented during the presentation. Results suggest a strong localization of the round goby to a sound source, with some differential sound specificity.

  7. Responses of round goby (Neogobius melanostomus) olfactory epithelium to steroids released by reproductive males.

    PubMed

    Laframboise, Alyson J; Zielinski, Barbara S

    2011-10-01

    The wild perciform teleost Neogobius melanostomus (the round goby) originated from the Ponto-Caspian region and is now a highly successful invasive species in the Laurentian Great Lakes. Males may attract females into their nests for spawning by releasing reproductive pheromones, and it has been previously shown that reproductive males synthesize and release the 5β-reduced and 3α-hydroxyl steroids 3α-hydroxy-5β-androstane-11,17-dione (11-oxo-etiocholanolone; 11-O-ETIO) and 3α-hydroxy-5β-androstane-11,17-dione 3-sulfate (11-oxo-etiocholanolone-3-sulfate; 11-O-ETIO-3-s) and 3α,17β-dihydroxy-5β-androstan-11-one 17-sulfate. In this study, we investigated properties of these released steroids by recording field potential responses from the olfactory epithelium (electro-olfactogram, EOG). The steroid 3α,17β-dihydroxy-5β-androstan-11-one 17-sulfate did not elicit olfactory responses while both 11-O-ETIO and 11-O-ETIO-3-s stimulated olfactory field potentials in the round goby, but not in the goldfish. Cross-adaptation analysis demonstrated that round gobies discriminated between11-O-ETIO and 11-O-ETIO-3-s (as well as etiocholanolone, ETIO) at the sensory level. Second messenger cascades depending on both cAMP and IP(3) were inferred for steroids from pharmacological inhibition studies, while the canonical teleost odors taurocholic acid (a bile acid) and L: -alanine (an amino acid) used only cAMP and IP(3), respectively. The round goby presents itself as an excellent species for the study of olfactory function of fish in the wild, given its possible use of these released steroids as pheromones.

  8. Evidence for ontogenetically and morphologically distinct alternative reproductive tactics in the invasive Round Goby Neogobius melanostomus

    PubMed Central

    de Jong, Karen; van Kessel, Nils; Hinde, Camilla A.; Nagelkerke, Leopold A. J.

    2017-01-01

    Alternative reproductive tactics are characterized by the occurrence of discrete alternative morphs that differ in behavioural, morphological and physiological traits within the same sex. Although much effort has been made to describe the behaviour, morphology and physiology of such alternative morphs, less effort has been invested investigating how much overlap there is in the characteristics of such morphs in natural populations. We studied random population samples of the invasive Round Goby Neogobius melanostomus from five different localities in the river Rhine system in the Netherlands. We found two morphologically and physiologically distinct male morphs which likely represent alternative reproductive tactics. Almost all mature males under 9.35 cm total length had a gonadosomatic index > 3%, suggestive of a sneaker tactic, while nearly all males above 9.35 cm has a gonadosomatic index of < 3%, suggestive of a parental tactic. Cheek size and eye diameter alone were sufficient to distinguish the two morphs. Gonads had a different relationship with size in the two morphs, indicating separate growth trajectories. The gonad mass of sneaker morphs would be ca. 7.5 times as high as the gonad mass of parental morphs of the same total length after extrapolation. Few (9%) intermediates were found, suggesting that the expression of alternative reproductive tactics is determined before the first breeding season. This contrasts with studies on other goby species, which show evidence of plastic tactics that can be affected by social circumstances. We conclude that it is possible to distinguish two alternative male morphs in the Dutch Round Goby population using morphological measurements alone. Although behavioural observations are needed to provide conclusive evidence, the difference in GSI between these morphs indicates that these morphs reflect alternative reproductive tactics. PMID:28369128

  9. Getting What Is Served? Feeding Ecology Influencing Parasite-Host Interactions in Invasive Round Goby Neogobius melanostomus

    PubMed Central

    Emde, Sebastian; Kochmann, Judith; Kuhn, Thomas; Plath, Martin; Klimpel, Sven

    2014-01-01

    Freshwater ecosystems are increasingly impacted by alien invasive species which have the potential to alter various ecological interactions like predator-prey and host-parasite relationships. Here, we simultaneously examined predator-prey interactions and parasitization patterns of the highly invasive round goby (Neogobius melanostomus) in the rivers Rhine and Main in Germany. A total of 350 N. melanostomus were sampled between June and October 2011. Gut content analysis revealed a broad prey spectrum, partly reflecting temporal and local differences in prey availability. For the major food type (amphipods), species compositions were determined. Amphipod fauna consisted entirely of non-native species and was dominated by Dikerogammarus villosus in the Main and Echinogammarus trichiatus in the Rhine. However, the availability of amphipod species in the field did not reflect their relative abundance in gut contents of N. melanostomus. Only two metazoan parasites, the nematode Raphidascaris acus and the acanthocephalan Pomphorhynchus sp., were isolated from N. melanostomus in all months, whereas unionid glochidia were only detected in June and October in fish from the Main. To analyse infection pathways, we examined 17,356 amphipods and found Pomphorhynchus sp. larvae only in D. villosus in the river Rhine at a prevalence of 0.15%. Dikerogammarus villosus represented the most important amphipod prey for N. melanostomus in both rivers but parasite intensities differed between rivers, suggesting that final hosts (large predatory fishes) may influence host-parasite dynamics of N. melanostomus in its introduced range. PMID:25338158

  10. Characterization of vitellogenin gene expression in round goby (Neogobius melanostomus) using a quantitative polymerase chain reaction assay.

    PubMed

    Bowley, Lucas A; Alam, Farhana; Marentette, Julie R; Balshine, Sigal; Wilson, Joanna Y

    2010-12-01

    A growing concern over endocrine disruption in aquatic species has prompted the development of molecular assays to monitor environmental impacts. This study describes the development of quantitative polymerase chain reaction (qPCR) assays to characterize the expression of two vitellogenin (Vtg) genes in the invasive round goby (Neogobius melanostomus). Fragments from the 18SrRNA (housekeeping gene), Vtg II, and Vtg III genes were cloned and sequenced. The qPCR assays were developed to detect hepatic Vtg expression in goby. The assays detected induction of both Vtg genes in nonreproductive males following a two-week laboratory exposure to 17β-estradiol (≥1 mg/kg i.p. injection). The assays were applied to goby from Hamilton Harbour, Lake Ontario (Canada), including those from sites where feminization and intersex of goby has been documented. Both Vtg genes had significantly higher expression in females compared to males. Male reproductive goby adopt either parental or sneaker tactics; Vtg II expression was higher in sneaker than in parental males but parental and nonreproductive males did not differ from each other. The Vtg III expression was significantly higher in sneaker males followed by parental males and nonreproductive males, respectively. The Vtg II and III expression in nonreproductive males was elevated in the contaminated site with documented intersex. This assay provides an important tool for the use of an invasive species in monitoring endocrine disruption in the Great Lakes region.

  11. An evaluation of behavioural endpoints: The pharmaceutical pollutant fluoxetine decreases aggression across multiple contexts in round goby (Neogobius melanostomus).

    PubMed

    McCallum, Erin S; Bose, Aneesh P H; Warriner, Theresa R; Balshine, Sigal

    2017-05-01

    Fluoxetine (Prozac™) is designed to alter human behaviour; however, because many physiological pathways are conserved across vertebrates, this drug may affect the behaviour of fish living in fluoxetine-polluted environments. Although a number of studies have used behaviour to document the sub-lethal effects of fluoxetine, the repeatability of these effects across experiments, across behavioural contexts, and over different exposure durations are rarely considered. Here, we conducted two experiments and assessed how fluoxetine exposure affected a range of fitness-related behaviours in wild round goby (Neogobius melanostomus). We found that fluoxetine impacts round goby behaviour at high (40 μg/l) doses, but not at environmentally relevant low doses (1 μg/l). In both experiments, an acute 3-day exposure to fluoxetine reduced round goby aggression in multiple behavioural contexts, but had no detectable effect on overall activity or social affiliative behaviour. While a chronic 28-day exposure to fluoxetine exposure still reduced aggression, this reduction was only detectable in one behavioural context. Our findings demonstrate the importance of repeated behavioural testing (both between and within experiments) and contribute to a growing body of literature evaluating the effects of fluoxetine and other pharmaceuticals on animal behaviour.

  12. Dispersal strategies, secondary range expansion and invasion genetics of the nonindigenous round goby, Neogobius melanostomus, in Great Lakes tributaries.

    PubMed

    Bronnenhuber, Jennifer E; Dufour, Brad A; Higgs, Dennis M; Heath, Daniel D

    2011-05-01

    Dispersal strategies are important mechanisms underlying the spatial distribution and colonizing ability of all mobile species. In the current study, we use highly polymorphic microsatellite markers to evaluate local dispersal and colonization dynamics of the round goby (Neogobius melanostomus), an aquatic invader expanding its range from lake to river environments in its introduced North American range. Genetic structure, genotype assignment and genetic diversity were compared among 1262 round gobies from 20 river and four lake sites in three Great Lakes tributaries. Our results indicate that a combination of short-distance diffusion and long-distance dispersal, collectively referred to as 'stratified dispersal', is facilitating river colonization. Colonization proceeded upstream yearly (approximately 500 m/year; 2005-2009) in one of two temporal replicates while genetic structure was temporally stable. Contiguous dispersal from the lake was observed in all three rivers with a substantial portion of river fish (7.3%) identified as migrants. Genotype assignment indicated a separate introduction occurred upstream of the invasion front in one river. Genetic diversity was similar and relatively high among lake and recently colonized river populations, indicating that founder effects are mitigated through a dual-dispersal strategy. The remarkable success of round goby as an aquatic invader stresses the need for better diffusion models of secondary range expansion for presumably sessile invasive species.

  13. The effect of elevated steroids released by reproductive male round gobies, Neogobius melanostomus, on olfactory responses in females.

    PubMed

    Laframboise, Alyson J; Katare, Yogesh; Scott, Alexander P; Zielinski, Barbara S

    2011-03-01

    The round goby, Neogobius melanostomus, is a highly successful invasive species in the Laurentian Great Lakes. Previous behavioral studies implied that females are attracted by pheromones to the nests of reproductive males, and that males release putative steroidal pheromones--unconjugated as well as conjugated forms of 3α-hydroxy-5β-androstane-11,17-dione (11-O-ETIO)-following stimulation of the hypothalamic--gonadal axis with salmon gonadotropin releasing hormone analog (sGnRHa). In this study, we tested the olfactory system of females in response to extracts containing these released steroids. We compared electrical field potential responses from the olfactory epithelium (electro-olfactogram, EOG) of non-reproductive females to methanol extracts of water that previously held males, collected before and after injection of the males with sGnRHa or saline. The females showed increased EOG responses to the post-injection extracts when males were treated with sGnRHa but not saline. This finding provides further evidence for interactions between male and female N. melanostomus via steroidal reproductive pheromones.

  14. Condition-dependent auditory processing in the round goby (Neogobius melanostomus): links to sex, reproductive condition and female estrogen levels.

    PubMed

    Zeyl, Jeffrey N; Love, Oliver P; Higgs, Dennis M

    2013-03-15

    Neural responses to sensory stimuli often differ between sexes, vary seasonally, and can be regulated by endocrine activity, but the ecological and physiological mechanisms driving such patterns are not well understood. The current study examined how auditory function in the round goby (Neogobius melanostomus), a vocal teleost, co-varied with sex, reproductive condition and female plasma 17β-estradiol level. Auditory evoked potentials were collected in response to tone pips (100-600 Hz) and a natural round goby pulse vocalization. Additionally, saccule hair cell densities were compared across reproductive groups. Auditory threshold was evaluated in terms of pressure and particle acceleration, and response amplitude and onset latency were measured at 10 dB above threshold. Relative to males, females displayed lower auditory thresholds in response to the natural vocalization and to tones at 300-600 Hz, and had a higher density of saccule hair cells. The 17β-estradiol level was positively associated with amplitude and latency for the pulse stimulus and with both threshold and amplitude for tones at 100-200 Hz in females. Relative to non-reproductive males, reproductive males exhibited longer response latencies at 100-200 Hz. The results demonstrate sexual dimorphism in auditory function in a teleost fish as well as intra-sexual variation, partially based on hormone levels. The current research further identifies links between auditory function and reproductive behaviors in fishes and provides a finer-scaled analysis of how this behavior is reflected at the level of the sensory systems facilitating signal reception.

  15. The fine structure of the sperm of the round goby (Neogobius melanostomus)

    USGS Publications Warehouse

    Allen, Jeffrey D.; Walker, Glenn K.; Nichols, Susan J.; Sorenson, Dorothy

    2004-01-01

    The fine structural details of the spermatozoon of the round goby are presented for the first time in this study. Scanning and transmission electron microscopic examination of testis reveals an anacrosomal spermatozoon with a slightly elongate head and uniformly compacted chromatin. The midpiece contains a single, spherical mitochondrion. Two perpendicularly oriented centrioles lie in a deep, eccentric nuclear fossa with no regularly observed connection to the nucleus. The flagellum develops bilateral fins soon after emerging from the fossa; each extends approximately 1 A?m from the axoneme and persists nearly the length of the flagellum.

  16. Shipping and natural environmental conditions determine the distribution of the invasive non-indigenous round goby Neogobius melanostomus in a regional sea

    NASA Astrophysics Data System (ADS)

    Kotta, Jonne; Nurkse, Kristiina; Puntila, Riikka; Ojaveer, Henn

    2016-02-01

    Introductions of non-indigenous species (NIS) are considered a major threat to aquatic ecosystems worldwide. While it is valuable to know the distributions and ranges of NIS, predictive spatial models along different environmental gradients are more useful for management of these species. In this study we modelled how external drivers and local environmental conditions contribute to the spatial distribution of an invasive species using the distribution of the round goby Neogobius melanostomus in the Baltic Sea as an example. Using the collected distribution data, an updated map on the species distribution and its invasion progress in the Baltic Sea was produced. The current range of the round goby observations is extensive, covering all major sub-basins of the Baltic Sea. The most recent observations appeared in the northern regions (Northern Baltic Proper, the Gulf of Bothnia and the Gulf of Finland) and on the eastern and western coasts of southern Sweden. Modelling results show that the distribution of the round goby is primarily related to local abiotic hydrological conditions (wave exposure). Furthermore, the probability of round goby occurrence was very high in areas in close proximity to large cargo ports. This links patterns of the round goby distribution in the Baltic Sea to shipping traffic and suggests that human factors together with natural environmental conditions are responsible for the spread of NIS at a regional sea scale.

  17. Changes in brain arginine vasotocin, isotocin, plasma 11-ketotestosterone and cortisol in round goby, Neogobius melanostomus, males subjected to overcrowding stress during the breeding season.

    PubMed

    Sokołowska, Ewa; Kleszczyńska, Agnieszka; Kalamarz-Kubiak, Hanna; Arciszewski, Bartłomiej; Kulczykowska, Ewa

    2013-06-01

    In natural spawning grounds, breeding round goby, Neogobius melanostomus, males are exposed to various social stimuli, including high density of same-sex competitors and separation from females. We hypothesize that breeding males subjected to overcrowding in the wild experience high stress that affects their socio-sexual behavior and their relationships among conspecifics. We designed an experiment to mimic natural stimulation when highly aggregated breeding males are subjected to same-sex opponents. Males were sampled sequentially from experimental tank stocked at decreasing fish densities of 15 fish/m(2), 9 fish/m(2) and 4 fish/m(2). We studied the effects of overcrowding on male behavior and selected hormones, brain arginine vasotocin (AVT) and isotocin (IT) and plasma 11-ketotestosterone (11-KT) and cortisol as these are known to play roles in reproduction and related social interactions. The highest brain AVT and plasma cortisol levels were measured in non-aggressive males kept in the overcrowded group of 15 fish/m(2). IT level was elevated in fish kept at the lower density of 9 fish/m(2), and at which the males began to display territoriality and aggression. The plasma level of 11-KT was similar in all the males. Brain AVT and IT and plasma cortisol along with behavioral observations can be applied as species-specific indicators of the well-being of round goby males.

  18. Release of free and conjugated forms of the putative pheromonal steroid 11-oxo-etiocholanolone by reproductively mature male round goby (Neogobius melanostomus Pallas, 1814).

    PubMed

    Katare, Yogesh Kumar; Scott, Alexander P; Laframboise, Alyson J; Li, Weiming; Alyasha'e, Zena; Caputo, Christopher B; Loeb, Stephen J; Zielinski, Barbara

    2011-02-01

    Previous studies of the round goby (Neogobius melanostomus Pallas, 1814), an invasive fish species in the Laurentian Great Lakes of North America, have shown that this species has the ability to both synthesize and smell steroids that have a 5 beta-reduced and 3 alpha-hydroxyl (5 beta,3 alpha) configuration. An enzyme-linked immunoassay (EIA) for 3 alpha-hydroxy-5 beta-androstane-11,17-dione (11-O-ETIO) has been used to show a substantial rise in the rate of release of immunoreactive compounds into the water when males are injected with salmon gonadotropin releasing hormone analogue. Similar increases were noted for 11-ketotestosterone and 17,20 beta-dihydroxypregn-4-en-3-one. Partitioning of the extracts between diethyl ether and water showed the presence of both free and conjugated immunoreactive 11-O-ETIO. Only conjugated immunoreactivity was found in urine (implying that free steroid is released via the gills). The identity of the conjugates was probed by using HPLC, EIA, and mass spectrometry and removal of sulfate and glucosiduronate groups. Immunoreactivity in the conjugated fraction was found to be due mainly to 3 alpha,17beta-dihydroxy-5 beta-androstan-11-one 17-sulfate. However, the evidence was also strong for the presence in water extracts of substantial amounts of 3 alpha-hydroxy-5 beta-androstane-11,17-dione 3-glucosiduronate (which could be detected only by EIA after removal of the glucosiduronate group with beta-glucuronidase). There were also small amounts of 3 alpha-hydroxy-5 beta-androstane-11,17-dione 3-sulfate and 3 alpha,17beta-dihydroxy-5 beta-androstan-11-one 17-glucosiduronate. These studies give some idea of the types, amounts, and ratios of 11-O-ETIO derivatives that are released by reproductive N. melanostomus and will aid further research into the putative pheromonal roles of 5 beta,3 alpha-reduced androgens in this species.

  19. Metazoa parasites of the invasive round goby Apollonia melanostoma (Neogobius melanostomus) (Pallas) (Gobiidae: Osteichthyes) in the Gulf of Gdańsk, Baltic Sea, Poland: a comparison with the Black Sea.

    PubMed

    Kvach, Yuriy; Skóra, Krzysztof E

    2007-03-01

    The known metazoa parasite fauna of the invasive round goby Apollonia melanostoma (formerly Neogobius melanostomus) consists of 12 species. The core of the parasite fauna comprises two species: Cryptocotyle concavum and Diplostomum spathaceum; secondary species are absent; satellite species include Cercariae gen. sp. and Ergasilus sieboldi; rare species are Acanthocephalus lucii, Anguillicola crassus, Bothriocephalus sp., Dichelyne minutus, Hysterothylacium aduncum, Pomphorhynchus laevis, Piscicola geometra, and Tylodelphys clavata. Fifty percent of metazoa parasites that occurred in the invasive round goby in the Gulf of Gdańsk (an invasion that was first detected in 1990) are also typically found in the native Gulf of Gdańsk gobiids. The round goby hosts common fish parasite species: C. concavum and D. minutus, but none that are unique to the species and no Ponto-Caspian parasites. Notably, the parasite species of the invasive round goby in the Gulf of Gdańsk includes species that are atypical for this species in its native habitat. In its new habitat, the round goby variously serves the roles of definitive, second intermediate, and paratenic host for different parasite species. The fish species is involved in a parasitic system that includes fish-eating birds, fishes of different ecological groups (predatory, planktivorous, and benthivorous), and invertebrates.

  20. The Effect of Gender, Tone, and Sound Location on the Response Behavior of Neogobius melanostomus (Round Goby) and the Possibility of Future Trapping of this Invasive Species in Lake Superior.

    PubMed

    Moynan, Crystal R; Neumann, Christine E; Welsh, Cynthia A

    2016-08-01

    Neogobius melanostomus (round goby) are a benthic dwelling invasive species of fish in the Great Lakes. This study was done to determine if a tone that mimics the frequency (175 Hz) of mating call of a male round goby would have an effect on male and female response. A testing tank and a simulated trap in front of a speaker at each end were used. Each fish was then placed individually into the small holding box that was in the center of the tank. A video camera was then turned on to record fish movement once the door was opened. Next, the artificial sound was turned on for 1 min (175, 300, 500 Hz, and no sound); 175 Hz mimics the conspecific mating call. This process was done for each frequency for each fish. The individual fish was then allowed to roam for 5 min. The video camera recorded fish location and behavior. From the videos, a continuous measure was collected according to when the fish crossed the center line. The hypothesis, if (N. melanostomus) hears different frequencies of sound projected from a certain location in a fish tank habitat, then the females will be attracted and spend more time on the sound-emitting side of the tank, which mimics the frequency of mating call of a male round goby (175 Hz, 13 pulse), was supported; females spent more time on the sound-emitting side of the tank and males avoided the sound-emitting side of the tank, analysis of variance p < 0.012.

  1. Maximum length and age of round gobies (Apollonia melanostomus) in Lake Huron

    USGS Publications Warehouse

    French, John R. P.; Black, M. Glen

    2009-01-01

    The round goby (Apollonia [Neogobius] melanostomus,) an invasive species, is generally smaller and shorter-lived in the Great Lakes than it native range. We examined 30 large male round gobies from trawl samples taken in Lake Huron and used otoliths to determine their age and back-calculated growth. Standard lengths ranged from 76 to 97 mm, and the oldest fish were age-5. Low water temperatures in nearshore regions of Lake Huron might cause slow growth and late maturation.

  2. Occurrence of Cyathocephalus truncatus (Cestoda) in fishes of the Great Lakes with emphasis on its occurrence in round gobies (Neogobius melanostomus) from Lake Huron

    USGS Publications Warehouse

    French, John R. P.; Muzzall, Patrick M.; Adams, Jean V.; Johnson, Kendra L.; Flores, Angela E.; Winkel, Andrea M.

    2005-01-01

    Cyathocephalus truncatus is a pathogenic cestode that is common in many Laurentian Great Lakes fish species, but the depth distribution of this cestode has not been studied. Cyathocephalus truncatus has been reported from 21 fish species and one hybrid representing seven orders and nine families in Lakes Superior, Michigan, Huron, and Ontario. We examined the intestinal contents of six species of fish collected in Michigan waters of Lake Huron, from DeTour to Harbor Beach, in 2001 to 2003 for the presence of this cestode species. Cyathocephalus truncatus was found in five native fish species and the exotic round goby. Prevalence (52%) and mean intensity (4.6 cestodes per infected fish) were highest in bloaters. This is the first reported occurrence of this cestode in round gobies from the Great Lakes. None of the gobies trawled from Lake Huron at depths of 27 to 46 m were infected, but prevalence and intensity of infection in round gobies increased significantly with depth from 55 to 73 m. Our diet study of round gobies indicated that they preyed heavily on amphipods (Diporeia hoyi) at depths of 55 to 73 m. Cyathocephalus truncatus was found in eight of 605 D. hoyi obtained by Ponar grab sampling. This suggests that C. truncatus eggs may be released from infected gobies and sink to deep basins with silt bottoms where D. hoyi occur.

  3. Interactions between invasive round gobies (Neogobius melanostomous) and fantail darters (Etheostoma flabellare) in a tributary of the St. Lawrence River, New York, USA

    USGS Publications Warehouse

    Abbett, Ross; Waldt, Emily M.; Johnson, James H.; McKenna, James E.; Dittman, Dawn E.

    2013-01-01

    The initial, rapid expansion of the invasive round goby (Neogobius melanostomus) throughout the Great Lakes drainage was largely confined to lentic systems. We recently observed round gobies ascending two tributaries of the St. Lawrence River. The expansion of gobies into small lotic environments may place ecologically similar species at risk. Fantail darter (Etheostoma flabellare) is one of the several benthic species of the New York Great Lakes drainages that are threatened by round goby invasion. We examined the habitat use and diet composition of fantail darters and round gobies in Mullet Creek, a third-order tributary of the St. Lawrence River, NY, USA. The objectives of this study were to determine the degree of habitat and diet overlap between fantail darters and round gobies in a tributary of the St. Lawrence River. Gobies and darters co-occurred at 22% of capture sites. Of the four habitat variables examined (cover, depth, substrate and velocity), only depth use was significantly different with gobies using deeper habitats than darters. Among the two species and size classes sampled (large vs. small), large darters had the most restricted habitat use requirements. There was variation in round goby and darter diet composition, but only moderate diet overlap occurred between fantail darters and round gobies (Cλ = 0.43). Conditions in Mullet Creek were appropriate for the evaluation of possible spatial and dietary competition between round goby and native darters. Early detection and management of round goby invasions is critical to maintaining ecological integrity of lotic ecosystems in the St. Lawrence Valley.

  4. Parasites of the recently established round goby (Negobius melanostomus) and tubenose goby (Proterorhinus marmoratus) (Gobiidae) from the St. Clair River and Lake St. Clair, Michigan, USA

    USGS Publications Warehouse

    Pronin, Nikolai M.; Fleischer, Guy W.; Baldanova, Darima R.; Pronina, Svetlana V.

    1997-01-01

    Specimens of the recently established European round goby (Negobius melanostomus Pallas, 1811) and tubenose goby (Proterorhinus marmoratus Pallas, 1811) were collected from different locations in the St. Clair River and Lake St. Clair, USA and were examined for parasites. Parasites were observed in 76% of the round gobies and 35% of the tubenose gobies. Four species of parasites in the gobies occur in the Black Sea watershed. Two of them have been reported in North America for the first time: Sphaeromyxa sevastopoli Naidenova, 1970 and Ichthyocotylurus pileatus (Rudolphi, 1802). Three parasite species found in the gobies are endemic to North America and were most likely obtained locally.

  5. What can morphology tell us about ecology of four invasive goby species?

    PubMed

    Jakubčinová, K; Simonović, P; Števove, B; Čanak Atlagić, J; Kováč, V

    2017-03-07

    This study presents a detailed comparative analysis of external morphology of four of the most invasive goby species in Europe (round goby Neogobius melanostomus, bighead goby Ponticola kessleri, monkey goby Neogobius fluviatilis and racer goby Ponticola gymnotrachelus) and interprets some ecological requirements of these species based on their morphological attributes. The results are evaluated within an ontogenetic context, and the morphological differences between the species are discussed in terms of the question: can special external shape adaptations help to assess the invasive potential of each species? The morphometric analyses demonstrate important differences between the four invasive gobies. Neogobius melanostomus appears to have the least specialized external morphology that may favour its invasive success: little specialization to habitat or diet means reduced restraints on overall ecological requirements. The other three species were found to possess some morphological specializations (P. kessleri to large prey, N. fluviatilis to sandy habitats and P. gymnotrachelus to macrophytes), but none of these gobies have managed to colonize such large areas or to reach such overall abundances as N. melanostomus.

  6. Determination of PCB Elimination Coefficients in Round Goby and Tubenose Goby.

    PubMed

    Sun, Xin; Johnson, Tim B; Drouillard, Ken G

    2016-09-01

    Whole-body elimination coefficients of polychlorinated biphenyls (PCBs) were determined in two Great Lakes invasive fish species, round goby (Neogobius melanostomus) and tubenose goby (Proterorhinus semilunaris). Elimination rates were determined for a set of model PCB congeners (n = 12 congeners) dosed to fish by intraperitoneal injection and allowed to depurate at a temperature of 21.4°C for 90 days. Eight PCBs (PCB 6, 21, 57, 62, 68, 89, 112 and 125) exhibited significant elimination by round goby and had corresponding half lives ranging from 13 to 39.8 days. For tubenose goby, four congeners (PCBs 21, 57, 62 and 68) exhibited significant elimination with half lives in the range from 18.8 to 48.8 days. Whole-body elimination rate coefficients were significantly higher for round gobies compared to tubenose goby. In both cases, PCB elimination rate coefficients were negatively related to chemical log KOW.

  7. Diel diet composition and feeding activity of round goby in the nearshore region of Lake Ontario

    USGS Publications Warehouse

    Johnson, James H.; McKenna, James E.; Nack, Christopher C.; Chalupnicki, Marc A.

    2008-01-01

    Expansion of the invasive round goby Apollonia melanostoma (=Neogobius melanostomus) throughout the Great Lakes drainage has created considerable concern among fisheries management agencies. These concerns have led to several studies on the biology and impact of the goby in the basin. However, little information exists on diel patterns in food consumption of the round goby. We examined the diets of 300 round gobies collected during crepuscular, diurnal, and nocturnal periods in Lake Ontario. There was little variation in the diel diet composition of the goby, as chironomid larvae were the major prey consumed during each period. Feeding intensity of the round goby was significantly (P<0.05) greater at night than during crepuscular or diurnal periods.

  8. Use of electrical barriers to deter movement of round goby

    USGS Publications Warehouse

    Savino, Jacqueline F.; Jude, David J.; Kostich, Melissa J.; Coutant, Charles C.

    2001-01-01

    An electrical barrier was chosen as a possible means to deter movement of round goby Neogobius melanostomus. Feasibility studies in a 2.1-m donut-shaped tank determined the electrical parameters necessary to inhibit round goby from crossing the 1-m stretch of the benthic, electrical barrier. Increasing electrical pulse duration and voltage increased effectiveness of the barrier in deterring round goby movement through the barrier. Differences in activity of round goby during daytime and nocturnal tests did not change the effectiveness of the barrier. In field verification studies, an electrical barrier was placed between two blocking nets in the Shiawassee River, Michigan. The barrier consisted of a 6-m wide canvas on which were laid four cables carrying the electrical current. Seven experiments were conducted, wherein 25 latex paint-marked round goby were introduced upstream of the electrical barrier and recovered 24 h later upstream, on, and downstream of the barrier. During control studies, round goby moved across the barrier within 20 min from release upstream. With the barrier on and using the prescribed electrical settings shown to inhibit passage in the laboratory, the only marked round goby found below the barrier were dead. At reduced pulse durations, a few round goby (mean one/test) were found alive, but debilitated, below the barrier. The electrical barrier could be incorporated as part of a program in reducing movement of adult round goby through artificial connections between the watersheds.

  9. Use of electrical barriers to deter movement of round goby

    USGS Publications Warehouse

    Savino, Jacqueline F.; Jude, David J.; Kostich, Melissa J.; Coutant, Charles C.

    2001-01-01

    An electrical barrier was chosen as a possible means to deter movement of round goby Neogobius melanostomus. Feasibility studies in a 2.1-m donut-shaped tank determined the electrical parameters necessary to inhibit round goby from crossing the 1-m stretch of the benthic, electrical barrier. Increasing electrical pulse duration and voltage increased effectiveness of the barrier in deterring round goby movement through the barrier. Differences in activity of round goby during daytime and nocturnal tests did not change the effectiveness of the barrier. In field verification studies, an electrical barrier was placed between two blocking nets in the Shiawassee River, Michigan. The barrier consisted of a 6-m wide canvas on which were laid four cables carrying the electrical current. Seven experiments were conducted, wherein 25 latex paint-marked round goby were introduced upstream of the electrical barrier and recovered 24 h later upstream, on, and downstream of the barrier. During control studies, round goby moved across the barrier within 20 min from release upstream. With the barrier on and using the prescribed electrical settings shown to inhibit passage in the laboratory, the only marked round goby found below the barrier were dead. At reduced pulse durations, a few round goby (mean one/test) were found alive, but debilitated, below the barrier. The electrical barrier could be incorporated as part of a program in reducing movement of adult round goby through artificial connections between watersheds.

  10. Occurrence and food habits of the round goby in the profundal zone of southwestern Lake Ontario

    USGS Publications Warehouse

    Walsh, M.G.; Dittman, D.E.; O'Gorman, R.

    2007-01-01

    Little is known about the ecology of round goby (Neogobius melanostomus), an invasive benthic fish, in the profundal zone of the Great Lakes. In April 2002–2005 we caught increasing numbers of round gobies with a bottom trawl in the 45–150 m depth range of southwestern Lake Ontario. In 2005, we examined gut contents of 30 round gobies from each of three depths, 55, 95, and 130 m, and qualitatively compared gut contents with density of benthic invertebrates determined by Ponar grabs. Round goby guts contained mostly Dreissena spp. and opposum shrimp, Mysis relicta (Mysis); the frequency of occurrence of dreissenids in guts decreased with depth, whereas the frequency of occurrence of Mysis in guts increased with depth. Abundance of these invertebrates in the environment followed the same pattern, although dreissenids of optimum edible size (3–12 mm) were still abundant (1,373/m2) at 130 m, where round gobies primarily consumed Mysis, suggesting that round gobies may switch from dreissenids to more profitable prey when it is available. Other food items were ostracods and fish, with ostracods generally eaten by smaller round gobies and fish eaten by larger round gobies. Occurrence and increasing abundance of round gobies in the profundal zone and predation on Mysis by round goby could have far-reaching consequences for the Lake Ontario fish community.

  11. Diets and diet overlap of nonindigenous gobies and small benthic native fishes co-inhabiting the St. Clair River, Michigan

    USGS Publications Warehouse

    French, John R. P.; Jude, David J.

    2001-01-01

    Round gobies (Neogobius melanostomus), after successfully reproducing in the early 1990s, decimated populations of mottled sculpins (Cottus bairdi) and possibly logperch (Percina caprodes) in the St. Clair River. Studies were conducted during 1994 to determine whether diets of round and tubenose (Proterorhinus marmoratus) gobies overlapped with those of native forage fishes. In the nearshore zone (depth ≤ 1 m), round and tubenose gobies, logperch, and rainbow darters (Etheostoma caeruleum) of similar sizes (total lengths < 75 mm) consumed mainly small-sized macroinvertebrates (dipterans, Caenis, and amphipods) during June 1994. Logperch and rainbow darters were present in the nearshore zone only during this month. At the crest of the channel slope (depth = 3 m), round gobies and northern madtoms (Noturus stigmosus) ate mostly ephemeropteran nymphs (Hexagenia and Baetisca), while predation on zebra mussels (Dreissena polymorpha) and other mollusks by round gobies was minimal. Northern madtoms did not feed on mollusks. Diet overlap between round gobies and native fishes was not observed at the channel slope (depth = 5 m and 7 m) due to heavy predation on mollusks by round gobies. Young-of-the-year (YOY) round gobies migrated to deeper water in autumn and became prey of mottled sculpins and northern madtoms. Eggs and YOY of mottled sculpins may have become vulnerable to predation by both round gobies and native fishes in deeper water, since adult mottled sculpins were apparently confined to the channel with limited home range because aggressive round gobies occupied preferred shallow habitat, including spawning sites.

  12. Evidence for predatory control of the invasive round goby

    USGS Publications Warehouse

    Madenjian, C.P.; Stapanian, M.A.; Witzel, L.D.; Einhouse, D.W.; Pothoven, S.A.; Whitford, H.L.

    2011-01-01

    We coupled bioenergetics modeling with bottom trawl survey results to evaluate the capacity of piscivorous fish in eastern Lake Erie to exert predatory control of the invading population of round goby Neogobius melanostomus. In the offshore (>20 m deep) waters of eastern Lake Erie, burbot Lota lota is a native top predator, feeding on a suite of prey fishes. The round goby invaded eastern Lake Erie during the late 1990s, and round goby population size increased dramatically during 1999–2004. According to annual bottom trawl survey results, round goby abundance in offshore waters peaked in 2004, but then declined during 2004–2008. Coincidentally, round goby became an important component of burbot diet beginning in 2003. Using bottom trawling and gill netting, we estimated adult burbot abundance and age structure in eastern Lake Erie during 2007. Diet composition and energy density of eastern Lake Erie burbot were also determined during 2007. This information, along with estimates of burbot growth, burbot mortality, burbot water temperature regime, and energy densities of prey fish from the literature, were incorporated into a bioenergetics model application to estimate annual consumption of round goby by the adult burbot population. Results indicated that the adult burbot population in eastern Lake Erie annually consumed 1,361 metric tons of round goby. Based on the results of bottom trawling, we estimated the biomass of yearling and older round goby in offshore waters eastern Lake Erie during 2007–2008 to be 2,232 metric tons. Thus, the adult burbot population was feeding on round goby at an annual rate equal to 61% of the estimated round goby standing stock. We concluded that the burbot population had high potential to exert predatory control on round goby in offshore waters of eastern Lake Erie.

  13. Dietary habits of invasive Ponto-Caspian gobies in the Croatian part of the Danube River basin and their potential impact on benthic fish communities.

    PubMed

    Piria, Marina; Jakšić, Goran; Jakovlić, Ivan; Treer, Tomislav

    2016-01-01

    Invasive Ponto-Caspian (P-C(1)) gobies have recently caused dramatic changes in fish assemblage structures throughout the Danube basin. While their presence in the Croatian part of the basin has been noted and distribution studied, their dietary habits and impacts on native fish communities have, until now, been unknown. In 2011, 17 locations in the Sava River Basin were sampled for fish and 15 for benthic invertebrates. Fish population monitoring data, available for nine seasons (2003-2006 and 2010-2014) and 12 locations, were used to analyse the impacts of P-C gobies on benthic fish abundance. Gut content analysis indicates that the monkey goby Neogobius fluviatilis diet is very diverse, but dominated by Trichoptera, Chironomidae, Bivalvia and Odonata. The diet overlaps considerably with the round goby Neogobius melanostomus diet, although Gastropoda are dominant in the latter's diet. Small fish and Gammarus sp. dominate the bighead goby Ponticola kessleri diet. Comparison of gut content with the prey available in the environment indicates that monkey and round gobies exhibit preference for Trichoptera, Megaloptera and Coleoptera, and bighead goby for Trichoptera, Gammarus sp. and Pisces. P-C gobies in the Sava River are spreading upstream, towards the reaches with lower fish diversity. Analyses indicate potentially positive impacts of P-C gobies' presence on some fish populations: round and bighead goby on Balkan golden loach Sabanejewia balcanica and monkey goby on common carp Cyprinus carpio, crucian carp Carassius carassius, burbot Lota lota and Balkan loach Cobitis elongata. However, there are also indications that bighead and round goby could adversely impact the native chub Squalius cephalus and zingel Zingel zingel populations, respectively. As P-C gobies are still in the expansionary period of invasion and the ecosystem still adapting to new circumstances, continued monitoring of fish population dynamics in the Sava basin is needed to determine the

  14. Activity, aggression, and habitat use of ruffe (Gymnocephalus cernuus) and round goby (Apollonia melanostoma) under laboratory conditions

    USGS Publications Warehouse

    Savino, J.F.; Riley, S.C.; Holuszko, M.J.

    2007-01-01

    Potential negative ecological interactions between ruffe Gymnocephalus cernuus and round gobyApollonia melanostoma (formerly Neogobius melanostomus) might affect the colonization dynamics of these invasive species where they are sympatric in the Great Lakes. In order to determine the potential for ecological interactions between these species, we examined the activity, aggression, and habitat use of round gobies and ruffe in single species and mixed species laboratory experiments. Trials included conditions in which food was concentrated (in light or darkness) or scattered. Results showed that ruffe were more active than gobies, particularly when food was scattered. Activity of both species was significantly lower during darkness. Round gobies were significantly more aggressive than ruffe, and total aggression was lower in mixed species trials. Habitat use by ruffe and round gobies overlapped considerably, but we observed significant differences between species in their use of specific habitats that depended on experimental conditions. Overall, ruffe used open habitats more often than did round gobies, primarily when food was scattered. Round gobies used rocks significantly more frequently than did ruffe, but their use of rock habitat decreased during dark conditions. Ruffe were found more often in plant habitats and less often near the wall of the pool in trials during daylight with concentrated food. Activity and habitat use of ruffe and round goby did not significantly differ between single and mixed species trials. Overall, we found little evidence for negative ecological interactions between ruffe and round goby in these laboratory experiments.

  15. Age and growth of round gobies in Lake Huron: Implications for food web dynamics

    USGS Publications Warehouse

    Duan, You J.; Madenjian, Charles P.; Xie, Cong X.; Diana, James S.; O'Brien, Timothy P.; Zhao, Ying M.; He, Ji X.; Farha, Steve A.; Huo, Bin

    2016-01-01

    Although the round goby (Neogobius melanostomus) has become established throughout the Laurentian Great Lakes, information is scarce on spatial variation in round goby growth between and within lakes. Based on a sample of 754 specimens captured in 2014, age, growth, and mortality of round gobies at four locations in Lake Huron were assessed via otolith analysis. Total length (TL) of round gobies ranged from 44 to 111 mm for Saginaw Bay, from 45 to 115 mm for Rockport, from 50 to 123 mm for Hammond Bay, and from 51 to 118 mm for Thunder Bay. Estimated ages of round gobies ranged from 2 to 5 years for Saginaw Bay, from 2 to 6 years for Rockport, and from 2 to 7 years for Hammond Bay and Thunder Bay. Sex-specific, body–otolith relationships were used to back-calculate total lengths at age, which were then fitted to von Bertalanffy growth models. For each sex, round goby growth showed significant spatial variation among the four locations within Lake Huron. At all four locations in Lake Huron, males grew significantly faster than females and attained a larger asymptotic length than females. Annual mortality rate estimates were high (62 to 85%), based on catch-curve analysis, suggesting that round gobies may be under predatory control in Lake Huron.

  16. Invasion history, proliferation, and offshore diet of the round goby Neogobiusmelanostomus in western Lake Huron, USA

    USGS Publications Warehouse

    Schaeffer, Jeffrey S.; Bowen, Anjanette; Thomas, Michael; French, John R. P.; Curtis, Gary L.

    2005-01-01

    We used data from three trawl surveys during 1996-2003 to document range expansion, population trends, and use of offshore habitats by round gobies in the U.S. waters of Lake Huron. Round gobies (Neogobius melanostomus) were not detected in any survey until 1997, but by 2003 they had been recorded at 18 of the 28 sites sampled. The only areas not colonized were offshore habitats in northern Lake Huron. Round goby abundance increased during 1997-2001, thereafter overall abundance either increased (offshore) or became variable (nearshore and Saginaw Bay). Mean lengths varied among surveys primarily due to high abundance of age-0 gobies in Saginaw Bay samples. Round gobies were found up to 34 km offshore at depths of 73 m. Round gobies consumed a wide range of invertebrate prey, but focused on dreissenids in shallow water (27-46 m), and native invertebrates at greater depths. The pattern of round goby dispersal was consistent with a pattern of simultaneous initial introductions at shipping ports followed by natural dispersal, and lakewide population size has probably not stabilized

  17. Age and growth of round gobies in Lake Michigan, with preliminary mortality estimation

    USGS Publications Warehouse

    Huo, Bin; Madenjian, Charles P.; Xie, Cong X.; Zhao, Yingming; O'Brien, Timothy P.; Czesny, Sergiusz J.

    2015-01-01

    The round goby (Neogobius melanostomus) is a prevalent invasive species throughout Lake Michigan, as well as other Laurentian Great Lakes, yet little information is available on spatial variation in round goby growth within one body of water. Age and growth of round goby at three areas of Lake Michigan were studied by otolith analysis from a sample of 659 specimens collected from 2008 to 2012. Total length (TL) ranged from 48 to 131 mm for Sturgeon Bay, from 50 to 125 mm for Waukegan, and from 54 to 129 mm for Sleeping Bear Dunes. Ages ranged from 2 to 7 years for Sturgeon Bay, from 2 to 5 years for Waukegan, and from 2 to 6 years for Sleeping Bear Dunes. Area-specific and sex-specific body–otolith relationships were used to back-calculate estimates of total length at age, which were fitted to von Bertalanffy models to estimate growth rates. For both sexes, round gobies at Sleeping Bear Dunes and Waukegan grew significantly faster than those at Sturgeon Bay. However, round goby growth did not significantly differ between Sleeping Bear Dunes and Waukegan for either sex. At all three areas of Lake Michigan, males grew significantly faster than females. Based on catch curve analysis, estimates of annual mortality rates ranged from 0.79 to 0.84. These relatively high mortality rates suggested that round gobies may be under predatory control in Lake Michigan.

  18. Expansion of tubenose gobies Proterorhinus semilunaris into western Lake Erie and potential effects on native species

    USGS Publications Warehouse

    Kocovsky, P.M.; Tallman, J.A.; Jude, D.J.; Murphy, D.M.; Brown, J.E.; Stepien, C.A.

    2011-01-01

    The Eurasian freshwater tubenose goby Proterorhinus semilunaris (formerly Proterorhinus marmoratus) invaded the Laurentian Great Lakes in the 1990s, presumably via ballast water from transoceanic cargo ships. Tubenose gobies spread throughout Lake St. Clair, its tributaries, and the Detroit River system, and also are present in the Duluth-Superior harbor of Lake Superior. Using seines and bottom trawls, we collected 113 tubenose gobies between July 2007 and August 2009 at several locations in western Lake Erie. The number and range of sizes of specimens collected suggest that that tubenose gobies have become established and self-sustaining in the western basin of Lake Erie. Tubenose gobies reached maximum densities in sheltered areas with abundant macrophyte growth, which also is their common habitat in native northern Black Sea populations. The diet of tubenose gobies was almost exclusively invertebrates, suggesting dietary overlap with other benthic fishes, such as darters (Etheostoma spp. and Percina sp.), madtoms (Noturus spp.), and sculpins (Cottus spp.). A single mitochondrial DNA haplotype was identified, which is the most common haplotype found in the original colonization area in the Lake St. Clair region, suggesting a founder effect. Tubenose gobies, like round gobies Neogobius melanostomus, have early life stages that drift owing to vertical migration, which probably allowed them to spread from areas of colonization. The Lake St. Clair-Lake Erie corridor appears to have served as an avenue for them to spread to the western basin of Lake Erie, and abundance of shallow macrophyte-rich habitats may be a key factor facilitating their further expansion within Lake Erie and the remainder of the Laurentian Great Lakes.

  19. Detection of viral hemorrhagic septicemia in round gobies in New York State (USA) waters of Lake Ontario and the St. Lawrence River.

    PubMed

    Groocock, G H; Getchell, R G; Wooster, G A; Britt, K L; Batts, W N; Winton, J R; Casey, R N; Casey, J W; Bowser, P R

    2007-07-16

    In May 2006 a large mortality of several thousand round gobies Neogobius melanostomus (Pallas, 1814) occurred in New York waters of the St. Lawrence River and Lake Ontario. Necropsies of sampled fish from these areas showed pallor of the liver and gills, and hemorrhagic areas in many organs. Histopathologic examination of affected tissues revealed areas of necrosis and hemorrhage. Inoculations of fathead minnow Pimephales promelas (Rafinesque, 1820) cell cultures with dilutions of tissue samples from the necropsied gobies produced a cytopathic effect within 5 d post-inoculation. Samples of cell culture supernatant were tested using RT-PCR and confirmed the presence of viral hemorrhagic septicemia virus (VHSV). Sequence analysis of the VHSV isolate resulted in its assignment to the type-IVb subgroup. The detection of VHSV in a relatively recent invasive fish species in the Great Lakes and the potential impact of VHSV on the ecology and economy of the area will require further investigation and careful management considerations.

  20. Diet overlap between juvenile flatfish and the invasive round goby in the central Baltic Sea

    NASA Astrophysics Data System (ADS)

    Ustups, D.; Bergström, U.; Florin, A. B.; Kruze, E.; Zilniece, D.; Elferts, D.; Knospina, E.; Uzars, D.

    2016-01-01

    The present study offers a comprehensive analysis of changes in the abundance and diet composition of juvenile flounder (Platichthys flesus) and turbot (Psetta maxima), along with other dominant coastal fish species, before and after the establishment of the alien round goby off an exposed stretch of coast in the eastern Baltic Sea. In the study area, the round goby (Neogobius melanostomus) was recorded for the first time in 2009. After a few years of low abundance, a sharp increase in the population occurred. After the round goby invasion, flatfish juveniles exhibited an increased diet overlap with other species and had a lower feeding success, reflecting an increase in resource competition. For juvenile turbot, the increase was mainly caused by the round goby, while for flounder it was due to both the round goby and the lesser sandeel (Ammodytes tobianus). Juvenile turbot, whose dominant food item before the round goby establishment had been mysids, shifted their diet towards Crangon crangon, reflecting a decrease in mysid abundance by three orders of magnitude and a concurrent doubling in C. crangon abundance in the habitat. At the same time a significant decrease in turbot recruitment was observed. Juvenile flounder had the widest food spectrum of the studied species. When the availability of the primary food item, Bathyporeia pilosa, decreased, flounder juveniles adapted by increasing the share of zooplankton in their diets. No changes in flounder feeding success and recruitment were observed. However, the recruitment estimates of flounder and turbot show an increasing co-variation after the round goby invasion, suggesting that recruitment of the species may currently be regulated by processes in the common nursery habitat.

  1. Low prevalence of VHSV detected in round goby collected in offshore regions of Lake Ontario

    USGS Publications Warehouse

    Cornwell, Emily R.; Getchell, Rodman G.; Groocock, Geoffrey H.; Walsh, Maureen G.; Bowser, Paul R.

    2012-01-01

    Since the first reports of mortalities due to viral hemorrhagic septicemia virus (VHSV) type IVb in the Laurentian Great Lakes basin during 2005 (Lake St. Clair, USA and Bay of Quinte, Lake Ontario, Canada), many groups have conducted surveillance efforts for the virus, primarily in nearshore areas. The round goby (Neogobius melanostomus) has been identified as a key species to target for surveillance, because they have a very high probability of infection at a given site. Our objective in this study was to document and quantify VHSV in round gobies in offshore waters of Lake Ontario using molecular techniques. We collected 139 round gobies from depths ranging from 55 to 150 m using bottom trawls during the early spring of 2011 and detected VHSV in 4 individuals (1/26 fish at 95 m, 2/12 fish at 105 m, and 1/24 fish at 135 m). These results expand the known depth range of VHSV in the Great Lakes. They also have implications on the management of the spread of VHSV within infected bodies of water related to the mixing of populations of fish that would remain distinct in their breeding habitats, but then have the opportunity to mix in their overwintering habitats, as well as to increase overlap of predator and prey species in overwintering habitats.

  2. Distribution, abundance, and range of the round goby, Apollina melanostoma, in the Duluth-Superior Harbor and St. Louis River estuary, 1998-2004

    USGS Publications Warehouse

    Bergstrom, M.A.; Evrard, L.M.; Mensinger, A.F.

    2008-01-01

    Round gobies were first discovered in the Duluth-Superior Harbor, Lake Superior, in 1995. Anecdotal sightings by anglers and others suggested that the infestation was growing and expanding; however, direct evidence of the distribution and expansion rate in the harbor was largely unknown. Distribution and range of the round goby, Apollonia melanostoma, (formerly Neogobius melanostomus) was assessed using bottom trawl sampling throughout the Duluth-Superior Harbor, and portions of the lower St. Louis River from 1998 to 2004. Previous to 1998, round gobies only were reported to occupy the harbor between the two shipping entries (river kilometer 1 to 7). By 2004, they expanded throughout the harbor and upstream to river kilometer 13, but remained absent in western Lake Superior. The number of round gobies captured per 5 minutes of trawling (catch per unit effort, CPUE) increased from less than 1 fish in 1998 to an average 5.4 ?? 1.2 SE fish in 2004, indicating a large increase in the population. The median yearly fish total length varied from 56.0 to 81.5 mm and wet weight varied from 2.3 to 7.0 g. As nest guarding male round gobies were located in rocky habitats inaccessible to trawling, the initial years were dominated by female round gobies with a 16:1 female to male ratio, but by 2002 the maximum ratio was 2:1. The ratio change may be indicative of the increasing population forcing males from their preferred rocky habitat onto open substrates that were more accessible to trawling.

  3. Bigger Is Better: Characteristics of Round Gobies Forming an Invasion Front in the Danube River

    PubMed Central

    Brandner, Joerg; Cerwenka, Alexander F.; Schliewen, Ulrich K.; Geist, Juergen

    2013-01-01

    Few studies have systematically investigated differences in performance, morphology and parasitic load of invaders at different stages of an invasion. This study analyzed phenotype-environment correlations in a fish invasion from initial absence until establishment in the headwater reach of the second largest European river, the Danube. Here, the round goby (Neogobius melanostomus) formed 73% of the fish abundance and 58% of the fish biomass in rip-rap bank habitats after establishment. The time from invasion until establishment was only about two years, indicating rapid expansion. Founder populations from the invasion front were different from longer established round goby populations in demography, morphology, feeding behaviour, sex ratio and parasitic load, indicating that plasticity in these traits determines invasion success. Competitive ability was mostly dependent on growth/size-related traits rather than on fecundity. As revealed by stable isotope analyses, specimens at the invasion front had a higher trophic position in the food web and seem to benefit from lower food competition. Somatic performance seems to be more important than investment in reproduction during the early stages of the invasion process and upstream-directed range expansion is not caused by out-migrating weak or juvenile individuals that were forced to leave high density areas due to high competition. This mechanism might be true for downstream introductions via drift. Greater abundance and densities of acanthocephalan endoparasites were observed at the invasion front, which contradicts the expectation that invasion success is determined by lower parasitic pressure in newly invaded areas. Overall, the pronounced changes in fish and invertebrate communities with a dominance of alien species suggest invasional meltdown and a shift of the upper Danube River towards a novel ecosystem with species that have greater resistance to goby predation. This seems to contribute to overcoming

  4. Detection of viral hemorrhagic septicemia in round gobies in New York State (USA) waters of Lake Ontario and the St. Lawrence River

    USGS Publications Warehouse

    Groocock, G.H.; Getchell, R.G.; Wooster, G.A.; Britt, K.L.; Batts, W.N.; Winton, J.R.; Casey, R.N.; Casey, J.W.; Bowser, P.R.

    2007-01-01

    In May 2006 a large mortality of several thousand round gobies Neogobius melanostomus (Pallas, 1814) occurred in New York waters of the St. Lawrence River and Lake Ontario. Necropsies of sampled fish from these areas showed pallor of the liver and gills, and hemorrhagic areas in many organs. Histopathologic examination of affected tissues revealed areas of necrosis and hemorrhage. Inoculations of fathead minnow Pimephales promelas (Rafinesque, 1820) cell cultures with dilutions of tissue samples from the necropsied gobies produced a cytopathic effect within 5 d post-inoculation. Samples of cell culture supernatant were tested using RT-PCR and confirmed the presence of viral hemorrhagic septicemia virus (VHSV). Sequence analysis of the VHSV isolate resulted in its assignment to the type-IVb subgroup. The detection of VHSV in a relatively recent invasive fish species in the Great Lakes and the potential impact of VHSV on the ecology and economy of the area will require further investigation and careful management considerations. ?? Inter-Research 2007.

  5. Parasitic fauna of Gobiidae in Mazandaran coastal zones, north of Iran 2011.

    PubMed

    Youssefi, Mohammad Reza; Roushan, Reza Habibnejad; Hosseinifard, Seyed Mehdi

    2016-06-01

    Gobiidae is considered as one of the diverse families of fishes in Caspian Sea. Due to abundant species and no harvest, this family plays an important role in ecology and feed chain of fishes in Caspian Sea. Present study was performed to determine parasitic fauna of Gobiidae in southern parts of Caspian Sea (coasts of Nowshahr, Sorkhrood, Jouybar, Sari and Amirabad). Primarily, length and weight of each fish was measured. Then, fish's various organs were examined by routine parasitology methods. From 150 fishes which were caught from six studied coastal zones, 51 (34 %) were infected. Majority of caught fishes was belonged to sand goby (Neogobius fluviatilis pallasi) and round goby (Neogobius melanostomus) was the least. Highest rate of infection was seen in N. fluviatilis pallasi while, this percentage in round goby (N. melanostomus) was low (8.57 %) and in Caspian bighead goby (Neogobius kessleri gorlap) no parasitic infection was observed. Most of infected fishes were from Jouybar coastal zone while Nowshahr coastal zone had the lowest infection rate. In present study parasites such as Dactylogyrus, Rhobdochona fortuneti and Bothrocephalus gowkogensis were diagnosed in Caspian gobies. Regarding importance of gobies in chain feed of other fishes and their indirect economic importance, need of diagnosing of gobies parasitic fauna seems to be essential.

  6. Rockpool Gobies Change Colour for Camouflage

    PubMed Central

    Stevens, Martin; Lown, Alice E.; Denton, Alexander M.

    2014-01-01

    Camouflage is found in a wide range of species living in numerous habitat types, offering protection from visually guided predators. This includes many species from the intertidal zone, which must cope with background types diverse in appearance and with multiple predator groups foraging at high and low tide. Many animals are capable of either relatively slow (hours, days, weeks) or rapid (seconds and minutes) colour change in order to better resemble the background against which they are found, but most work has been restricted to a few species or taxa. It is often suggested that many small intertidal fish are capable of colour change for camouflage, yet little experimental work has addressed this. Here, we test rock gobies (Gobius paganellus) for colour change abilities, and whether they can tune their appearance to match the background. In two experiments, we place gobies on backgrounds of different brightness (black or white), and of different colours (red and blue) and use digital image analysis and modelling of predator (avian) vision to quantify colour and luminance (perceived lightness) changes and camouflage. We find that gobies are capable of rapid colour change (occurring within one minute), and that they can change their luminance on lighter or darker backgrounds. When presented on backgrounds of different colours, gobies also change their colour (hue and saturation) while keeping luminance the same. These changes lead to predicted improvements in camouflage match to the background. Our study shows that small rockpool fish are capable of rapid visual change for concealment, and that this may be an important mechanism in many species to avoid predation, especially in complex heterogeneous environments. PMID:25333382

  7. Experimental evidence that ecological effects of an invasive fish are reduced at high densities.

    PubMed

    Kornis, Matthew S; Carlson, Jedchada; Lehrer-Brey, Gabrielle; Vander Zanden, M Jake

    2014-05-01

    Understanding the relationship between invasive species density and ecological impact is a pressing topic in ecology, with implications for environmental management and policy. Although it is widely assumed that invasive species impact will increase with density, theory suggests interspecific competition may diminish at high densities due to increased intraspecific interactions. To test this theory, we experimentally examined intra- and interspecific interactions between a globally invasive fish, round goby (Neogobius melanostomus), and three native species at different round goby densities in a tributary of the Laurentian Great Lakes. Eighteen 2.25 m(2) enclosures were stocked with native fish species at natural abundances, while round gobies were stocked at three different densities: 0 m(-2), 2.7 m(-2), and 10.7 m(-2). After 52 days, native fish growth rate was significantly reduced in the low density goby treatment, while growth in the high density goby treatment mirrored the goby-free treatment for two of three native species. Invertebrate density and gut content weight of native fishes did not differ among treatments. Conversely, gut content weight and growth of round gobies were lower in the high goby density treatment, suggesting interactions between round gobies and native fishes are mediated by interference competition amongst gobies. Our experiment provides evidence that invasive species effects may diminish at high densities, possibly due to increased intraspecific interactions. This is consistent with some ecological theory, and cautions against the assumption that invasive species at moderate densities have low impact.

  8. Assessment of rarity of the blackmouth shiner Notropis melanostomus (Cyprinidae) based on museum and recent survey data

    USGS Publications Warehouse

    O'Connell, M. T.; Uzee O'Connell, A.M.; Williams, J.D.

    2005-01-01

    Accurate knowledge of an organism's distribution is necessary for conserving species with small or isolated populations. A perceived rarity may only reflect inadequate sampling effort and suggest the need for more research. We used a recently developed method to evaluate the distribution of a rare fish species, the blackmouth shiner Notropis melanostomus Bortone 1989 (Cyprinidae), which occurs in disjunct populations in Mississippi and Florida. Until 1995, N. melanostomus had been collected from only three localities in Mississippi, but in 1995, eight new localities were discovered. We analyzed museum records of fish collections from Mississippi, Florida, and Alabama to compare sampling effort before and after 1995. Results supported our predictions that 1) pre-1995 data would indicate inadequate sampling effort in Mississippi, 2) additional post-1995 sampling improved confidence in the currently known Mississippi distribution, and 3) there has not been enough sampling to accurately represent the actual distribution of N. melanostomus in Florida and across its entire known range. This last prediction was confirmed with the recent (2003) discovery of the first N. melanostomus in Alabama.

  9. Postflood persistence and recolonization of endangered tidewater goby populations

    USGS Publications Warehouse

    Lafferty, Kevin D.; Swift, Camm C.; Ambrose, Richard F.

    1999-01-01

    Before-and-after surveys at several southern California sites indicated that populations of endangered tidewater goby Eucyclogobius newberryi persisted through heavy flooding in 1995. This was contrary to our expectations that flooding might have led to extirpation in some smaller wetlands. There was also no significant change in tidewater goby density before and after the flooding. Several apparent recolonization events coincided with the flood, suggesting that flooding may be important for the long-term persistence of the species.

  10. A new anglerfish from eastern Australia and New Caledonia (Lophiiformes: Chaunacidae: Chaunacops), with new data and submersible observation of Chaunacops melanostomus.

    PubMed

    Ho, H-C; McGrouther, M

    2015-03-01

    A new deep-sea anglerfish of the genus Chaunacops is described based on three specimens collected from eastern Australia and New Caledonia. It differs from its congeners in having fine dermal spinules, mixed with simple and bifurcate ones, densely covering the body, four neuromasts on the pectoral series of the lateral line and a combination of other characteristics. Data for Chaunacops melanostomus based on 31 specimens newly collected from Western Australia are provided. An underwater observation of C. melanostomus made by a remotely operated vehicle is also provided.

  11. An eDNA Assay to Monitor a Globally Invasive Fish Species from Flowing Freshwater.

    PubMed

    Adrian-Kalchhauser, Irene; Burkhardt-Holm, Patricia

    2016-01-01

    Ponto-Caspian gobies are a flock of five invasive fish species that have colonized freshwaters and brackish waters in Europe and North America. One of them, the round goby Neogobius melanostomus, figures among the 100 worst invaders in Europe. Current methods to detect the presence of Ponto-Caspian gobies involve catching or sighting the fish. These approaches are labor intense and not very sensitive. Consequently, populations are usually detected only when they have reached high densities and when management or containment efforts are futile. To improve monitoring, we developed an assay based on the detection of DNA traces (environmental DNA, or eDNA) of Ponto-Caspian gobies in river water. The assay specifically detects invasive goby DNA and does not react to any native fish species. We apply the assay to environmental samples and demonstrate that parameters such as sampling depth, sampling location, extraction protocol, PCR protocol and PCR inhibition greatly impact detection. We further successfully outline the invasion front of Ponto-Caspian gobies in a large river, the High Rhine in Switzerland, and thus demonstrate the applicability of the assay to lotic environments. The eDNA assay requires less time, equipment, manpower, skills, and financial resources than the conventional monitoring methods such as electrofishing, angling or diving. Samples can be taken by untrained individuals, and the assay can be performed by any molecular biologist on a conventional PCR machine. Therefore, this assay enables environment managers to map invaded areas independently of fishermen's' reports and fish community monitorings.

  12. Gobi Desert, China as seen from STS-59

    NASA Technical Reports Server (NTRS)

    1994-01-01

    View to the south by southwest across the southern Gobi Desert (China) across the Chi-Lien-Shan or Quilienshan or Nanshan (Mountains) in Gansu Province to Lake Quinghai or Ch'ing-Hai (orthography varies with political conditions and scholarship) in Quinghai Province. The lake has a surface elevation of 10,450 feet, partially filling one of the easternmost closed drainage basins of Central Asia.

  13. Little Galloo Island, Lake Ontario: Two decades of studies on the diet, fish consumption, and management of double-crested cormorants

    USGS Publications Warehouse

    Johnson, James H.; McCullough, Russell D.; Farquhar, James F.; Mazzocchi, Irene

    2015-01-01

    The double-crested cormorant (Phalacrocorax auritus) colony at Little Galloo Island, Lake Ontario has been a Great Lakes focal point of controversy regarding cormorant–fish interactions for over two decades. We examined cormorant diet and fish consumption at the colony from 1992 to 2013. During this time period, two events, management actions and round goby (Neogobius melanostomus) invasion, occurred that affected the number of fish consumed by cormorants and their diet composition. The purpose of this study was to evaluate the effects of round goby on the feeding ecology of cormorants and evaluate the efficacy of management actions on meeting cormorant population targets at the colony. Round goby first appeared in the diet in 2004 (0.8%) and within one year were the primary prey (29.3%). The presence of round goby in the diet of cormorants: (1) eliminated seasonal variability in diet composition, (2) reversed seasonal trends in the number of fish consumed daily, (3) increased daily fish consumption, and (4) significantly reduced the consumption of other species including yellow perch and smallmouth bass. Management actions, such as egg oiling and culling, were also effective in reducing nesting activity and the number of cormorant feeding days at the Little Galloo Island colony. There is evidence that the combination of management actions and round goby may have allowed some population recovery of yellow perch and smallmouth bass in eastern Lake Ontario.

  14. Courtship Sounds Advertise Species Identity and Male Quality in Sympatric Pomatoschistus spp. Gobies

    PubMed Central

    Pedroso, Silvia S.; Barber, Iain; Svensson, Ola; Fonseca, Paulo J.; Amorim, Maria Clara P.

    2013-01-01

    Acoustic signals can encode crucial information about species identity and individual quality. We recorded and compared male courtship drum sounds of the sand goby Pomatoschistus minutus and the painted goby P. pictus and examined if they can function in species recognition within sympatric populations. We also examined which acoustic features are related to male quality and the factors that affect female courtship in the sand goby, to determine whether vocalisations potentially play a role in mate assessment. Drums produced by the painted goby showed significantly higher dominant frequencies, higher sound pulse repetition rates and longer intervals between sounds than those of the sand goby. In the sand goby, male quality was predicted by visual and acoustic courtship signals. Regression analyses showed that sound amplitude was a good predictor of male length, whereas the duration of nest behaviour and active calling rate (i.e. excluding silent periods) were good predictors of male condition factor and fat reserves respectively. In addition, the level of female courtship was predicted by male nest behaviour. The results suggest that the frequency and temporal patterns of sounds can encode species identity, whereas sound amplitude and calling activity reflects male size and fat reserves. Visual courtship duration (nest-related behaviour) also seems relevant to mate choice, since it reflects male condition and is related to female courtship. Our work suggests that acoustic communication can contribute to mate choice in the sand goby group, and invites further study. PMID:23755129

  15. Courtship sounds advertise species identity and male quality in sympatric Pomatoschistus spp. gobies.

    PubMed

    Pedroso, Silvia S; Barber, Iain; Svensson, Ola; Fonseca, Paulo J; Amorim, Maria Clara P

    2013-01-01

    Acoustic signals can encode crucial information about species identity and individual quality. We recorded and compared male courtship drum sounds of the sand goby Pomatoschistus minutus and the painted goby P. pictus and examined if they can function in species recognition within sympatric populations. We also examined which acoustic features are related to male quality and the factors that affect female courtship in the sand goby, to determine whether vocalisations potentially play a role in mate assessment. Drums produced by the painted goby showed significantly higher dominant frequencies, higher sound pulse repetition rates and longer intervals between sounds than those of the sand goby. In the sand goby, male quality was predicted by visual and acoustic courtship signals. Regression analyses showed that sound amplitude was a good predictor of male length, whereas the duration of nest behaviour and active calling rate (i.e. excluding silent periods) were good predictors of male condition factor and fat reserves respectively. In addition, the level of female courtship was predicted by male nest behaviour. The results suggest that the frequency and temporal patterns of sounds can encode species identity, whereas sound amplitude and calling activity reflects male size and fat reserves. Visual courtship duration (nest-related behaviour) also seems relevant to mate choice, since it reflects male condition and is related to female courtship. Our work suggests that acoustic communication can contribute to mate choice in the sand goby group, and invites further study.

  16. Groundwater isotope survey in the Southern Gobi Region, Mongolia

    NASA Astrophysics Data System (ADS)

    Bayanzul, B. B.; Nemer, B.; Kaland, V.; Groen, K.; Naidan, J.; Linden, W. V. D.

    2014-12-01

    The strategically biggest mineral deposits are located in South Gobi Region, Mongolia and the Mongolian government has been adhering the policy to operate them in near short terms. Groundwater is one of the important resources since rainfall and surface water availability are limited. This survey was made for the purpose to determination to principle of originating groundwater potentials. For the purpose, groundwater age was investigated with the stable isotope, radiocarbon and tritium method. They were analyzed in the laboratory of CIO of Rijksuniversiteit Groningen (The Centre of Isotope Research), Institute of Groundwater Ecology from the Helmholtz Zentrum and the German Research Center for Environmental Health (GmbH) in Munich, Germany. Deep groundwater has radiocarbon ages from 13,000 to 45,000 years before present (0.4-18.4% modern C) and δ13C values from -10.0 to -4.6‰, for which it is difficult to assign absolute ages, although these values probably represent the Late Glacial period and late Pleistocene age. Shallow groundwater had tritium values of <1 to 20.8 TU, from which only 2 locations can be referred as recently infiltrated (since 1953) - or recent mixed with fossil groundwater. Groundwater aquifers were mainly found in Cretaceous sediments that have filled-up large basins in the Gobi and there is a good possibility that aquifers are interconnected via these basin sediments, although sedimentary facies changes and geological faults may form barriers to groundwater flow.

  17. A potential new energy pathway in Central Lake Erie: The round goby connection

    USGS Publications Warehouse

    Johnson, T.B.; Bunnell, D.B.; Knight, C.T.

    2005-01-01

    Round gobies, invasive fish that entered Lake Erie in 1994, are altering energy, contaminant, and nutrient pathways. Our objective was to quantify how they alter energy pathways in the central basin of Lake Erie by describing their diet and identifying the degree to which predatory fish feed upon round gobies. We used bioenergetic models parameterized with data collected in the central basin between 1995 and 2002 to estimate the type and amount of prey eaten, the biomass accumulation rate for the round goby population, and a partitioning of the food energy into “new” energy derived from dreissenids as opposed to existing energy derived from zooplankton and non-dreissenid benthic prey. Mean (± SE) prey consumption peaked at 5.98 ± 2.17×104 tonnes wet mass in 1999 coincident with the maximum population size of 4.2 ± 1.5 billion round gobies. Zooplankton (40.2% by biomass) and dreissenid mussels (38.3%) dominated the prey consumed. Almost 90% of the zooplankton biomass was consumed by age-0 round gobies, while over 80% of the dreissenids were eaten by older ages. Standing stock biomass of round gobies ranged between 203 and 4,803 tonnes y−1 (interannual range), with an additional 475 to 8,943 tonnes of biomass accumulating through growth each year. Piscivorous fish showed an increasing reliance on round gobies as prey, with round gobies being the dominant prey fish in the diets of benthic-oriented predators. Hence, by being one of the few benthivores that exploit dreissenid mussels as prey, our analyses reveal that round gobies transfer new energy up the central Lake Erie food web.

  18. Assessing of heavy metal concentrations in the tissues of Rutilus rutilus caspicus and Neogobius gorlap from Miankaleh international wetland.

    PubMed

    Alipour, Hossein; Pourkhabbaz, Alireza; Hassanpour, Mehdi

    2013-11-01

    The concentrations of four heavy metals (Pb, Cd, Ni and Cr) were measured in tissues of pelagic (Rutilus caspicus) and benthic (Neogobius gorlap) fishes from the Miankaleh international wetland. The maximum concentrations of Pb, Cd, Ni, and Cr (2.06, 1.20, 1.14 and 0.70 μg g(-1), respectively) were measured in the liver of N. gorlap, while the lowest concentrations were measured in muscle tissue collected from R. caspicus (Pb 0.67; Cd 0.25; Ni 0.21 and Cr 0.08 μg g(-1)). The mean concentrations of metals in liver of R. caspicus and N. gorlap followed a trend where Pb > Cd > Ni > Cr, whereas in R. caspicus and N. gorlap gills and N. gorlap muscle the following trend was observed Pb > Ni > Cd > Cr. The data of presented study show that the liver and gill tissues have higher metal concentrations than muscle and also the metal concentrations in tissues of N. gorlap (benthic) were higher in comparison with R. caspicus (pelagic).

  19. Lateralized behavior in the attacks of largemouth bass on Rhinogobius gobies corresponding to their morphological antisymmetry.

    PubMed

    Yasugi, Masaki; Hori, Michio

    2012-07-15

    Vertebrates show left-right biases in turning direction, limb usage, predator-escape response and use of sensory organs. In particular, some fishes are known to have lateral biases in predatory behaviors corresponding to their morphological antisymmetry. To reveal the effects of these laterally biased behaviors on predator-prey interaction, we conducted behavioral tests of predatory events between largemouth bass, Micropterus salmoides, and freshwater gobies, Rhinogobius sp., both of which have individuals with a well-developed left side and individuals with a well-developed right side. The left-developed bass tended to approach the goby clockwise from behind, whereas right-developed individuals tended to approach counterclockwise. Congruently, left-developed gobies began their escape maneuvers at a longer distance from bass when they were approached clockwise than when they were approached counterclockwise, whereas right-developed gobies showed the reverse tendency. The longer the distance between bass and gobies at the start of goby escape, the more the subsequent bass strike or dash was delayed. Under these conditions, predation should be more successful when a left (right)-developed bass meets a right (left)-developed goby, and less successful when a left (right)-developed bass meets a left (right)-developed goby. This prediction was consistent with the difference in predation success in our test and in field data from Lake Biwa, Japan. We conclude that lateral biases in the behavioral direction of each morphological type will generate bias in predation success between different combinations of predator and prey types, leading to the maintenance of antisymmetric dimorphism through negative frequency-dependent natural selection.

  20. Invaders eating invaders: Exploitation of novel alien prey by the alien shimofuri goby in the San Francisco Estuary, California

    USGS Publications Warehouse

    Matern, S.A.; Brown, L.R.

    2005-01-01

    The shimofuri goby (Tridentiger bifasciatus), which is native to Asian estuaries, was recently introduced to the San Francisco Estuary, California, USA. We conducted gut content analyses to examine the goby's feeding ecology in this highly invaded estuary. Shimofuri gobies were generalist predators on benthic invertebrates, consuming seasonally abundant prey, especially amphipods (Corophium spp.). In addition, shimofuri goby utilized two novel prey items not exploited by other resident fishes - hydroids (Cordylophora caspia) and barnacle (Balanus improvisus) cirri, both of which are alien. The shimofuri goby's feeding ecology appears well-suited to the fluctuating environment of the San Francisco Estuary and may partially explain observed increases in shimofuri goby abundance compared with declines in populations of some native species. ?? Springer 2005.

  1. Waterfalls drive parallel evolution in a freshwater goby.

    PubMed

    Kano, Yuichi; Nishida, Shin; Nakajima, Jun

    2012-08-01

    Waterfalls may affect fish distribution and genetic structure within drainage networks even to the extent of leading evolutionary events. Here, parallel evolution was studied by focusing on waterfall and the landlocked freshwater goby Rhinogobius sp. YB (YB), which evolved from amphidromous R. brunneus (BR). The fish fauna was surveyed at 30 sites in 11 rivers on Iriomote Island, Japan, the geography of which was characterized by terraces/tablelands with many waterfalls. We found that all YB individuals were distributed only above waterfalls (height 6.8-58.7 m), whereas BR, and other fishes, were mostly distributed below waterfalls. Mitochondrial DNA analysis showed that every YB local population above the waterfall was independently evolved from BR. In contrast, cluster analysis of nine morphological characters, such as fin color and body pattern, showed that the morphology of YB individuals held a similarity beyond the genetic divergence, suggesting parallel evolution has occurred relating to their morphology. Genetic distance between each YB local population and BR was significantly correlated with waterfall height (r(2) = 0.94), suggesting that the waterfalls have been heightened due to the constant geological erosion and that their height represents the isolation period of YB local populations from BR (ca. 11,000-88,000 years). Each local population of BR was once landlocked in upstream by waterfall formation, consequently evolving to YB in each site. Although the morphology of YB had a high degree of similarity among local populations, finer scale analysis showed that the morphology of YB was significantly correlated with the genetic distance from BR. Consequently, there could be simultaneous multiple phases of allopatric/parallel evolution of the goby due to variations in waterfall height on this small island.

  2. Diet shift of double-crested cormorants in eastern Lake Ontario associated with the expansion of the invasive round goby

    USGS Publications Warehouse

    Johnson, James H.; Ross, Robert M.; McCullough, Russell D.; Mathers, Alastair

    2010-01-01

    The proliferation of the invasive round goby (Apollonia melanostoma) in the Great Lakes has caused shifts in the trophic ecology in some areas. We examined the diet of double-crested cormorants (Phalacrocorax auritas) prior to, and immediately after, round goby population expansion at two colonies, Pigeon and Snake Islands, in eastern Lake Ontario from 1999 to 2007. Cormorant diet was determined from the examination of 10,167 pellets collected over the nine-year period. By the second year round gobies were found in the diet (2002 at Snake Island and 2003 at Pigeon Island) they were the main species consumed by cormorants at each colony. The dominance of round goby in cormorant diets had a significant effect on both daily fish consumption and seasonal trends in fish consumption compared to the pre-goby years. Seasonal differences that were observed during the pre-goby years were lost once gobies became the main diet component of cormorants. The rapid switch to a benthic prey such as round goby, from a largely limnetic fish diet demonstrates the adaptive foraging ability of cormorants. Round goby may act as a buffer for yellow perch and smallmouth bass, two sport fish impacted by cormorant predation in eastern Lake Ontario.

  3. The importance of gobies (Gobiidae, Teleostei) as hosts and transmitters of parasites in the SW Baltic

    NASA Astrophysics Data System (ADS)

    Zander, C. D.; Strohbach, U.; Groenewold, S.

    1993-02-01

    The parasite fauna of five goby species (Gobiidae, Teleostei) was investigated in the Baltic Sea during the period 1987 to 1990. 13 parasite species were found in samples from the Lübeck Bight: Bothriocephalus scorpii, Schistocephalus sp. (Cestoda); Cryptocotyle concavum, Cryptocotyle lingua, Podocotyle atomon, Derogenes varicus (Digenea); Hysterothylacium sp. (cf. auctum), Contracaecum sp., Anisakis simplex (Nematoda); Corynosoma sp., Echinorhynchus gadi, Neoechinorhynchus rutili, Pomphorhynchus laevis (Acanthocephala). The number of parasite species were: 10 in the sand goby Pomatoschistus minutus, 8 in the black goby Gobius niger, 7 in the two-spotted goby Gobiusculus flavescens, 6 in the common goby Pomatoschistus microps, and 5 in the painted goby Pomatoschistus pictus. Neoechinorhynchus rutili occurred only in P. minutus, and Corynosoma sp. only in G. niger. The extent to which the gobies were parasitized clearly depended on the respective ways of life and, moreover, on the kind of prey ingested by the hosts. Additionally, the age of the hosts might be important. The highest rate of parasitism, more than 60%, was reached by Hysterothylacium sp. in G. niger and by Cryptocotyle concavum in P. microps. Infestation incidence lay mostly below 40% which means a satellite species status (Holmes, 1991). The number of parasite species was highest in summer; the highest intensities of single parasites occurred in spring ( Podocotyle atomon) or autumn ( Crytocotyle concavum). Bothriocephalus scorpii, Hysterothylacium sp. and Podocotyle infested their juvenile hosts very early, but only Hysterothylacium was accumulated by G. niger during its whole life span, whereas Bothriocephalus persisted also in older gobies in low intensities. The cercariae of Cryptocotyle spp. penetrate actively into their hosts; all the other parasites named were transmitted in larval form by prey organisms which consisted mainly of planktonic and benthic crustaceans. The gobies were final hosts

  4. Gut content analysis of Lake Michigan waterbirds in years with avian botulism type E mortality, 2010–2012

    USGS Publications Warehouse

    Essian, David A.; Chipault, Jennifer G.; Lafrancois, Brenda M.; Leonard, Jill B.K.

    2016-01-01

    Waterbird die-offs caused by Clostridium botulinum neurotoxin type E (BoNT/E) have occurred sporadically in the Great Lakes since the late 1960s, with a recent pulse starting in the late 1990s. In recent die-offs, round gobies (Neogobius melanostomus) have been implicated as vectors for the transfer of BoNT/E to fish-eating birds due to the round goby invasion history and their importance as prey. Dreissenid mussels (Dreissena spp.) are also potentially involved in BoNT/E transmission to birds and round gobies. We examined gut contents of waterbirds collected in Lake Michigan during die-offs in 2010–2012, and the gut contents of culled, presumably BoNT/E-free double-crested cormorants (Phalacrocorax auritus). Round gobies were found in 86% of the BoNT/E-positive individuals, 84% of the BoNT/E-negative birds, and 94% of the BoNT/E-free cormorants examined. Double-crested cormorants, ring-billed gulls (Larus delewarensis), and common loons (Gavia immer) consumed larger-sized round gobies than horned and red-necked grebes (Podiceps auritus and Podiceps grisegena), white-winged scoters (Melanitta deglandi), and long-tailed ducks (Clangula hymealis). Other common prey included dreissenid mussels, terrestrial insects, and alewives (Alosa pseudoharengus). Our data emphasize the importance of round gobies and mussels in diets of Lake Michigan waterbirds and suggest they may play a role in the transfer of BoNT/E to waterbirds; however, round gobies and mussels were found in BoNT/E-positive, -negative, and -free individuals, suggesting that other factors, such as alternative trophic pathways for toxin transfer, bird migratory timing and feeding locations, prey behavior, and individual physiological differences across birds may affect the likelihood that a bird will succumb to BoNT/E intoxication.

  5. Connectivity of the Asiatic wild ass population in the Mongolian Gobi

    PubMed Central

    Kaczensky, Petra; Kuehn, Ralph; Lhagvasuren, Badamjav; Pietsch, Stephanie; Yang, Weikang; Walzer, Chris

    2011-01-01

    Long-distance migrations of wildlife have been identified as important biological phenomena, but their conservation remains a major challenge. The Mongolian Gobi is one of the last refuges for the Asiatic wild ass (Equus hemionus) and other threatened migratory mammals. Using historic and current distribution ranges, population genetics, and telemetry data we assessed the connectivity of the wild ass population in the context of natural and anthropogenic landscape features and the existing network of protected areas. In the Mongolian Gobi mean biomass production is highly correlated with human and livestock density and seems to predict wild ass occurrence at the upper level. The current wild ass distribution range largely falls into areas below the 250 gC/m2/year productivity isoline, suggesting that under the present land use more productive areas have become unavailable for wild asses. Population genetics results identified two subpopulations and delineated a genetic boundary between the Dzungarian and Transaltai Gobi for which the most likely explanation are the mountain ranges separating the two areas. Home ranges and locations of 19 radiomarked wild asses support the assumed restricting effects of more productive habitats and mountain ranges and additionally point towards a barrier effect of fences. Furthermore, telemetry data shows that in the Dzungarian and Transaltai Gobi individual wild ass rarely ventured outside of the protected areas, whereas in the southeast Gobi asses only spend a small fraction of their time within the protected area network. Conserving the continuity of the wild ass population will need a landscape level approach, also including multi-use landscapes outside of protected areas, particularly in the southeast Gobi. In the southwest Gobi, allowing for openings in the border fence to China and managing the border area as an ecological corridor would connect three large protected areas together covering over 70,000 km2 of wild ass

  6. Connectivity of the Asiatic wild ass population in the Mongolian Gobi.

    PubMed

    Kaczensky, Petra; Kuehn, Ralph; Lhagvasuren, Badamjav; Pietsch, Stephanie; Yang, Weikang; Walzer, Chris

    2011-02-01

    Long-distance migrations of wildlife have been identified as important biological phenomena, but their conservation remains a major challenge. The Mongolian Gobi is one of the last refuges for the Asiatic wild ass (Equus hemionus) and other threatened migratory mammals. Using historic and current distribution ranges, population genetics, and telemetry data we assessed the connectivity of the wild ass population in the context of natural and anthropogenic landscape features and the existing network of protected areas. In the Mongolian Gobi mean biomass production is highly correlated with human and livestock density and seems to predict wild ass occurrence at the upper level. The current wild ass distribution range largely falls into areas below the 250 gC/m(2)/year productivity isoline, suggesting that under the present land use more productive areas have become unavailable for wild asses. Population genetics results identified two subpopulations and delineated a genetic boundary between the Dzungarian and Transaltai Gobi for which the most likely explanation are the mountain ranges separating the two areas. Home ranges and locations of 19 radiomarked wild asses support the assumed restricting effects of more productive habitats and mountain ranges and additionally point towards a barrier effect of fences. Furthermore, telemetry data shows that in the Dzungarian and Transaltai Gobi individual wild ass rarely ventured outside of the protected areas, whereas in the southeast Gobi asses only spend a small fraction of their time within the protected area network. Conserving the continuity of the wild ass population will need a landscape level approach, also including multi-use landscapes outside of protected areas, particularly in the southeast Gobi. In the southwest Gobi, allowing for openings in the border fence to China and managing the border area as an ecological corridor would connect three large protected areas together covering over 70,000 km(2) of wild ass

  7. GobyWeb: simplified management and analysis of gene expression and DNA methylation sequencing data.

    PubMed

    Dorff, Kevin C; Chambwe, Nyasha; Zeno, Zachary; Simi, Manuele; Shaknovich, Rita; Campagne, Fabien

    2013-01-01

    We present GobyWeb, a web-based system that facilitates the management and analysis of high-throughput sequencing (HTS) projects. The software provides integrated support for a broad set of HTS analyses and offers a simple plugin extension mechanism. Analyses currently supported include quantification of gene expression for messenger and small RNA sequencing, estimation of DNA methylation (i.e., reduced bisulfite sequencing and whole genome methyl-seq), or the detection of pathogens in sequenced data. In contrast to previous analysis pipelines developed for analysis of HTS data, GobyWeb requires significantly less storage space, runs analyses efficiently on a parallel grid, scales gracefully to process tens or hundreds of multi-gigabyte samples, yet can be used effectively by researchers who are comfortable using a web browser. We conducted performance evaluations of the software and found it to either outperform or have similar performance to analysis programs developed for specialized analyses of HTS data. We found that most biologists who took a one-hour GobyWeb training session were readily able to analyze RNA-Seq data with state of the art analysis tools. GobyWeb can be obtained at http://gobyweb.campagnelab.org and is freely available for non-commercial use. GobyWeb plugins are distributed in source code and licensed under the open source LGPL3 license to facilitate code inspection, reuse and independent extensions http://github.com/CampagneLaboratory/gobyweb2-plugins.

  8. GobyWeb: Simplified Management and Analysis of Gene Expression and DNA Methylation Sequencing Data

    PubMed Central

    Dorff, Kevin C.; Chambwe, Nyasha; Zeno, Zachary; Simi, Manuele; Shaknovich, Rita; Campagne, Fabien

    2013-01-01

    We present GobyWeb, a web-based system that facilitates the management and analysis of high-throughput sequencing (HTS) projects. The software provides integrated support for a broad set of HTS analyses and offers a simple plugin extension mechanism. Analyses currently supported include quantification of gene expression for messenger and small RNA sequencing, estimation of DNA methylation (i.e., reduced bisulfite sequencing and whole genome methyl-seq), or the detection of pathogens in sequenced data. In contrast to previous analysis pipelines developed for analysis of HTS data, GobyWeb requires significantly less storage space, runs analyses efficiently on a parallel grid, scales gracefully to process tens or hundreds of multi-gigabyte samples, yet can be used effectively by researchers who are comfortable using a web browser. We conducted performance evaluations of the software and found it to either outperform or have similar performance to analysis programs developed for specialized analyses of HTS data. We found that most biologists who took a one-hour GobyWeb training session were readily able to analyze RNA-Seq data with state of the art analysis tools. GobyWeb can be obtained at http://gobyweb.campagnelab.org and is freely available for non-commercial use. GobyWeb plugins are distributed in source code and licensed under the open source LGPL3 license to facilitate code inspection, reuse and independent extensions http://github.com/CampagneLaboratory/gobyweb2-plugins. PMID:23936070

  9. Prehistoric ruptures of the Gurvan Bulag fault, Gobi Altay, Mongolia

    USGS Publications Warehouse

    Prentice, C.S.; Kendrick, K.; Berryman, K.; Bayasgalan, A.; Ritz, J.F.; Spencer, J.Q.

    2002-01-01

    The 1957 Gobi Altay M8.3 earthquake in southern Mongolia was associated with the simultaneous rupture of several faults, including the Gurvan Bulag reverse fault, which is located about 25 km south of the main strike-slip Bogd fault. Our study of paleoseismic excavations across the Gurvan Bulag fault suggests that the penultimate surface rupture occurred after 6.0 ka, most likely between 2.6 and 4.4 ka, and a possible earlier rupture occurred after 7.3 ka. Our interpretation of the stratigraphic relations in one of the exposures suggests that at least five earthquakes have generated surface rupture of the Gurvan Bulag fault since the abandonment of an ancient alluvial fan surface. Luminescence dating of sediment associated with this surface indicates that it formed either 26.6 ?? 2.1 ka or 16.1 ?? 2.0 ka. These data imply that the recurrence intervals for surface faulting on the Gurvan Bulag and Bogd faults are similar, on the order of several thousands of years, but that the penultimate surface ruptures of the two faults did not occur during the same earthquake.

  10. Convergent Aspects of Acoustic Communication in Darters, Sculpins, and Gobies.

    PubMed

    Zeyl, Jeffrey N; Malavasi, Stefano; Holt, Daniel E; Noel, Patricia; Lugli, Marco; Johnston, Carol E

    2016-01-01

    Darters (Perciformes, Percidae), sculpins (Perciformes, Cottidae), and gobioids (Gobiiformes, Gobioidei) exhibit convergent life history traits, including a benthic lifestyle and a cavity nesting spawning mode. Soniferous species within these taxa produce pulsed and/or tonal sounds with peak frequencies below 200 Hz (with some exceptions), primarily in agonistic and/or reproductive contexts. The reduced or absent swim bladders found in these taxa limit or prevent both hearing enhancement via pressure sensitivity and acoustic amplification of the contracting sonic muscles, which are associated with the skull and pectoral girdle. While such anatomies constrain communication to low frequency channels, optimization of the S/N (signal-to-noise) ratio in low frequency channels is evident for some gobies, as measured by habitat soundscape frequency windows, nest cavity sound amplification, and audiograms. Similar S/N considerations are applicable to many darter and sculpin systems. This chapter reviews the currently documented diversity of sound production in darters, sculpins, and gobioids within a phylogenetic context, examines the efficacy of signal transmission from senders to receivers (sound production mechanisms, audiograms, and masking challenges), and evaluates the potential functional significance of sound attributes in relation to territorial and reproductive behaviours.

  11. Mate sampling and choosiness in the sand goby

    PubMed Central

    Lindström, Kai; Lehtonen, Topi K.

    2013-01-01

    To date, mate choice studies have mostly focused on establishing which mates are chosen or how the choices are performed. Here, we combined these two approaches by empirically testing how latency to mate is affected by various search costs, variation in mate quality and female quality in the sand goby (Pomatoschistus minutus). Our results show that females adjust their mating behaviour according to the costs and benefits of the choice situation. Specifically, they mated sooner when access to males was delayed and when the presence of other females presented a mate sampling cost. We also found a positive link between size variation among potential mating partners and spawning delay in some (but not all) experimental conditions. By contrast, we did not find the number of available males or the females' own body size (‘quality’) to affect mating latency. Finally, female mating behaviour varied significantly between years. These findings are notable for demonstrating that (i) mate sampling time is particularly sensitive to costs and, to a lesser degree, to variation among mate candidates, (ii) females' mating behaviour is sensitive to qualitative rather than to quantitative variation in their environment, and (iii) a snapshot view may describe mate sampling behaviour unreliably. PMID:23804620

  12. First stable isotope analysis of Asiatic wild ass tail hair from the Mongolian Gobi.

    PubMed

    Horacek, Micha; Sturm, Martina Burnik; Kaczensky, Petra

    Stable isotope analysis has become a powerful tool to study feeding ecology, water use or movement pattern in contemporary, historic and ancient species. Certain hair and teeth grow continuously, and when sampled longitudinally can provide temporally explicit information on dietary regime and movement pattern. In an initial trial, we analysed a tail sample of an Asiatic wild ass (Equus hemionus) from the Mongolian Gobi. We found seasonal variations in H, C and N isotope patterns, likely being the result of temporal variations in available feeds, water supply and possibly physiological status. Thus stable isotope analysis shows promise to study the comparative ecology of the three autochthonous equid species in the Mongolian Gobi.

  13. An eDNA Assay to Monitor a Globally Invasive Fish Species from Flowing Freshwater

    PubMed Central

    Adrian-Kalchhauser, Irene; Burkhardt-Holm, Patricia

    2016-01-01

    Ponto-Caspian gobies are a flock of five invasive fish species that have colonized freshwaters and brackish waters in Europe and North America. One of them, the round goby Neogobius melanostomus, figures among the 100 worst invaders in Europe. Current methods to detect the presence of Ponto-Caspian gobies involve catching or sighting the fish. These approaches are labor intense and not very sensitive. Consequently, populations are usually detected only when they have reached high densities and when management or containment efforts are futile. To improve monitoring, we developed an assay based on the detection of DNA traces (environmental DNA, or eDNA) of Ponto-Caspian gobies in river water. The assay specifically detects invasive goby DNA and does not react to any native fish species. We apply the assay to environmental samples and demonstrate that parameters such as sampling depth, sampling location, extraction protocol, PCR protocol and PCR inhibition greatly impact detection. We further successfully outline the invasion front of Ponto-Caspian gobies in a large river, the High Rhine in Switzerland, and thus demonstrate the applicability of the assay to lotic environments. The eDNA assay requires less time, equipment, manpower, skills, and financial resources than the conventional monitoring methods such as electrofishing, angling or diving. Samples can be taken by untrained individuals, and the assay can be performed by any molecular biologist on a conventional PCR machine. Therefore, this assay enables environment managers to map invaded areas independently of fishermen’s’ reports and fish community monitorings. PMID:26814998

  14. Use of main channel and two backwater habitats by larval fishes in the Detroit River

    USGS Publications Warehouse

    McDonald, Erik A.; McNaught, A. Scott; Roseman, Edward F.

    2014-01-01

    Recent investigations in the Detroit River have revealed renewed spawning activity by several important fishes, but little is known about their early life history requirements. We surveyed two main channel and two backwater areas in the lower Detroit River weekly from May to July 2007 to assess habitat use by larval fishes. Backwater areas included a soft-sediment embayment (FI) and a hard-sediment area (HIW). Main channel sites were located adjacent to each backwater area. Water temperature, velocity and clarity measurements and zooplankton samples were collected weekly. A macrophyte assessment was conducted in July. Growth and diet of larval yellow perch (Perca flavescens), bluegill (Lepomis macrochirus) and round goby (Neogobius melanostomus) were used to assess habitat quality. Macrophyte diversity and percent cover were higher and velocity lower at FI than HIW. Although larval fish diversity was highest in the main channel, yellow perch and bluegill larvae only grew beyond the yolk stage at FI, where they preferentially selected copepods, while Daphnia were selected in the main channel. Round goby ate harpacticoid copepods and Daphnia and grew at similar rates in HIW and the main channel. These data indicate that FI was a valuable nursery area for yellow perch and bluegill, whereas HIW was better suited to round goby. We only assessed two backwater areas, thus a complete census of wetland areas in the Detroit River is needed to identify valuable habitats. Restoration of shallow backwater areas is essential for rehabilitating fish populations and should be a priority in the Detroit River.

  15. Tetrodotoxin poisoning caused by Goby fish consumption in southeast China: a retrospective case series analysis

    PubMed Central

    You, Jie; Yue, YaJun; Xing, Feng; Xia, Wei; Lai, ShaoYang; Zhang, FengLei

    2015-01-01

    OBJECTIVES: To investigate an unusual outbreak of tetrodotoxin poisoning in Leizhou, southeast China, a case series analysis was conducted to identify the source of illness. METHODS: A total of 22 individuals experienced symptoms of poisoning, including tongue numbness, dizziness, nausea and limb numbness and weakness. Two toxic species, Amoya caninus and Yongeichthys nebulosus, were morphologically identified from the batches of gobies consumed by the patients. Tetrodotoxin levels in the blood and Goby fish samples were detected using liquid chromatography-tandem mass spectrometry. RESULTS: The tetrodotoxin levels in the remaining cooked Goby fish were determined to be 2090.12 µg/kg. For Amoya caninus, the toxicity levels were 1858.29 µg/kg in the muscle and 1997.19 µg/kg in the viscera and for Yongeichthys nebulosus, they were 2783.00 µg/kg in the muscle and 2966.21 µg/kg in the viscera. CONCLUSION: This outbreak demonstrates an underestimation of the risk of Goby fish poisoning. Furthermore, the relationships among the toxic species, climates and marine algae present should be clarified in the future. PMID:25672425

  16. Phylogenetic evidence for recent diversification of obligate coral-dwelling gobies compared with their host corals☆

    PubMed Central

    Duchene, David; Klanten, Selma O.; Munday, Philip L.; Herler, Jürgen; van Herwerden, Lynne

    2013-01-01

    The rich diversity of coral reef organisms is supported, at least in part, by the diversity of coral reef habitat. Some of the most habitat specialised fishes on coral reefs are obligate coral-dwelling gobies of the genus Gobiodon that inhabit a range of coral species, mostly of the genus Acropora. However, the role of this specialised pattern of habitat use in the evolution of coral-dwelling gobies is not well understood. Diversification of coral-dwelling gobies may be driven by the diversification of their host corals (cospeciation), or alternatively, diversification of these fishes may have occurred independently of the diversification of host corals. The cospeciation hypothesis assumes similar timing in evolution of the gobies and their host corals. We used four genes for each group and the available fossil records to reconstruct and date phylogenies for 20 species of Gobiodon from the Indo-Pacific and the Red Sea, and for 28 species of the coral genus Acropora. Our results indicate that Gobiodon diversified mostly in the last ∼5 My, whereas Acropora corals have consistently diversified since the Eocene, making the hypothesis of cospeciation untenable. The fully resolved molecular phylogeny of the genus Gobiodon is in part at odds with previous analyses incorporating morphological data and indicates that some morphological traits form paraphyletic clades within Gobiodon. Our phylogeny supports a hypothesis in which Gobiodon diversified in the Indo-Pacific Ocean and then radiated recently, with multiple new variants found in the Red Sea. PMID:23680856

  17. Phylogenetic evidence for recent diversification of obligate coral-dwelling gobies compared with their host corals.

    PubMed

    Duchene, David; Klanten, Selma O; Munday, Philip L; Herler, Jürgen; van Herwerden, Lynne

    2013-10-01

    The rich diversity of coral reef organisms is supported, at least in part, by the diversity of coral reef habitat. Some of the most habitat specialised fishes on coral reefs are obligate coral-dwelling gobies of the genus Gobiodon that inhabit a range of coral species, mostly of the genus Acropora. However, the role of this specialised pattern of habitat use in the evolution of coral-dwelling gobies is not well understood. Diversification of coral-dwelling gobies may be driven by the diversification of their host corals (cospeciation), or alternatively, diversification of these fishes may have occurred independently of the diversification of host corals. The cospeciation hypothesis assumes similar timing in evolution of the gobies and their host corals. We used four genes for each group and the available fossil records to reconstruct and date phylogenies for 20 species of Gobiodon from the Indo-Pacific and the Red Sea, and for 28 species of the coral genus Acropora. Our results indicate that Gobiodon diversified mostly in the last ∼5My, whereas Acropora corals have consistently diversified since the Eocene, making the hypothesis of cospeciation untenable. The fully resolved molecular phylogeny of the genus Gobiodon is in part at odds with previous analyses incorporating morphological data and indicates that some morphological traits form paraphyletic clades within Gobiodon. Our phylogeny supports a hypothesis in which Gobiodon diversified in the Indo-Pacific Ocean and then radiated recently, with multiple new variants found in the Red Sea.

  18. Invasive Ponto-Caspian Amphipods and Fish Increase the Distribution Range of the Acanthocephalan Pomphorhynchus tereticollis in the River Rhine

    PubMed Central

    Emde, Sebastian; Rueckert, Sonja; Palm, Harry W.; Klimpel, Sven

    2012-01-01

    Non-indigenous species that become invasive are one of the main drivers of biodiversity loss worldwide. In various freshwater systems in Europe, populations of native amphipods and fish are progressively displaced by highly adaptive non-indigenous species that can perform explosive range extensions. A total of 40 Ponto-Caspian round gobies Neogobius melanostomus from the Rhine River near Düsseldorf, North Rhine-Westphalia, Germany, were examined for metazoan parasites and feeding ecology. Three metazoan parasite species were found: two Nematoda and one Acanthocephala. The two Nematoda, Raphidascaris acus and Paracuaria adunca, had a low prevalence of 2.5%. The Acanthocephala, Pomphorhynchus tereticollis, was the predominant parasite species, reaching a level of 90.0% prevalence in the larval stage, correlated with fish size. In addition, four invasive amphipod species, Corophium curvispinum (435 specimens), Dikerogammarus villosus (5,454), Echinogammarus trichiatus (2,695) and Orchestia cavimana (1,448) were trapped at the sampling site. Only D. villosus was infected with P. tereticollis at a prevalence of 0.04%. The invasive goby N. melanostomus mainly preys on these non-indigenous amphipods, and may have replaced native amphipods in the transmission of P. tereticollis into the vertebrate paratenic host. This study gives insight into a potential parasite-host system that consists mainly of invasive species, such as the Ponto-Caspian fish and amphipods in the Rhine. We discuss prospective distribution and migration pathways of non-indigenous vertebrate (round goby) and invertebrates (amphipods) under special consideration of parasite dispersal. PMID:23300895

  19. Invasive Ponto-Caspian amphipods and fish increase the distribution range of the acanthocephalan Pomphorhynchus tereticollis in the river Rhine.

    PubMed

    Emde, Sebastian; Rueckert, Sonja; Palm, Harry W; Klimpel, Sven

    2012-01-01

    Non-indigenous species that become invasive are one of the main drivers of biodiversity loss worldwide. In various freshwater systems in Europe, populations of native amphipods and fish are progressively displaced by highly adaptive non-indigenous species that can perform explosive range extensions. A total of 40 Ponto-Caspian round gobies Neogobius melanostomus from the Rhine River near Düsseldorf, North Rhine-Westphalia, Germany, were examined for metazoan parasites and feeding ecology. Three metazoan parasite species were found: two Nematoda and one Acanthocephala. The two Nematoda, Raphidascaris acus and Paracuaria adunca, had a low prevalence of 2.5%. The Acanthocephala, Pomphorhynchus tereticollis, was the predominant parasite species, reaching a level of 90.0% prevalence in the larval stage, correlated with fish size. In addition, four invasive amphipod species, Corophium curvispinum (435 specimens), Dikerogammarus villosus (5,454), Echinogammarus trichiatus (2,695) and Orchestia cavimana (1,448) were trapped at the sampling site. Only D. villosus was infected with P. tereticollis at a prevalence of 0.04%. The invasive goby N. melanostomus mainly preys on these non-indigenous amphipods, and may have replaced native amphipods in the transmission of P. tereticollis into the vertebrate paratenic host. This study gives insight into a potential parasite-host system that consists mainly of invasive species, such as the Ponto-Caspian fish and amphipods in the Rhine. We discuss prospective distribution and migration pathways of non-indigenous vertebrate (round goby) and invertebrates (amphipods) under special consideration of parasite dispersal.

  20. Recent changes in burbot growth in Lake Erie

    USGS Publications Warehouse

    Stapanian, M.A.; Edwards, W.H.; Witzel, L.D.

    2011-01-01

    Recruitment of burbot Lota lota in eastern Lake Erie, estimated by catches of age-4 burbot, was high during 1997–2001 and then abruptly declined to low levels during 2002–2007. The invasive round goby Neogobius melanostomus, a benthic species, was first collected in trawl assessments in eastern Lake Erie in 1999, and was first found in stomachs of burbot in 2001. By 2003, round goby became an important prey in the diet of burbot. We hypothesized that the combined effects of low recruitment and consumption of round goby would result in increased size-at-age in burbot. We reasoned that: (i) decreased competition for resources among juveniles should result in larger adults, and (ii) consumption of a benthic prey by a bottom-dwelling predator such as burbot should require less foraging in the water column, and thus less energetic expenditure. We divided our data into two temporal periods: one in which burbot belonged to strong year classes and ate few, if any round goby (i.e., year classes 1989–1997 collected during 1997–2001) and one in which burbot belonged to weak year classes and probably ate round gobies by age 4 (year classes 1998–2003 collected during 2002–2007). Mass and total lengths at ages 4–7 were generally higher during the second period. However, the rates of growth between ages 4 and 7 were not different for the two periods. The results indicate that greater growth at ages 0–4 resulted in larger size at ages 4–7 in the latter period. More information on juvenile diet and growth in burbot is needed for effective conservation of burbot stocks.

  1. Gyrodactylus proterorhini in its non-native range: distribution and ability to host-switch in freshwaters.

    PubMed

    Ondračková, Markéta

    2016-08-01

    Successful co-introduction of a parasite and its host relies not only on presence of the parasite on host individuals in the founder population but also on the ability of both host and parasite to persist in the new area. Gyrodactylus proterorhini (Monogenea) has been successfully co-introduced with its Ponto-Caspian goby hosts (Babka gymnotrachelus, Neogobius fluviatilis, Neogobius melanostomus, Ponticola kessleri, Proterorhinus semilunaris) to many freshwater systems in Europe and is now widely distributed over four large European river basins (Danube, Rhine, Scheldt and Vistula). Within Europe, higher infection levels are documented in sites further from the native host range. In North America, however, G. proterorhini appears to be absent. Host specificity of G. proterorhini tested under natural conditions showed accidental host-switching onto local fish species (native Perca fluviatilis and non-native Perccottus glenii) in the river Vistula. Further examination of host-switching under experimental conditions, however, showed that G. proterorhini were unable to survive on non-gobiid hosts longer than 24 h. Our results indicate extremely low potential for host-switching of introduced G. proterorhini to non-gobiid hosts, at least in the freshwater systems of Central and Western Europe.

  2. Invasive dreissenid mussels and round gobies: a benthic pathway for the trophic transfer of microcystin.

    PubMed

    Poste, Amanda E; Ozersky, Ted

    2013-09-01

    In the present preliminary study, the authors identify 2 pathways through which invasive dreissenid mussels can transfer microcystin to higher trophic levels: either directly, through consumption by benthivorous fish such as the round goby; or indirectly, through their biodeposits, which are an important food source for benthic invertebrates. The results suggest that dreissenid mussels represent a potentially important benthic pathway for the food web transfer of microcystin.

  3. Aeolian sediment transport over gobi: Field studies atop the Mogao Grottoes, China

    NASA Astrophysics Data System (ADS)

    Tan, Lihai; Zhang, Weimin; Qu, Jianjun; Wang, Junzhan; An, Zhishan; Li, Fang

    2016-06-01

    This paper reports on field studies of aeolian sediment transport over a rough surface-gobi atop the Mogao Grottoes, China, in relation to sediment entrainment, saltation mass flux and transport rate prediction. Wind speeds were measured with five cup anemometers at different heights and sediment entrainment and transport measured with horizontal and vertical sediment traps coupled to weighing sensors, where sediment entrainment and transport were measured synchronously with wind speeds. Four sediment transport events, with a measurement duration ranging between 2.5 and 11 h, were studied. The entrainment threshold determined by the horizontal sediment trap varied between 0.28 and 0.33 m s-1, and the effect of non-erodible roughness elements-gravels increased the entrainment threshold approximately by 1.8 times compared to a uniform sand surface. Unlike the non-monotone curve shape of sediment flux density profile over gobi measured in wind tunnels, the flux density profile measured in the field showed an exponential form. Aeolian sediment transport over gobi could be predicted by an Owen-type saltation model: q = Aρ /gu∗ (u∗2- u∗t2), where q is sediment transport rate, A is a soil-related dimensionless factor, u∗ is the friction velocity, u∗t is the threshold friction velocity, g is the gravitational acceleration, ρ is the air density. This study indicates that the sediment flux sampling using horizontal and vertical sediment traps coupled to weighing sensors provides a practical method to determine values for A in this model that can provide good estimates of sediment transport rates in gobi areas.

  4. Acoustic communication in two freshwater gobies: ambient noise and short-range propagation in shallow streams.

    PubMed

    Lugli, M; Fine, M L

    2003-07-01

    Noise is an important theoretical constraint on the evolution of signal form and sensory performance. In order to determine environmental constraints on the communication of two freshwater gobies Padogobius martensii and Gobius nigricans, numerous noise spectra were measured from quiet areas and ones adjacent to waterfalls and rapids in two shallow stony streams. Propagation of goby sounds and waterfall noise was also measured. A quiet window around 100 Hz is present in many noise spectra from noisy locations. The window lies between two noise sources, a low-frequency one attributed to turbulence, and a high-frequency one (200-500 Hz) attributed to bubble noise from water breaking the surface. Ambient noise from a waterfall (frequencies below 1 kHz) attenuates as much as 30 dB between 1 and 2 m, after which values are variable without further attenuation (i.e., buried in the noise floor). Similarly, courtship sounds of P. martensii attenuate as much as 30 dB between 5 and 50 cm. Since gobies are known to court in noisy as well as quiet locations in these streams, their acoustic communication system (sounds and auditory system) must be able to cope with short-range propagation dictated by shallow depths and ambient noise in noisy locations.

  5. Urban particle size distributions during two contrasting dust events originating from Taklimakan and Gobi Deserts.

    PubMed

    Zhao, Suping; Yu, Ye; Xia, Dunsheng; Yin, Daiying; He, Jianjun; Liu, Na; Li, Fang

    2015-12-01

    The dust origins of the two events were identified using HYSPLIT trajectory model and MODIS and CALIPSO satellite data to understand the particle size distribution during two contrasting dust events originated from Taklimakan and Gobi deserts. The supermicron particles significantly increased during the dust events. The dust event from Gobi desert affected significantly on the particles larger than 2.5 μm, while that from Taklimakan desert impacted obviously on the particles in 1.0-2.5 μm. It is found that the particle size distributions and their modal parameters such as VMD (volume median diameter) have significant difference for varying dust origins. The dust from Taklimakan desert was finer than that from Gobi desert also probably due to other influencing factors such as mixing between dust and urban emissions. Our findings illustrated the capacity of combining in situ, satellite data and trajectory model to characterize large-scale dust plumes with a variety of aerosol parameters.

  6. In the Green Desert: Non-formal Distance Education Project for Nomadic Women of the Gobi Desert, Mongolia. Education for All: Making It Work. Innovations Series, 12.

    ERIC Educational Resources Information Center

    Robinson, Bernadette

    With the disintegration of the former Soviet Union, Mongolia was severed from its exterior financial and technical support. The dramatic shift in socioeconomic conditions created a need for new forms of adult education. The nomadic women of the Gobi Desert were targeted as most at risk, and the Gobi Women's Project conducted a needs assessment in…

  7. In vivo and in vitro phenotypic differences between Great Lakes VHSV genotype IVb isolates with sequence types vcG001 and vcG002

    USGS Publications Warehouse

    Imanse, Sierra M.; Cornwell, Emily R.; Getchell, Rodman G.; Kurath, Gael; Bowser, Paul R.

    2014-01-01

    Viral hemorrhagic septicemia virus (VHSV) is an aquatic rhabdovirus first recognized in farmed rainbow trout in Denmark. In the past decade, a new genotype of this virus, IVb was discovered in the Laurentian Great Lakes basin and has caused several massive die-offs in some of the 28 species of susceptible North American freshwater fishes. Since its colonization of the Great Lakes, several closely related sequence types within genotype IVb have been reported, the two most common of which are vcG001 and vcG002. These sequence types have different spatial distributions in the Great Lakes. The aim of this study was to determine whether the genotypic differences between representative vcG001 (isolate MI03) and vcG002 (isolate 2010-030 #91) isolates correspond to phenotypic differences in terms of virulence using both in vitro and in vivo approaches. In vitro infection of epithelioma papulosum cyprini (EPC), bluegill fry (BF-2), and Chinook salmon embryo (CHSE) cells demonstrated some differences in onset and rate of growth in EPC and BF-2 cells, without any difference in the quantity of RNA produced. In vivo infection of round gobies (Neogobius melanostomus) via immersion exposure to different concentrations of vcG001 or vcG002 caused a significantly greater mortality in round gobies exposed to 102 plaque forming units ml− 1 of vcG001. These experiments suggest that there are phenotypic differences between Great Lakes isolates of VHSV genotype IVb.

  8. In vivo and in vitro phenotypic differences between Great Lakes VHSV genotype IVb isolates with sequence types vcG001 and vcG002.

    PubMed

    Imanse, Sierra M; Cornwell, Emily R; Getchell, Rodman G; Kurath, Gael; Bowser, Paul R

    2014-12-01

    Viral hemorrhagic septicemia virus (VHSV) is an aquatic rhabdovirus first recognized in farmed rainbow trout in Denmark. In the past decade, a new genotype of this virus, IVb was discovered in the Laurentian Great Lakes basin and has caused several massive die-offs in some of the 28 species of susceptible North American freshwater fishes. Since its colonization of the Great Lakes, several closely related sequence types within genotype IVb have been reported, the two most common of which are vcG001 and vcG002. These sequence types have different spatial distributions in the Great Lakes. The aim of this study was to determine whether the genotypic differences between representative vcG001 (isolate MI03) and vcG002 (isolate 2010-030 #91) isolates correspond to phenotypic differences in terms of virulence using both an in vitro and in vivo approach. In vitro infection of epithelioma papulosum cyprini (EPC), bluegill fry (BF-2), and Chinook salmon embryo (CHSE) cells demonstrated some differences in onset and rate of growth in EPC and BF-2 cells, without any difference in the quantity of RNA produced. In vivo infection of round gobies (Neogobius melanostomus) via immersion exposure to different concentrations of vcG001 or vcG002 caused a significantly greater mortality in round gobies exposed to 10(2) plaque forming units ml(-1) of vcG001. These experiments suggest that there are phenotypic differences between Great Lakes isolates of VHSV genotype IVb.

  9. An approach to incorporate individual personality in modeling fish dispersal across in-stream barriers.

    PubMed

    Hirsch, Philipp Emanuel; Thorlacius, Magnus; Brodin, Tomas; Burkhardt-Holm, Patricia

    2017-01-01

    Animal personalities are an important factor that affects the dispersal of animals. In the context of aquatic species, dispersal modeling needs to consider that most freshwater ecosystems are highly fragmented by barriers reducing longitudinal connectivity. Previous research has incorporated such barriers into dispersal models under the neutral assumption that all migrating animals attempt to ascend at all times. Modeling dispersal of animals that do not perform trophic or reproductive migrations will be more realistic if it includes assumptions of which individuals attempt to overcome a barrier. We aimed to introduce personality into predictive modeling of whether a nonmigratory invasive freshwater fish (the round goby, Neogobius melanostomus) will disperse across an in-stream barrier. To that end, we experimentally assayed the personalities of 259 individuals from invasion fronts and established round goby populations. Based on the population differences in boldness, asociability, and activity, we defined a priori thresholds with bolder, more asocial, and more active individuals having a higher likelihood of ascent. We then combined the personality thresholds with swimming speed data from the literature and in situ measurements of flow velocities in the barrier. The resulting binary logistic regression model revealed probabilities of crossing a barrier which depended not only on water flow and fish swimming speed but also on animal personalities. We conclude that risk assessment through predictive dispersal modeling across fragmented landscapes can be advanced by including personality traits as parameters. The inclusion of behavior into modeling the spread of invasive species can help to improve the accuracy of risk assessments.

  10. In vivo and in vitro phenotypic differences between Great Lakes VHSV genotype IVb isolates with sequence types vcG001 and vcG002

    PubMed Central

    Imanse, Sierra M.; Cornwell, Emily R.; Getchell, Rodman G.; Kurath, Gael; Bowser, Paul R.

    2014-01-01

    Viral hemorrhagic septicemia virus (VHSV) is an aquatic rhabdovirus first recognized in farmed rainbow trout in Denmark. In the past decade, a new genotype of this virus, IVb was discovered in the Laurentian Great Lakes basin and has caused several massive die-offs in some of the 28 species of susceptible North American freshwater fishes. Since its colonization of the Great Lakes, several closely related sequence types within genotype IVb have been reported, the two most common of which are vcG001 and vcG002. These sequence types have different spatial distributions in the Great Lakes. The aim of this study was to determine whether the genotypic differences between representative vcG001 (isolate MI03) and vcG002 (isolate 2010-030 #91) isolates correspond to phenotypic differences in terms of virulence using both an in vitro and in vivo approach. In vitro infection of epithelioma papulosum cyprini (EPC), bluegill fry (BF-2), and Chinook salmon embryo (CHSE) cells demonstrated some differences in onset and rate of growth in EPC and BF-2 cells, without any difference in the quantity of RNA produced. In vivo infection of round gobies (Neogobius melanostomus) via immersion exposure to different concentrations of vcG001 or vcG002 caused a significantly greater mortality in round gobies exposed to 102 plaque forming units ml−1 of vcG001. These experiments suggest that there are phenotypic differences between Great Lakes isolates of VHSV genotype IVb. PMID:25722533

  11. Use of chemical communication in the management of freshwater aquatic species that are vectors of human diseases or are invasive.

    PubMed

    Corkum, Lynda D; Belanger, Rachelle M

    2007-01-01

    Chemical communication occurs when both originator (signaller) and one or more receiver(s) possess specializations for chemical exchange of information. Chemical information can be used by a wide variety of species to locate food and mates, avoid predators and engage in social interactions. In this review, we focus on chemical signalling between mates or cues from nest sites or hosts by selected aquatic pest species and indicate how chemical information can be used to manage pests. The pests are vectors of disease (blood-sucking insects) or invasive species (crayfishes and fishes) that have exhibited detrimental effects on indigenous species. Pheromones released by females attract and stimulate males in some taxa (insects, crayfish, goldfish, and crucian carp), whereas pheromones released by males attract females in others (round goby, sea lamprey). Other chemicals (e.g., habitat odours or odours given off by developmental stages of conspecifics) can affect oviposition decisions of pest species. In areas of aquatic environments where other cues may be limited (e.g., visual), freshwater organisms may rely solely on chemical signals or in concert with environmental cues for reproduction. Once the chemical structure of odour attractants are identified and shown to lure conspecifics to traps, odorants or their blends can be used to control the aquatic pests. There is promise for the application of pheromone traps to control the malarian vector (Anopheles gambiae) or invasive species such as signal crayfish (Pacifastacus leniusculus), sea lamprey (Petromyzon marinus) and the round goby (Neogobius melanostomus) by disrupting the reproductive behaviours of these species.

  12. Size Dependent Male Reproductive Tactic in the Two-Spotted Goby (Gobiusculus flavescens)

    PubMed Central

    Jensen, K. H.; Mayer, I.; Jakobsen, P. J.

    2015-01-01

    Male investment in testes and sperm duct gland in the polygamous nest breeding two-spotted goby Gobiusculus flavescens (Fabricius) was investigated in relation to time in reproductive season and individual physical parameters. This small teleost fish is most likely the most abundant species found along the rocky shores of the North East Atlantic. The two-spotted goby has a single reproductive season, during which nest-caring males can raise several clutches of offspring. According to the literature the males are on average larger than the females. Here we report for the first time a population showing a reversal of this trend, with males on average being smaller than females, a difference likely caused by a large proportion of small males. Early in the breeding season these small males have typical sneaker characters, with relatively large testes and small seminal duct glands compared to the larger dominant territorial males. The presence of these two alternative male reproductive tactics is confirmed by histological studies, which shows the presence of sperm in the sperm duct glands (SDG) of smaller males, but not in the SDG of intermediate and larger males. To our knowledge, males with typical sneaker characters have not been reported in earlier studied populations of two-spotted goby. Interestingly we found that testes investment declined significantly over the course of the breeding season, and that this reduction was significantly more pronounced in small compared to the large males. Further, a significant increase in seminal duct gland (SDG) mass was observed for the smaller males over the breeding season. We propose that this indicates a possible shift in mating tactic by smaller males from a parasitic to a nest-holding tactic over the course of the breeding season. Thus, the observed size dependent plasticity in investment in SDG over time suggests that the reproductive tactic of G. flavescens is conditional, and possibly influenced by mate availability and

  13. Spatial variability and stocks of soil organic carbon in the Gobi desert of Northwestern China.

    PubMed

    Zhang, Pingping; Shao, Ming'an

    2014-01-01

    Soil organic carbon (SOC) plays an important role in improving soil properties and the C global cycle. Limited attention, though, has been given to assessing the spatial patterns and stocks of SOC in desert ecosystems. In this study, we quantitatively evaluated the spatial variability of SOC and its influencing factors and estimated SOC storage in a region (40 km2) of the Gobi desert. SOC exhibited a log-normal depth distribution with means of 1.6, 1.5, 1.4, and 1.4 g kg(-1) for the 0-10, 10-20, 20-30, and 30-40 cm layers, respectively, and was moderately variable according to the coefficients of variation (37-42%). Variability of SOC increased as the sampling area expanded and could be well parameterized as a power function of the sampling area. Significant correlations were detected between SOC and soil physical properties, i.e. stone, sand, silt, and clay contents and soil bulk density. The relatively coarse fractions, i.e. sand, silt, and stone contents, had the largest effects on SOC variability. Experimental semivariograms of SOC were best fitted by exponential models. Nugget-to-sill ratios indicated a strong spatial dependence for SOC concentrations at all depths in the study area. The surface layer (0-10 cm) had the largest spatial dependency compared with the other layers. The mapping revealed a decreasing trend of SOC concentrations from south to north across this region of the Gobi desert, with higher levels close to an oasis and lower levels surrounded by mountains and near the desert. SOC density to depths of 20 and 40 cm for this 40 km2 area was estimated at 0.42 and 0.68 kg C m(-2), respectively. This study provides an important contribution to understanding the role of the Gobi desert in the global carbon cycle.

  14. Reproductive tactics of male bearded goby (Sufflogobius bibarbatus) in anoxic and hypoxic waters

    NASA Astrophysics Data System (ADS)

    Seivåg, Maria Larsen; Salvanes, Anne Gro Vea; Utne-Palm, Anne Christine; Kjesbu, Olav Si'gurd

    2016-03-01

    The bearded goby (Sufflogobius bibarbatus), a key species in the northern Benguela Upwelling Ecosystem, tolerates extremely low levels of oxygen. Yet little is known about how its reproduction is affected by these harsh living conditions. The distribution patterns of alternative reproductive tactics of male bearded goby across the continental shelf off Namibia were investigated. Histology and stereology were for the first time used to validate macroscopic maturity development by estimating volume fraction of the different stages of spermatogenesis using "Delesse principle", an approach so far for teleosts barely used in studies on testes but applied in advanced oocyte estimation. The macroscopic scale appeared suitable for the purpose, and the prevalence of territorial and sneaker tactics could therefore be documented. The sneakers had relative large testes and small seminal vesicles (SV), with the opposite being the case for the territorials. A third, numerous category with intermediate sized testes and SV was also recognized with unclear underlying tactical rationale, although regression analyses indicated similar investment in testes weight in relation to somatic weight as for the territorials. Low oxygen levels were the most important factor limiting spawning activity in territorial males. Our data suggested the existence of a spawning site on the outer shelf of the central Namibian shelf where the bottom water is hypoxic (oxygen saturation of 6.2-6.7%) while the anoxic middle shelf area (oxygen saturation of 1.7-2.9%) appeared to show too low oxygen levels for spawning to take place. Hence, significant parts of this large shelf area appear unsuited for successful reproduction of the bearded goby, in particular for nest building by the territorials.

  15. Co-phylogeographic study of the flatworm Gyrodactylus gondae and its goby host Pomatoschistus minutus.

    PubMed

    Huyse, Tine; Oeyen, Merel; Larmuseau, Maarten H D; Volckaert, Filip A M

    2017-04-01

    We performed a comparative phylogeographic study on the monogenean flatworm Gyrodactylus gondae Huyse, Malmberg & Volckaert 2005 (Gyrodactylidae) and its sand goby host Pomatoschistus minutus (Pallas, 1770) (Gobiidae). G. gondae is a host-specific parasite with a direct life cycle and a very short generation time. These properties are expected to increase the chance to track the genealogical history of the host with genetic data of the parasite ('magnifying glass principle'). To investigate this hypothesis we screened nine sand goby populations (n=326) along the Atlantic coasts of Europe for Gyrodactylus specimens. Low parasite prevalence resulted in partially overlapping host and parasite datasets. Ninety-two G. gondae collected on five sand goby populations were subsequently sequenced for a 460bp cytochrome c oxidase subunit II (coxII) fragment, which, in combination with previously published haplotype data for the hosts, allowed for partially overlapping host and parasite datasets. Haplotype diversity was lowest in the Irish Sea while nucleotide diversity was highest in the Southern North Sea. The host population also showed the lowest diversity in the Irish Sea but the highest nucleotide diversity, based on cytochrome b sequences of 850bp, was found in Skagerrak. Phylogeographic networks suggest postglacial expansion in both the host and the parasite. Pair-wise population differentiation was however not consistently higher in the parasite than in the host, rejecting the magnifying glass hypothesis for this host-parasite system. The parasite network offered limited resolution and was characterized by many extinctions and/or missing haplotypes, which could be attributed to 1) sampling bias, 2) size fluctuations in the parasite populations resulting in frequent extinctions and genetic drift and 3) the relatively young age of the host-parasite association. A more exhaustive study including a broader geographical and genomic coverage is needed to discriminate among

  16. Spatial Variability and Stocks of Soil Organic Carbon in the Gobi Desert of Northwestern China

    PubMed Central

    Zhang, Pingping; Shao, Ming'an

    2014-01-01

    Soil organic carbon (SOC) plays an important role in improving soil properties and the C global cycle. Limited attention, though, has been given to assessing the spatial patterns and stocks of SOC in desert ecosystems. In this study, we quantitatively evaluated the spatial variability of SOC and its influencing factors and estimated SOC storage in a region (40 km2) of the Gobi desert. SOC exhibited a log-normal depth distribution with means of 1.6, 1.5, 1.4, and 1.4 g kg−1 for the 0–10, 10–20, 20–30, and 30–40 cm layers, respectively, and was moderately variable according to the coefficients of variation (37–42%). Variability of SOC increased as the sampling area expanded and could be well parameterized as a power function of the sampling area. Significant correlations were detected between SOC and soil physical properties, i.e. stone, sand, silt, and clay contents and soil bulk density. The relatively coarse fractions, i.e. sand, silt, and stone contents, had the largest effects on SOC variability. Experimental semivariograms of SOC were best fitted by exponential models. Nugget-to-sill ratios indicated a strong spatial dependence for SOC concentrations at all depths in the study area. The surface layer (0–10 cm) had the largest spatial dependency compared with the other layers. The mapping revealed a decreasing trend of SOC concentrations from south to north across this region of the Gobi desert, with higher levels close to an oasis and lower levels surrounded by mountains and near the desert. SOC density to depths of 20 and 40 cm for this 40 km2 area was estimated at 0.42 and 0.68 kg C m−2, respectively. This study provides an important contribution to understanding the role of the Gobi desert in the global carbon cycle. PMID:24733073

  17. Ejaculate of sneaker males is pheromonally inconspicuous in the black goby, Gobius niger (Teleostei, Gobiidae).

    PubMed

    Locatello, L; Mazzoldi, C; Rasotto, M B

    2002-11-01

    The black goby, Gobius niger, shows alternative male mating tactics, i.e., parental and sneaker males. Males release a sexual pheromone that attracts females and stimulates aggressive displays in males. This pheromone is produced by the mesorchial gland, a structure well developed in parental males but markedly undeveloped in sneakers. We measured the behavioral response of parental males to the ejaculates of males performing different reproductive tactics. Parental males reacted to the ejaculate of other parental males, with stereotypic aggressive behaviors, but not to the ejaculate of sneakers; consequently sneaker male ejaculate appears to be pheromonally inconspicuous.

  18. Fall diets of red-breasted merganser (Mergus serrator) and walleye (Sander vitreus) in Sandusky Bay and adjacent waters of western Lake Erie

    USGS Publications Warehouse

    Bur, M.T.; Stapanian, M.A.; Bernhardt, G.; Turner, M.W.

    2008-01-01

    Although published studies indicate the contrary, there is concern among many sport anglers that migrating red-breasted mergansers (Mergus serrator) and other waterbirds pose a competitive threat to sport fish species such as walleye (Sander vitreus) in Lake Erie. We quantified the diet of autumn-migrant mergansers and walleye during 1998-2000 in Sandusky Bay and adjacent waters of western Lake Erie. We hypothesized that the diets of both predators would be similar in species composition, but because of different foraging ecologies their diets would differ markedly in size of prey consumed. In addition to predator samples, we used trawl data from the same general area as an index of prey availability. We found that mergansers fed almost exclusively on fish (nine species). Gizzard shad (Dorosoma cepedianum), emerald shiner (Notropis atherinoides) and round goby (Neogobius melanostomus) were consumed in the greatest numbers, most frequently and comprised the greatest biomass. Walleye fed exclusively on fish: gizzard shad, alewife (Alosa psuedoharengus) and emerald shiner were consumed in the greatest numbers, most frequently and comprised the greatest biomass. Diet overlap between mergansers and walleye was 67% by weight and 66% by species frequency. Mean total lengths of gizzard shad, emerald shiner and round goby found in walleye stomachs exceeded those captured in trawls by 47%, on average. Mean total lengths of gizzard shad, emerald shiner and round goby were greater in walleye stomachs than in merganser stomachs. Mean total lengths of emerald shiner and round goby were less in merganser stomachs than in trawls. Our results suggest that although the diets of walleye and mergansers overlapped considerably, mergansers generally consumed smaller fish than walleye. Given the abundance and diversity of prey species available, and the transient nature of mergansers on Lake Erie during migration, we conclude that competition for food between these species is minimal.

  19. Chemical amplification in an invaded food web: seasonality and ontogeny in a high-biomass, low-diversity ecosystem.

    PubMed

    Ng, Carla A; Berg, Martin B; Jude, David J; Janssen, John; Charlebois, Patrice M; Amaral, Luis A N; Gray, Kimberly A

    2008-10-01

    The global spread of invasive species is changing the structure of aquatic food webs worldwide. The North American Great Lakes have proved particularly vulnerable to this threat. In nearshore areas, invasive benthic species such as dreissenid mussels and round gobies (Neogobius melanostomus) have gained dominance in recent years. Such species are driving the flow of energy and material from the water column to the benthic zone, with dramatic effect on nutrient and contaminant cycling. Here, we develop a stage-structured model of a benthified food web in Lake Michigan with seasonal resolution and show how its bioaccumulation patterns differ from expected ones. Our model suggests that contaminant recycling through the consumption of lipid-rich fish eggs and mussel detritus is responsible for these differences. In southern Lake Michigan's Calumet Harbor (Chicago, IL, USA), round gobies have nitrogen isotope signatures with considerable spread, with some values higher than their predators and others lower than their prey. Contrary to patterns observed in linear pelagic systems, we predict that polychlorinated biphenyl (PCB) concentrations in these fish decrease with increasing size due to the lipid- and benthos-enriched diets of smaller fish. We also present here round goby PCB concentrations measured in 2005 after an invasional succession in Calumet Harbor and demonstrate how the change from one invasive mussel species to another may have led to a decrease in round goby PCB accumulation. Our results suggest that benthic-dominated systems differ from pelagic ones chiefly due to the influence of detritus and that these effects are exacerbated in systems with low species diversity and high biomass.

  20. Groundwater Dynamics and Evapotranspiration Processes from Gobi Desert to Riparian Zone in Water-Limited Environment

    NASA Astrophysics Data System (ADS)

    Wang, P.; Pozdniakov, S. P.; Grinevsky, S. O.; Niu, G. Y.; Yu, J.; Du, C.

    2014-12-01

    Evapotranspiration (ET) including evaporation from soil surfaces and transpiration through plants' stomata exerts dominant controls on shallow groundwater dynamics under hyper-arid climates. Our analyses of diurnal and seasonal groundwater dynamics at desert sites in northwestern China for the period 2010-2014 showed that different patterns of groundwater dynamics in a Gobi-desert and riparian zones are highly related to ET processes. To quantify ET in the hyper-arid climates, we developed diagnostic indicators of the groundwater-ET relationship and a methodology based on seasonal groundwater level fluctuation approach. Under similar climates and depth to the water table (2-2.5 m), ET in the riparian zones as a result of direct root water uptake (RWU) through riparian shrubs (0.63-0.73 mm/d at the Tamarix ramosissima site and 1.89-2.33 mm/d at the Populus euphratica site) is much greater than that in a Gobi-desert site (0.12-0.27 mm/d). Numerical simulations using a one-dimensional land surface model with a RWU model that explicitly describes root-groundwater interactions indicate that direct RWU at the riparian sites is primarily dependent on the root dynamics that interacts with groundwater dynamics.

  1. Acoustic communication in two freshwater gobies: the relationship between ambient noise, hearing thresholds and sound spectrum.

    PubMed

    Lugli, M; Yan, H Y; Fine, M L

    2003-04-01

    Two freshwater gobies Padogobius martensii and Gobius nigricans live in shallow (5-70 cm) stony streams, and males of both species produce courtship sounds. A previous study demonstrated high noise levels near waterfalls, a quiet window in the noise around 100 Hz at noisy locations, and extremely short-range propagation of noise and goby signals. To investigate the relationship of this acoustic environment to communication, we determined audiograms for both species and measured parameters of courtship sounds produced in the streams. We also deflated the swimbladder in P. martensii to determine its effect on frequency utilization in sound production and hearing. Both species are maximally sensitive at 100 Hz and produce low-frequency sounds with main energy from 70 to 100-150 Hz. Swimbladder deflation does not affect auditory threshold or dominant frequency of courtship sounds and has no or minor effects on sound amplitude. Therefore, both species utilize frequencies for hearing and sound production that fall within the low-frequency quiet region, and the equivalent relationship between auditory sensitivity and maximum ambient noise levels in both species further suggests that ambient noise shapes hearing sensitivity.

  2. Extirpation and recolonization in a metapopulation of an endangered fish, the tidewater goby

    USGS Publications Warehouse

    Lafferty, K.D.; Swift, C.C.; Ambrose, R.F.

    1999-01-01

    The tidewater goby (Eucyclogobius newberryi), an endangered species in the United States, occurs in a series of isolated coastal wetlands in California. Using historical presence-absence data and our own surveys, we estimated annual rates of extirpation and recolonization for several populations of the goby in southern California. As predicted, large wetlands had lower rates of extirpation than small wetlands. There was a negative but statistically nonsignificant correlation between recolonization rate and distance to the nearest northerly source population. Populations at small sites were sensitive to drought, presumably because droughts can eliminate suitable habitat at small wetlands. Populations in small wetlands have declined over time, even after accounting for variation in stream flow, supporting the species' endangered status. Our study emphasizes the need to understand metapopulation dynamics for conserving species where the unit of conservation is a local population. It is also emphasizes the importance of not treating metapopulations as identical units. Finally, our results provide a means for describing the decline of a species that is complex in time and space and provide insight into how to target protection measures among metapopulations.

  3. Body size correlates with fertilization success but not gonad size in grass goby territorial males.

    PubMed

    Pujolar, Jose Martin; Locatello, Lisa; Zane, Lorenzo; Mazzoldi, Carlotta

    2012-01-01

    In fish species with alternative male mating tactics, sperm competition typically occurs when small males that are unsuccessful in direct contests steal fertilization opportunities from large dominant males. In the grass goby Zosterisessor ophiocephalus, large territorial males defend and court females from nest sites, while small sneaker males obtain matings by sneaking into nests. Parentage assignment of 688 eggs from 8 different nests sampled in the 2003-2004 breeding season revealed a high level of sperm competition. Fertilization success of territorial males was very high but in all nests sneakers also contributed to the progeny. In territorial males, fertilization success correlated positively with male body size. Gonadal investment was explored in a sample of 126 grass gobies collected during the period 1995-1996 in the same area (61 territorial males and 65 sneakers). Correlation between body weight and testis weight was positive and significant for sneaker males, while correlation was virtually equal to zero in territorial males. That body size in territorial males is correlated with fertilization success but not gonad size suggests that males allocate much more energy into growth and relatively little into sperm production once the needed size to become territorial is attained. The increased paternity of larger territorial males might be due to a more effective defense of the nest in comparison with smaller territorial males.

  4. Stomach fullness modulates prey size choice in the frillfin goby, Bathygobius soporator.

    PubMed

    Tomida, Leonardo; Lee, James T; Barreto, Rodrigo E

    2012-10-01

    Behaviours related to foraging and feeding in predator-prey systems are fundamental to our understanding of food webs. From the perspective of a predator, the selection of prey size depends upon a number of factors including prey vulnerability, prey size, and the predator's motivation to eat. Thus, feeding motivation and prey visual cues are supposed to influence predator decisions and it is predicted that prey selection by visual cues is modulated by the predator's stomach fullness prior to attacking a prey. This study was conducted using an animal model from the rocky shores ecosystem, a predatory fish, the frillfin goby Bathygobius soporator, and a benthic prey, the mottled shore crab Pachygrapsus transversus. Our results demonstrate that frillfin gobies are capable of visually evaluating prey size and that the size evaluation process is modulated by the level of stomach fullness. Predators with an empty stomach (0% fullness) attacked prey that was larger than the predicted optimal size. Partially satiated predators (50% stomach fullness) selected prey close to the optimal size, while fully satiated predators (100% stomach fullness) showed no preference for size. This finding indicates an integrative response of the predator that depends on the input of both internal and external sensory information when choosing prey. Predator perceptions of visual cues (prey size) and stomach fullness modulate foraging decisions. As a result, a flexible feeding behaviour emerges, evidencing a clearly adaptive response in line with optimal foraging theory predictions.

  5. Face Your Fears: Cleaning Gobies Inspect Predators despite Being Stressed by Them

    PubMed Central

    Soares, Marta C.; Bshary, Redouan; Cardoso, Sónia C.; Côté, Isabelle M.; Oliveira, Rui F.

    2012-01-01

    Social stressors typically elicit two distinct behavioural responses in vertebrates: an active response (i.e., “fight or flight”) or behavioural inhibition (i.e., freezing). Here, we report an interesting exception to this dichotomy in a Caribbean cleaner fish, which interacts with a wide variety of reef fish clients, including predatory species. Cleaning gobies appraise predatory clients as potential threat and become stressed in their presence, as evidenced by their higher cortisol levels when exposed to predatory rather than to non-predatory clients. Nevertheless, cleaning gobies neither flee nor freeze in response to dangerous clients but instead approach predators faster (both in captivity and in the wild), and interact longer with these clients than with non-predatory clients (in the wild). We hypothesise that cleaners interrupt the potentially harmful physiological consequences elicited by predatory clients by becoming increasingly proactive and by reducing the time elapsed between client approach and the start of the interaction process. The activation of a stress response may therefore also be responsible for the longer cleaning service provided by these cleaners to predatory clients in the wild. Future experimental studies may reveal similar patterns in other social vertebrate species when, for instance, individuals approach an opponent for reconciliation after a conflict. PMID:22802925

  6. Chriolepis prolata, a new species of Atlantic goby (Teleostei: Gobiidae) from the North American continental shelf.

    PubMed

    Hastings, Philip A; Findley, Lloyd T

    2015-01-08

    A new species of seven-spined goby of the genus Chriolepis is described from five specimens collected from the continental shelf of the northeastern Gulf of Mexico and Atlantic Ocean off South Carolina in depths of ca 54 to 110 m. The "Platform Goby", Chriolepis prolata, is distinguishable from all other western Atlantic species currently assigned to the genus Chriolepis and the morphologically similar genus Varicus in having pelvic-fin rays one through four branched, the fifth (innermost) pelvic-fin ray unbranched and relatively long (longer than the second ray to longer than all other pelvic-fin rays); most lateral body scales ctenoid, extending anteriorly in a wedge to a level anterior to the first dorsal-fin insertion or nearly to the pectoral-fin axil, with two or more rows of small cycloid scales extending anteriorly to near the pectoral-fin axil, cycloid scales along the bases of the dorsal and anal fins, and no scales on the belly; and the first two anal-fin pterygiophores inserted anterior to the first haemal spine. It closely resembles C. bilix but differs from that species which has a scaled belly, a shorter fifth pelvic-fin ray, prolonged dorsal-fin spines and smaller teeth in the lower jaw. An earlier report of C. bilix from Florida waters apparently refers to C. prolata. 

  7. Sedimentation History and Provenance Analysis of a Late Mesozoic Rifting Event at Tavan Har, East Gobi, Mongolia

    ERIC Educational Resources Information Center

    Davidson, Sarah Cain

    2005-01-01

    The East Gobi Basin (EGB), which covers over 1.5 million square kilometers in southeastern Mongolia, is one of several basins in eastern China and Mongolia that was formed by extension and intracontinental rifting during the late Mesozoic. For reasons that are poorly understood, the continental lithosphere covering areas that are now known as…

  8. Spatial dynamics of the bearded goby and its key fish predators off Namibia vary with climate and oxygen availability

    PubMed Central

    SALVANES, ANNE GRO V; BARTHOLOMAE, CHRIS; YEMANE, DAWIT; GIBBONS, MARK J; KAINGE, PAUL; KRAKSTAD, JENS-OTTO; ROUAULT, MATHIEU; STABY, ARVED; SUNDBY, SVEIN

    2015-01-01

    Hypoxia [O2 < 2.0 mL L−1 (87 μmol kg−1)] and severely hypoxic water masses [O2 < 0.5 mL L−1 (21.8 μmol kg−1)] are increasing in coastal marine ecosystems due to eutrophication and warming. Here, we investigate the response of the suboxic-tolerant endemic fish, Sufflogobius bibarbatus, to variations in the thermal and oxygen environment, as well as to predation pressure, using 22 yr worth of satellite and in situ data. We show that environmental variation and predation pressure affect the goby population, which has expanded over the last decade while that of horse mackerel has contracted. These changes co-occurred with a general warming in the north and central shelf areas (north of 24.5°S). Spring warming positively affected both goby and hake abundances, but not the horse mackerel, suggesting different responses to surface temperature. The goby habitat contracted when predators were abundant, particularly in the north, which is the fringe of its distributional area. The implications of the differential tolerance of gobies and their predators for climate variations are discussed. PMID:26167105

  9. Zebra mussel beds: an effective feeding ground for Ponto-Caspian gobies or suitable shelter for their prey?

    PubMed Central

    Kobak, Jarosław; Jermacz, Łukasz; Kakareko, Tomasz; Prądzynski, Daniel; Łodygowska, Małgorzata; Montowska, Karolina; Bącela-Spychalska, Karolina

    2016-01-01

    Aggregations of the Ponto-Caspian invasive zebra mussel (Dreissena polymorpha) constitute a suitable habitat for macroinvertebrates, considerably increasing their abundance and providing effective antipredator protection. Thus, the overall effect of a mussel bed on particular predator species may vary from positive to negative, depending on both prey density increase and predator ability to prey in a structurally complex habitat. Alien Ponto-Caspian goby fish are likely to be facilitated when introduced into new areas by zebra mussels, provided that they are capable of utilizing mussel beds as habitat and feeding grounds. We ran laboratory experiments to find which prey (chironomid larvae) densities (from ca. 500 to 2,000 individuals m−2) in a mussel bed make it a more beneficial feeding ground for the racer goby Babka gymnotrachelus (RG) and western tubenose goby Proterorhinus semilunaris (WTG) compared to sandy and stone substrata (containing the basic prey density of 500 ind. m−2). Moreover, we checked how food availability affects habitat selection by fish. Mussel beds became more suitable for fish than alternative mineral substrata when food abundance was at least two times higher (1,000 vs. 500 ind. m−2), regardless of fish size and species. WTG was associated with mussel beds regardless of its size and prey density, whereas RG switched to this habitat when it became a better feeding ground than alternative substrata. Larger RG exhibited a stronger affinity for mussels than small individuals. WTG fed more efficiently from a mussel bed at high food abundances than RG. A literature review has shown that increasing chironomid density, which in our study was sufficient to make a mussel habitat an attractive feeding ground for the gobies, is commonly observed in mussel beds in the field. Therefore, we conclude that zebra mussels may positively affect the alien goby species and are likely to facilitate their establishment in novel areas, contributing to an

  10. Critical body residues, Michaelis-Menten analysis of bioaccumulation, lethality and behaviour as endpoints of waterborne Ni toxicity in two teleosts.

    PubMed

    Leonard, Erin M; Marentette, Julie R; Balshine, Sigal; Wood, Chris M

    2014-03-01

    Traditionally, water quality guidelines/criteria are based on lethality tests where results are expressed as a function of waterborne concentrations (e.g. LC50). However, there is growing interest in the use of uptake and binding relationships, such as biotic ligand models (BLM), and in bioaccumulation parameters, such as critical body residue values (e.g. CBR50), to predict metal toxicity in aquatic organisms. Nevertheless, all these approaches only protect species against physiological death (e.g. mortality, failed recruitment), and do not consider ecological death which can occur at much lower concentrations when the animal cannot perform normal behaviours essential for survival. Therefore, we investigated acute (96 h) Ni toxicity in two freshwater fish species, the round goby (Neogobius melanostomus) and rainbow trout (Oncorhynchus mykiss) and compared LC, BLM, and CBR parameters for various organs, as well as behavioural responses (spontaneous activity). In general, round goby were more sensitive. Ni bioaccumulation displayed Michaelis-Menten kinetics in most tissues, and round goby gills had lower Kd (higher binding affinity) but similar Bmax (binding site density) values relative to rainbow trout gills. Round goby also accumulated more Ni than did trout in most tissues at a given exposure concentration. Organ-specific 96 h acute CBR values tended to be higher in round goby but 96 h acute CBR50 and CBR10 values in the gills were very similar in the two species. In contrast, LC50 and LC10 values were significantly higher in rainbow trout. With respect to BLM parameters, gill log KNiBL values for bioaccumulation were higher by 0.4-0.8 log units than the log KNiBL values for toxicity in both species, and both values were higher in goby (more sensitive). Round goby were also more sensitive with respect to the behavioural response, exhibiting a significant decline of 63-75 % in movements per minute at Ni concentrations at and above only 8 % of the LC50 value

  11. Local adaptation despite high gene flow in the waterfall-climbing Hawaiian goby, Sicyopterus stimpsoni.

    PubMed

    Moody, K N; Hunter, S N; Childress, M J; Blob, R W; Schoenfuss, H L; Blum, M J; Ptacek, M B

    2015-02-01

    Environmental heterogeneity can promote the emergence of locally adapted phenotypes among subpopulations of a species, whereas gene flow can result in phenotypic and genotypic homogenization. For organisms like amphidromous fishes that change habitats during their life history, the balance between selection and migration can shift through ontogeny, making the likelihood of local adaptation difficult to predict. In Hawaiian waterfall-climbing gobies, it has been hypothesized that larval mixing during oceanic dispersal counters local adaptation to contrasting topographic features of streams, like slope gradient, that can select for predator avoidance or climbing ability in juvenile recruits. To test this hypothesis, we used morphological traits and neutral genetic markers to compare phenotypic and genotypic distributions in recruiting juveniles and adult subpopulations of the waterfall-climbing amphidromous goby, Sicyopterus stimpsoni, from the islands of Hawai'i and Kaua'i. We found that body shape is significantly different between adult subpopulations from streams with contrasting slopes and that trait divergence in recruiting juveniles tracked stream topography more so than morphological measures of adult subpopulation differentiation. Although no evidence of population genetic differentiation was observed among adult subpopulations, we observed low but significant levels of spatially and temporally variable genetic differentiation among juvenile cohorts, which correlated with morphological divergence. Such a pattern of genetic differentiation is consistent with chaotic genetic patchiness arising from variable sources of recruits to different streams. Thus, at least in S. stimpsoni, the combination of variation in settlement cohorts in space and time coupled with strong postsettlement selection on juveniles as they migrate upstream to adult habitats provides the opportunity for morphological adaptation to local stream environments despite high gene flow.

  12. The Gyrodactylus (Monogenea, Gyrodactylidae) parasite fauna of freshwater sand gobies (Teleostei, Gobioidei) in their centre of endemism, with description of seven new species.

    PubMed

    Vanhove, Maarten P M; Economou, Alcibiades N; Zogaris, Stamatis; Giakoumi, Sofia; Zanella, Davor; Volckaert, Filip A M; Huyse, Tine

    2014-02-01

    While Gobioidei comprises showcases of (adaptive) radiation, the scientific interest they yielded did not ensure full understanding of goby biodiversity. Even in a well-studied region like Europe, wide knowledge gaps remain. Sand gobies represent one of the few clades whose monogenean parasites have been thoroughly studied. However, in the Balkans, part of the sand gobies' centre of endemism, these parasites were unstudied. We focus on Greek and Croatian freshwater gobies. From five sand goby species, the first parasites are reported, describing seven new Gyrodactylus species. Economidichthys pygmaeus harbours Gyrodactylus benedeni sp. n. and Gyrodactylus dorlodoti sp. n. Its congener E. trichonis hosts G. meelkopae sp. n. Knipowitschia milleri was found to host G. charon sp. n., K. thessala is infected by G. bios sp. n., and K. croatica by G. douglasadamsi sp. n. and G. hellemansi sp. n. Gyrodactylus bubyri was found on its type host K. caucasica. A diverse parasite fauna is expected for a region known for its biodiversity and endemism. The contribution of parasites to species richness in such hotspots is overlooked. The observed species richness per host is rather low compared to the better-studied eastern Atlantic sand gobies. Host vicariance is considered to mediate parasite specificity in this fauna. Some new flatworm species display unique morphological features, such as the remarkable size of the marginal hook sickle proper compared to its foot in the Economidichthys parasites, or a characteristically kinked marginal hook sickle in G. douglasadamsi sp. n. These features reflect their hosts' endemism in the Balkans.

  13. From yellow perch to round goby: A review of double-crested cormorant diet and fish consumption at three St. Lawrence River colonies, 1999–2013

    USGS Publications Warehouse

    Johnson, James H.; Farquhar, James F; Klindt, Rodger M; Mazzocchi, Irene; Mathers, Alastair

    2015-01-01

    The number of double-crested cormorants (Phalacrocorax auritus) in the upper St. Lawrence River has increased markedly since the early 1990s. In 1999, a binational study was initiated to examine the annual diet composition and fish consumption of cormorants at colonies in the upper river. Since 1999, 14,032 cormorant pellets, collected from May through September each year, have been examined from St. Lawrence River colonies to estimate fish consumption and determine temporal and spatial variation in diet. Seasonal variation in diet composition within a colony was low. Prior to 2006 yellow perch was the primary fish consumed by cormorants in the upper St. Lawrence River. Round goby were first observed in cormorant diets in 2003 and by 2006 were the main fish consumed at two of the three colonies. The time interval it took from the first appearance of round goby in the diet at a colony to when goby were the dominant prey species varied by island, ranging from two to five years. Daily fish consumption at each cormorant colony increased significantly from the pre-round goby to post-round goby period. The mean annual biomass of yellow perch consumed decreased significantly during the post-round goby period at the three colonies. Reduced consumption of yellow perch by cormorants may alleviate suspected localized impacts on perch near some of the larger river colonies.

  14. Exploring potential effects of cormorant predation on the fish community in Saginaw Bay, Lake Huron

    USGS Publications Warehouse

    DeBruyne, Robin L.; Fielder, David G.; Roseman, Edward; Butchko, Peter H.

    2017-01-01

    Stakeholders and fishery managers expressed concern that double-crested cormorant Phalacrocorax auritus predation may be a factor in the recent poor survival of yellow perch Perca flavescens in Saginaw Bay. We quantified cormorant diets from two nesting colonies in Saginaw Bay during April–September in 2013 and 2014, with special emphasis on impacts to yellow perch. Cormorants (n = 691) were collected when returning to colonies after foraging. Stomachs were removed and preserved in the field. Diet items were identified, enumerated, and measured (n = 23.373). Cormorant diets from Saginaw Bay indicate a heavy reliance on round goby and Notropis species as prey during the breeding season, consistent with other areas of the Great Lakes where round goby and cormorants coincide. Respectively, the three most common prey species observed by number (%) and biomass (%) pooled across years and sites were round goby Neogobius melanostomus (56.6%, 42.1%), emerald shiner Notropis antherinoides (25.2%, 12.5%), and yellow perch (8.0%, 14.1%). Diet composition was more variable at Spoils Island than at Little Charity Island. Overall cormorant consumption (estimated using cormorant consumption demand rates) of yellow perch was compared to walleye consumption. Cormorant consumption of age-1 yellow perch was 13–17% as much as mean walleye consumption of yellow perch in 2013 and 8–11% in 2014. The cumulative effects of walleye and spring cormorant predation likely represent a recruitment bottleneck for yellow perch in Saginaw Bay. Future studies determining age-specific abundance of yellow perch would facilitate better determination of cormorant predation significance.

  15. Characteristics of the disastrous wind-sand environment along railways in the Gobi area of Xinjiang, China

    NASA Astrophysics Data System (ADS)

    Cheng, Jian-jun; Jiang, Fu-qiang; Xue, Chun-xiao; Xin, Guo-wei; Li, Kai-chong; Yang, Yin-hai

    2015-02-01

    Based on detailed long-term data of wind regimes collected from typical ventilation sites along the railways in the Gobi area of Xinjiang, this study systematically analyzes the characteristics of the disastrous wind-sand environment along the railways by combining gradient sand sampling data collected by a wind-drift sand monitoring system and site survey data. Wind direction and speed rose diagrams revealed the prevailing wind direction in each wind area along the railways, and this is the wind direction from which the maximum frequency of sandstorms occurred. Drift potential characteristic parameters (RDP, RDD) and the direction variability (RDP/DP) showed that each wind area along the Gobi railway featured a long wind period, with strong power in a single wind direction. The special geological environment of the Gobi determines the wind-drift sand that features gravel of large grain size and unsaturation, which are different from the wind-drift sand in deserts. With increasing wind velocity, the density of the wind-drift sand increased steadily; however, at a certain critical value, the density surged. This study on the wind-sand environment of the Gobi has significance for railway safety. The critical value of wind velocity corresponded to an abrupt increase in the wind-drift sand density and should be taken into account during the planning process of railway safety passage, since this will lead to a decrease in frontal visual distance, and an associated decrease in safety. Additionally, the specific features of wind-drift sand activities, such as the abruptness and higher than usual sand height, should be considered during the process of designing sand-damage-control engineering measures.

  16. Monitoring the spring-summer surface energy budget transition in the Gobi Desert using AVHRR GAC data. [Global Area Coverage

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.; Reiter, Elmar R.

    1986-01-01

    A research program has been started in which operationally available weather satellites radiance data are used to reconstruct various properties of the diurnal surface energy budget over sites for which detailed estimates of the complete radiation, heat, and moisture exchange process are available. In this paper, preliminary analysis of the 1985 Gobi Desert summer period results is presented. The findings demonstrate various important relationships concerning the feasibility of retrieving the amplitudes of the diurnal surface energy budget processes for daytime and nighttime conditions.

  17. Measurements of the surface energy budget in the southern Gobi Desert of China, and in the Rocky Mountains of Colorado

    NASA Technical Reports Server (NTRS)

    Reiter, E. R.; Smith, E. A.; Sheaffer, J. D.

    1985-01-01

    Observations of the land surface energy balance were made in the Gobi desert and at two mountain sites in northern Colorado. The Gobi study included 12 days of observations in spring (April 8 to 20, 1984) and 31 days in summer at the same site (June 17 to July 18, 1984). The Colorado study included 126 days (March 13 to July 17, 1984) at a valley site and 34 days (July 31 to September 3, 1984) at a mountain top location. The data for each study included continuous observations of upward and downward radiative fluxes in three wave bands, soil temperature and moisture at four levels, air temperature and humidity at four levels and UVW wind components at three levels. Analyses of the Gobi data include definition of the impact of variable atmospheric moisture on the surface energy balance between spring and summer. In addition, diurnal wind circulations forced by heating of the northern edge of the Tibetan Plateau were observed during both periods.

  18. Stream ambient noise, spectrum and propagation of sounds in the goby Padogobius martensii: sound pressure and particle velocity.

    PubMed

    Lugli, Marco; Fine, Michael L

    2007-11-01

    The most sensitive hearing and peak frequencies of courtship calls of the stream goby, Padogobius martensii, fall within a quiet window at around 100 Hz in the ambient noise spectrum. Acoustic pressure was previously measured although Padogobius likely responds to particle motion. In this study a combination pressure (p) and particle velocity (u) detector was utilized to describe ambient noise of the habitat, the characteristics of the goby's sounds and their attenuation with distance. The ambient noise (AN) spectrum is generally similar for p and u (including the quiet window at noisy locations), although the energy distribution of u spectrum is shifted up by 50-100 Hz. The energy distribution of the goby's sounds is similar for p and u spectra of the Tonal sound, whereas the pulse-train sound exhibits larger p-u differences. Transmission loss was high for sound p and u: energy decays 6-10 dB10 cm, and sound pu ratio does not change with distance from the source in the nearfield. The measurement of particle velocity of stream AN and P. martensii sounds indicates that this species is well adapted to communicate acoustically in a complex noisy shallow-water environment.

  19. Increased piscivory by lake whitefish in Lake Huron

    USGS Publications Warehouse

    Pothoven, Steven A.; Madenjian, Charles P.

    2013-01-01

    We evaluated the diet of Lake Whitefish Coregonus clupeaformis in Lake Huron during 2002–2011 to determine the importance of Round Goby Neogobius melanostomus and other fish as prey items. Lake Whitefish that had reached approximately 400 mm in length incorporated fish into their diets. The overall percentage of adult Lake Whitefish in Lake Huron that had eaten fish increased from 10% in 2002–2006 to 20% in 2007–2011, with a corresponding decrease in the frequency of Lake Whitefish that ate Dreissena spp. from 52% to 33%. During 2002–2006, Round Goby (wet mass, 38%), sculpins (Cottidae) (34%), and Ninespine Stickleback Pungitius pungitius (18%) were the primary fish eaten, whereas Round Goby accounted for 92% of the fish eaten in 2007–2011. Overall, Round Goby were found in the fewest Lake Whitefish stomachs in the north region of Lake Huron (6%) and in the most in the central (23%) and south (19%) regions of the lake. In the central region, Round Goby were eaten during all seasons that were sampled (spring through fall). In the south region, Round Goby were eaten only in the winter and spring but not in the summer when Dreissena spp. and spiny water flea Bythotrephes longimanus dominated the diet. Based on the 2007–2011 diet composition, an individual Lake Whitefish would need to have increased their consumption relative to that in 1983–1994 by 6% in the north region, 12% in the central region, and 41% in the southern region in order to achieve the same growth that was observed before dreissenid mussels arrived. However, Lake Whitefish weight adjusted for length only increased by 2% between 2002–2006 and 2007–2011 in the central region, decreased by 4% in the northern region, and remained constant in the southern region. This suggests that a shift toward more frequent piscivory does not necessarily improve the condition of a generalist feeder like Lake Whitefish.

  20. Ozone in the Mongolian Gobi desert: Large-scale concentrations and dry deposition

    NASA Astrophysics Data System (ADS)

    Meixner, Franz X.; Behrendt, Thomas; Ermel, Michael; Hempelmann, Nils; Jöckel, Patrick

    2013-04-01

    For the first time, measurements of surface ozone mixing ratio have been performed from semi-arid steppe to arid/hyper-arid Mongolian Gobi desert. During 12-29 August 2009, ozone mixing ratio was continuously measured from a mobile platform (4x4 Furgon SUV). The survey (3060 km / 229171km2) started at the Mongolian capital Ulaan-Baatar (47.9582°N, 107.0190°E ), heading to south-west (Echin Gol, 43.2586°N, 99.0255°E), eastward to Dalanzadgad (43.6061°N, 104.4445°E), and finally back to Ulaan-Baatar. Ambient air was sampled (approx. 1 L/min) through a 4 m long PTFE-intake line along a forward facing boom mounted on the roof of a 4x4 Furgon SUV. Ozone mixing ratio has been measured by UV-spectroscopy using a mobile dual-cell ozone analyzer (model 205, 2BTechnologies, Boulder, U.S.A.). While ozone signals were measured every 5 seconds, 1 minute averages and standard deviations have been calculated on-line and stored into the data logger. The latter are used to identify and to discriminate against unrealistic low or high ozone mixing ratios which have been due to occasionally passing plumes of vehicle exhaust and/or biomass burning gases, as well as gasoline (at gas filling stations). Even under desert conditions, the temporal behaviour of ozone mixing ratio was characterized by considerable and regular diel variations. Minimum mixing ratios (15-25 ppb) occurred early in the morning (approx. 06:00 local), when surface depletion of ozone (by dry deposition) can not be compensated by supply from the free troposphere due to thermodynamic stability of the nocturnal boundary layer. Late in the afternoon (approx. 17:00 local), under conditions of a turbulently well mixed convective boundary layer, maximum ozone mixing ratios (45-55 ppb) were reached. Daily amplitudes of the diel cycle of ozone mixing ratio were in the order of 30 ppb (steppe), 20 ppb (arid desert), to approx. 5 ppb (hyper-arid Gobi desert (Shargyn Gobi)). Ozone surface measurements were compared to

  1. Mesozoic-Cenozoic Reconstruction of the East Gobi Fault Zone, Southern Mongolia

    NASA Astrophysics Data System (ADS)

    Heumann, M. J.; Johnson, C. L.; Webb, L. E.; Taylor, J. P.

    2009-12-01

    We present reconstructions based on multifaceted sedimentary basin and structural analyses that constrain the timing and character of intracontinental deformation observed in Mesozoic rift sub-basins (Unegt and Zuunbayan) and Permian deposystems (Bulgan Uul and Nomgon) along the East Gobi Fault Zone (EGFZ), southeastern Mongolia. The rocks studied throughout the EGFZ record nearly 300 million years of history including final closure of the paleo Tethys Sea during the Permian, Late Triassic sinistral shearing, Jurassic transpression followed by rift initiation, Early Cretaceous rifting, mid-Cretaceous basin inversion, and early Cenozoic left-lateral strike-slip faulting. Integrated studies of detrital zircon geochronology, field mapping and 2-D seismic survey fault-generation interpretation are critical to unraveling deformational events recorded in the pre-, syn-, and post-rift sedimentary units of these sub-basins. These efforts also shed light on paleogeographic reconstructions for the south Gobi following closure of the paleo Tethys Sea and docking of the North China block in the late Permian. Extensive detrital zircon analyses on 23 sandstone units used as piercing points along the EGFZ to indicate roughly 270 km of total sinistral offset has occurred along the EGFZ since the Late Permian, approximately 90 km of which has occurred since the mid Cretaceous. Therefore ~180 km of left-lateral offset along the EGFZ has occurred in the Triassic and Jurassic periods of deformation and have implications for published tectonic models. Fault generation maps produced from proprietary 2-D seismic reflection surveys, and correlation to outcrop, suggest the localized partitioning of deformation throughout the basins with time, often focusing along basin-bounding faults. Reinterpretation of the available seismic data highlights areas north (e.g., Har Hotol locality) of the main North Zuunbayan strike-slip fault (the NZB fault), which show a strikingly different deformational

  2. Fungal Ferromanganese Mineralisation in Cretaceous Dinosaur Bones from the Gobi Desert, Mongolia.

    PubMed

    Owocki, Krzysztof; Kremer, Barbara; Wrzosek, Beata; Królikowska, Agata; Kaźmierczak, Józef

    2016-01-01

    Well-preserved mycelia of fungal- or saprolegnia-like biota mineralised by ferromanganese oxides were found for the first time in long bones of Late Cretaceous dinosaurs from the Gobi Desert (Nemegt Valley, Mongolia). The mycelia formed a biofilm on the wall of the bone marrow cavity and penetrated the osteon channels of the nearby bone tissue. Optical microscopy, Raman, SEM/EDS, SEM/BSE, electron microprobe and cathodoluminescence analyses revealed that the mineralisation of the mycelia proceeded in two stages. The first stage was early post-mortem mineralisation of the hyphae by Fe/Mn-oxide coatings and microconcretions. Probably this proceeded in a mildly acidic to circumneutral environment, predominantly due to heterotrophic bacteria degrading the mycelial necromass and liberating Fe and Mn sorbed by the mycelia during its lifetime. The second stage of mineralisation, which proceeded much later following the final burial of the bones in an alkaline environment, resulted from the massive precipitation of calcite and occasionally barite on the iron/manganese-oxide-coated mycelia. The mineral phases produced by fungal biofilms colonising the interiors of decaying dinosaur bones not only enhance the preservation (fossilisation) of fungal remains but can also be used as indicators of the geochemistry of the dinosaur burial sites.

  3. Hypoxia-induced mobilization of stored triglycerides in the euryoxic goby Gillichthys mirabilis.

    PubMed

    Gracey, Andrew Y; Lee, Tsung-Han; Higashi, Richard M; Fan, Teresa

    2011-09-15

    Environmental hypoxia is a common challenge that many aquatic organisms experience in their habitat. Responding to hypoxia requires metabolic reprogramming so that energy-demanding processes are regulated to match available energy reserves. In this study we explored the transcriptional control of metabolic reorganization in the liver of a hypoxia-tolerant burrow-dwelling goby, Gillichthys mirabilis. Gene expression data revealed that pathways associated with triglyceride hydrolysis were upregulated by hypoxia whereas pathways associated with triglyceride synthesis were downregulated. This finding was supported by tissue histology, which showed that the size of hepatic lipid droplets declined visibly during exposure to hypoxia. Proton nuclear magnetic resonance analysis confirmed the mobilization of hepatic triglycerides, which declined 2.7-fold after 5 days of hypoxia. The enzyme, adipose triglyceride lipase, was implicated in the mobilization of triglycerides because its expression increased at the level of both transcript and protein. This observation raises questions regarding the regulation of fat metabolism during hypoxia and the role played by the hypoxia-responsive gene leptin.

  4. The first dromaeosaurid (Dinosauria: Theropoda) from the Lower Cretaceous Bayan Gobi Formation of Nei Mongol, China

    PubMed Central

    Pei, Rui; Tan, Qingwei; Xu, Xing

    2015-01-01

    The first dromaeosaurid theropod from the Lower Cretaceous Bayan Gobi Formation is identified based on an incompletely preserved partially-articulated left leg, increasing the known diversity of its understudied ecosystem. The leg belongs to specimen IVPP V22530 and includes a typical deinonychosaurian pedal phalanx II-2 with a distinct constriction between the enlarged proximal end and the distal condyle as well as a typical deinonychosaurian enlarged pedal phalanx II-3. It possesses a symmetric metatarsus and a slender and long MT V that together suggest it is a dromaeosaurid. Two anatomical traits suggest the leg is microraptorine-like, but a more precise taxonomic referral was not possible: metatarsals II, III and IV are closely appressed distally and the ventral margin of the medial ligament pit of phalanx II-2 is close to the centre of the rounded distal condyle. This taxonomic status invites future efforts to discover additional specimens at the study locality because—whether it is a microraptorine or a close relative—this animal is expected to make important contributions to our understanding of dromaeosaurid evolution and biology. IVPP V22530 also comprises of an isolated dromaeosaurid manual ungual, a proximal portion of a right theropod anterior dorsal rib and an indeterminate bone mass that includes a collection of ribs. Neither the rib fragment nor the bone mass can be confidently referred to Dromaeosauridae, although they may very well belong to the same individual to whom the left leg belongs. PMID:26664809

  5. Measuring the Impacts of Community-based Grasslands Management in Mongolia's Gobi

    PubMed Central

    Leisher, Craig; Hess, Sebastiaan; Boucher, Timothy M.; van Beukering, Pieter; Sanjayan, M.

    2012-01-01

    We assessed a donor-funded grassland management project designed to create both conservation and livelihood benefits in the rangelands of Mongolia's Gobi desert. The project ran from 1995 to 2006, and we used remote sensing Normalized Differential Vegetation Index data from 1982 to 2009 to compare project grazing sites to matched control sites before and after the project's implementation. We found that the productivity of project grazing sites was on average within 1% of control sites for the 20 years before the project but generated 11% more biomass on average than the control areas from 2000 to 2009. To better understand the benefits of the improved grasslands to local people, we conducted 280 household interviews, 8 focus group discussions, and 31 key informant interviews across 6 districts. We found a 12% greater median annual income as well as a range of other socioeconomic benefits for project households compared to control households in the same areas. Overall, the project generated measurable benefits to both nature and people. The key factors underlying project achievements that may be replicable by other conservation projects include the community-driven approach of the project, knowledge exchanges within and between communities inside and outside the country, a project-supported local community organizer in each district, and strong community leadership. PMID:22312436

  6. Mate preference in the painted goby: the influence of visual and acoustic courtship signals.

    PubMed

    Amorim, M Clara P; da Ponte, Ana Nunes; Caiano, Manuel; Pedroso, Silvia S; Pereira, Ricardo; Fonseca, Paulo J

    2013-11-01

    We tested the hypothesis that females of a small vocal marine fish with exclusive paternal care, the painted goby, prefer high parental-quality mates such as large or high-condition males. We tested the effect of male body size and male visual and acoustic courtship behaviour (playback experiments) on female mating preferences by measuring time spent near one of a two-choice stimuli. Females did not show preference for male size but preferred males that showed higher levels of courtship, a trait known to advertise condition (fat reserves). Also, time spent near the preferred male depended on male courtship effort. Playback experiments showed that when sound was combined with visual stimuli (a male confined in a small aquarium placed near each speaker), females spent more time near the male associated with courtship sound than with the control male (associated with white noise or silence). Although male visual courtship effort also affected female preference in the pre-playback period, this effect decreased during playback and disappeared in the post-playback period. Courtship sound stimuli alone did not elicit female preference in relation to a control. Taken together, the results suggest that visual and mainly acoustic courtship displays are subject to mate preference and may advertise parental quality in this species. Our results indicate that visual and acoustic signals interplay in a complex fashion and highlight the need to examine how different sensory modalities affect mating preferences in fish and other vertebrates.

  7. Painted Goby Larvae under High-CO2 Fail to Recognize Reef Sounds.

    PubMed

    Castro, Joana M; Amorim, M Clara P; Oliveira, Ana P; Gonçalves, Emanuel J; Munday, Philip L; Simpson, Stephen D; Faria, Ana M

    2017-01-01

    Atmospheric CO2 levels have been increasing at an unprecedented rate due to anthropogenic activity. Consequently, ocean pCO2 is increasing and pH decreasing, affecting marine life, including fish. For many coastal marine fishes, selection of the adult habitat occurs at the end of the pelagic larval phase. Fish larvae use a range of sensory cues, including sound, for locating settlement habitat. This study tested the effect of elevated CO2 on the ability of settlement-stage temperate fish to use auditory cues from adult coastal reef habitats. Wild late larval stages of painted goby (Pomatoschistus pictus) were exposed to control pCO2 (532 μatm, pH 8.06) and high pCO2 (1503 μatm, pH 7.66) conditions, likely to occur in nearshore regions subjected to upwelling events by the end of the century, and tested in an auditory choice chamber for their preference or avoidance to nighttime reef recordings. Fish reared in control pCO2 conditions discriminated reef soundscapes and were attracted by reef recordings. This behaviour changed in fish reared in the high CO2 conditions, with settlement-stage larvae strongly avoiding reef recordings. This study provides evidence that ocean acidification might affect the auditory responses of larval stages of temperate reef fish species, with potentially significant impacts on their survival.

  8. Transition of surface energy budget in the Gobi Desert between spring and summer seasons

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.; Reiter, Elmar R.; Gao, Youxi

    1986-01-01

    The surface energetics of the southwest Gobi Desert, including the temporal variations and diurnally averaged properties of the surface energy budget components, was investigated. The field program was conducted during the spring and summer of 1984, with the measurement system designed to monitor radiative exchange, heat/moisture storage in the soil, and sensible and latent heat exhange between the ground and the atmosphere. Results of the analysis reveal a seasonal transition feature not expected of a midlatitude desert. Namely, the differences in both surface radiation exchange and the distibution of sensible and latent heat transfer arise within a radiatively forced environment that barely deviates from spring to summer in terms of available solar energy at the surface. Both similarities and differences in the spring and summer surface energy budgets arise from differences imparted to the system by an increase in the summertime atmospheric moisture content. Changes in the near-surface mixing ratio are shown to alter the effectiveness of the desert surface in absorbing radiative energy and redistibuting it to the lower atmosphere through sensible and latent heat exchange.

  9. Age and growth of the common goby, Pomatoschistus microps, on the south coast of England

    NASA Astrophysics Data System (ADS)

    Fouda, M. M.; Miller, P. J.

    1981-02-01

    Seasonal changes in scale appearance and body growth pattern have been studied in a Teign Estuary (Devon) population of the common goby, Pomatoschistus microps (Kroyer), with additional material from St. Anthony, on Gillan Harbour, Cornwall. Examination of caudal peduncle scales showed similarity in annulus formation with other populations earlier investigated around the British Isles. The time of scale annulus formation in the Teign estuary was established from monthly changes in mean terminal sclerite width. After the first winter of life, an annulus of narrow sclerites is produced on resumption of growth in spring, and a second annulus laid down in summer between early June and August, corresponding to growth retardation during the peak of the long breeding season (April to August). The growth pattern shows a period of rapid growth in immature fish during the first summer and early autumn of life and declines or ceases in late autumn and winter. Vigorous resumption of growth in spring and early summer is followed by a decline in growth rate during the peak breeding season, and then growth recovery in September and October. Change in monthly mean terminal sclerite width of scales reflects somewhat earlier changes in somatic growth. Back-calculated growth suggests a static population during the breeding season. Various influences on growth are noted, including reproduction and scale regeneration.

  10. Evolution of mating systems in coral reef gobies and constraints on mating system plasticity

    NASA Astrophysics Data System (ADS)

    Hernaman, V.; Munday, P. L.

    2007-09-01

    Social and mating systems can be influenced by the distribution, abundance, and economic defendability of breeding partners and essential resources. Polygyny is predicted where males can economically defend multiple females or essential resources used by females. In contrast, monogamy is predicted where neither sex can monopolise multiple partners, either directly or through resource control, but where one mate is economically defendable. The mating system and reproductive behaviour of five species of coral reef goby were investigated and contrasted with population density and individual mobility. The two most abundant species ( Asterropteryx semipunctatus and Istigobius goldmanni) were polygynous. In contrast, the less populous and more widely dispersed epibenthic species ( Amblygobius bynoensis, Amblygobius phalaena and Valenciennea muralis) were pair forming and monogamous. All five species had low mobility, mostly remaining within metres (3 epibenthic species) or centimetres (2 cryptobenthic species) of a permanent shelter site. Interspecific differences in the mating system may have been shaped by differences in population density and the ability of reproductive individuals to economically defend breeding partners/sites. However, in a test of mating system plasticity, males of the three monogamous species did not mate polygynously when given the opportunity to do so in experimental manipulations of density and sex ratio. Mate guarding and complex spawning characteristics, which have likely co-evolved with the monogamous mating system, could contribute to mating system inflexibility by making polygynous mating unprofitable for individuals of the pair forming species, even when presented with current-day ecological conditions that usually favour polygyny.

  11. Painted Goby Larvae under High-CO2 Fail to Recognize Reef Sounds

    PubMed Central

    Castro, Joana M.; Amorim, M. Clara P.; Oliveira, Ana P.; Gonçalves, Emanuel J.; Munday, Philip L.; Simpson, Stephen D.

    2017-01-01

    Atmospheric CO2 levels have been increasing at an unprecedented rate due to anthropogenic activity. Consequently, ocean pCO2 is increasing and pH decreasing, affecting marine life, including fish. For many coastal marine fishes, selection of the adult habitat occurs at the end of the pelagic larval phase. Fish larvae use a range of sensory cues, including sound, for locating settlement habitat. This study tested the effect of elevated CO2 on the ability of settlement-stage temperate fish to use auditory cues from adult coastal reef habitats. Wild late larval stages of painted goby (Pomatoschistus pictus) were exposed to control pCO2 (532 μatm, pH 8.06) and high pCO2 (1503 μatm, pH 7.66) conditions, likely to occur in nearshore regions subjected to upwelling events by the end of the century, and tested in an auditory choice chamber for their preference or avoidance to nighttime reef recordings. Fish reared in control pCO2 conditions discriminated reef soundscapes and were attracted by reef recordings. This behaviour changed in fish reared in the high CO2 conditions, with settlement-stage larvae strongly avoiding reef recordings. This study provides evidence that ocean acidification might affect the auditory responses of larval stages of temperate reef fish species, with potentially significant impacts on their survival. PMID:28125690

  12. Groundwater storage changes from GRACE satellite in the Southern Gobi Region of Mongolia

    NASA Astrophysics Data System (ADS)

    Nemer, B.; Yanping, C.; Bayanzul, B. B.; Altangerel, E. E.

    2014-12-01

    Groundwater is an important resource in the Southern Gobi Region of Mongolia because rainfall and surface water availability are severely limited and the demands are expected to increase rapidly with the development of mining and new population centers. Groundwater systems are more complex and yet its distribution and quantity are poorly known. The purpose of the research is to evaluate the potential utility of GRACE (Gravity Recovery and Climate Experiment) satellites to monitor groundwater storage in the arid area. Regional groundwater storage changes in SGR are estimated using monthly GRACE total water storage change data. Groundwater storage change estimates are compared to groundwater level measurements of 66 shallow dug wells and 72 deep boreholes for the period 2004-2012. Groundwater storage decreases during the cold season and increases during the warm season. Seasonal groundwater change calculated from GRACE total water storage is highly correlated to groundwater level measurements in shallow aquifers. There is no correlation between groundwater storage changes derived from GRACE and deep aquifer. The result indicates that GRACE can be used to monitor large area where groundwater observation is limited, especially unconfined shallow aquifers.

  13. Fungal Ferromanganese Mineralisation in Cretaceous Dinosaur Bones from the Gobi Desert, Mongolia

    PubMed Central

    Wrzosek, Beata; Królikowska, Agata

    2016-01-01

    Well-preserved mycelia of fungal- or saprolegnia-like biota mineralised by ferromanganese oxides were found for the first time in long bones of Late Cretaceous dinosaurs from the Gobi Desert (Nemegt Valley, Mongolia). The mycelia formed a biofilm on the wall of the bone marrow cavity and penetrated the osteon channels of the nearby bone tissue. Optical microscopy, Raman, SEM/EDS, SEM/BSE, electron microprobe and cathodoluminescence analyses revealed that the mineralisation of the mycelia proceeded in two stages. The first stage was early post-mortem mineralisation of the hyphae by Fe/Mn-oxide coatings and microconcretions. Probably this proceeded in a mildly acidic to circumneutral environment, predominantly due to heterotrophic bacteria degrading the mycelial necromass and liberating Fe and Mn sorbed by the mycelia during its lifetime. The second stage of mineralisation, which proceeded much later following the final burial of the bones in an alkaline environment, resulted from the massive precipitation of calcite and occasionally barite on the iron/manganese-oxide-coated mycelia. The mineral phases produced by fungal biofilms colonising the interiors of decaying dinosaur bones not only enhance the preservation (fossilisation) of fungal remains but can also be used as indicators of the geochemistry of the dinosaur burial sites. PMID:26863014

  14. Hidden faults in the Gobi Desert (Inner Mongolia, China) revealed by microtremor analysis, ground-penetrating radar and SQUID-supported transient electromagnetics

    NASA Astrophysics Data System (ADS)

    Rudersdorf, Andreas; Hölz, Sebastian; Torgoev, Almaz; Havenith, Hans-Balder; Reicherter, Klaus

    2013-04-01

    The endorheic Gaxun Nur Basin (GNB, also Ejina Basin, Hei river Basin, Ruoshui Basin) in the eastern Gobi desert is situated between the northern Tibetan Plateau and the Gobi Altai mountains. Recent fault activity is concentrated on the sinistral Altyn Tagh Fault, its eastern continuations and the Qilian Shan frontal thrust in the south, which are induced by the stress field of the India-Eurasia continental collision. In the north, the basin is bound by the Gobi Altai mountains with the major sinistral Gobi-Tien Shan Fault System. The basin is dominated by a very flat topography, active alluvial sedimentation from the south and eolian erosion by northwesterly winds. The basin formation and basement structure is poorly known. The sedimentary succession of up to 300 m thickness comprises intercalations of alluvial fan deposits, dune sands, lake sediments and playa evaporites. The latter tend to concentrate in the northern part of the basin, where the basin is limited by the Gobi Altai mountains. The top of the diversified successions and the Gobi surface itself is covered by gravels. Instrumental seismicity and paleoseismic records are rather low and earlier tectonic and paleoseismological investigations are sparse. We, therefore, conducted microtremor analyses and transient electromagnetics with a liquid nitrogen cooled SQUID magnetometer to reveal basement-basin interaction structures; ground-penetrating radar surveys were also carried out to investigate shallow reworking processes. First results show connections between subsurface data and a large-scale (>20 km long) lineament fingerprint from remote sensing studies. Here, we focus on a NW-SE striking lineament west of the city of Ejina, which shows only minor topographic evidence for fault activity. An earlier drill core nearby resulted in dating irregularities in the upper 60m, which are believed to be related to the lineament. Microtremor analysis shows a significant offset of the basement topography and ground

  15. A New Species of the Bay Goby Genus Eucyclogobius, Endemic to Southern California: Evolution, Conservation, and Decline

    PubMed Central

    Swift, Camm C.; Spies, Brenton; Ellingson, Ryan A.; Jacobs, David K.

    2016-01-01

    A geographically isolated set of southern localities of the formerly monotypic goby genus Eucyclogobius is known to be reciprocally monophyletic and substantially divergent in mitochondrial sequence and nuclear microsatellite-based phylogenies relative to populations to the north along the California coast. To clarify taxonomic and conservation status, we conducted a suite of analyses on a comprehensive set of morphological counts and measures from across the range of Eucyclogobius and describe the southern populations as a new species, the Southern Tidewater Goby, Eucyclogobius kristinae, now separate from the Northern Tidewater Goby Eucyclogobius newberryi (Girard 1856). In addition to molecular distinction, adults of E. kristinae are diagnosed by: 1) loss of the anterior supratemporal lateral-line canals resulting in higher neuromast counts, 2) lower pectoral and branched caudal ray counts, and 3) sets of measurements identified via discriminant analysis. These differences suggest ecological distinction of the two species. Previous studies estimated lineage separation at 2–4 million years ago, and mitochondrial sequence divergence exceeds that of other recognized fish species. Fish from Santa Monica Artesian Springs (Los Angeles County) northward belong to E. newberryi; those from Aliso Creek (Orange County) southward constitute E. kristinae. The lagoonal habitat of Eucyclogobius has been diminished or degraded, leading to special conservation status at state and federal levels beginning in 1980. Habitat of the newly described species has been impacted by a range of anthropogenic activities, including the conversion of closing lagoons to open tidal systems in the name of restoration. In the last 30 years, E. kristinae has only been observed in nine intermittently occupied lagoonal systems in northern San Diego County; it currently persists in only three sites. Thus, the new species is in imminent danger of extinction and will require ongoing active management

  16. Observational study of surface spectral radiation and corresponding albedo over Gobi, desert, and bare loess surfaces in northwestern China

    NASA Astrophysics Data System (ADS)

    Zheng, Z.; Dong, W.; Li, Z.; Zhao, W.; Hu, S.; Yan, X.; Zhao, J.; Wei, Z.

    2015-12-01

    In this paper, the field experiments on ground surface spectral broadband solar radiation (SR) and corresponding albedo were introduced at three man-made sites at Gobi, desert, and bare loess zones during three different intensive observational periods (IOP) from 2010 to 2013 in Gansu Province, respectively. The continuous and high temporal resolution records of ground surface solar radiation are presented, including global (GR), ultraviolet (UV), visible (VIS), and near-infrared radiation (NIR). The corresponding albedos are analyzed over three typical non-vegetated underlying surfaces in arid and semiarid and semihumid regions of northwestern China. The preliminary investigations were carried out. The results show that the variation trends of UV, VIS, and NIR are coincident with the GR, and the irradiances are gradually decreasing throughout the IOP at each site; the energy ratios of VIS/GR are all approximately 40.2%, and the ratios of NIR/GR are all approximately 54.4% at the Gobi, desert, and bare loess zones; and the averaged albedos of the soil for VIS are 0.231, 0.211, and 0.142 and for the NIR are 0.266, 0.252, and 0.255 over the Gobi, desert, and bare loess land surfaces, respectively. The energy ratios of VIS/GR and NIR/GR are not 50% as prescribed for all of the soil color classes in most of land surface models (LSMs). The observational soil albedo values for NIR are not twice to that of the VIS as predicted in some LSMs for the underlying surface at the three sites. GR albedo is determined by the energy ratios of SR/GR and SR albedos.

  17. Observational study of surface spectral radiation and corresponding albedo over Gobi, desert, and bare loess surfaces in northwestern China

    NASA Astrophysics Data System (ADS)

    Zheng, Zhiyuan; Dong, Wenjie; Li, Zhenchao; Zhao, Wei; Hu, Shanshan; Yan, Xiaodong; Zhao, Jiaqi; Wei, Zhigang

    2015-02-01

    In this paper, the field experiments on ground surface spectral broadband solar radiation (SR) and corresponding albedo were introduced at three man-made sites at Gobi, desert, and bare loess zones during three different intensive observational periods (IOP) from 2010 to 2013 in Gansu Province, respectively. The continuous and high temporal resolution records of ground surface solar radiation are presented, including global (GR), ultraviolet (UV), visible (VIS), and near-infrared radiation (NIR). The corresponding albedos are analyzed over three typical nonvegetated underlying surfaces in arid and semiarid and semihumid regions of northwestern China. The preliminary investigations were carried out. The results show that the variation trends of UV, VIS, and NIR are coincident with the GR, and the irradiances are gradually decreasing throughout the IOP at each site; the energy ratios of VIS/GR are all approximately 40.2%, and the ratios of NIR/GR are all approximately 54.4% at the Gobi, desert, and bare loess zones; and the averaged albedos of the soil for VIS are 0.231, 0.211, and 0.142 and for the NIR are 0.266, 0.252, and 0.255 over the Gobi, desert, and bare loess land surfaces, respectively. The energy ratios of VIS/GR and NIR/GR are not 50% as prescribed for all of the soil color classes in most of land surface models (LSMs). The observational soil albedo values for NIR are not twice to that of the VIS as predicted in some LSMs for the underlying surface at the three sites. GR albedo is determined by the energy ratios of SR/GR and SR albedos.

  18. Angler-caught piscivore diets reflect fish community changes in Lake Huron

    USGS Publications Warehouse

    Roseman, Edward F.; Schaeffer, Jeff; Bright, Ethan; Fielder, David G.

    2014-01-01

    Examination of angler-caught piscivore stomachs revealed that Lake Trout Salvelinus namaycush, Chinook Salmon Oncorhynchus tshawytscha, and Walleyes Sander vitreus altered theirdiets in response to unprecedented declines in Lake Huron's main-basin prey fish community.Diets varied by predator species, season, and location but were nearly always dominated numerically by some combination of Alewife Alosa pseudoharengus, Rainbow Smelt Osmerus mordax, Emerald Shiner Notropis atherinoides, Round Goby Neogobius melanostomus, or terrestrial insects. Rainbow Trout Oncorhynchus mykiss (steelhead), Coho Salmon Oncorhynchus kisutch, and Atlantic Salmon Salmo salar had varied diets that reflected higher contributions of insects. Compared with an earlier (1983–1986) examination of angler-caught predator fishes from Lake Huron, the contemporary results showed an increase in consumption of nontraditional prey (including conspecifics), use of smaller prey, and an increase in insects in the diet, suggesting that piscivores were faced with chronic prey limitation during this study. The management of all piscivores in Lake Huron will likely require consideration of the pervasive effects of changes in food webs, especially if prey fish remain at low levels.

  19. Evidence that sea lamprey control led to recovery of the burbot population in Lake Erie

    USGS Publications Warehouse

    Stapanian, M.A.; Madenjian, C.P.; Witzel, L.D.

    2006-01-01

    Between 1987 and 2003, the abundance of burbot Lota lota in eastern Lake Erie increased significantly, especially in Ontario waters. We considered four hypotheses to explain this increase: (1) reduced competition with lake trout Salvelinus namaycush, the other major coldwater piscivore in Lake Erie; (2) increased abundance of the two main prey species, rainbow smelt Osmerus mordax and round goby Neogobius melanostomus; (3) reduced interference with burbot reproduction by alewives Alosa pseudoharengus; and (4) reduced predation by sea lampreys Petromyzon marinus on burbot. Species abundance data did not support the first three hypotheses. Our results suggested that the apparent recovery of the burbot population of Lake Erie was driven by effective sea lamprey control. Sea lamprey predation appeared to be the common factor affecting burbot abundance in Lakes Michigan, Huron, Erie, and Ontario. In addition, relatively high alewife density probably depressed burbot abundance in Lakes Ontario and Michigan. We propose that a healthy adult lake trout population may augment burbot recovery in some lakes by serving as a buffer against sea lamprey predation and will not negatively impact burbot through competition.

  20. Diet of lake trout and burbot in northern Lake Michigan during spring: Evidence of ecological interaction

    USGS Publications Warehouse

    Jacobs, Gregory R.; Madenjian, Charles P.; Bunnell, David B.; Holuszko, Jeffrey D.

    2010-01-01

    We used analyses of burbot (Lota lota) and lake trout (Salvelinus namaycush) diets taken during spring gill-net surveys in northern Lake Michigan in 2006-2008 to investigate the potential for competition and predator-prey interactions between these two species. We also compared our results to historical data from 1932. During 2006-2008, lake trout diet consisted mainly of alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax), whereas burbot utilized a much wider prey base including round goby (Neogobius melanostomus), rainbow smelt, alewives, and sculpins. Using the Schoener's diet overlap index, we found a higher potential for interspecific competition in 1932 than in 2006-2008, though diet overlap was not significant in either time period. No evidence of cannibalism by lake trout or lake trout predation on burbot was found in either time period. In 2006-2008, however, lake trout composed 5.4% (by weight) of burbot diet. To determine whether this predation could be having an impact on lake trout rehabilitation efforts in northern Lake Michigan, we developed a bioenergetic-based consumption estimate for burbot on Boulder Reef (a representative reef within the Northern Refuge) and found that burbot alone can consume a considerable proportion of the yearling lake trout stocked annually, depending on burbot density. Overall, we conclude that predation, rather than competition, is the more important ecological interaction between burbot and lake trout, and burbot predation may be contributing to the failed lake trout rehabilitation efforts in Lake Michigan.

  1. Regional differences in size-at-age of the recovering burbot (Lota lota) population in Lake Erie

    USGS Publications Warehouse

    Stapanian, M.A.; Madenjian, C.P.; Tost, J.

    2007-01-01

    The burbot Lota lota population in Lake Erie increased dramatically between 1995 and 2003, due mainly to control of the sea lamprey Petromyzon marinus, which began in the late 1980s. We estimated total length- and weight-at-age at capture for burbot caught in annual gillnet surveys of eastern Lake Erie during August 1994–2003. Mean total length was generally greater for burbot age 4–9 years that were caught in New York waters than in either Ontario or Pennsylvania waters of Lake Erie. Similarly, mean weight was greater for burbot at ages 4 through 6 years in New York waters than in either Ontario or Pennsylvania waters. Age-9 burbot caught in Ontario waters had greater mean weight and mean total length than did age-9 burbot caught in Pennsylvania waters. One possible explanation for greater length- and weight-at-age for New York burbot may be greater abundance of prey fishes, particularly rainbow smelt Osmerus mordax and round goby Neogobius melanostomus in New York waters. Total lengths at ages 4–10 years were generally greater for burbot caught in Lake Erie during 1994–2003 than those from published studies of other large lakes in North America that we considered, including for Lake Erie in 1946. The regional differences in size-at-age have important management ramifications, particularly because a commercial fishery targeting burbot has been considered for Ontario waters of Lake Erie.

  2. Impacts of aquatic nonindigenous invasive species on the Lake Erie ecosystem

    USGS Publications Warehouse

    Austen, Madeline J.W.; Ciborowski, Jan J.H.; Corkum, Lynda D.; Johnson, Tim B.; MacIsaac, Hugh J.; Metcalfe-Smith, Janice L.; Schloesser, Donald W.; George, Sandra E.

    2002-01-01

    Lake Erie is particularly vulnerable to the introduction and establishment of aquatic nonindigenous invasive species (NIS) populations. A minimum of 144 aquatic NIS have been recorded in the Lake Erie basin including several species [e.g., Eurasian watermilfoil (Myriophyllum spicatum); zebra mussel (Dreissena polymorpha); quagga mussel (Dreissena bugensis); an amphipod (Echinogammarus ischnus); round goby (Neogobius melanostomus); and sea lamprey (Petromyzon marinus)] that have had discernible impacts on the lake's ecology. NIS pose threats to the Lake Erie ecosystem for a variety of reasons including their ability to proliferate quickly, compete with native species, and transfer contaminants (e.g., PCBs) and disease through the food web. Six of the 14 beneficial use impairments listed in Annex 2 of the Great Lakes Water Quality Agreement are impaired in Lake Erie, in part as a result of the introduction of NIS. The Lake Erie Lakewide Management Plan (LaMP) has adopted an ecosystem approach to restore beneficial use impairments in the lake. Furthermore, a research consortium, known as the Lake Erie Millennium Network, is working alongside the LaMP, to address research problems regarding NIS, the loss of habitat, and the role of contaminants in the Lake Erie ecosystem.

  3. In situ exposure to wastewater effluent reduces survival but has little effect on the behaviour or physiology of an invasive Great Lakes fish.

    PubMed

    McCallum, Erin S; Du, Sherry N N; Vaseghi-Shanjani, Maryam; Choi, Jasmine A; Warriner, Theresa R; Sultana, Tamanna; Scott, Graham R; Balshine, Sigal

    2017-03-01

    Treated effluents from wastewater treatment plants (WWTP) are a significant source of anthropogenic contaminants, such as pharmaceuticals, in the aquatic environment. Although our understanding of how wastewater effluent impacts fish reproduction is growing, we know very little about how effluent affects non-reproductive physiology and behaviours associated with fitness (such as aggression and activity). To better understand how fish cope with chronic exposure to wastewater effluent in the wild, we caged round goby (Neogobius melanostomus) for three weeks at different distances from a wastewater outflow. We evaluated the effects of this exposure on fish survival, behaviour, metabolism, and respiratory traits. Fish caged inside the WWTP and close to the outfall experienced higher mortality than fish from the reference site. Interestingly, those fish that survived the exposure performed similarly to fish caged at the reference site in tests of aggressive behaviour, startle-responses, and dispersal. Moreover, the fish near WWTP outflow displayed similar resting metabolism (O2 consumption rates), hypoxia tolerance, haemoglobin concentration, haematocrit, and blood-oxygen binding affinities as the fish from the more distant reference site. We discuss our findings in relation to exposure site water quality, concentrations of pharmaceutical and personal care product pollutants, and our test species tolerance.

  4. Deepwater demersal fish community collapse in Lake Huron

    USGS Publications Warehouse

    Riley, S.C.; Roseman, E.F.; Nichols, S.J.; O'Brien, T. P.; Kiley, C.S.; Schaeffer, J.S.

    2008-01-01

    Long-term fish community surveys were carried out in the Michigan waters of Lake Huron using bottom trawls from 1976 to 2006. Trends in abundance indices for common species (those caught in 10% or more of trawl tows) were estimated for two periods: early (1976-1991) and late (1994-2006). All common species significantly decreased in abundance during the late period with the exception of the johnny darter Etheostoma nigrum and spottail shiner Notropis hudsonius, which showed no significant trends, and the round goby Neogobius melanostomus, which increased in abundance. Percentage decreases in abundance indices between 1994-1995 and 2005-2006 ranged from 66.4% to 99.9%, and seven species decreased in abundance by more than 90%. The mean biomass of all common species in 2006 was the lowest observed in the time series and was less than 5% of that observed in the mid-1990s. The mean number of common species captured per trawl has also decreased since the mid-1990s. Several factors, including recent invasion of the lake by multiple exotic species, may have contributed to these declines, but insufficient published data are currently available to determine which factors are most important. Our observations suggest that significant changes have occurred in the ecology of Lake Huron since the mid-1990s. The extent of these changes indicates that the deepwater demersal fish community in Lake Huron is undergoing collapse.

  5. Predation on walleye eggs by fish on reefs in western Lake Erie

    USGS Publications Warehouse

    Roseman, E.F.; Taylor, W.W.; Hayes, D.B.; Jones, A.L.; Francis, J.T.

    2006-01-01

    We examined diets of fishes from gillnet and egg pump collections conducted on reefs in western Lake Erie during walleye (Sander vitreus) egg incubation periods from 1994–1999 and 2004 to assess incidence of walleye eggs in fish diets. We collected no potential egg predators in samples taken in 1994 but from 1995–1999 and in 2004 we caught 22 different species of fish on reefs in addition to spawning walleye. In most years, white perch (Morone americana) stomachs contained more walleye eggs than any other species on the reefs averaging 253 eggs per stomach. We also found lower numbers of walleye eggs in the stomachs of channel catfish (Ictalurus punctatus; 53 eggs/stomach), johnny darter (Etheostoma nigrum; 2 eggs/stomach), logperch (Percina caprodes; 10 eggs/stomach), quillback (Carpiodes cyprinus; 184 eggs/stomach), rock bass (Ambloplites rupestris; 3 eggs/stomach), round goby (Neogobius melanostomus; 4 eggs/stomach), sculpin (Cottidae; 21 eggs/stomach), silver chub (Macrhybopsis storeriana; 3 eggs/stomach), spottail shiner (Notropis hudsonius; 14 eggs/stomach), trout-perch (Percopsis omiscomaycus; 30 eggs/stomach), white sucker (Catastomus commersonii; 20 eggs/stomach), and yellow perch (Perca flavescens; 181 eggs/stomach). Similar to other studies of predation on walleye eggs, our results indicate that prolonged incubation periods increase the potential for egg loss due to predation.

  6. Dreissenid mussels are not a "dead end" in Great Lakes food webs

    USGS Publications Warehouse

    Madenijan, Charles P.; Pothoven, Steven A.; Schneeberger, Philip J.; Ebener, Mark P.; Mohr, Lloyd C.; Nalepa, Thomas F.; Bence, James R.

    2010-01-01

    Dreissenid mussels have been regarded as a “dead end” in Great Lakes food webs because the degree of predation on dreissenid mussels, on a lakewide basis, is believed to be low. Waterfowl predation on dreissenid mussels in the Great Lakes has primarily been confined to bays, and therefore its effects on the dreissenid mussel population have been localized rather than operating on a lakewide level. Based on results from a previous study, annual consumption of dreissenid mussels by the round goby (Neogobius melanostomus) population in central Lake Erie averaged only 6 kilotonnes (kt; 1 kt = one thousand metric tons) during 1995–2002. In contrast, our coupling of lake whitefish (Coregonus clupeaformis) population models with a lake whitefish bioenergetics model revealed that lake whitefish populations in Lakes Michigan and Huron consumed 109 and 820 kt, respectively, of dreissenid mussels each year. Our results indicated that lake whitefish can be an important predator on dreissenid mussels in the Great Lakes, and that dreissenid mussels do not represent a “dead end” in Great Lakes food webs. The Lake Michigan dreissenid mussel population has been estimated to be growing more than three times faster than the Lake Huron dreissenid mussel population during the 2000s. One plausible explanation for the higher population growth rate in Lake Michigan would be the substantially higher predation rate by lake whitefish on dreissenid mussels in Lake Huron.

  7. Ecology and population status of trout-perch (Percopsis omiscomaycus) in western Lake Erie

    USGS Publications Warehouse

    Kocovsky, Patrick; Stoneman, Andrea T.; Kraus, Richard T.

    2014-01-01

    Trout-perch Percopsis omiscomaycus is among the most abundant benthic species in Lake Erie, but comparatively little is known about its ecology. Although others have conducted extensive studies on trout-perch ecology, those efforts predated invasions of white perch Morone americana, Dreissena spp., Bythotrephes longimanus and round goby Neogobius melanostomus, suggesting the need to revisit past work. Trout-perch were sampled with bottom trawls at 56 sites during June and September 2010. We examined diets, fecundity, average annual mortality, sex ratio, and long-term population trends at sites sampled since 1961. Trout-perch abundance fluctuated periodically, with distinct shorter- (4-year) and longer-term (over period of 50 years) fluctuations. Males had higher average annual mortality than females. Both sexes were equally abundant at age 0, but females outnumbered males 4:1 by age 2. Diets of trout-perch were dominated by macroinvertebrates, particularly chironomids and Hexagenia sp. Size distributions of trout-perch eggs varied widely and exhibited multiple modes indicative of protracted batch spawning. A review of the few other studies of trout-perch revealed periodic fluctuations in sex ratio of adults, which in light of our evidence of periodicity in abundance suggests the potential for sex-ratio-mediated intrinsic population regulation. Despite the introduction of numerous invasive species in Lake Erie, trout-perch remain one of the most abundant benthic invertivores and the population is relatively stable.

  8. Lake Michigan offshore ecosystem structure and food web changes from 1987 to 2008

    USGS Publications Warehouse

    Rogers, Mark W.; Bunnell, David B.; Madenjian, Charles P.; Warner, David M.

    2014-01-01

    Ecosystems undergo dynamic changes owing to species invasions, fisheries management decisions, landscape modifications, and nutrient inputs. At Lake Michigan, new invaders (e.g., dreissenid mussels (Dreissena spp.), spiny water flea (Bythotrephes longimanus), round goby (Neogobius melanostomus)) have proliferated and altered energy transfer pathways, while nutrient concentrations and stocking rates to support fisheries have changed. We developed an ecosystem model to describe food web structure in 1987 and ran simulations through 2008 to evaluate changes in biomass of functional groups, predator consumption, and effects of recently invading species. Keystone functional groups from 1987 were identified as Mysis, burbot (Lota lota), phytoplankton, alewife (Alosa pseudoharengus), nonpredatory cladocerans, and Chinook salmon (Oncorhynchus tshawytscha). Simulations predicted biomass reductions across all trophic levels and predicted biomasses fit observed trends for most functional groups. The effects of invasive species (e.g., dreissenid grazing) increased across simulation years, but were difficult to disentangle from other changes (e.g., declining offshore nutrient concentrations). In total, our model effectively represented recent changes to the Lake Michigan ecosystem and provides an ecosystem-based tool for exploring future resource management scenarios.

  9. Ensemble forecasting of potential habitat for three invasive fishes

    USGS Publications Warehouse

    Poulos, Helen M.; Chernoff, Barry; Fuller, Pam L.; Butman, David

    2012-01-01

    Aquatic invasive species pose major ecological and economic threats to aquatic ecosystems worldwide via displacement, predation, or hybridization with native species and the alteration of aquatic habitats and hydrologic cycles. Modeling the habitat suitability of alien aquatic species through spatially explicit mapping is an increasingly important risk assessment tool. Habitat modeling also facilitates identification of key environmental variables influencing invasive species distributions. We compared four modeling methods to predict the potential continental United States distributions of northern snakehead Channa argus (Cantor, 1842), round goby Neogobius melanostomus (Pallas, 1814), and silver carp Hypophthalmichthys molitrix (Valenciennes, 1844) using maximum entropy (Maxent), the genetic algorithm for rule set production (GARP), DOMAIN, and support vector machines (SVM). We used inventory records from the USGS Nonindigenous Aquatic Species Database and a geographic information system of 20 climatic and environmental variables to generate individual and ensemble distribution maps for each species. The ensemble maps from our study performed as well as or better than all of the individual models except Maxent. The ensemble and Maxent models produced significantly higher accuracy individual maps than GARP, one-class SVMs, or DOMAIN. The key environmental predictor variables in the individual models were consistent with the tolerances of each species. Results from this study provide insights into which locations and environmental conditions may promote the future spread of invasive fish in the US.

  10. Revising the distribution of a threatened goby, Apocryptodon punctatus (Perciformes, Oxudercidae), in Japan with the discovery of an isolated population

    PubMed Central

    Murase, Atsunobu; Inui, Ryutei; Miki, Ryohei; Miyazaki, Yusuke

    2017-01-01

    Abstract Five specimens of a threatened goby, Apocryptodon punctatus (21.2–40.1 mm in standard length), were collected at a mudflat site of Kushima City, Miyazaki Prefecture, Kyushu, southern Japan over two seasons, autumn (September 2015) and spring (April 2016). A review of distributional records of Apocryptodon punctatus revealed that this population represents the southernmost record of the species in Japanese waters, and is isolated ca. 200 km south-southwest from the nearest point of the main range of the species along the Pacific coast of Japan. Publicising this population will help conserve it and its vulnerable habitat. PMID:28228668

  11. Proteomic analysis of cardiac response to thermal acclimation in the eurythermal goby fish Gillichthys mirabilis.

    PubMed

    Jayasundara, Nishad; Tomanek, Lars; Dowd, W Wesley; Somero, George N

    2015-05-01

    Cardiac function is thought to play a central role in determining thermal optima and tolerance limits in teleost fishes. Investigating proteomic responses to temperature in cardiac tissues may provide insights into mechanisms supporting the thermal plasticity of cardiac function. Here, we utilized a global proteomic analysis to investigate changes in cardiac protein abundance in response to temperature acclimation (transfer from 13°C to 9, 19 and 26°C) in a eurythermal goby, Gillichthys mirabilis. Proteomic data revealed 122 differentially expressed proteins across acclimation groups, 37 of which were identified using tandem mass-spectrometry. These 37 proteins are involved in energy metabolism, mitochondrial regulation, iron homeostasis, cytoprotection against hypoxia, and cytoskeletal organization. Compared with the 9 and 26°C groups, proteins involved in energy metabolism increased in 19°C-acclimated fish, indicating an overall increase in the capacity for ATP production. Creatine kinase abundance increased in 9°C-acclimated fish, suggesting an important role for the phosphocreatine energy shuttle in cold-acclimated hearts. Both 9 and 26°C fish also increased abundance of hexosaminidase, a protein directly involved in post-hypoxia stress cytoprotection of cardiac tissues. Cytoskeletal restructuring appears to occur in all acclimation groups; however, the most prominent effect was detected in 26°C-acclimated fish, which exhibited significantly increased actin levels. Overall, proteomic analysis of cardiac tissue suggests that the capacity to adjust ATP-generating processes is crucial to the thermal plasticity of cardiac function. Furthermore, G. mirabilis may optimize cellular functions at temperatures near 19°C, which lies within the species' preferred temperature range.

  12. Toxic coral gobies reduce the feeding rate of a corallivorous butterflyfish on Acropora corals

    NASA Astrophysics Data System (ADS)

    Dirnwoeber, M.; Herler, J.

    2013-03-01

    The obligate coral-dwelling gobiid genus Gobiodon inhabits Acropora corals and has developed various physiological, morphological and ethological adaptations towards this life habit. While the advantages of this coral-fish association are well documented for Gobiodon, possible fitness-increasing factors for the host coral are unknown. This study examines the influence of coral-dwelling gobies on the feeding behaviour of obligate corallivorous butterflyfishes. In an aquarium experiment using video observation, the corallivorous butterflyfish Chaetodon austriacus fed significantly less on corals inhabited by two Gobiodon species compared to unoccupied coral colonies of similar size. The more agonistic species G. histrio, which mostly displayed directed movements towards butterflyfishes, decreased butterflyfish bite rate by 62-98 % compared to uninhabited colonies. For Gobiodon sp. 3, which mostly displayed undirected movements in response to visits by C. austriacus, bite rate reduction was 64-68 %. The scale-less skin of Gobiodon spp. is covered by mucus that is toxic and multi-functional by reducing predation as well as affecting parasite attachment. A choice flume experiment suggests that the highly diluted skin mucus of Gobiodon spp. also functions as a corallivore repellent. This study demonstrates that Gobiodon spp. exhibit resource defence against coral-feeding butterflyfishes and also that coral colonies without resident Gobiodon suffer higher predation rates. Although the genus Gobiodon is probably a facultative corallivore, this study shows that by reducing predation on inhabited colonies by other fishes, these obligate coral-dwellers either compensate for their own fitness-decreasing impact on host colonies or live in a mutualistic association with them.

  13. Survival, growth and stress response of juvenile tidewater goby, Eucyclogobius newberryi, to interspecific competition for food

    PubMed Central

    Chase, Daniel A.; Flynn, Erin E.; Todgham, Anne E.

    2016-01-01

    Reintroduction of endangered fishes to historic habitat has been used as a recovery tool; however, these fish may face competition from other fishes that established in their native habitat since extirpation. This study investigated the physiological response of tidewater goby, Eucyclogobius newberryi, an endangered California fish, when competing for food with threespine stickleback, Gasterosteus aculeatus, a native species, and rainwater killifish, Lucania parva, a non-native species. Survival, growth and physiological indicators of stress (i.e. cortisol, glucose and lactate concentrations) were assessed for juvenile fish held for 28 days in two food-limited conditions. When fed a 75% ration, survival of E. newberryi was significantly lower when held with G. aculeatus. In all fish assemblages, weight and relative condition decreased then stabilized over the 28 day experiment, while length remained unchanged. Whole-body cortisol in E. newberryi was not affected by fish assemblage; however, glucose and lactate concentrations were significantly higher with conspecifics than with other fish assemblages. When fed a 50% ration, survival of E. newberryi decreased during the second half of the experiment, while weight and relative condition decreased and length remained unchanged in all three fish assemblages. Cortisol concentrations were significantly higher for all fish assemblages compared with concentrations at the start of the experiment, whereas glucose and lactate concentrations were depressed relative to concentrations at the start of the experiment, with the magnitude of decrease dependent on the species assemblage. Our findings indicate that E. newberryi exhibited reduced growth and an elevated generalized stress response during low food availability. In response to reduced food availability, competition with G. aculeatus had the greatest physiological effect on E. newberryi, with minimal effects from the non-native L. parva. This study presents the first

  14. Prey preference of snow leopard (Panthera uncia) in South Gobi, Mongolia.

    PubMed

    Shehzad, Wasim; McCarthy, Thomas Michael; Pompanon, Francois; Purevjav, Lkhagvajav; Coissac, Eric; Riaz, Tiayyba; Taberlet, Pierre

    2012-01-01

    Accurate information about the diet of large carnivores that are elusive and inhabit inaccessible terrain, is required to properly design conservation strategies. Predation on livestock and retaliatory killing of predators have become serious issues throughout the range of the snow leopard. Several feeding ecology studies of snow leopards have been conducted using classical approaches. These techniques have inherent limitations in their ability to properly identify both snow leopard feces and prey taxa. To examine the frequency of livestock prey and nearly-threatened argali in the diet of the snow leopard, we employed the recently developed DNA-based diet approach to study a snow leopard population located in the Tost Mountains, South Gobi, Mongolia. After DNA was extracted from the feces, a region of ∼100 bp long from mitochondrial 12S rRNA gene was amplified, making use of universal primers for vertebrates and a blocking oligonucleotide specific to snow leopard DNA. The amplicons were then sequenced using a next-generation sequencing platform. We observed a total of five different prey items from 81 fecal samples. Siberian ibex predominated the diet (in 70.4% of the feces), followed by domestic goat (17.3%) and argali sheep (8.6%). The major part of the diet was comprised of large ungulates (in 98.8% of the feces) including wild ungulates (79%) and domestic livestock (19.7%). The findings of the present study will help to understand the feeding ecology of the snow leopard, as well as to address the conservation and management issues pertaining to this wild cat.

  15. Desert pastoralists' negative and positive effects on rare wildlife in the Gobi.

    PubMed

    Ekernas, L Stefan; Sarmento, Wesley M; Davie, Hannah S; Reading, Richard P; Murdoch, James; Wingard, Ganchimeg J; Amgalanbaatar, Sukh; Berger, Joel

    2017-04-01

    In arid regions of the developing world, pastoralists and livestock commonly inhabit protected areas, resulting in human-wildlife conflict. Conflict is inextricably linked to the ecological processes shaping relationships between pastoralists and native herbivores and carnivores. To elucidate relationships underpinning human-wildlife conflict, we synthesized 15 years of ecological and ethnographic data from Ikh Nart Nature Reserve in Mongolia's Gobi steppe. The density of argali (Ovis ammon), the world's largest wild sheep, at Ikh Nart was among the highest in Mongolia, yet livestock were >90% of ungulate biomass and dogs >90% of large-carnivore biomass. For argali, pastoral activities decreased food availability, increased mortality from dog predation, and potentially increased disease risk. Isotope analyses indicated that livestock accounted for >50% of the diet of the majority of gray wolves (Canis lupus) and up to 90% of diet in 25% of sampled wolves (n = 8). Livestock composed at least 96% of ungulate prey in the single wolf pack for which we collected species-specific prey data. Interviews with pastoralists indicated that wolves annually killed 1-4% of Ikh Nart's livestock, and pastoralists killed wolves in retribution. Pastoralists reduced wolf survival by killing them, but their livestock were an abundant food source for wolves. Consequently, wolf density appeared to be largely decoupled from argali density, and pastoralists had indirect effects on argali that could be negative if pastoralists increased wolf density (apparent competition) or positive if pastoralists decreased wolf predation (apparent facilitation). Ikh Nart's argali population was stable despite these threats, but livestock are increasingly dominant numerically and functionally relative to argali. To support both native wildlife and pastoral livelihoods, we suggest training dogs to not kill argali, community insurance against livestock losses to wolves, reintroducing key native prey species

  16. Using diets to reveal overlap and egg predation among benthivorous fishes in Lake Michigan

    USGS Publications Warehouse

    Mychek-Londer, Justin G.; Bunnell, David B.; Stott, Wendylee; Diana, James S.; French, John R. P.; Chriscinske, Margret

    2013-01-01

    Ecological stability in the Laurentian Great Lakes has been altered by nonindigenous species, such as the Round Goby Neogobius melanostomus and dreissenid mussels, and by declines in native amphipods Diporeia spp. We evaluated whether these changes could influence diet overlap between three benthivorous fishes (Slimy Sculpin Cottus cognatus, Deepwater Sculpin Myoxocephalus thompsonii, and Round Goby) and whether predation on eggs of native species was occurring. We examined diets of fish collected at depths of 69–128 m in Lake Michigan offshore of Frankfort and Muskegon, Michigan, and Two Rivers and Sturgeon Bay, Wisconsin, during January–May 2009 and 2010. Important prey (by dry weight proportion and by percent frequency of occurrence) for Slimy Sculpin were Mysis (0.34; 45%), Diporeia (0.16; 34%), and Limnocalanus macrurus (0.22; 68%); important prey for Deepwater Sculpin were Mysis (0.74; 92%) and Diporeia (0.16; 54%). Round Goby consumed mainly bivalves (i.e., dreissenids: 0.68; 95%) and Mysis (0.15; 37%). The two sculpin species consumed the eggs of Bloaters Coregonus hoyi (Slimy Sculpin: 0.04, 11%; Deepwater Sculpin: 0.02, 7%) and the eggs of Deepwater Sculpin (Slimy Sculpin: 0.03, 13%; Deepwater Sculpin: 0.05, 16%) during February–May at all sites. Round Goby also consumed eggs of these species but at lower levels (≤0.01; <1%). Diet overlap was identified between sculpin species at Frankfort and Sturgeon Bay, suggesting possible interspecific competition, but their diets did not overlap at Two Rivers; diet overlap was never observed between Round Goby and either sculpin species. Given that (1) diet overlap varied by site and (2) diet proportions varied spatially more than temporally, benthivores appear to be exhibiting localized responses to recent ecological changes. Overall, these results reveal that egg predation and interspecific competition could be important interactions to consider in future examinations of the population dynamics of these

  17. The influence of colony size and coral health on the occupation of coral-associated gobies (Pisces: Gobiidae)

    NASA Astrophysics Data System (ADS)

    Schiemer, L.; Niedermüller, S.; Herler, J.

    2009-03-01

    Fishes of the genus Gobiodon are habitat specialists by their association with Acropora corals. Little is known about the parameters that define host coral quality for these fishes, in particular their breeding pairs. Data were collected in the northern Red Sea using 10 × 1-m belt transects in different reefs and zones. Gobiid density was highly correlated with coral density over all sites and zones, and the more specialized goby species preferred coral species that are less vulnerable to environmental stress. Moreover, the occupation rate of corals by goby breeding pairs significantly increased with colony size and decreased with partial mortality of colonies. Logistic regression showed that both coral size (being most important) and partial mortality are key factors influencing the occupation by breeding pairs. This study provides the first evidence that breeding pairs of coral-associated gobiids have more advanced habitat requirements than con-specifics in other social states. As coral reefs are threatened worldwide and habitat loss and degradation increase, this information will help predict the potential effects on those reef fishes obligatorily associated with live corals.

  18. From sneaker to parental male: change of reproductive traits in the black goby, Gobius niger (Teleostei, Gobiidae).

    PubMed

    Immler, Simone; Mazzoldi, Carlotta; Rasotto, Maria Berica

    2004-02-01

    This study focuses on the consequences of the switch of tactic from parasitic to parental male in the black goby, Gobius niger (Teleostei: Gobiidae), a species showing two alternative male mating tactics. Older and larger males defend nests, court, and perform parental care on eggs, while younger and smaller ones behave as parasites, sneaking into nests while spawning occurs. Males adopting different tactics are known to present differences in primary and secondary sex traits. The social context of sneaker males was manipulated to induce a tactic switch. Sneakers were kept under two different experimental treatments with or without a female, and under exclusion of male-male competition. Males changed tactics, courting females, spawning, and performing parental care. All males showed substantial changes in primary sexual traits, such as a reduction in gonadal development and an increase in the investment in accessory structures. The experimental groups differed in the functionality of gonads and accessory organs and in the development of the secondary sex traits. These results demonstrate that the moment of switching is not genetically fixed in the black goby. Sneaker males are able to quickly reallocate energy in primary and secondary sex traits, in accordance with the adopted tactic. Several aspects of this flexible reproductive pattern resemble the socially controlled sex change found in sequential hermaphrodites.

  19. Consequences of extreme life history traits on population persistence: do short-lived gobies face demographic bottlenecks?

    NASA Astrophysics Data System (ADS)

    Lefèvre, Carine D.; Nash, Kirsty L.; González-Cabello, Alonso; Bellwood, David R.

    2016-06-01

    The majority of coral reef goby species are short-lived, with some highly abundant species living less than 100 d. To understand the role and consequences of this extreme life history in shaping coral reef fish populations, we quantitatively documented the structure of small reef fish populations over a 26-month period (>14 short-lived fish generations) at an inshore reef on the Great Barrier Reef, Australia. Most species with life spans >1 yr, such as pomacentrids, exhibited a peak in recruitment during the austral summer, driving seasonal changes in the small fish community composition. In contrast, there were no clear changes in goby community composition, despite the abundance of short-lived, high turnover species. Species of Eviota, the most abundant gobiid genus observed, showed remarkably similar demographic profiles year-round, with consistent densities of adults as well as recently recruited juveniles. Our results demonstrate ongoing recruitment of these small cryptic fishes, which appears to compensate for an exceptionally short life span on the reef. Our results suggest that gobiid populations are able to overcome demographic limitations, and by maintaining reproduction, larval survival and recruitment throughout the year, they may avoid population bottlenecks. These findings also underline the potential trophodynamic importance of these small species; because of this constant turnover, Eviota species and other short-lived fishes may be particularly valuable contributors to the flow of energy on coral reefs, underpinning the year-round trophic structure.

  20. Chronic nickel bioaccumulation and sub-cellular fractionation in two freshwater teleosts, the round goby and the rainbow trout, exposed simultaneously to waterborne and dietborne nickel.

    PubMed

    Leonard, Erin M; Banerjee, Upasana; D'Silva, Joshua J; Wood, Chris M

    2014-09-01

    Rainbow trout and round goby were exposed for 30 days to waterborne and dietary Ni in combination at two waterborne concentration ranges (6.2-12 μmol/L, 68-86 μmol/L), the lower of which is typical of contaminated environments. The prey (black worms; Lumbriculus variegatus) were exposed for 48 h in the effluent of the fish exposure tanks before being fed to the fish (ration=2% body weight/day). Ni in gills, gut, and prey was fractionated into biologically inactive metal [BIM=metal-rich granules (MRG) and metallothionein-like proteins (MT)] and biologically active metal [BAM=organelles (ORG) and heat-denaturable proteins (HDP)]. Gobies were more sensitive than trout to chronic Ni exposure. Possibly, this greater sensitivity may have been due to the goby's pre-exposure to pollutants at their collection site, as evidenced by ∼2-fold greater initial Ni concentrations in both gills and gut relative to trout. However, this was followed by ∼2-16× larger bioaccumulation in both the gills and the gut during the experimental exposure. On a subcellular level, ∼3-40× more Ni was associated with the BAM fraction of goby in comparison to trout. Comparison of the fractional distribution of Ni in the prey versus the gut tissue of the predators suggested that round goby were more efficient than rainbow trout in detoxifying Ni taken up from the diet. Assessing sub-cellular distribution of Ni in the gills and gut of two fish of different habitat and lifestyles revealed two different strategies of Ni bioaccumulation and sub-cellular distribution. On the one hand, trout exhibited an ability to regulate gill Ni bioaccumulation and maintain the majority of the Ni in the MT fraction of the BIM. In contrast goby exhibited large Ni spillovers to both the HDP and ORG fractions of the BAM in the gill. However, the same trend was not observed in the gut, where the potential acclimation of goby to pollutants from their collection site may have aided their ability to regulate Ni

  1. Physical mechanisms of the summer precipitation variations in the Taklimakan and Gobi Desert

    NASA Astrophysics Data System (ADS)

    Huang, W.; Feng, S.; Chen, J.; Chen, F.

    2013-12-01

    The Taklimakan and the adjacent Gobi Desert (TD in short) in northwestern China is one of the most arid regions in the middle latitudes, where water is scarce year round. Using observational precipitation and the reanalysis data, this study investigated the variations of summer precipitation in TD and their association with water vapor flux and atmospheric circulation. Though the long-term mean water vapor is mostly comes from the west, the variations of summer precipitation in TD is dominated by the water vapor flux from the south, originated from the Arabian Sea. The anomalous water vapor flux is closely associated with the meridional teleconnection pattern around 50-80°E and the zonal teleconection pattern along the Asian westerly jet in summer. The meridional teleconnection connecting the Central Asia and the tropical Indian Ocean, and the zonal pattern resembles the ';Silk Road pattern'. The two wave trains connected in Central Asia. The anomalous pressure gradient force between negative height anomalies in Central Asia and the positive height anomalies in Arabian Sea/India and North Central China lead to anomalous ascending motion in TD and bring more water vapor from the Arabian Sea to pass over the Tibetan Plateau to fuel the precipitation development in the study region. These mechanisms lead to out-of-phase relationship between TD precipitation and Indian summer monsoon in the instrumental period and the past 2000 years. The vertically integrated summer water vapor flux (arrows) and 300hPa geopotential height (contour) regressed against the summer precipitation in TD during 1960-2010. Shadings (blue arrows) indicate the correlations between the geopotential height (water vapor flux) and the TD precipitation are significant at the 95% confidence level. The Guliya ice core is marked as star and the proxy monsoon records in Arabian Sea (box cores 723A and RC2730) are marked as triangles. Summer climatological water vapor budget and the correaltion between

  2. Estimates of lake trout (Salvelinus namaycush) diet in Lake Ontario using two and three isotope mixing models

    USGS Publications Warehouse

    Colborne, Scott F.; Rush, Scott A.; Paterson, Gordon; Johnson, Timothy B.; Lantry, Brian F.; Fisk, Aaron T.

    2016-01-01

    Recent development of multi-dimensional stable isotope models for estimating both foraging patterns and niches have presented the analytical tools to further assess the food webs of freshwater populations. One approach to refine predictions from these analyses is to include a third isotope to the more common two-isotope carbon and nitrogen mixing models to increase the power to resolve different prey sources. We compared predictions made with two-isotope carbon and nitrogen mixing models and three-isotope models that also included sulphur (δ34S) for the diets of Lake Ontario lake trout (Salvelinus namaycush). We determined the isotopic compositions of lake trout and potential prey fishes sampled from Lake Ontario and then used quantitative estimates of resource use generated by two- and three-isotope Bayesian mixing models (SIAR) to infer feeding patterns of lake trout. Both two- and three-isotope models indicated that alewife (Alosa pseudoharengus) and round goby (Neogobius melanostomus) were the primary prey items, but the three-isotope models were more consistent with recent measures of prey fish abundances and lake trout diets. The lake trout sampled directly from the hatcheries had isotopic compositions derived from the hatchery food which were distinctively different from those derived from the natural prey sources. Those hatchery signals were retained for months after release, raising the possibility to distinguish hatchery-reared yearlings and similarly sized naturally reproduced lake trout based on isotopic compositions. Addition of a third-isotope resulted in mixing model results that confirmed round goby have become an important component of lake trout diet and may be overtaking alewife as a prey resource.

  3. Assessment of lake sturgeon (Acipenser fulvescens) spawning efforts in the lower St. Clair River, Michigan

    USGS Publications Warehouse

    Nichols, S. Jerrine; Kennedy, Gregory; Crawford, Eric; Allen, Jeffrey; French, John; Black, Glen; Blouin, Marc; Hickey, James P.; Chernyak, Sergei; Haas, Robert; Thomas, Michael

    2003-01-01

    One of the most threatened remaining populations of lake sturgeon in the Great Lakes is found in the connecting channels between Lake Huron and Lake Erie. Only two spawning grounds are presently known to be active in this region, and both are in the St. Clair River. The spawning reef in the St. Clair River delta has been recently colonized by round gobies (Neogobius melanostomus) in densities up to 25/m2, raising concerns regarding predation on the benthic-oriented eggs and larvae of the sturgeon. Investigations in 1998–1999 showed that while round goby predation does occur, a number of other factors may be equally affecting sturgeon spawning success, including few spawning adults (< 60), suspected poaching pressure, low retention rate of eggs on the reef, low hatch rate (~0.5%), the presence of organic contaminants, and predation from native and exotic invertebrates and fish. Overall, we estimate that less than 1% of the eggs deposited during a spawning run survive to hatch. We were able to increase the egg hatch rate to 16% by placing eggs in predator-exclusion chambers on the reef. The fate of the larvae is uncertain. Two weeks after hatching, no larvae were found on the reef. We were unable to find them anywhere else in the river, nor was predation on larvae noted in either year. There were factors other than predation affecting larval survival in 1999. There was a higher silt load on the reef than in 1998 and large numbers of dead larvae were found. Recruitment success from this site could be improved by utilizing techniques to increase the number of eggs on the reef, such as reducing the illegal take of adult fish and by placing eggs in predator-exclusion chambers to increase hatch rate.

  4. Seasonal and interannual effects of hypoxia on fish habitat quality in central Lake Erie

    USGS Publications Warehouse

    Arend, Kristin K.; Beletsky, Dmitry; DePinto, Joseph; Ludsin, Stuart A.; Roberts, James J.; Rucinski, Daniel K.; Scavia, Donald; Schwab, David J.; Höök, Tomas O.

    2011-01-01

    1. Hypoxia occurs seasonally in many stratified coastal marine and freshwater ecosystems when bottom dissolved oxygen (DO) concentrations are depleted below 2–3 mg O2 L-1. 2. We evaluated the effects of hypoxia on fish habitat quality in the central basin of Lake Erie from 1987 to 2005, using bioenergetic growth rate potential (GRP) as a proxy for habitat quality. We compared the effect of hypoxia on habitat quality of (i) rainbow smelt, Osmerus mordax mordax Mitchill (young-of-year, YOY, and adult), a cold-water planktivore, (ii) emerald shiner, Notropis atherinoides Rafinesque (adult), a warm-water planktivore, (iii) yellow perch, Perca flavescens Mitchill (YOY and adult), a cool-water benthopelagic omnivore and (iv) round goby Neogobius melanostomus Pallas (adult) a eurythermal benthivore. Annual thermal and DO profiles were generated from 1D thermal and DO hydrodynamics models developed for Lake Erie’s central basin. 3. Hypoxia occurred annually, typically from mid-July to mid-October, which spatially and temporally overlaps with otherwise high benthic habitat quality. Hypoxia reduced the habitat quality across fish species and life stages, but the magnitude of the reduction varied both among and within species because of the differences in tolerance to low DO levels and warm-water temperatures. 4. Across years, trends in habitat quality mirrored trends in phosphorus concentration and water column oxygen demand in central Lake Erie. The per cent reduction in habitat quality owing to hypoxia was greatest for adult rainbow smelt and round goby (mean: -35%), followed by adult emerald shiner (mean: -12%), YOY rainbow smelt (mean: -10%) and YOY and adult yellow perch (mean: -8.5%). 5. Our results highlight the importance of differential spatiotemporally interactive effects of DO and temperature on relative fish habitat quality and quantity. These effects have the potential to influence the performance of individual fish species as well as population dynamics

  5. The use of environmental DNA in invasive species surveillance of the Great Lakes commercial bait trade.

    PubMed

    Nathan, Lucas R; Jerde, Christopher L; Budny, Michelle L; Mahon, Andrew R

    2015-04-01

    Over 180 non-native species have been introduced in the Laurentian Great Lakes region, many posing threats to native species and ecosystem functioning. One potential pathway for introductions is the commercial bait trade; unknowing or unconcerned anglers commonly release unused bait into aquatic systems. Previous surveillance efforts of this pathway relied on visual inspection of bait stocks in retail shops, which can be time and cost prohibitive and requires a trained individual that can rapidly and accurately identify cryptic species. Environmental DNA (eDNA) surveillance, a molecular tool that has been used for surveillance in aquatic environments, can be used to efficiently detect species at low abundances. We collected and analyzed 576 eDNA samples from 525 retail bait shops throughout the Laurentian Great Lake states. We used eDNA techniques to screen samples for multiple aquatic invasive species (AIS) that could be transported in the bait trade, including bighead (Hypophthalmichthys nobilis) and silver carp (H. molitrix), round goby (Neogobius melanostomus), tubenose goby (Proterorhinus marmoratus), Eurasian rudd (Scardinius erythrophthalmus), and goldfish (Carassius auratus). Twenty-seven samples were positive for at least one target species (4.7% of samples), and all target species were found at least once, except bighead carp. Despite current regulations, the bait trade remains a potential pathway for invasive species introductions in the Great Lakes region. Alterations to existing management strategies regarding the collection, transportation, and use of live bait are warranted, including new and updated regulations, to prevent future introductions of invasive species in the Great Lakes via the bait trade.

  6. Paleomagnetic and palynologic analyses of Albian to Santonian strata at Bayn Shireh, Burkhant, and Khuren Dukh, eastern Gobi Desert, Mongolia

    USGS Publications Warehouse

    Hicks, J.F.; Brinkman, D.L.; Nichols, D.J.; Watabe, M.

    1999-01-01

    Cretaceous terrestrial sediments deposited in a series of intracratonic basins across the Gobi Desert region of southern Mongolia and northern China contain a unique and diverse vertebrate fauna. In 1996 an expedition jointly sponsored by the Mongolian Paleontological Center and the Hayashibara Museum of Natural Sciences revisited a number of famous vertebrate fossil localities in the eastern Gobi region of Mongolia and, as part of a broad geological and paleontological study, collected a series of paleomagnetic samples from measured sections at Bayn Shireh, Burkhant and Khuren Dukh, as well as from an unmeasured locality adjacent to Khuren Dukh. Expedition members also collected palynologic samples from Khuren Dukh and the adjacent locality. Paleomagnetic analysis shows that all the sites from which samples were collected display detrital remnant magnetization that is consistently normal in polarity. The measured Cretaceous magnetic directions are oriented to the east or northeast of the present day expected direction (declination 356.2??, inclination 65.2??), and they are wholly concordant with that expected for a mid-latitude Northern Hemisphere sampling locality, and with the directions for this period reported by other workers. These results, when considered in tandem with the known biostratigraphy, strongly suggest that the sedimentary deposits at all four localities in the eastern Gobi correlate to the normal polarity chron 34 (the Cretaceous Long Normal), which ranges in age from approximately 121 to 83.5 million years. Previous vertebrate, invertebrate and palynological data from Khuren Dukh suggest that the lower and middle parts of the stratigraphic interval exposed there (which have been assigned to the Shinekhudag Formation) are 'Khukhtekian' in age and correspond to the Aptian-Albian interval that can be broadly correlated to the older, Early Cretaceous part of the Cretaceous Long Normal, C34n. New palynologic data presented here indicate that these

  7. Cathodoluminescence characterization of quartz grains from the Upper Cretaceous of dinosaur fossil localities in the Gobi desert, Mongolia

    NASA Astrophysics Data System (ADS)

    Saneyoshi, M.; Nishido, H.; Masuda, R.; Tsogtbaatar, K.; Chinzorig, T.

    2013-12-01

    The Upper Cretaceous eolian sediments in Mongolia's Gobi desert are one of the most important occurrences of the dinosaurs in the world. Large numbers of confiscated dinosaur fossils illegally worked out by poachers has been stored in the Mongolian Paleontological Center at Ulaanbaatar. In most cases, their localities are unknown. The purpose of this study is to identify their localities by cathodoluminescence (CL) features of quartz grains attached to the dinosaur specimens by comparing to the quartz samples collected from the sediments of circumjacent resources in this area. This study focuses on the confiscated specimen which makes up the nest with the babies' Protoceratops. Most of all Protoceratops in every growth process, have been discovered from the Djadokhta Formation in the Gobi desert. This formation crops out at Tugrikin Shireh and Bayn Dzak in the central part of the Gobi desert, and is derived from medium- to fine-grained sand mainly composed of quartz grains, of which sedimentary environments should be obvious to be eolian. The formation age of the sand beds at Tugrikin Shireh and Bayn Dzak has been estimated to be Middle Campanian. CL spectra of quartz have been demonstrated to show different features between the quartz from hydrothermal, plutonic, volcanic and metamorphic origins, suggesting the spectra reflect the condition of the quartz formation and the local environment. Therefore, we have applied the CL characterization of quartz grains to the evaluation of the provenance of the desert sediments. The quartz grains after sieving (#60-80 mesh size) were embedded in the brass holders with non-luminescent epoxy resin, and their surfaces were polished with 1 μm diamond abrasive. Color CL images obtained by the Luminoscope exhibit blue, violet and red emissions in the grains, suggesting various types of emission centers in the quartz. SEM-CL analysis was conducted using an SEM (JSM-5410) combined with a grating monochromator (Mono CL2) to measure

  8. Stable isotopes suggest differences in diet between historic and reintroduced Przewalskís horses in the Gobi desert

    NASA Astrophysics Data System (ADS)

    Burnik Šturm, Martina; Spasskaya, Natalia N.; Sablin, Mikhail V.; Voigt, Christian C.; Kaczensky, Petra

    2016-04-01

    In historic times, two wild equid species, the Przewalski᾽s horse (PH; Equus ferus przewalskii) and the Asiatic wild ass (khulan, KH; Equus hemionus), roamed the Eurasian steppes. By the end of the 1960s, PHs had been driven to extinction in the wild and the range of KHs became severely restricted to the least productive habitats. However, PHs survived in captivity and reintroductions since the 1990s have brought the species back to parts of its native range in Mongolia and northern China where they again overlap with KHs. Ecological research on PHs and KHs has increased in recent years, but very little information is available on the ecology of the original PHs prior to extinction in the wild. We applied stable isotope analysis (13C, 15N, and 2H) of segmentally cut tail hair of PHs and KHs, collected during expeditions in NW China and SW Mongolia in 1889-1899, to draw inferences about the species feeding ecology. We compared tail hair isotope patterns of historic individuals to those of their extant counterparts from the Mongolian Gobi. A previous study of isotopic tail hair signatures of extant PHs (N=6) and KHs (N=6) suggested species specific differences in diet, with PHs being year-round grazers, but KHs switching between being grazers in summer and mixed feeders in winter (Burnik Šturm et al., in prep.). The comparison of isotope patterns of extant with historic samples confirms diet seasonality in historic KHs (N=3), but detects the same seasonality in five out of six PHs, suggesting that historic PHs had a different isotopic dietary niche than extant PHs. While we are still unable to fully understand the underlying reasons for this change in PHs, our results clearly suggest that the isotopic dietary niche of PHs was wider in the past, suggesting a higher diet flexibility, and overlapped with that of KHs, suggesting a high competition potential over Gobi pastures between the two equid species in historic times. Reference: Burnik Šturm, M., Ganbaatar, O

  9. The relationships between temperature changes and reproductive investment in a Mediterranean goby: Insights for the assessment of climate change effects

    NASA Astrophysics Data System (ADS)

    Zucchetta, M.; Cipolato, G.; Pranovi, F.; Antonetti, P.; Torricelli, P.; Franzoi, P.; Malavasi, S.

    2012-04-01

    The relationships between changes in water temperature and the timing and level of reproductive investment were investigated in an estuarine fish, inhabiting the Venice lagoon: the grass goby Zosterisessor ophiocephalus. A time series of the mean monthly values of gonado-somatic index was coupled with thermal profiles of lagoon water temperatures over 14 years, from 1997 to 2010. Results showed that the reproductive investment was positively affected by water temperature changes, both in terms of monthly thermal anomalies and cumulative degree days. A predictive model was also developed to assess the temporal shift of reproductive peaks as a response to inter-annual thermal fluctuations. This model allowed the detection of deviations from the median level, indicating that during warmer years, the reproductive peak tended to occur earlier than during colder years. The model is therefore proposed as a tool to predict anticipated consequences of climate change on fish phenology in transitional waters, regarding recurrent biological phenomena, such as reproduction and recruitment.

  10. A study of variation characteristics of Gobi broadband emissivity based on field observational experiments in northwestern China

    NASA Astrophysics Data System (ADS)

    Zheng, Zhi-yuan; Wei, Zhi-gang; Wen, Zhi-ping; Dong, Wen-jie; Li, Zhen-chao; Wen, Xiao-hang; Zhu, Xian; Chen, Chen; Hu, Shan-shan

    2017-02-01

    Land surface emissivity is a significant variable in energy budgets, land cover assessments, and environment and climate studies. However, the assumption of an emissivity constant is being used in Gobi broadband emissivity (GbBE) parameterization scheme in numerical models because of limited knowledge surrounding the spatiotemporal variation characteristics of GbBE. To address this issue, we analyzed the variation characteristics of GbBE and possible impact factor-surface soil moisture based on long-term continuous and high temporal resolution field observational experiments over a typical Gobi underlying surface in arid and semiarid areas in northwestern China. The results indicate that GbBE has obvious daily and diurnal variation features, especially diurnal cycle characteristics. The multi-year average of the daily average of GbBE is in the range of 0.932 to 0.970 with an average of 0.951 ± 0.008, and the average diurnal GbBE is in the range of 0.880 to 0.940 with an average of 0.906 ± 0.018. GbBE varies with surface soil moisture content. We observed a slight decrease in GbBE with an increase in soil moisture, although this change was not very obvious because of the low soil moisture in this area. Nevertheless, we think that soil moisture must be one of the most significant impact factors on GbBE in arid and semiarid areas. Soil moisture must be taken into account into the parameterization schemes of bare soil broadband emissivity in land surface models. Additional field experiments and studies should be carried out in order to clarify this issue.

  11. Variations in the structure of airborne bacterial communities in Tsogt-Ovoo of Gobi desert area during dust events.

    PubMed

    Maki, Teruya; Kurosaki, Yasunori; Onishi, Kazunari; Lee, Kevin C; Pointing, Stephen B; Jugder, Dulam; Yamanaka, Norikazu; Hasegawa, Hiroshi; Shinoda, Masato

    2017-01-01

    Asian dust events transport the airborne bacteria in Chinese desert regions as well as mineral particles and influence downwind area varying biological ecosystems and climate changes. However, the airborne bacterial dynamics were rarely investigated in the Gobi desert area, where dust events are highly frequent. In this study, air samplings were sequentially performed at a 2-m high above the ground at the sampling site located in desert area (Tsogt-Ovoo of Gobi desert; Mongolia 44.2304°N, 105.1700°E). During the dust event days, the bacterial cells and mineral particles increased to more than tenfold of concentrations. MiSeq sequencing targeting 16S ribosomal DNA revealed that the airborne bacteria in desert area mainly belonged to the classes Acidobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Bacilli, Alpha-proteobacteria, Beta-proteobacteria, and Gamma-proteobacteria. The bacterial community structures were different between dust events and non-dust events. The air samples collected at the dust events indicated high abundance rates of Alpha-proteobacteria, which were reported to dominate on the leaf surfaces of plants or in the saline lake environments. After the dust events, the members of Firmicutes (Bacilli) and Bacteroidetes, which are known to form endospore and attach with coarse particles, respectively, increased their relative abundances in the air samples. Presumably, the bacterial compositions and diversities in atmosphere significantly vary during dust events, which carry some particles from grassland (phyllo-sphere), dry lake, and sand surfaces, as well as some bacterial populations such as Firmicutes and Bacteroidetes maintain in the atmosphere for longer time.

  12. Impacts of climatic change on carbon storage in the Sahara?Gobi desert belt since the Last Glacial Maximum

    NASA Astrophysics Data System (ADS)

    Lioubimtseva, E.; Simon, B.; Faure, H.; Faure-Denard, L.; Adams, J. M.

    1998-05-01

    Reconstructions of palaeolandscapes for intervals with different climatic conditions help define regional trends in palaeobiomass and carbon storage due to global climatic change. The Sahara-Gobi desert belt stretches for about 15,000 km from the Atlantic coast to Northern China. Natural vegetation zones have undergone a number of significant shifts and complex qualitative changes under the contrasting climatic conditions of the Last Glacial Maximum (LGM) and the Holocene Climatic Optimum (HCO). The results presented here are based on palynological, pedological and sedimentological evidence, which indicate that the amount of carbon stored in vegetation and soils would have been much smaller during the Glacial Maximum than in the interglacial and post glacial times. Comparison of a set of palaeogeographic maps of this region for the chosen time-slices (ca. 20-18 ka, 9-8 ka and the present) allows us to discuss land biomass changes. Dry and cool conditions during the LGM resulted in the spread of arid and semi-arid ecosystems at northern and southern margins of the desert belt. The southern limit of the Sahara migrated southward at least 400 km relative to its present position, and almost 1000 km south compared to the mid-Holocene. The northern margin of the temperate deserts and dry steppes of Central Asia shifted northward for not less than 200-300 km over Kazakhstan, southern Siberia and Mongolia. In this study we have quantified variations of the main ecosystems from the LGM to the HCO in terms of changes in carbon storage. Each vegetation zone has been assigned a carbon density for living and dead (soil) organic matter. During the last world deglaciation, the Sahara-Gobi desert belt was a sink for approximately 200 Gt of atmospheric carbon, but since the mid-Holocene, it has been a source of carbon.

  13. The impact of Gobi Desert Dust on the increase of POC at Station PAPA.

    NASA Astrophysics Data System (ADS)

    Saydam, A. C.; Senyuva, H. Z.

    2003-04-01

    It has been suggested that the temporal and spatial variability of bioavailable iron delivered to the ocean may be controlled via in-cloud photochemical reduction of desert dust, assisted by the impact of oxalate released by fungi in the desert soil. The basic process in the photochemical production of bioavailable iron through decarboxylation reaction involves simultaneous action of oxalate released by the fungus encapsulated in a cloud droplet, above some threshold solar radiation. Therefore, diurnal and latitudinal variations in solar irradiation and the sporadic nature of rain along the path of the synoptic-scale atmospheric depressions are the governing factors that determine spatial and temporal distribution of phytoplankton Bishop et al's (2002) report on the biotic response of subarctic North Pacific to a natural iron fertilization following the passage of a cloud of Gobi desert dust through two autonomous robotic floats equipped to measure Particulate Organic Carbon (POC) provided for the first time direct continuous observations of the upper ocean biological response to episodic events such as dust storms. The data provided by these two "Carbon Explorers" also gave us an opportunity to test our hypothesis. The TOMS and SeaWIfS satellite imagery clearly confirms the presence of dust all over the subarctic North Pacific, the NOAA READY meteorological archive confirms the presence of precipitation over the station PAPA while the DMSP/SSMI data further confirm the patchy distribution of wet deposition at around station PAPA for the days concerned. However, we would like to stress that daytime, wet deposition is the crucial factor. Otherwise, during the passage of this dust pulse and subsequent dry deposition over the subartic Pacific Ocean the entire ocean surface should have increased its POC concentrations and should have been recorded by various satellite sensors. Thus following this work the scientific community is getting closer to conduct a large

  14. Changes in sperm motility in response to osmolality/Ca2+ in three Indonesian fresh water teleosts: goby (Oxyeleotris marmorata), Java carp (Puntius javanicus), and catfish (Clarias batrachus).

    PubMed

    Morita, Masaya; Okuno, Makoto; Susilo, Endang Sri; Setyo, Bambang Pramono; Martarini, Diptarina; Harnadi, Lilik; Takemura, Akihiro

    2006-03-01

    Sperm of most fresh water teleosts become motile when released into the hypotonic fresh water environment, but the role of osmolality and Ca2+ on sperm motility is not clear. Osmotic pressure and Ca2+ concentrations increase from fresh water to brackish water. Java carp Puntius javanicus and catfish Clarias batrachus live and reproduce only in fresh water. On the other hand, goby Oxyeleotris marmorata can acclimate and reproduce from fresh water to brackish water. In the present study, sperm motility and trajectory were compared among these three Indonesian endemic species. Sperm of Java carp, goby, and catfish begun to move in the hypotonic condition (< 200 mOsm/kg). However, the response to Ca2+ was different among these teleosts. In the presence of Ca2+, Java carp sperm swam in circular paths and immediately become quiescent, suggesting that Java carp sperm motility is activated in hypotonic aquatic environment without Ca2+. Goby sperm swam straightforward in the presence or absence of Ca2+. Percentages of motile sperm increased in 100-200 mOsm/kg but suppressed by removal of Ca2+. Regarding sperm motility and trajectory, no response was found in catfish sperm. These results suggest that a response to Ca2+ is different among sperm of the three species and suited to their habitat.

  15. Early Paleozoic oceanic inliers and reconstruction of accretionary tectonics in the Middle Gobi region, Mongolia: Evidence from SHRIMP zircon U-Pb dating and geochemistry

    NASA Astrophysics Data System (ADS)

    Zhu, Mingshuai; Miao, Laicheng; Baatar, Munkhtsengel; Zhang, Fochin; Anaad, Chimedtseren; Yang, Shunhu; Li, Xingbo

    2016-09-01

    The ophiolites that occur as inliers among the Late Paleozoic formations in the Middle Gobi area are crucial for understanding the tectonic evolution of South Mongolia. In this paper, we conducted detailed studies on the Namdain hundy ophiolite to provide some constraints on the Early Paleozoic evolution of the Middle Gobi region in Mongolia. The ophiolite mainly consists of ultramafic rocks (carbonatation), plagiogranite, metagabbro, basalt and chert. The metagabbro and plagiogranite from Namdain hundy ophiolite yielded SHRIMP zircon U-Pb ages of 528 ± 7 Ma and 519 ± 5 Ma, respectively. Though most of the volcanic rocks of this ophiolite show supra-subduction zone (SSZ) affinity, samples with OIB and N-MORB geochemical features were also identified, indicating genesis in a forearc setting. The granodiorite intruding into the Namdain hundy ophiolite yielded a SHRIMP zircon U-Pb age of 491 ± 3 Ma, which constrained the upper age limit of ophiolite emplacement. This granodiorite shows adakitic geochemical affinity, attesting to the existence of Cambrian paleo - subduction in South Mongolia. Based on the available data so far, we suggest the Middle Gobi area comprises of the Manlay accretion complex, the island arc and the Biluutiin ovoo back-arc basin. The spatial configuration of these three tectonic belts suggests that the polarity of the paleo-ocean subduction was from south to north in the Early Paleozoic, forming a trench-arc-basin system south of the Central Mongolia microcontinent.

  16. How cuckoldry can decrease the opportunity for sexual selection: data and theory from a genetic parentage analysis of the sand goby, Pomatoschistus minutus.

    PubMed

    Jones, A G; Walker, D; Kvarnemo, C; Lindström, K; Avise, J C

    2001-07-31

    Alternative mating strategies are common in nature and are generally thought to increase the intensity of sexual selection. However, cuckoldry can theoretically decrease the opportunity for sexual selection, particularly in highly polygamous species. We address here the influence of sneaking (fertilization thievery) on the opportunity for sexual selection in the sand goby Pomatoschistus minutus, a marine fish species in which males build and defend nests. Our microsatellite-based analysis of the mating system in a natural sand goby population shows high rates of sneaking and multiple mating by males. Sneaker males had fertilized eggs in approximately 50% of the assayed nests, and multiple sneakers sometimes fertilized eggs from a single female. Successful males had received eggs from 2 to 6 females per nest (mean = 3.4). We developed a simple mathematical model showing that sneaking in this polygynous sand goby population almost certainly decreases the opportunity for sexual selection, an outcome that contrasts with the usual effects of cuckoldry in socially monogamous animals. These results highlight a more complex and interesting relationship between cuckoldry rates and the intensity of sexual selection than previously assumed in much of the literature on animal mating systems.

  17. Effects of endocrine-disrupting chemicals on expression of ubiquitin C-terminal hydrolase mRNA in testis and brain of the Japanese common goby.

    PubMed

    Mochida, Kazuhiko; Ohkubo, Nobuyuki; Matsubara, Takahiro; Ito, Katsutoshi; Kakuno, Akira; Fujii, Kazunori

    2004-11-18

    We investigated the effects of endocrine-disrupting chemicals (EDCs) on the expression of ubiquitin C-terminal hydrolase (UCH) mRNA in the testis and brain of the Japanese common goby, Acanthogobius flavimanus. The cDNA sequence of goby UCH contained an open reading frame encoding 220 amino acid residues (M(r)=24,223) with 51.3% overall sequence identity with human and mouse UCHL1. A competitive PCR assay was used to quantify the levels of UCH mRNA in the testis and brain of male gobies after exposure to bisphenol A, nonylphenol, or estradiol-17beta for 3 weeks. Exposure to estradiol-17beta at a nominal concentration of 100 ng/L induced significant increase in UCH mRNA levels in both testis and brain (P<0.05), whereas exposure to nonylphenol induced a significant decrease in UCH mRNA levels in the testis (P<0.01). These results suggest that EDCs can either positively or negatively regulate UCH mRNA levels.

  18. Lake sediments documented late Quaternary humid pulses in the Gobi Desert of southern Mongolia: Vegetation, hydrologic and paleoglaciation inferences

    NASA Astrophysics Data System (ADS)

    Yu, Kaifeng; Lehmkuhl, Frank; Schlütz, Frank; Diekmann, Bernhard; Mischke, Steffen; Grunert, Jörg; Murad, Waheed; Nottebaum, Veit; Stauch, Georg

    2016-04-01

    Considerable efforts have been devoted to decipher the late Quaternary moisture and thermal history of the arid central Asia. However, an array of paramount aspects has inhibited our complete understanding of the broad pattern and underlying mechanisms: (i) Biased or even contradictory conclusions may be achieved due to the interpretations of different proxies. (ii) Most of the works poured attention into Holocene period, only few records can extend back to earlier marine isotope stages. (iii) Substantial spatial heterogeneity is noteworthy in the area. Exceeding amounts of studies were carried out in Lake Baikal catchments, northern and western Mongolia, while only two works were hitherto conducted in southern Mongolia. (iv) It remains elusive with respect to how and to what extent have East Asian Summer Monsoon and Westerlies affected the thermal and moisture signals in this spectacular arid region. To address this set of issues, two parallel cores (ONW I, 6.00 m; ONW II, 13.36 m) were retrieved from Orog Nuur, Gobi Desert of southern Mongolia. An array of multidisciplinary investigations involving geomorphologic mapping, radiocarbon dating, geochemical and biotic studies (i.e., palynological and ostracod valve analyses) provide a comprehensive data set for inferences of hydrological perturbations, vegetation development and phases of glacier expansions over the last ~50 ka. Orog Nuur catchment depicted a broadly vulnerable ecosystem that was dominated by Artemisia steppe community in the late Pleistocene, and Chenopodiaceae desert steppe in the Holocene. In addition, the Termination I is ideally documented in a complete suite of geochemical, palynological, and ostracod signatures. In general, the thermal and moisture history in the Gobi Desert were as follows: (i) MIS3 had a relatively warm temperature and sufficient moisture supply in particular between ~40 ka and ~26 ka; (ii) The MIS2 was subject to cold temperature and moisture deficit, which was interrupted

  19. Ecological differences in three autochthonous equid species in Mongolian Gobi inferred from stable isotopes in tail hair

    NASA Astrophysics Data System (ADS)

    Burnik Šturm, Martina; Voigt, Christian C.; Oyunsaikhan, Ganbaatar; Kaczensky, Petra

    2014-05-01

    In the Dzungarian Gobi of Mongolia three equid species, Asiatic wild ass (Equus hemionus), domestic horse (Equus caballus), and re-introduced Przewalski's horse (Equus ferus przewalskii) share the same habitat and thus provide a unique opportunity for comparative ecological studies. In our project we use the stable isotope analysis of tail hair as a tool to study feeding ecology, water use and movement pattern of the three extant sympatric equid species to reveal species specific differences and thus strengthen our understanding of the ecological adaptations of the three species to the harsh environment of the Gobi desert. Since tail hair grow continuously and is isotopically inert after formation, when sampled and analysed longitudinally, provides temporary explicit information on dietary regime and movement pattern. We use the carbon isotopes in the tail hair to determine the quantitative dependence of each animal on isotopically distinct C3 (grasses) and C4 (multitude of annuals and perennials) diet. Nitrogen isotopes reflect the isotopic composition of the diet and hydrogen isotopes reflect the isotopic composition of the water that animals utilize, while both elements have been reported to also give information on the physical status of the animal. Combined isotope data will be used to describe the movement patterns and habitat use of the three equid species. We will present the methodology and first preliminary results of carbon and nitrogen isotope analysis of potential forage plants of the study area and of the tail hair analysis. Among the analysed plants, collected in the pilot sampling campaign in 2012 (n = 192), we identified 14 C3 and two C4species and found no general trend that could explain the effect of altitude on carbon isotopic composition in C3 plants and no correlation between carbon isotopic composition and longitude or latitude. We performed additional, more detailed plant sampling in 2013. The first results obtained from the tail hair

  20. Habitat selection of two gobies (Microgobius gulosus, Gobiosoma robustum): influence of structural complexity, competitive interactions and presence of a predator

    USGS Publications Warehouse

    Schofield, P.J.

    2003-01-01

    Herein I compare the relative importance of preference for structurally complex habitat against avoidance of competitors and predators in two benthic fishes common in the Gulf of Mexico. The code goby Gobiosoma robustum Ginsburg and clown goby Microgobius gulosus (Girard) are common, ecologically similar fishes found throughout the Gulf of Mexico and in the southeastern Atlantic Ocean. In Florida Bay, these fishes exhibit habitat partitioning: G. robustum is most abundant in seagrass-dominated areas while M. gulosus is most abundant in sparsely vegetated habitats. In a small-scale field survey, I documented the microhabitat use of these species where their distributions overlap. In a series of laboratory experiments, I presented each species with structured (artificial seagrass) versus nonstructured (bare sand) habitats and measured their frequency of choosing either habitat type. I then examined the use of structured versus nonstructured habitats when the two species were placed together in a mixed group. Finally, I placed a predator (Opsanus beta) in the experimental aquaria to determine how its presence influenced habitat selection. In the field, G. robustum was more abundant in seagrass and M. gulosus was more abundant in bare mud. In the laboratory, both species selected grass over sand in allopatry. However, in sympatry, M. gulosus occupied sand more often when paired with G. robustum than when alone. G. robustum appears to directly influence the habitat choice of M. gulosus: It seems that M. gulosus is pushed out of the structured habitat that is the preferred habitat of G. robustum. Thus, competition appears to modify the habitat selection of these species when they occur in sympatry. Additionally, the presence of the toadfish was a sufficient stimulus to provoke both M. gulosus and G. robustum to increase their selection for sand (compared to single-species treatments). Distribution patterns of M. gulosus and G. robustum

  1. Aeolian processes and dune morphology in the Gobi and Badain Jaran Desert using LandSat Imagery.

    NASA Astrophysics Data System (ADS)

    Cardinale, Marco; Cannito, Arturo; Marinangeli, Lucia

    2014-05-01

    The Gobi and Badain Jaran Deserts are parts of the vast sand sea of the Alashan Region, one of the greatest dunefield in China [1]. They lie between the southern Mongolia and the northern China (latitude 37° 06'N - 41°50'N; longitude 99°10'E - 107°09'E) [2]. The studied area is characterized by an arid climate with low average annual rainfall between 50-60mm, extreme fluctuation in temperature, very strong winds and by the occurrence of mega dunes and permanent lakes within the dunefield [3]. According to our morphological analysis, wind action has been one of the main factors that have shaped the surface features inside the investigated area. We produce a detailed geomorphological map of the desertic zone, highlighting the aeolian morphologies, in order to characterize aeolian deposits and processes. The LandSat ETM+ data [4], providing a continuous coverage of the dune fields with no gaps, were processed using ENVI software and then ingested in a GIS project. We also used DTMs (30m / pixel) from Aster data [5]. The dune morphology was classified using McKee criteria [6] and we interpreted the pattern of the complex ergs as the result of self - organization within complex systems [7]. Compound transverse mega dunes and barchanoid dunes developed under a variable wind regime, star dunes in the northern area near the mountain have been formed under a multi directional wind regime. The area covered by mega dunes suggests a complex evolution of these features dominated by the wind activity. Different episodes of deposition, erosion and motion, could explain the height of these dunes measured by the DTMs. The diverse aeolian features identified in the investigated area suggest that aeolian activity play a key role for the evolution of the surface morphologies of the Gobi Desert. To understand the local dynamics of aeolian processes, we are currently comparing these features with meteorological data from mesoscale wind models. References: [1] E. D.McKee. A Study of

  2. Diet composition and feeding ecology of the naked goby Gobiosoma bosc (Gobiidae) from four western Atlantic estuaries.

    PubMed

    D'Aguillo, M C; Harold, A S; Darden, T L

    2014-08-01

    The feeding ecology of the small-bodied benthic naked goby Gobiosoma bosc, a western Atlantic species that occurs in estuaries and other inshore habitats from Connecticut to Texas U.S.A., was investigated in a total of four estuaries spanning South Carolina, North Carolina, Maryland and New Jersey. Gut content analysis of 391 individuals revealed that G. bosc is a benthic microcarnivore that feeds primarily on polychaetes, gammarid amphipods and harpacticoid copepods. Diet composition varied with body size, tidal creek within an estuary and geographic region. Analyses of gut fullness suggest that G. bosc is a daytime visual predator and that nest and egg guarding during the reproductive season reduce foraging activity in mature males. Additionally, G. bosc infected with adult digenean parasites of the gut foraged more intensely than uninfected individuals, a relationship that was strongest for reproductively mature males. Regionally, significant variation in dietary breadth was documented and may reflect a foraging response to a decrease in prey diversity moving from estuaries of higher salinity and lower latitude to estuaries of lower salinity and higher latitude. These results contribute to an understanding of the life history of G. bosc and the role played by this common species in estuarine food webs.

  3. Can environmental conditions affect smallholders' climate change perception? Evidence from an aridity gradient in the Gobi desert.

    NASA Astrophysics Data System (ADS)

    Rueff, Henri

    2016-04-01

    There is a growing interest in smallholders' climate change perception (CCP). Understanding what people perceive in relation to the climate they endure supports national climate change adaptation policy especially relevant to uncertain and resource-scarce environments. Most research so far focused on the accuracy of CCP compared to observed climatic data. However, the potential effect of factors influencing peoples' perceptions remains largely unstudied. This research tests two hypotheses in a desert environment; first, that CCP varies along an aridity gradient, and, second, that respondents are more consistent (answers less far apart) in their CCP when facing more climate shocks, which supports the first hypothesis. A semi-structured survey was conducted among nomadic (Mongolia) (n=180) and semi-nomadic (Inner Mongolia-China) (n=180) herders, to analyse perception along an aridity gradient (proxied by Normalised Difference Vegetation Index) covering an array of climate change issues in the Gobi. Results suggests that environmental conditions have a significant effect on CCP but only in terms of experienced climate shocks. The CCP for other climatic variables (rain, season length) is more diffused and can poorly be predicted by the surrounding environment smallholders live in. Institutional contrasts between China and Mongolia explain marginally differences of perception. Further research is needed to validate these results among smallholders on other environmental gradient types, for examples along altitudinal biome stratification in mountain environments.

  4. Isolation and characterization of two serine proteases from metagenomic libraries of the Gobi and Death Valley deserts.

    PubMed

    Neveu, Julie; Regeard, Christophe; DuBow, Michael S

    2011-08-01

    The screening of environmental DNA metagenome libraries for functional activities can provide an important source of new molecules and enzymes. In this study, we identified 17 potential protease-producing clones from two metagenomic libraries derived from samples of surface sand from the Gobi and Death Valley deserts. Two of the proteases, DV1 and M30, were purified and biochemically examined. These two proteases displayed a molecular mass of 41.5 kDa and 45.7 kDa, respectively, on SDS polyacrylamide gels. Alignments with known protease sequences showed less than 55% amino acid sequence identity. These two serine proteases appear to belong to the subtilisin (S8A) family and displayed several unique biochemical properties. Protease DV1 had an optimum pH of 8 and an optimal activity at 55°C, while protease M30 had an optimum pH >11 and optimal activity at 40°C. The properties of these enzymes make them potentially useful for biotechnological applications and again demonstrate that metagenomic approaches can be useful, especially when coupled with the study of novel environments such as deserts.

  5. Varicus lacerta, a new species of goby (Teleostei, Gobiidae, Gobiosomatini, Nes subgroup) from a mesophotic reef in the southern Caribbean.

    PubMed

    Tornabene, Luke; Robertson, D Ross; Baldwin, Carole C

    2016-01-01

    We describe a new species of goby, Varicus lacerta sp. n., which was collected from a mesophotic reef at Curacao, southern Caribbean. The new species is the tenth species of Varicus, all of which occur below traditional SCUBA depths in the wider Caribbean area. Its placement in the genus Varicus is supported by a molecular phylogenetic analysis of three nuclear genes and the mitochondrial gene cytochrome b. In addition, the new species has one anal-fin pterygiophore inserted anterior to the first haemal spine, which distinguishes Varicus species from most species in the closely related and morphologically similar genus Psilotris. Varicus lacerta sp. n. is distinguished from all other named species of Varicus by the absence of scales, having highly branched, feather-like pelvic-fin rays, and in its live coloration. We provide the cytochrome c oxidase I DNA barcode of the holotype and compare color patterns of all species of Varicus and Psilotris for which color photographs or illustrations are available. This study is one of several recent studies demonstrating the utility of manned submersibles in exploring the diversity of poorly studied but species-rich deep-reef habitats.

  6. Two species of goby, Boleophthalmus pectinirostris and Scartelaos sp., as the new second intermediate hosts of heterophyid fluke in Korea

    PubMed Central

    Kim, Jung-A; Song, Hyun-Jae

    2005-01-01

    A survey was performed in order to determine the infection status of the metacercariae of heterophyid fluke in two goby species, Boleophthalmus pectinirostris and Scartelaos sp., collected from Gangjin-gun, and Shinan-gun, Sooncheon-shi, Jeollanam-do, Republic of Korea. A total of three metacercariae of Heterophyopsis continua was found in only one B. pectinirostris (10.0%) from Gangjin-gun. Heterophyes nocens metacercariae were detected in 24 B. pectinirostris (96.0%) and 14 Scartelaos sp. (63.6%) from Shinan-gun. Heterophyopsis continua metacercariae were found in 11 B. pectinirostris (44.0%) and 21 Scartelaos sp. (95.5%) from Shinan-gun. Stictodora fuscata metacercariae were detected in 18 B. pectinirostris (72.0%) from Shinan-gun. No metacercariae were detected in 20 B. pectinirostris from Sooncheon-shi. From the above results, this study is the first to prove that B. pectinirostris and Scartelaos sp. serve as the second intermediate hosts of some heterophyid flukes in Korea. PMID:16340306

  7. Varicus lacerta, a new species of goby (Teleostei, Gobiidae, Gobiosomatini, Nes subgroup) from a mesophotic reef in the southern Caribbean

    PubMed Central

    Tornabene, Luke; Robertson, D. Ross; Baldwin, Carole C.

    2016-01-01

    Abstract We describe a new species of goby, Varicus lacerta sp. n., which was collected from a mesophotic reef at Curacao, southern Caribbean. The new species is the tenth species of Varicus, all of which occur below traditional SCUBA depths in the wider Caribbean area. Its placement in the genus Varicus is supported by a molecular phylogenetic analysis of three nuclear genes and the mitochondrial gene cytochrome b. In addition, the new species has one anal-fin pterygiophore inserted anterior to the first haemal spine, which distinguishes Varicus species from most species in the closely related and morphologically similar genus Psilotris. Varicus lacerta sp. n. is distinguished from all other named species of Varicus by the absence of scales, having highly branched, feather-like pelvic-fin rays, and in its live coloration. We provide the cytochrome c oxidase I DNA barcode of the holotype and compare color patterns of all species of Varicus and Psilotris for which color photographs or illustrations are available. This study is one of several recent studies demonstrating the utility of manned submersibles in exploring the diversity of poorly studied but species-rich deep-reef habitats. PMID:27408581

  8. Characteristics of hydrologic transfer between soil and atmosphere over Gobi near oasis at the end of summer

    NASA Astrophysics Data System (ADS)

    Zhang, Qiang; Song, Lianchun; Huang, Ronghui; Wei, Guoan; Wang, Sheng; Tian, Hui

    2003-05-01

    By utilizing the data observed at Dunhuang during August and September 2000 in the “Field Experiment on Interaction between Land and Atmosphere in the Arid Region of Northwest China (FEILARNC)”, the characteristics of the soil moisture, temperature, and atmospheric humidity are analyzed. It is found that the thickness of the soil temperature active layer is about 5 cm and much thinner than is typical, that not only the atmospheric humidity gradient is often inverted but also the soil moisture gradient in the shallow layer in the Gobi near oasis, that the diurnal variation of soil moisture can be divided into the four stages that are called the wet stage, the losing-water stage, the dry stage, and the attaining-water stage. It is shown that in soil moisture profiles, the depth of the soil moisture active layer is about 10 cm and soil moisture inversion is the main feature in the shallow layer during the wet stage. Such a feature as soil moisture inversion indicates that soil in the shallow layer can inhale moisture from the air through condensation in the nighttime and exhale moisture to the air through evaporation in the daytime. The condensation and evaporation constitute together the full respiration process of moisture on the ground. The formation of soil moisture inversion is related with the state of soil temperature and moisture, the intensity of atmospheric humidity inversion, and the atmospheric thermodynamic stability.

  9. Simultaneous spawning by female stream goby Rhinogobius sp. and the association with brood cannibalism by nesting males.

    PubMed

    Ito, S; Iwao, H; Sakata, J; Inoue, M; Omori, K; Yanagisawa, Y

    2016-09-01

    A laboratory experiment was conducted by varying the undersurface area of nesting substratum and the number of females in an experimental tank to elucidate the determinants of the mating pattern in the stream goby, Rhinogobius sp. cross-band type. Males with larger nests tended to attract two or more females to their nest in a tank. Moreover, males spawned simultaneously with multiple females and entire brood cannibalism by males was rarely observed under a female-biased sex ratio. When males spawned with a single female with low fecundity, however, entire brood cannibalism occurred at a high frequency, suggesting that a male guarding a nest with fewer eggs consumes the brood. Therefore, spawning behaviour of females that leads to a large egg mass would decrease the risk of entire brood cannibalism. In this species, simultaneous spawning by multiple females in a nest serves as a female counter-measure against entire brood cannibalism. These results suggest that a conflict of interest between the sexes through brood cannibalism is a major determinant of simultaneous spawning.

  10. Hidden faults in the Gobi Desert (Inner Mongolia, China) - evidence for fault activity in a previously tectonically stable zone

    NASA Astrophysics Data System (ADS)

    Rudersdorf, Andreas; Haedke, Hanna; Reicherter, Klaus

    2013-04-01

    The Gaxun Nur Basin (GNB, also Ejina Basin, Hei River Basin, Ruoshui Basin) north of the Tibetan Plateau and the Hexi Corridor is an endorheic basin bounded by the Bei Shan ranges in the west, the Gobi Altai mountains in the north and the Badain Jaran sand desert in the east. The basin is fed from the south by the braided drainage system of the Hei He (Hei River) and its tributaries, which originate in the Qilian Shan; terminal lakes like the dried Gaxun Nur and Sogo Nur are and have been temporal. The sedimentary succession of up to 300 m comprises intercalations of not only alluvial deposits but also lake sediments and playa evaporites. The basin has been regarded as tectonically inactive by earlier authors; however, the dating of sediments from an earlier drill core in the basin center provided some implications for tectonic activity. Subsequent remote sensing efforts revealed large lineaments throughout the basin which are now considered as possible fault line fingerprints. We investigated well preserved Yardangs (clay terraces) in the northeastern part of the GNB, in the vicinity of the Juyanze (paleo) lake, and found evidence for Holocene active tectonics (seismites). We present a lithological analysis of the relevant sequences and conclusions on the recent tectonic activity within the study area.

  11. Loss of reproductive output caused by an invasive species

    PubMed Central

    Tremblay, Maude E. M.; Morris, Todd J.; Ackerman, Josef D.

    2016-01-01

    We investigated whether Neogobius melanostomus, an invader of biodiversity ‘hot-spots’ in the Laurentian Great Lakes region, facilitates or inhibits unionid mussel recruitment by serving as a host or sink for their parasitic larvae (glochidia). Infestation and metamorphosis rates of four mussel species with at-risk (conservation) status (Epioblasma torulosa rangiana, Epioblasma triquetra, Lampsilis fasciola and Villosa iris) and one common species (Actinonaias ligamentina) on N. melanostomus were compared with rates on known primary and marginal hosts in the laboratory. All species successfully infested N. melanostomus, but only E. triquetra, V. iris and A. ligamentina successfully metamorphosed into juveniles, albeit at very low rates well below those seen on even the marginal hosts. Neogobius melanostomus collected from areas of unionid occurrence in the Grand and Sydenham rivers (Ontario, Canada) exhibited glochidial infection rates of 39.4% and 5.1%, respectively, with up to 30 glochidia representing as many as six unionid species per fish. A mathematical model suggests that N. melanostomus serve more as a sink for glochidia than as a host for unionids, thereby limiting recruitment success. This represents a novel method by which an invasive species affects a native species. PMID:27152202

  12. Loss of reproductive output caused by an invasive species.

    PubMed

    Tremblay, Maude E M; Morris, Todd J; Ackerman, Josef D

    2016-04-01

    We investigated whether Neogobius melanostomus, an invader of biodiversity 'hot-spots' in the Laurentian Great Lakes region, facilitates or inhibits unionid mussel recruitment by serving as a host or sink for their parasitic larvae (glochidia). Infestation and metamorphosis rates of four mussel species with at-risk (conservation) status (Epioblasma torulosa rangiana, Epioblasma triquetra, Lampsilis fasciola and Villosa iris) and one common species (Actinonaias ligamentina) on N. melanostomus were compared with rates on known primary and marginal hosts in the laboratory. All species successfully infested N. melanostomus, but only E. triquetra, V. iris and A. ligamentina successfully metamorphosed into juveniles, albeit at very low rates well below those seen on even the marginal hosts. Neogobius melanostomus collected from areas of unionid occurrence in the Grand and Sydenham rivers (Ontario, Canada) exhibited glochidial infection rates of 39.4% and 5.1%, respectively, with up to 30 glochidia representing as many as six unionid species per fish. A mathematical model suggests that N. melanostomus serve more as a sink for glochidia than as a host for unionids, thereby limiting recruitment success. This represents a novel method by which an invasive species affects a native species.

  13. No vertical axis rotations during Neogene transpressional orogeny in the NE Gobi Altai: coinciding Mongolian and Eurasian early Cretaceous apparent polar wander paths

    NASA Astrophysics Data System (ADS)

    Straathof, G. B.; Hinsbergen, D. V.; Kuiper, K. F.; Cunningham, W.; Wijbrans, J.

    2007-12-01

    Here we test the role of vertical axis rotations during transpressional mountain building. To this end, we carried out a paleomagnetic study in the NE Gobi Altai of southern Mongolia, sampling widely exposed lower Cretaceous lavas allowing comparison of rotation histories of the Ih Bogd, Baga Bogd and Artz Bogd restraining bends at the eastern termination of the Bogd strike-slip zone. We provide new 40Ar/39Ar ages to show that the stratigraphy of mafic lavas and fluvio-lacustrine sediments on the southern flanks of Mt Ih Bogd and Mt Baga Bogd have ages between ~125 and ~122 Ma, and a mafic sill that intrudes the sequence has an age of 118.2 ± 0.8 Ma. The lavas are older than previously dated lavas south of Artz Bogd, with ages of 119-115 Ma. Paleomagnetic results from the 119-115 Ma lavas south of Artz Bogd show a significant steeper inclination than both results from 125-122 Ma lavas of Baga Bogd and Ih Bogd, as well as from newly sampled and previously published younger lavas and necks of the 107-92 Ma Tsost Magmatic Field and Shovon and Khurmen Uul basalts. We explain this result by insufficient averaging of secular variation and small errors induced by overcorrection of bedding tilt. We show that individual lavas in the SE Artz Bogd locality represent individual spot readings of the Earth's magnetic field and integrate all results obtained from lower Cretaceous lavas in the Gobi Altai. We present a pole, or rather, an apparent polar wander path without significant plate motion from ~125-95 Ma, with n=126, ë=80.8, ö=158.4, ê=25.3, A95=2.5, paleo-latitude = 48.2 with a scatter Së=16.7 (Sl=15.3, Su=17.8) and a regionally consistent direction for the Gobi Altai of D/I = 11.1/65.9, ÄD/ÄI = 3.8/1.9. This is one of the best-determined paleopoles/APWP's for Asia. There is no significant deviation of the 125-95 Ma pole position of the Gobi Altai from the reference positions of Eurasia. Formation of the Ih Bogd, Baga Bogd and Artz Bogd restraining bends was thus

  14. Devonian and carboniferous arcs of the oyu tolgoi porphyry Cu-Au district, South Gobi region, Mongolia

    USGS Publications Warehouse

    Wainwright, A.J.; Tosdal, R.M.; Forster, C.N.; Kirwin, D.J.; Lewis, P.D.; Wooden, J.L.

    2011-01-01

    The Central Asian orogenic belt consists of microcontinental blocks and mobile belts positioned between the Siberian craton and the Tarim and North China cratons. Extending across Asia for 5000 km, the belt consists of terranes that decrease in age southward away from the Siberian craton. A time-stratigraphic-structural sequence for the rocks is critical to defining the tectonic evolution of the belt. In the Oyu Tolgoi area of the South Gobi Desert (Mongolia), Devonian and Carboniferous rocks record the construction of multiple arcs, formation of a giant porphyry Cu-Au system, exhumation, and polyphase deformation. The oldest rocks are basaltic volcanic and subvolcanic rocks of the Devonian Alagbayan Group intruded by Late Devonian quartz monzodiorite stocks and dikes, which host giant porphyry Cu-Au deposits. The rocks were exhumed, overlain by pyroclastic rocks, and then tectonically buried by marine mafic supracrustal rocks prior to the youngest Devonian granodiorite intrusions. The postmineral Carboniferous Gurvankharaat Group unconformably overlying the deformed terrane consists of effusive, pyroclastic, subvolcanic and volcaniclastic rocks, as well as sedimentary units. The supracrustal rocks underwent polyphase shortening after 330 Ma and prior to 290 Ma. Variations in stratigraphic sequences suggest that the region is underlain by a submarine arc that became emergent during the Upper Devonian and remained subaerial to shallow subaqueous through much of the Carboniferous. Xenocrystic zircons in igneous rocks suggest that the offshore arcs were sufficiently close to ancient crust to have interacted with detritus shed into marine basins, most likely from the Siberian craton and fringing early Paleozoic terranes. ?? 2011 Geological Society of America.

  15. Vigorous dynamics underlie a stable population of the endangered snow leopard Panthera uncia in Tost Mountains, South Gobi, Mongolia.

    PubMed

    Sharma, Koustubh; Bayrakcismith, Rana; Tumursukh, Lkhagvasumberel; Johansson, Orjan; Sevger, Purevsuren; McCarthy, Tom; Mishra, Charudutt

    2014-01-01

    Population monitoring programmes and estimation of vital rates are key to understanding the mechanisms of population growth, decline or stability, and are important for effective conservation action. We report, for the first time, the population trends and vital rates of the endangered snow leopard based on camera trapping over four years in the Tost Mountains, South Gobi, Mongolia. We used robust design multi-season mark-recapture analysis to estimate the trends in abundance, sex ratio, survival probability and the probability of temporary emigration and immigration for adult and young snow leopards. The snow leopard population remained constant over most of the study period, with no apparent growth (λ = 1.08+-0.25). Comparison of model results with the "known population" of radio-collared snow leopards suggested high accuracy in our estimates. Although seemingly stable, vigorous underlying dynamics were evident in this population, with the adult sex ratio shifting from being male-biased to female-biased (1.67 to 0.38 males per female) during the study. Adult survival probability was 0.82 (SE+-0.08) and that of young was 0.83 (SE+-0.15) and 0.77 (SE +-0.2) respectively, before and after the age of 2 years. Young snow leopards showed a high probability of temporary emigration and immigration (0.6, SE +-0.19 and 0.68, SE +-0.32 before and after the age of 2 years) though not the adults (0.02 SE+-0.07). While the current female-bias in the population and the number of cubs born each year seemingly render the study population safe, the vigorous dynamics suggests that the situation can change quickly. The reduction in the proportion of male snow leopards may be indicative of continuing anthropogenic pressures. Our work reiterates the importance of monitoring both the abundance and population dynamics of species for effective conservation.

  16. Adaptive radiation of gobies in the interstitial habitats of gravel beaches accompanied by body elongation and excessive vertebral segmentation

    PubMed Central

    Yamada, Tomohiko; Sugiyama, Tomoshige; Tamaki, Nana; Kawakita, Atsushi; Kato, Makoto

    2009-01-01

    Background The seacoasts of the Japanese Arc are fringed by many gravel beaches owing to active tectonic uplift and intense denudation caused by heavy rainfall. These gravel beaches are inhabited by gobies of the genus Luciogobius that burrow into the gravel sediment and live interstitially. Although their habitat and morphology (e. g., reduced fins, elongated, scale-less body, and highly segmented vertebral column) are highly unusual among fishes, little is known on how their morphological evolution has facilitated the colonization of interstitial habitats and promoted extensive diversification. We conducted thorough sampling of Luciogobius and related species throughout Japan, and performed molecular phylogenetic analysis to explore the patterns of morphological evolution associated with gravel beach colonization. Results An analysis of the mitochondrial cytochrome b gene suggested a remarkable diversity of previously unrecognized species. The species-level phylogeny based on six protein-coding nuclear genes clearly indicated that interstitial species cluster into two distinct clades, and that transitions from benthic or demersal habits to interstitial habits are strongly correlated with an increase in vertebral number. Colonization of gravel beach habitats is estimated to have occurred ca. 10 Ma, which coincides with the period of active orogenesis of the Japanese landmass. Different species of interstitial Luciogobius inhabit sediments with different granulometric properties, suggesting that microhabitat partitioning has been an important mechanism facilitating speciation in these fishes. Conclusion This is the first study to document the adaptation to interstitial habitats by a vertebrate. Body elongation and excessive vertebral segmentation had been the key aspects enhancing body flexibility and fishes' ability to burrow into the gravel sediment. The rich diversity of coastal gravel habitats of the Japanese Arc has likely promoted the adaptive radiation of

  17. The simultaneous uptake of dietary and waterborne Cd in gastrointestinal tracts of marine yellowstripe goby Mugilogobius chulae.

    PubMed

    Guo, Zhiqiang; Gao, Na; Wu, Yun; Zhang, Li

    2017-04-01

    Aquatic animals under waterborne metal exposure are also very likely exposed to elevated dietary metals. This study quantified the simultaneous uptake of dietary and waterborne Cd in gastrointestinal tracts (GT) of marine yellowstripe goby using a dual stable isotope tracer method. The Cd spiked diet (10-100 μg g(-1), (111)Cd as tracers) were fed to the fish as a single meal, and then the fish were exposed to waterborne Cd (0-500 μg L(-1), (113)Cd as tracers) for 48 h, during which the time-course uptake of Cd in the stomach and intestine was determined. The findings revealed that the dietary Cd uptake mainly occurred within 12 h after feeding. The fish exposed to 500 μg L(-1) waterborne Cd showed significantly lower Cd assimilation efficiency (2.07%) than the control group (3.48%) at the dietary Cd of 100 μg g(-1). Moreover, during 4-12 h when there was chyme in the GT, the waterborne Cd uptake in the intestine was lowest but the stomach showed the highest waterborne Cd uptake rate. The uptake of dietary and waterborne Cd, and the relative importance of dietary vs waterborne Cd was positively correlated with the Cd concentration in the chyme. Overall, this research demonstrated that there was interaction between dietary and waterborne Cd uptake in the GT of marine fish. The simultaneous uptake of metal from two routes is far more complex than the situation of a single route of metal uptake, which should be evaluated in determining metal bioaccumulation and toxicity in both laboratory and field metal exposure scenario.

  18. Effect and mechanism of waterborne prolonged Zn exposure influencing hepatic lipid metabolism in javelin goby Synechogobius hasta.

    PubMed

    Huang, Chao; Luo, Zhi; Hogstrand, Christer; Chen, Feng; Shi, Xi; Chen, Qi-Liang; Song, Yu-Feng; Pan, Ya-Xiong

    2016-07-01

    The present study was conducted to determine the effect and mechanism of waterborne Zn exposure influencing hepatic lipid deposition and metabolism in javelin goby Synechogobius hasta. S. hasta were exposed to four waterborne Zn concentrations (Zn 0.005 [control], 0.18, 0.36 and 0.55 mg l(-1) , respectively) for 60 days. Sampling occurred at days 20, 40 and 60, respectively. Zn exposure increased Zn content, declined hepatic lipid content and reduced viscerosomatic and hepatosomatic indices and lipogenic enzyme activities, including 6-phosphogluconate dehydrogenase (6PGD), glucose-6-phosphate dehydrogenase (G6PD), malic enzyme (ME) and fatty acid synthase (FAS). At days 20 and 60, Zn exposure decreased hepatic mRNA levels of 6PGD, G6PD, ME, FAS, acetyl-CoA carboxylase (ACC)α, ACCβ, hormone-sensitive lipase (HSL)a, HSLb, sterol-regulator element-binding protein (SREBP)-1, peroxisome proliferators-activated receptor (PPAR)α and PPARγ. However, the mRNA levels of CPT 1 and adipose triglyceride lipase increased following Zn exposure. On day 40, Zn exposure reduced hepatic mRNA expression of 6PGD, G6PD, ME, FAS, ACCα, ACCβ, HSLa, HSLb, SREBP-1 and PPARγ but increased mRNA expression of CPT 1, adipose triglyceride lipase and PPARα. General speaking, Zn exposure reduced hepatic lipid content by inhibiting lipogenesis and stimulating lipolysis. For the first time, the present study provided evidence that chronic Zn exposure differentially influenced mRNA expression and activities of genes and enzymes involved in lipogenic and lipolytic metabolism in a duration-dependent manner, and provided new insight into the relationship between metal elements and lipid metabolism. Copyright © 2015 John Wiley & Sons, Ltd.

  19. [Mass-transfer, utilization, and diffusion of oxygen in skeletal muscles of the stenohaline goby Gobius cobitus Pallas under conditions of hypoosmotic medium].

    PubMed

    Soldatov, A A

    2012-01-01

    Effect of hypoosmotic conditions of medium on oxygen regime of skeletal muscles of the stenohalin goby Gobius cobitus Pallas was studied under conditions of experiment. The control fish group was maintained at 12-14 %o, the experimental one - at 4.8-5.6 per thousand. Duration of the experiment - 44-45 days, water temperature - 15 +/- 1 degrees C, photoperiod - 12 day/12 night. It was established that under conditions of external hypoosmia there occurred hydration of the goby skeletal muscles and a decrease of their diffusion capability with respect to oxygen. The latter was accompanied by the tissue P(O2) decrease, which is indicated by low values of P(O2) in the venous blood outflowing from muscles. For the first 14-16 days of adaptation to the hypoosmotic medium there were restricted processes of mass transfer and oxygen utilization, which was associated with a decrease of the voluminous tissue blood flow and the blood oxygen concentration. These changes occurred on the background of the blood plasma hydration and a decrease of the number of circulated erythrocytes, and then they were completely compensated.

  20. Experimental transmission of VHSV genotype IVb by predation.

    PubMed

    Getchell, Rodman G; Cornwell, Emily R; Groocock, Geoffrey H; Wong, Po Ting; Coffee, Laura L; Wooster, Gregory A; Bowser, Paul R

    2013-12-01

    Preliminary surveillance of wild baitfish during the 2006 viral hemorrhagic septicemia virus genotype IVb (VHSV IVb) outbreaks indicated Emerald Shiners Notropis atherinoides and Bluntnose Minnow Pimephales notatus were infected with high levels of VHSV without showing clinical signs of disease. The movement and use of baitfish was recognized as the most probable vector for the introduction of VHSV to inland waters, such as Conesus Lake and Skaneateles Lake in New York, Budd Lake in Michigan, and Little Lake Butte des Morts and Lake Winnebago in Wisconsin. While numerous government agencies implemented restrictions to stop the movement of potentially infected baitfish into new waters and prevent the spread of VHSV IVb, until now, studies to investigate whether these initial introductions were by an oral route of infection have not occurred. Our studies identified infected Fathead Minnow Pimephales promelas as suitable vectors for transmitting VHSV IVb when fed to Tiger Muskellunge ( ♂ Northern Pike Esox lucius × ♀ Muskellunge Esox masquinongy) during laboratory trials. Six of 16 Tiger Muskellunge were infected with VHSV IVb after consumption of infected Fathead Minnows when assayed with quantitative reverse transcriptase polymerase chain reaction and viral isolation in cell culture. Weekly sampling of water and feces from these Tiger Muskellunge individually reared showed intermittent shedding of VHSV IVb. Those exposed to similarly VHSV IVb-inoculated fathead minnows by cohabitation only became infected in 1 case out of 16. A similar trial of 12 Tiger Muskellunge fed Round Goby Neogobius melanostomus that survived a VHSV IVb immersion challenge did not result in infection. Overall, our findings imply that consumption of infected wild baitfish may be a risk factor for introduction of VHSV.

  1. Great lakes prey fish populations: a cross-basin overview of status and trends based on bottom trawl surveys, 1978-2012

    USGS Publications Warehouse

    Gorman, Owen T.

    2012-01-01

    The assessment of prey fish stocks in the Great Lakes have been conducted annually with bottom trawls since the 1970s by the Great Lakes Science Center, sometimes assisted by partner agencies. These stock assessments provide data on the status and trends of prey fish that are consumed by important commercial and recreational fishes. Although all these annual surveys are conducted using bottom trawls, they differ among the lakes in the proportion of the lake covered, seasonal timing, bottom trawl gear used, and the manner in which the trawl is towed (across or along bottom contours). Because each assessment is unique in one or more important aspects, direct comparison of prey fish catches among lakes is not straightforward. However, all of the assessments produce indices of abundance or biomass that can be standardized to facilitate comparisons of status and trends across all the Great Lakes. In this report, population indices were standardized to the highest value for a time series within each lake for the following principal prey species: cisco (Coregonus artedi), bloater (C. hoyi), rainbow smelt (Osmerus mordax), and alewife (Alosa pseudoharengus). Indices were also provided for round goby (Neogobius melanostomus), an invasive fish that has proliferated throughout the basin over the past 18 years. These standardized indices represent the best available long-term indices of relative abundance for these fishes across all of the Great Lakes. In this report, standardized indices are presented in graphical form along with synopses to provide a short, informal cross-basin summary of the status and trends of principal prey fishes. In keeping with this intent, tables, references, and a detailed discussion were omitted.

  2. Metals in edible fish from Vistula River and Dead Vistula River channel, Baltic Sea.

    PubMed

    Wyrzykowska, Barbara; Falandysz, Jerzy; Jarzyńska, Grażyna

    2012-01-01

    Metals including Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Pb, Sr and Zn were determined in muscle tissue of 12 fish species by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and cold vapour-atomic absorption spectroscopy (CV-AAS). Fish were collected from Vistula River at lower course and Dead Vistula River channel in south of Baltic Sea in Poland. The fish species examined include Round Goby (Neogobius melanostomus), Crucian Carp (Carassius carassius), Bull-rout (Myoxocephalus scorpius), Tench (Tinca tinca), Bream (Abramis brama), Burbot (Lota lot), Perch (Perca perca), Roach (Rutilus rutilus), Silver Carp (Hypophthalmichthys molitrix), Pikeperch (Stizostediun lucioperca), Brown salmon (Salmo trutta m. Trutta) and Eel (Anguilla anguilla). The median values of metal concentrations in fresh muscle tissue of 11 fish species varied as follows: Al < 0.5-60; Ba < 0.05-0.31; Ca 120-1800; Cd < 0.05-0.096; Co < 0.10; Cr < 0.10-0.50; Cu < 0.15-0.77; Fe 1.5-21; Hg 0.0058-0.65; K 1800-4200; Mg 130-560; Mn 0.12-0.59; Na 350-840; Ni < 0.2-0.31; Pb < 0.75; Sr 0.079-2.9; Zn 3.3-23 μg/g fresh weight. The Target Hazard Quotient (THQ) values calculated in this study for Cd and Hg from muscles of fish species collected from Vistula River were low in the range of 0.4 for Hg and 0.8 for Cd.

  3. Bathythermal habitat use by strains of Great Lakes- and Finger Lakes-origin lake trout in Lake Huron after a change in prey fish abundance and composition

    USGS Publications Warehouse

    Bergstedt, Roger A.; Argyle, Ray L.; Krueger, Charles C.; Taylor, William W.

    2012-01-01

    A study conducted in Lake Huron during October 1998–June 2001 found that strains of Great Lakes-origin (GLO) lake trout Salvelinus namaycush occupied significantly higher temperatures than did Finger Lakes-origin (FLO; New York) lake trout based on data from archival (or data storage) telemetry tags that recorded only temperature. During 2002 and 2003, we implanted archival tags that recorded depth as well as temperature in GLO and FLO lake trout in Lake Huron. Data subsequently recorded by those tags spanned 2002–2005. Based on those data, we examined whether temperatures and depths occupied by GLO and FLO lake trout differed during 2002–2005. Temperatures occupied during those years were also compared with occupied temperatures reported for 1998–2001, before a substantial decline in prey fish biomass. Temperatures occupied by GLO lake trout were again significantly higher than those occupied by FLO lake trout. This result supports the conclusion of the previous study. The GLO lake trout also occupied significantly shallower depths than FLO lake trout. In 2002–2005, both GLO and FLO lake trout occupied significantly lower temperatures than they did in 1998–2001. Aside from the sharp decline in prey fish biomass between study periods, the formerly abundant pelagic alewife Alosa pseudoharengus virtually disappeared and the demersal round goby Neogobius melanostomus invaded the lake and became locally abundant. The lower temperatures occupied by lake trout in Lake Huron during 2002–2005 may be attributable to changes in the composition of the prey fish community, food scarcity (i.e., a retreat to cooler water could increase conversion efficiency), or both.

  4. Thiamine and thiaminase status in forage fish of salmonines from Lake Michigan

    USGS Publications Warehouse

    Tillitt, D.E.; Zajicek, J.L.; Brown, S.B.; Brown, L.R.; Fitzsimons, J.D.; Honeyfield, D.C.; Holey, M.E.; Wright, G.M.

    2005-01-01

    Dietary sources of thiamine (vitamin B1) and thiamine-degrading enzymes (thiaminases) are thought to be primary factors in the development of thiamine deficiency among Great Lakes salmonines. We surveyed major forage fish species in Lake Michigan for their content of thiamine, thiamine vitamers, and thiaminase activity. Concentrations of total thiamine were similar (P ≤ 0.05) among most forage fishes (alewife Alosa pseudoharengus, bloater Coregonus hoyi, spottail shiner Notropis hudsonius, deepwater sculpin Myoxocephalus thompsonii, yellow perch Perca flavescens, ninespine stickleback Pungitius pungitius, and round goby Neogobius melanostomus) and slightly lower in rainbow smelt Osmerus mordax. Concentrations of total thiamine were all above the dietary requirements of coldwater fishes, suggesting the thiamine content of forage fish is not the critical factor in the development of thiamine deficiency in Lake Michigan salmonines. Thiamine pyrophosphate was the predominant form of thiamine in most species of forage fish, followed by free thiamine and thiamine monophosphate. Total thiamine was slightly greater in summer collections of alewife and rainbow smelt than in spring and fall collections, but the same was not true for bloater. Thiaminase activity varied among species and was greatest in gizzard shad Dorosoma cepedianum, spottail shiner, alewife, and rainbow smelt. Thiaminase activity in alewife varied among collection locations, season (greatest in spring), and size of the fish. Size and condition factors were positively correlated with both total thiamine and thiaminase activity in alewife. Thus, thiamine and thiaminase activity in forage fishes collected in Lake Michigan varied among species, seasons, year caught, and size (or condition). Therefore, multiple factors must be considered in the development of predictive models for the onset of thiamine deficiency in Great Lakes salmonines. Most importantly, thiaminase activity was great in alewives and

  5. Coupling age-structured stock assessment and fish bioenergetics models: a system of time-varying models for quantifying piscivory patterns during the rapid trophic shift in the main basin of Lake Huron

    USGS Publications Warehouse

    He, Ji X.; Bence, James R.; Madenjian, Charles P.; Pothoven, Steven A.; Dobiesz, Norine E.; Fielder, David G.; Johnson, James E.; Ebener, Mark P.; Cottrill, Adam R.; Mohr, Lloyd C.; Koproski, Scott R.

    2015-01-01

    We quantified piscivory patterns in the main basin of Lake Huron during 1984–2010 and found that the biomass transfer from prey fish to piscivores remained consistently high despite the rapid major trophic shift in the food webs. We coupled age-structured stock assessment models and fish bioenergetics models for lake trout (Salvelinus namaycush), Chinook salmon (Oncorhynchus tshawytscha), walleye (Sander vitreus), and lake whitefish (Coregonus clupeaformis). The model system also included time-varying parameters or variables of growth, length–mass relations, maturity schedules, energy density, and diets. These time-varying models reflected the dynamic connections that a fish cohort responded to year-to-year ecosystem changes at different ages and body sizes. We found that the ratio of annual predation by lake trout, Chinook salmon, and walleye combined with the biomass indices of age-1 and older alewives (Alosa pseudoharengus) and rainbow smelt (Osmerus mordax) increased more than tenfold during 1987–2010, and such increases in predation pressure were structured by relatively stable biomass of the three piscivores and stepwise declines in the biomass of alewives and rainbow smelt. The piscivore stability was supported by the use of alternative energy pathways and changes in relative composition of the three piscivores. In addition, lake whitefish became a new piscivore by feeding on round goby (Neogobius melanostomus). Their total fish consumption rivaled that of the other piscivores combined, although fish were still a modest proportion of their diet. Overall, the use of alternative energy pathways by piscivores allowed the increases in predation pressure on dominant diet species.

  6. Diet shifts by planktivorous and benthivorous fishes in northern Lake Michigan in response to ecosystem changes

    USGS Publications Warehouse

    Bunnell, David B.; Davis, Bruce M.; Chriscinske, Margret Ann; Keeler, Kevin M.; Mychek-Londer, Justin G.

    2015-01-01

    In Lake Michigan, diets of planktivorous and benthivorous fishes have varied over the past decades, in part owing to food web changes. To update diet information and compare them to a similar effort in 1994–1995, we analyzed the diets of seven benthivorous and planktivorous fish species collected along two northern Lake Michigan transects that spanned nearshore (18 m), intermediate (46 m), and offshore (91, 110, 128 m) bottom depths during spring, summer, and autumn of 2010. Calanoid copepods (e.g., Limnocalanus macrurus, Leptodiaptomus sicilis, and Senecella calanoides) comprised a majority of the diets in at least one season for all sizes of alewife (Alosa pseudoharengus), bloater (Coregonus hoyi), and rainbow smelt (Osmerus mordax). Similarly, Mysis diluviana was the highest proportion in at least one season for large sizes of alewife, bloater, and rainbow smelt, as well as slimy sculpin (Cottus cognatus) and deepwater sculpin (Myoxocephalus thompsonii). The diets of the remaining two species, ninespine stickleback (Pungitius pungitius) and round goby (Neogobius melanostomus), were dominated by herbivorous cladocerans or dreissenid mussels, respectively. Interspecific diet overlap was minimal at 18 and 46 m. In offshore waters, however, overlap was relatively high, driven by frequent consumption of Mysis. Relative to 1994–1995, 2010 diets revealed increased feeding on calanoid copepods and Mysis, with corresponding declining consumption of Diporeia spp. and herbivorous cladocerans. Relative diet weight was also higher in 1994–1995 than in 2010 for small and large bloater and both sculpin species. We hypothesize that the shifts in diets are reflective of community-level changes in invertebrate prey availability.

  7. Long-term impacts of invasive species on a native top predator in a large lake system

    USGS Publications Warehouse

    Rush, Scott A.; Paterson, Gordon; Johnson, Tim B.; Drouillard, Ken G.; Haffner, Gordon D.; Hebert, Craig E.; Arts, Michael T.; McGoldrick, Daryl J.; Backus, Sean M.; Lantry, Brian F.; Lantry, Jana R.; Schaner, Ted; Fisk, Aaron T.

    2012-01-01

    1. Declining abundances of forage fish and the introduction and establishment of non-indigenous species have the potential to substantially alter resource and habitat exploitation by top predators in large lakes. 2. We measured stable isotopes of carbon (δ13C) and nitrogen (δ15N) in field-collected and archived samples of Lake Ontario lake trout (Salvelinus namaycush) and five species of prey fish and compared current trophic relationships of this top predator with historical samples. 3. Relationships between δ15N and lake trout age were temporally consistent throughout Lake Ontario and confirmed the role of lake trout as a top predator in this food web. However, δ13C values for age classes of lake trout collected in 2008 ranged from 1.0 to 3.9‰ higher than those reported for the population sampled in 1992. 4. Isotope mixing models predicted that these changes in resource assimilation were owing to the replacement of rainbow smelt (Osmerus mordax) by round goby (Neogobius melanostomus) in lake trout diet and increased reliance on carbon resources derived from nearshore production. This contrasts with the historical situation in Lake Ontario where δ13C values of the lake trout population were dominated by a reliance on offshore carbon production. 5. These results indicate a reduced capacity of the Lake Ontario offshore food web to support the energetic requirements of lake trout and that this top predator has become increasingly reliant on prey resources that are derived from nearshore carbon pathways.

  8. Emission, transport, and radiative effects of mineral dust from the Taklimakan and Gobi deserts: comparison of measurements and model results

    NASA Astrophysics Data System (ADS)

    Chen, Siyu; Huang, Jianping; Kang, Litai; Wang, Hao; Ma, Xiaojun; He, Yongli; Yuan, Tiangang; Yang, Ben; Huang, Zhongwei; Zhang, Guolong

    2017-02-01

    The Weather Research and Forecasting Model with chemistry (WRF-Chem model) was used to investigate a typical dust storm event that occurred from 18 to 23 March 2010 and swept across almost all of China, Japan, and Korea. The spatial and temporal variations in dust aerosols and the meteorological conditions over East Asia were well reproduced by the WRF-Chem model. The simulation results were used to further investigate the details of processes related to dust emission, long-range transport, and radiative effects of dust aerosols over the Taklimakan Desert (TD) and Gobi Desert (GD). The results indicated that weather conditions, topography, and surface types in dust source regions may influence dust emission, uplift height, and transport at the regional scale. The GD was located in the warm zone in advance of the cold front in this case. Rapidly warming surface temperatures and cold air advection at high levels caused strong instability in the atmosphere, which strengthened the downward momentum transported from the middle and low troposphere and caused strong surface winds. Moreover, the GD is located in a relatively flat, high-altitude region influenced by the confluence of the northern and southern westerly jets. Therefore, the GD dust particles were easily lofted to 4 km and were the primary contributor to the dust concentration over East Asia. In the dust budget analysis, the dust emission flux over the TD was 27.2 ± 4.1 µg m-2 s-1, which was similar to that over the GD (29 ± 3.6 µg m-2 s-1). However, the transport contribution of the TD dust (up to 0.8 ton d-1) to the dust sink was much smaller than that of the GD dust (up to 3.7 ton d-1) because of the complex terrain and the prevailing wind in the TD. Notably, a small amount of the TD dust (PM2.5 dust concentration of approximately 8.7 µg m-3) was lofted to above 5 km and transported over greater distances under the influence of the westerly jets. Moreover, the direct radiative forcing induced by dust

  9. Large males fight and court more across a range of social environments: an experiment on the two spotted goby Gobiusculus flavescens.

    PubMed

    Wacker, S; de Jong, K; Forsgren, E; Amundsen, T

    2012-07-01

    The present study explored how male size relates to mating competition across a natural range of male and female densities in the two-spotted goby Gobiusculus flavescens. Across this range of social environments, large males were more than twice as likely as small ones to chase other males, to become nest-holders, and to court females, but large males were not significantly more likely to engage in agonistic fin displays. Overall, the study showed that large males court and fight more than small ones across a wide, yet natural, span of social environments. Having a large body size appears to confer competitive advantage for males in any social environment of the study species. Further studies are needed to disentangle whether the benefit of large size is mainly in competition over resources, over matings as such, or both.

  10. Morphological and molecular identification of Gyrodactylus bubyri Osmanov, 1965 (Monogenea: Gyrodactylidae) from Caucasian dwarf goby, Knipowitschia caucasica (Berg) (Actinopterygii: Gobionellidae) from a Black Sea lagoon.

    PubMed

    Stoyanov, Borislav; Huyse, Tine; Pankov, Plamen; Georgiev, Boyko B

    2016-04-01

    Gyrodactylus bubyri Osmanov, 1965, a monogenean parasite of Caucasian dwarf goby Knipowitschia caucasica (Berg) described from Aral Sea and subsequently reported from the same host from Strymon River, Greece, is recorded from Atanasovsko Lake, Bulgarian Black Sea coast (the first record of G. bubyri from the Black Sea basin). The species is redescribed by light and scanning electron microscopy as well as the ITS rDNA sequence is obtained. As comparative materials, specimens of G. bubyri from K. caucasica (Strymon River), G. charon Vanhove and Huyse in Vanhove et al., 2014 from Knipowitschia milleri (Acheron Delta, Greece) and G. micropsi Gläser, 1974 from Potamoschistus microps from North Sea (Belgium) are studied. Comparative morphology and molecular data demonstrate that G. micropsi is a junior synonym of G. bubyri (new synonymy). The validity of G. charon is questioned, pending examination of additional materials in order to prove it as a distinct species or as a junior synonym of G. bubyri.

  11. Turning up the heat: the effects of thermal acclimation on the kinetics of hsp70 gene expression in the eurythermal goby, Gillichthys mirabilis.

    PubMed

    Lund, Susan G; Ruberté, Marlena R; Hofmann, Gretchen E

    2006-04-01

    Most organisms respond to temperature fluctuations by altering the expression of an evolutionarily conserved family of proteins known as heat shock proteins (Hsps). Studies have shown Hsp expression and the activation of HSF1, one of the primary regulators of Hsp transcription, are highly malleable, varying with the recent thermal history of the organism; however, the mechanisms that confer plasticity to the regulation of this ubiquitous response are not well-understood. This study furthers our knowledge in this area by characterizing the activation kinetics of HSF1 and the corresponding transcription of hsp70 in the liver of the eurythermal goby, Gillichthys mirabilis, following a month-long acclimation at 13, 21 or 28 degrees C. Our data revealed HSF1 DNA-binding kinetics varied as a function of acclimation temperature and magnitude/duration of exposure, with gobies acclimated at 21 degrees C exhibiting the most robust response. Hsp70 mRNA followed a similar pattern with induction first occurring in the 13 and 21 degrees C fish, and then most robustly in the 28 degrees C group at 36 degrees C. The hsp70 mRNA induction pattern was corroborated by levels of HSF1 DNA-binding activity in each group and may have been lowest in the 28 degrees C group due to the 2-fold greater levels of hsp70 protein prior to thermal exposure. This study illustrates the integral role of HSF1 as a key regulator of Hsp induction and helps explain the plasticity of this response in ectothermic organisms.

  12. New Light on the Evolutionary History of the Common Goby (Pomatoschistus microps) with an Emphasis on Colonization Processes in the Mediterranean Sea

    PubMed Central

    Tougard, Christelle; Folly, Joy; Berrebi, Patrick

    2014-01-01

    Through the study of the phylogeographic structure and demographic history of the common goby, Pomatoschistus microps, the influence of Quaternary climatic changes on the evolutionary history of coastal and marine fishes is investigated. Because of its sedentary life cycle in Mediterranean lagoons, it is also a good model to study more specifically if the formation of lagoons during the Holocene had an impact on population structure and demography. Mitochondrial sequences of Northeastern Atlantic and Western Mediterranean specimens were used for phylogenetic reconstructions as well as divergence time estimates, demographic history and population structure analyses. Pomatoschistus microps was a highly supported monophyletic clade including four lineages. It may have appeared 77,000 yr ago, and the divergence of its lineages likely occured shortly thereafter (between 61,000 and 54,000 yr). Most lineages had polytomic topologies, low nucleotide diversity and demographic analyses providing evidence of population expansion. Each lineage was characterized by a large number of private haplotypes. Most haplotypes found in Mediterranean localities were endemic, and one was dominant. Complex reticulated relationships connecting North European, Atlantic and Mediterranean haplotypes were observed. Moderate to high population structure was underlined. Contrary to previous published studies, no significant differentiation was observed between Atlantic and Mediterranean populations, indicating that the Gibraltar Strait is not a phylogeographic break for P. microps. Indeed, molecular dating combined with the tree topologies, phylogeographic and demographic analyses as well as high haplotype diversity underline a recent and rapid population divergence during the last glacial. However, population structure indicates that differentiation is an ongoing process. From an ancestral population trapped in the Atlantic, this goby colonized first northern Europe and later the Mediterranean

  13. Slip rates and ages of past earthquakes along the western Bogd and Valley-of-Lake strike slip faults (Gobi-Altay, Mongolia)

    NASA Astrophysics Data System (ADS)

    Kurtz, R.; Ritz, J. F.; Klinger, Y.; Ferry, M. A.; Davaasambuu, B.; CHOI, J. H.; Magali, R.; Bollinger, L.; Braucher, R.; Ulzibat, M.; Odonbaatar, C.; Demberel, S.

    2015-12-01

    The Gobi-Altay massif in southwestern Mongolia recorded one of the largest intracontinental earthquakes during the XXth century (04.12.57, Mw~8). This left-lateral strike-slip earthquake ruptured a 260 km-long section along the eastern part of the Bogd fault. About 100km of additional ruptures (essentially reverse) were also documented along subsidiary faults. Previous morphological and paleoseismological investigations along the eastern Bogd Fault determined a long-term slip rate of ~1 mm/yr and a mean recurrence interval of 3000-4000 years for events similar to the 1957 earthquake. The active tectonics of the western part of the Gobi-Altay massif proves to be more complex than the eastern section. Deformation is occurring along two strike-slip fault systems, the Western Bogd fault and the Valley-of-Lakes fault. This raises the question of the distribution of the deformation in space and time. In order to determine slip rates and dates of past events along the Western Bogd and Valley of Lakes faults, we carried out tectonic geomorphology and paleoseismological investigations. Preliminary results from a first expedition in 2014 allow estimating a slip rate of 0.3 mm/yr along the Valley-of-Lakes fault during the past 150 ka. Further analyses from a second expedition in summer 2015, should allow testing whether this rate remained stable through time, notably over the Holocene period. They will also enable determining the slip rate and the age of the most recent surface-rupturing event along the Western Bogd fault.

  14. Geology and reconnaissance stable isotope study of the Oyu Tolgoi porphyry Cu-Au system, South Gobi, Mongolia

    USGS Publications Warehouse

    Khashgerel, B.-E.; Rye, R.O.; Hedenquist, J.W.; Kavalieris, I.

    2006-01-01

    The Oyu Tolgoi porphyry Cu-Au system in the South Gobi desert, Mongolia, comprises five deposits that extend over 6 km in a north-northeast-oriented zone. They occur in a middle to late Paleozoic are terrane and are related to Late Devonian quartz monzodiorite intrusions. The Hugo Dummett deposits are the northernmost and deepest, with up to 1,000 m of premineral sedimentary and volcanic cover rock remaining. They are the largest deposits discovered to date and characterized by high-grade copper (>2.5% Cu) and gold (0.5-2 g/t) mineralization associated with intense quartz veining and several phases of quartz monzodiorite intruded into basaltic volcanic host rocks. Sulfide minerals in these deposits are zoned outward from a bornite-dominated core to chalcopyrite, upward to pyrite ?? enargite and covellite at shallower depth. The latter high-sulfidation-state sulfides are hosted by advanced argillic alteration mineral associations. This alteration is restricted mainly to dacitic ash-flow tuff that overlies the basaltic volcanic rock and includes ubiquitous quartz and pyrophyllite, kaolinite, plus late dickite veins, as well as K alunite, Al phosphate-sulfate minerals, zunyite, diaspore, topaz, corundum, and andalusite. A reconnaissance oxygen-hydrogen and sulfur isotope study was undertaken to investigate the origin of several characteristic alteration minerals in the Oyu Tolgoi system, with particular emphasis on the Hugo Dummett deposits. Based on the isotopic composition of O, H, and S (??18O(SO4) = 8.8-20.1???, ??D = -73 to -43???, ??34S = 9.8-17.9???), the alunite formed from condensation of magmatic vapor that ascended to the upper parts of the porphyry hydrothermal system, without involvement of significant amounts of meteoric water. The isotopic data indicate that pyrophyllite (??18O = 6.5-10.9???, ??D = -90 to -106???) formed from a magmatic fluid with a component of meteoric water. Muscovite associated with quartz monzodiorite intrusions occurs in the core

  15. Great Lakes prey fish populations: a cross-basin overview of status and trends based on bottom trawl surveys, 1978-2013

    USGS Publications Warehouse

    Gorman, Owen T.; Weidel, Brian C.

    2014-01-01

    The assessment of Great Lakes prey fish stocks have been conducted annually with bottom trawls since the 1970s by the Great Lakes Science Center, sometimes assisted by partner agencies. These stock assessments provide data on the status and trends of prey fish that are consumed by important commercial and recreational fishes. Although all these annual surveys are conducted using bottom trawls, they differ among the lakes in the proportion of the lake covered, seasonal timing, trawl gear used, and the manner in which the trawl is towed (across or along bottom contours). Because each assessment is unique, population indices were standardized to the highest value for a time series within each lake for the following prey species: Cisco (Coregonus artedi), Bloater (C. hoyi), Rainbow Smelt (Osmerus mordax), Alewife (Alosa pseudoharengus), and Round Goby (Neogobius melanostomus). In this report, standardized indices are presented in graphical form along with synopses to provide a short, informal cross-basin summary of the status and trends of principal prey fishes. There was basin-wide agreement in the trends of age-1 and older biomass for all prey species, with the highest concordance occurring for coregonids and Rainbow Smelt, and weaker concordance for Alewife. For coregonids, the highest biomass occurred from the mid-1980s to the mid-1990s. Rainbow Smelt biomass declined slowly and erratically during the last quarter century. Alewife biomass was generally higher from the early 1980s through 1990s across the Great Lakes, but since the early 1990s, trends have been divergent across the lakes, though there has been a downward trend in all lakes since 2005. Recently, Lake Huron has shown resurgence in biomass of Bloater, achieving 75% of its maximum record in 2012 due to recruitment of a succession of strong and moderate year classes that appeared in 2005-2011. Also, strong recruitment of the 2010 year class of Alewife has led to a sharp increase in biomass of Alewife in

  16. Evidence for partial melting at northern Tavan Har and relationship to Late Triassic sinistral shear in the East Gobi Fault Zone, southeastern Mongolia

    NASA Astrophysics Data System (ADS)

    Stypula, M.; Webb, L. E.; Hagen-Peter, G. A.

    2009-12-01

    We present preliminary data and interpretations from an ongoing study focused on the timing, extent, and significance of partial melting at northern Tavan Har in southeastern Mongolia. Tavan Har is a basement block within the East Gobi Fault Zone. Regional studies of the East Gobi Fault Zone reveal at least three phases of reactivation during the Mesozoic, including the formation of a Late Triassic sinistral ductile shear zone that can be traced for ~250 km along strike. The metamorphic tectonites of the shear zone exposed in the northern Tavan Har block are dominated by steeply-dipping, NE-striking foliations and subhorizontal lineations. The lithologies of northern Tavan Har consist of mylonite, ultramylonite, amphibolite-facies gneiss, granitic gneiss, and migmatite. The suite of lithologies is observed to extend to the northern margin of the study region where they are overprinted at greenschist-facies conditions and ultimately truncated by the Northern Zuunbayan Fault. The granitic gneiss is a synkinematic pluton that truncates the western margin of Tavan Har and includes vestiges of amphibolite and mylonite lithologies. The amphibolite grade tectonites represent the highest metamorphic grade in relation to the shear zone. Mylonites located throughout the shear zone exhibit WNW plunging lineations. Many generations of dikes and veining are apparent throughout the field area, revealing variable degrees of folding and cross cutting relationships. The southern margin of the migmatite zone is in fault contact with Lower Cretaceous rift basin strata. Previous argon dating determined that the timing of ductile sinistral shear at amphibolite-facies conditions occurred c. 225 Ma. The same study obtained an age of 240 Ma for hornblende from a melanosome within the migmatite unit, giving significance to the question of the timing of partial melting and its relationship to the shear zone. New mapping and structural analysis of the southern margin of the northern Tavan

  17. A Holocene East Asian winter monsoon record at the southern edge of the Gobi Desert and its comparison with a transient simulation

    NASA Astrophysics Data System (ADS)

    Li, Yu; Morrill, Carrie

    2015-09-01

    The East Asian winter monsoon (EAWM) exhibits significant variability on intraseasonal, interannual, and interdecadal time scales and the variability can be extended to Holocene centennial and millennial scales. Previous Holocene EAWM proxy data records, which were mostly located in Central, Eastern and Southern China, did not show a consistent Holocene EAWM history. Therefore, it is difficult to provide insights into mechanisms of the long-term winter monsoon variability on the basis of the records. Eolian sediments at the southern edge of the Gobi Desert, Western China, are sensitive to the EAWM changes and less affected by the East Asian summer monsoon due to an obstruction of the Qinghai-Tibet Plateau. This paper presents a comparison between a well-dated Holocene EAWM record and coupled climate model simulations, so as to explore physical processes and influencing factors of the Holocene EAWM. Sediment samples from two Holocene eolian sedimentary sections [Huangyanghe (a) and Huangyanghe (b)] were acquired at the southern edge of the Gobi Desert. Chronologies were established based on twenty bulk organic matter AMS 14C ages and five pollen concentrates AMS 14C ages. Proxy data, including grain-size, total organic carbon, magnetic susceptibility and carbonate content were obtained from the two eolian sections. The grain-size standard deviation model was applied to determine components sensitive to variability of the Holocene EAWM. After a comparison of environmentally-sensitive grain-size components and proxy data, the 20-200 μm component at the Huangyanghe (a) and the 20-159 μm component at the Huangyanghe (b) section were selected as indicators of the Holocene EAWM, which show a strong early Holocene winter monsoon and a decline of the winter monsoon since the mid-Holocene. We also present equilibrium and transient simulations of the climate evolution for the Holocene using a state-of-art coupled climate model: the Community Climate System Model version 3

  18. DNA markers indicate low genetic diversity and high genetic divergence in the landlocked freshwater goby, Rhinogobius sp. YB, in the Ryukyu Archipelago, Japan.

    PubMed

    Ohara, Kenichi; Takagi, Motohiro; Hashimoto, Miho; Miyazaki, Kazunori; Hirashima, Kentaro

    2008-04-01

    Genetic diversity and genetic divergence were investigated in the landlocked goby Rhinogobius sp. YB by analysis of seven microsatellite DNA loci and the mtDNA control region sequence, and were compared with those of the closely related amphidromous species Rhinogobius sp. DA. Samples of Rhinogobius sp. YB and Rhinogobius sp. DA were collected from seven and four rivers, respectively. All pairwise Fst tests based on microsatellite DNA showed significant genetic differences, except for one pair of populations of Rhinogobius sp. DA (P<0.00064, alpha=78). The average Nei's genetic distance was 0.616 in Rhinogobius sp. YB and 0.394 in Rhinogobius sp. DA. Forty-two haplotypes were detected in both species, and almost all Rhinogobius sp. YB populations included different haplotypes. The means of allelic richness, Ho, and He in Rhinogobius sp. YB (2.057, 0.149, and 0.156, respectively) were significantly lower than in Rhinogobius sp. DA (4.868, 0.366, and 0.403, respectively; P<0.05). The high genetic divergence and low genetic diversity in Rhinogobius sp. YB may have resulted from repeated colonizations of rivers by different founders. Efforts to conserve genetic resources should take these evolutionarily significant units (ESU) of Rhinogobius sp. YB into account. The genetic markers used in this study provide simple and highly informative indicators for Rhinogobius sp. YB population management.

  19. Landscape dynamics assessment of dry climatic zones on the Baikal-Gobi transect from NDVI time series and field investigations data

    NASA Astrophysics Data System (ADS)

    Sayapina, D. O.; Zharnikova, M. A.; Tsydypov, B. Z.; Sodnomov, B. V.; Garmaev, E. Zh

    2016-11-01

    Starting in the eighties of the 20th century, the scientists of the Baikal Institute of Nature Management (BINM SB RAS) have been conducting field observations of the Transbaikalia geosystems transformation due to the change of climate and nature management. An utmost importance is placed on the study of a negative response of the land geosystems. This is shown through their deterioration, degradation, and desertification in particular. Through the years of research (1985-2015) in dry areas of the north of Central Asia, the scientists of the BINM SB RAS established a network of key sites for contact monitoring of the status and dynamics of the geosystems and the negative natural-anthropogenic processes along the Baikal-Gobi meridional transect (51-44° N, 105-107° E). The monitoring of the status and dynamics of the vegetation cover of some key sites is conducted by processing and analysis of multitemporal and multispectral Landsat and MODIS Terra imagery. An automatic analysis of the time variation of NDVI and a comparison with the progress of the index in the previous seasons are performed. The landscape indication of the key sites is made on the basis of satellite imagery and complete geobotanical descriptions. Landscape profiles and facies maps with natural boundaries are created.

  20. [Evaluation of the efficacity of coconut (Cocos nucifera), palm nut (Eleais guineensis) and gobi (Carapa procera) lotions and creams in indivirual protection against Simulium damnosum s.l. bites in Côte d'Ivoire].

    PubMed

    Sylla, M; Konan, L; Doannio, J M; Traoré, S

    2003-05-01

    With the interruption of larva treatments done by OCP as part of onchocerciasis control in West Africa, Simulium came back in abundance in forest regions and savannah fertile valleys. In addition to the severe discomfort, nuisance by Simulium is in certain cases incompatible with land use. Since ground treatment of larval breading sites using insecticides is not always possible or efficient, it is therefore a necessity to develop other methods among which individual protection against Simulium bites. The general objective of our study was to evaluate different vegetable oil compound repellent formulas against Simulium bites. Activities were carried out in savannah zone (Niakaramandougou) and in forest zone (Soubré) in Côte d'Ivoire. The methodology consisted in catching blackflies on volunteers whose legs were rubbed with a repellent. Gobi raw oil and coconut, palm nut and gobi formulas (lotions and creams) were tested. During each session, which lasted from 07:00 am to 12:00 and from 03:00 pm to 06:00 pm, one person did not apply any repellent and was used as the control person. The results of our experimentations show that for a given zone (savannah, forest), a repellent (coconut, palm nut, gobi) and a compound (shea butter, vaseline), there is no significant difference between protection rates obtained with lotions (maximum: 21 bites/person/day) and those obtained with creams (maximum: 30 bites/person/day). In other respects, the lotion of a given repellent seems to be efficient in savannah as in the forest, in protecting against Simulium bites. It is the same situation with creams. So, repellents can be an efficient solution against Simulium nuisance. However, experimentations should continue to confirm the high repellency of tested formulas, proceed to the identification of principles and evaluate the toxicity and irritant effect of repellents to be applied on the skin.

  1. Molecular cloning and mRNA tissue expression of thyroid hormone receptors in yellow catfish Pelteobagrus fulvidraco and Javelin goby Synechogobius hasta.

    PubMed

    Chen, Qi-Liang; Luo, Zhi; Tan, Xiao-Ying; Pan, Ya-Xiong; Zheng, Jia-Lang; Zou, Ming

    2014-02-25

    Thyroid hormones (THs) play a pivotal role in many physiological functions in vertebrates, including fish. Their effects are mediated by thyroid hormone receptors (TRs), which are members of the nuclear hormone receptor superfamily. In this study, full-length cDNA sequences of TRs from yellow catfish Pelteobagrus fulvidraco and Javelin goby Synechogobius hasta were cloned and their mRNA tissue expression profiles were determined. In P. fulvidraco, the validated cDNAs encoding for TRα and TRβ were 1789 and 1848 bp in length, encoding peptides of 401 and 378 amino acid residues, respectively. In addition, a TRβ spliced variant (named P. fulvidraco-TRβv), containing a 60-bp insertion, was detected. In S. hasta, cDNAs encoding for TRαA, TRαB and TRβ were 1827, 2295 and 2258 bp in length, encoding peptides of 401, 409 and 393 amino acid residues, respectively. The phylogenetic analysis revealed that TRα and TRβ cDNAs grouped into two separate clusters with other vertebrate counterparts and two TRα sequences grouped separately, suggesting that the two TRαs derived from paralogous genes that might arise during a teleost-specific genome duplication event. All TR mRNAs were detected in various tissues sampled. The mRNA levels of both TRα and TRβ from P. fulvidraco were the highest in brain, followed by liver, and lowest in heart, intestine, muscle, gill and spleen. However, in S. hasta, TRαA, TRαB and TRβ showed the highest mRNA levels in brain and lowest in muscle. Identification and mRNA tissue expression of TR genes from P. fulvidraco and S. hasta provide an initial step towards understanding their biological roles in the two fish species.

  2. Effect of increasing temperature in the differential activity of oxidative stress biomarkers in various tissues of the Rock goby, Gobius paganellus.

    PubMed

    Vinagre, Catarina; Madeira, Diana; Mendonça, Vanessa; Dias, Marta; Roma, Joana; Diniz, Mário S

    2014-06-01

    Oxidative stress biomarkers have been widely used in the development of ecological indices and in the assessment of exposure of aquatic organisms to contaminants from agricultural, industrial and urban pollution. However, temperature is known to also have a significant effect on oxidative stress biomarkers. This way, temperature is a confounding factor that may result in difficulties in the interpretation of oxidative stress biomarkers response patterns. Since climate change is expected to result in more frequent and intense heat wave events it is pertinent to investigate the effect of increasing temperature in the oxidative stress response of common aquatic organisms. It is also important to assess the differential response of different body tissues, given that they are differently exposed to temperature depending on their location and physiological function. This study investigates the effect of increasing temperature (20 °C-34 °C) in the response of multiple biomarkers of oxidative stress: lipid peroxidation, glutathione-S-transferase, superoxide dismutase and catalase activities, in the muscle, liver and gills of a common coastal fish, the Rock goby, Gobius paganellus. The response of the oxidative stress biomarkers analysed were always higher in the gills than in the other tissues. Muscle generally presented the lower levels of any of the biomarkers tested when compared to other tissues. Nevertheless, muscle tissue always responded significantly to temperature, as did the liver, while the gills were unresponsive in terms of lipid peroxidation and glutathione-S-transferase. Unresponsive tissues to temperature may be particularly interesting as indicators of pollution, given that temperature will not be a confounding variable in their oxidative stress response.

  3. Acute effects of Benzo[a]pyrene, anthracene and a fuel oil on biomarkers of the common goby Pomatoschistus microps (Teleostei, Gobiidae).

    PubMed

    Vieira, L R; Sousa, A; Frasco, M F; Lima, I; Morgado, F; Guilhermino, L

    2008-06-01

    The objective of this study was to investigate the effects of two different PAHs and a complex petrochemical mixture on the common goby, Pomatoschistus microps, using selected biomarkers as effect criteria. Benzo[a]pyrene (BaP) and anthracene were used as reference substances, while the water accommodated fraction of #4 fuel-oil (#4 WAF) was used as an example of a petrochemical mixture. P. microps was used since it is both a suitable bioindicator and a good test organism. Groups of fish were exposed to different concentrations of each of the test substances for 96 h and the activities of several enzymes commonly used as biomarkers were determined at the end of the bioassays. All the substances inhibited P. microps acetylcholinesterase (AChE) indicating that they have at least one mechanism of neurotoxicity in common: the disruption of cholinergic transmission by inhibition of AChE. An induction of lactate dehydrogenase (LDH) activity was found in fish exposed to BaP or to anthracene, suggesting an increase of the anaerobic pathway of energy production. On the contrary, inhibition of LDH was found in fish exposed to #4 WAF, suggesting a distinct effect of the mixture. An induction of P. microps glutathione S-transferase (GST) activity was found in fish exposed to BaP or to #4 WAF, while an inhibition was observed after exposure to anthracene. These results suggest that GST is involved in the detoxification of BaP and #4 WAF, but not of anthracene. All the substances increased catalase activity and isolated PAHs also increased superoxide dismutase, glutathione reductase and glutathione peroxidase activities, while #4 WAF did not cause significant alterations on these enzymes. These results suggest that all the substances may induce oxidative stress on P. microps, with BaP and anthracene apparently having more oxidative stress potential than #4 WAF.

  4. First field-based observations of δ 2H and δ 18O values of event-based precipitation, rivers and other water bodies in the Dzungarian Gobi, SW Mongolia

    PubMed Central

    Burnik Šturm, Martina; Ganbaatar, Oyunsaikhan; Voigt, Christian C.; Kaczensky, Petra

    2017-01-01

    ABSTRACT For certain remote areas like Mongolia, field-based precipitation, surface and ground water isotopic data are scarce. So far no such data exist for the Mongolian Gobi desert, which hinders the understanding of isotopic fractionation processes in this extreme, arid region. We collected 26 event-based precipitation samples, 39 Bij river samples, and 75 samples from other water bodies in the Dzungarian Gobi in SW Mongolia over a period of 16 months for hydrogen and oxygen stable isotope analysis. δ 2H and δ 18O values in precipitation show high seasonal variation and cover an extreme range: 175 ‰ for δ 2H and 24 ‰ for δ 18O values. The calculated local meteoric water line (LMWL) shows the isotopic characteristics of precipitation in an arid region. Individual water samples fall into one of three groups: within, above or below the 95 % confidence interval of LMWL. Data presented provide a basis for future studies in this region. PMID:27733073

  5. First field-based observations of δ(2)H and δ(18)O values of event-based precipitation, rivers and other water bodies in the Dzungarian Gobi, SW Mongolia.

    PubMed

    Burnik Šturm, Martina; Ganbaatar, Oyunsaikhan; Voigt, Christian C; Kaczensky, Petra

    2017-05-01

    For certain remote areas like Mongolia, field-based precipitation, surface and ground water isotopic data are scarce. So far no such data exist for the Mongolian Gobi desert, which hinders the understanding of isotopic fractionation processes in this extreme, arid region. We collected 26 event-based precipitation samples, 39 Bij river samples, and 75 samples from other water bodies in the Dzungarian Gobi in SW Mongolia over a period of 16 months for hydrogen and oxygen stable isotope analysis. δ(2)H and δ(18)O values in precipitation show high seasonal variation and cover an extreme range: 175 ‰ for δ(2)H and 24 ‰ for δ(18)O values. The calculated local meteoric water line (LMWL) shows the isotopic characteristics of precipitation in an arid region. Individual water samples fall into one of three groups: within, above or below the 95 % confidence interval of LMWL. Data presented provide a basis for future studies in this region.

  6. Morphological selection and the evaluation of potential tradeoffs between escape from predators and the climbing of waterfalls in the Hawaiian stream goby Sicyopterus stimpsoni.

    PubMed

    Blob, Richard W; Kawano, Sandy M; Moody, Kristine N; Bridges, William C; Maie, Takashi; Ptacek, Margaret B; Julius, Matthew L; Schoenfuss, Heiko L

    2010-12-01

    Environmental pressures may vary over the geographic range of a species, exposing subpopulations to divergent functional demands. How does exposure to competing demands shape the morphology of species and influence the divergence of populations? We explored these questions by performing selection experiments on juveniles of the Hawaiian goby Sicyopterus stimpsoni, an amphidromous fish that exhibits morphological differences across portions of its geographic range where different environmental pressures predominate. Juvenile S. stimpsoni face two primary and potentially opposing selective pressures on body shape as they return from the ocean to freshwater streams on islands: (1) avoiding predators in the lower reaches of a stream; and (2) climbing waterfalls to reach the habitats occupied by adults. These pressures differ in importance across the Hawaiian Islands. On the youngest island, Hawai'i, waterfalls are close to shore, thereby minimizing exposure to predators and placing a premium on climbing performance. In contrast, on the oldest major island, Kaua'i, waterfalls have eroded further inland, lengthening the exposure of juveniles to predators before migrating juveniles begin climbing. Both juvenile and adult fish show differences in body shape between these islands that would be predicted to improve evasion of predators by fish from Kaua'i (e.g., taller bodies that improve thrust) and climbing performance for fish from Hawai'i (e.g., narrower bodies that reduce drag), matching the prevailing environmental demand on each island. To evaluate how competing selection pressures and functional tradeoffs contribute to the divergence in body shape observed in S. stimpsoni, we compared selection imposed on juvenile body shape by (1) predation by the native fish Eleotris sandwicensis versus (2) climbing an artificial waterfall (∼100 body lengths). Some variables showed opposing patterns of selection that matched predictions: for example, survivors of predation had

  7. Endoplasmic reticulum stress and dysregulation of calcium homeostasis mediate Cu-induced alteration in hepatic lipid metabolism of javelin goby Synechogobius hasta.

    PubMed

    Song, Yu-Feng; Huang, Chao; Shi, Xi; Pan, Ya-Xiong; Liu, Xu; Luo, Zhi

    2016-06-01

    The present study was conducted to investigate the effect of Cu exposure on endoplasmic reticulum (ER) stress and Ca(2+) homeostasis, and also explore the underlying mechanism of the ER stress and Ca(2+) homeostasis in the Cu-induced change of hepatic lipid metabolism in javelin goby Synechogobius hasta. To this end, four experiments were conducted. In experiment 1, the full-length cDNA sequences of two ER molecular chaperones [glucose-regulated protein 78 (GRP78) and calreticulin (CRT)] and three ER stress sensors [PKR-like ER kinase (PERK), inositol requiring enzyme (IRE)-1α, and activating transcription factor (ATF)-6α] cDNAs were firstly characterized from S. hasta. The predicted amino acid sequences for the S. hasta GRP78, CRT, PERK, IRE-1α and ATF-6α revealed that the proteins contained all of the structural features characteristic in other species. mRNAs of the five genes were expressed in various tissues, but their mRNA levels varied among tissues. In experiment 2, S. hasta were exposed to four waterborne Cu concentrations (control, 19μg/l, 38μg/l, and 57μg/l, respectively) for 60days. Cu exposure evoked ER stress in liver of S. hasta in a time- and concentration-course change. In experiment 3, specific inhibitors, 2-aminoethyldiphenyl borate (2-APB) and dantrolene, were used to explore whether Ca(2+) release from ER was involved in the Cu-induced ER stress change. Dantrolene and 2-APB prevented Cu-induced intracellular Ca(2+) elevation, which demonstrated the release of Ca(2+) from the ER was mediated by both RyR and IP3R. In experiment 4, a chemical chaperone, 4-phenyl butyric acid (4-PBA), was used to demonstrate whether Cu-induced alteration in lipid metabolism was suppressed through the attenuation of ER stress. Cu exposure evoked ER stress and sterol-regulator element-binding protein-1c (SREBP-1c) activation in hepatocytes of S. hasta, resulting in dysregulation of hepatic lipid metabolism. 4-PBA attenuated the Cu-induced elevation of m

  8. Bycatch, bait, anglers, and roads: quantifying vector activity and propagule introduction risk across lake ecosystems.

    PubMed

    Drake, D Andrew R; Mandrak, Nicholas E

    2014-06-01

    Long implicated in the invasion process, live-bait anglers are highly mobile species vectors with frequent overland transport of fishes. To test hypotheses about the role of anglers in propagule transport, we developed a social-ecological model quantifying the opportunity for species transport beyond the invaded range resulting from bycatch during commercial bait operations, incidental transport, and release to lake ecosystems by anglers. We combined a gravity model with a stochastic, agent-based simulation, representing a 1-yr iteration of live-bait angling and the dynamics of propagule transport at fine spatiotemporal scales (i.e., probability of introducing n propagules per lake per year). A baseline scenario involving round goby (Neogobius melanostomus) indicated that most angling trips were benign; irrespective of lake visitation, anglers failed to purchase and transport propagules (benign trips, median probability P = 0.99912). However, given the large number of probability trials (4.2 million live-bait angling events per year), even the rarest sequence of events (uptake, movement, and deposition of propagules) is anticipated to occur. Risky trips (modal P = 0.00088 trips per year; approximately 1 in 1136) were sufficient to introduce a substantial number of propagules (modal values, Poisson model = 3715 propagules among 1288 lakes per year; zero-inflated negative binomial model = 6722 propagules among 1292 lakes per year). Two patterns of lake-specific introduction risk emerged. Large lakes supporting substantial angling activity experienced propagule pressure likely to surpass demographic barriers to establishment (top 2.5% of lakes with modal outcomes of five to 76 propagules per year; 303 high-risk lakes with three or more propagules, per year). Small or remote lakes were less likely to receive propagules; however, most risk distributions were leptokurtic with a long right tail, indicating the rare occurrence of high propagule loads to most waterbodies

  9. Early diagenetic stabilization of trace elements in reptile bone remains as an indicator of Maastrichtian Late Paleocene climatic changes: evidence from the Naran Bulak locality, the Gobi Desert (South Mongolia)

    NASA Astrophysics Data System (ADS)

    Samoilov, V. S.; Benjamini, Ch.; Smirnova, E. V.

    2001-08-01

    Maastrichtian dinosaur bone remains from the Naran Bulak locality (the Gobi Desert) with well-preserved bone textural features are enriched in some trace elements, primarily in REE. These features of vertebrate fossils were formed during diagenesis following rapid burial in mudflow sediments, and prior to postfossilization epigenetic changes. Trace elements are mainly concentrated in diagenetic apatite. Their contents in the bones correlate with that in their enclosing sediments for both maxima and minima. Fossil and sediment compositions were established under the influence of paleoclimate. They are correlated with long-term climatic changes with the aridity maximum at the K/T boundary. Climatic changes were recorded via the change of salinity of waters interacting with the buried vertebrate remains.

  10. From source to sink in the sediment cascade of the Hei-River Basin: Implications for late Quaternary landscape dynamics in the Gobi Desert, NW China

    NASA Astrophysics Data System (ADS)

    Schimpf, Stefan; Nottebaum, Veit; Diekmann, Bernhard; Hartmann, Kai; Lehmkuhl, Frank; Wünnemann, Bernd; Zhang, Chi

    2014-05-01

    The Hei River Basin with a catchment size of ~130,000 km² is host to one of the largest continental alluvial fans in the world. The basin comprises: (1) its high-elevated river sources in the glacier and the permafrost zone of the Qilian Mountains, (2) the semi-arid foreland of the Hexi Corridor in the middle reaches and (3) the endorheic Ejina Basin (Gaxun Nur Basin) as its recent sink. The river basin is characterized by small subcatchments of hyper-arid mountain ranges of the Gobi-Tienshan and Beishan as well as of smooth and fuzzy water divides of the Hexi-Corridor and the Badain Jaran Sand Sea. Up to 300 m of Quaternary sediments establish the large Ejina Basin, with a size of 28,000 km², as an excellent archive for environmental reconstructions located at the recent intersection of westerly and monsoonal air masses. Three sediment cores (up to 230 m long) provide evidence of sedimentation dynamics over the last 250,000 years, and cover at least two terminations since OIS 6. The sediments have to be regarded as a result of the interplay between tectonic activity and climate dynamics, accompanied by a related eolian and hydrological response of the catchment. Thus, it is crucial to understand and reconstruct the sedimentary processes along the huge sediment cascades, and to identify the most important sediment sources. Here we present a provenance analysis from mineralogical fingerprints of modern sediments that have been deposited along recent pathways from the sources to the Ejina Basin. The methodical approach combines the analysis of clay minerals, bulk mineralogy, and bulk geochemistry. Furthermore, we use heavy mineral data obtained from automated particle-analysis via a computer-controlled scanning electron microscope (CCSEM) and XRD measurements. We analyzed ~200 surface samples from the whole catchment as reference material, as well as the upper 19 m of cored sediments, to gain insight into temporal changes of depositional processes and provenance

  11. Effects of 17α-ethinyl estradiol exposure on estrogen receptors α and β and vitellogenins A, B and C mRNA expression in the liver of sand goby (Pomatoschistus minutus).

    PubMed

    Humble, Joseph L; Saaristo, Minna; Lindström, Kai; Lehtonen, Kari K; Craft, John A

    2014-05-01

    This study aims to characterize the estrogen receptor (er) in sand goby (Pomatoschistus minutus) and determine the temporal effects of 17α-ethinyl estradiol (EE2) on erα and vitellogenin (vtg) gene expression in males. Two partial cDNA sequences (erα and erβ1) are presented showing conserved structural features with ers of other species. Transcript levels for both ers were low in control fish but EE2 exposure (11 ng/L, for 29 days) increased both to a pattern similar to vitellogenic females. The relative expression of three vtg genes (vtga, vtgb and vtgc) along with erα was determined in control and male fish exposed to EE2 (11 ng/L) at multiple time-points over 29 days. All four transcripts were significantly induced due to exposure and expression rose during the time course with distinct temporal patterns and vtga reached a substantially higher level at the end of the time course coinciding with rapid elevation in erα expression.

  12. Influence of salinity on the localization of Na+/K +-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and CFTR anion channel in chloride cells of the Hawaiian goby (Stenogobius hawaiiensis)

    USGS Publications Warehouse

    McCormick, S.D.; Sundell, K.; Bjornsson, Bjorn Thrandur; Brown, C.L.; Hiroi, J.

    2003-01-01

    Na+/K+-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR) are the three major transport proteins thought to be involved in chloride secretion in teleost fish. If this is the case, the levels of these transporters should be high in chloride cells of seawater-acclimated fish. We therefore examined the influence of salinity on immunolocalization of Na +/K+-ATPase, NKCC and CFTR in the gills of the Hawaiian goby (Stenogobius hawaiiensis). Fish were acclimated to freshwater and 20??? and 30??? seawater for 10 days. Na+/K +-ATPase and NKCC were localized specifically to chloride cells and stained throughout most of the cell except for the nucleus and the most apical region, indicating a basolateral/tubular distribution. All Na+/K +-ATPase-positive chloride cells were also positive for NKCC in all salinities. Salinity caused a slight increase in chloride cell number and size and a slight decrease in staining intensity for Na+/K +-ATPase and NKCC, but the basic pattern of localization was not altered. Gill Na+/K+-ATPase activity was also not affected by salinity. CFTR was localized to the apical surface of chloride cells, and only cells staining positive for Na+/K+-ATPase were CFTR-positive. CFTR-positive cells greatly increased in number (5-fold), area stained (53%) and intensity (29%) after seawater acclimation. In freshwater, CFTR immunoreactivity was light and occurred over a broad apical surface on chloride cells, whereas in seawater there was intense immunoreactivity around the apical pit (which was often punctate in appearance) and a light subapical staining. The results indicate that Na+/K +-ATPase, NKCC and CFTR are all present in chloride cells and support current models that all three are responsible for chloride secretion by chloride cells of teleost fish.

  13. Influence of salinity on the localization of Na+/K+-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and CFTR anion channel in chloride cells of the Hawaiian goby (Stenogobius hawaiiensis).

    PubMed

    McCormick, Stephen D; Sundell, Kristina; Björnsson, Björn Thrandur; Brown, Christopher L; Hiroi, Junya

    2003-12-01

    Na+/K+-ATPase, Na+/K+/2Cl- cotransporter (NKCC) and cystic fibrosis transmembrane conductance regulator (CFTR) are the three major transport proteins thought to be involved in chloride secretion in teleost fish. If this is the case, the levels of these transporters should be high in chloride cells of seawater-acclimated fish. We therefore examined the influence of salinity on immunolocalization of Na+/K+-ATPase, NKCC and CFTR in the gills of the Hawaiian goby (Stenogobius hawaiiensis). Fish were acclimated to freshwater and 20 per thousand and 30 per thousand seawater for 10 days. Na+/K+-ATPase and NKCC were localized specifically to chloride cells and stained throughout most of the cell except for the nucleus and the most apical region, indicating a basolateral/tubular distribution. All Na+/K+-ATPase-positive chloride cells were also positive for NKCC in all salinities. Salinity caused a slight increase in chloride cell number and size and a slight decrease in staining intensity for Na+/K+-ATPase and NKCC, but the basic pattern of localization was not altered. Gill Na+/K+-ATPase activity was also not affected by salinity. CFTR was localized to the apical surface of chloride cells, and only cells staining positive for Na+/K+-ATPase were CFTR-positive. CFTR-positive cells greatly increased in number (5-fold), area stained (53%) and intensity (29%) after seawater acclimation. In freshwater, CFTR immunoreactivity was light and occurred over a broad apical surface on chloride cells, whereas in seawater there was intense immunoreactivity around the apical pit (which was often punctate in appearance) and a light subapical staining. The results indicate that Na+/K+-ATPase, NKCC and CFTR are all present in chloride cells and support current models that all three are responsible for chloride secretion by chloride cells of teleost fish.

  14. Neurohypophysial Hormones Regulate Amphibious Behaviour in the Mudskipper Goby

    PubMed Central

    Sakamoto, Tatsuya; Nishiyama, Yudai; Ikeda, Aoi; Takahashi, Hideya; Hyodo, Susumu; Kagawa, Nao; Sakamoto, Hirotaka

    2015-01-01

    The neurohypophysial hormones, arginine vasotocin and isotocin, regulate both hydromineral balance and social behaviors in fish. In the amphibious mudskipper, Periophthalmus modestus, we previously found arginine-vasotocin-specific regulation of aggressive behavior, including migration of the submissive subordinate into water. This migration also implies the need for adaptation to dehydration. Here, we examined the effects of arginine vasotocin and isotocin administration on the amphibious behavior of individual mudskippers in vivo. The mudskippers remained in the water for an increased period of time after 1–8 h of intracerebroventricular (ICV) injection with 500 pg/g arginine vasotocin or isotocin. The ‘frequency of migration’ was decreased after ICV injection of arginine vasotocin or isotocin, reflecting a tendency to remain in the water. ICV injections of isotocin receptor antagonist with arginine vasotocin or isotocin inhibited all of these hormonal effects. In animals kept out of water, mRNA expression of brain arginine vasotocin and isotocin precursors increased 3- and 1.5-fold, respectively. Given the relatively wide distribution of arginine vasotocin fibres throughout the mudskipper brain, induction of arginine vasotocin and isotocin under terrestrial conditions may be involved also in the preference for an aquatic habitat as ligands for brain isotocin receptors. PMID:26230718

  15. Feeding behaviour of Black Sea bottom fishes: Did it change over time?

    NASA Astrophysics Data System (ADS)

    Bănaru, Daniela; Harmelin-Vivien, Mireille

    2009-11-01

    This study was designed to improve knowledge in feeding behaviour of the round goby ( Apollonia melanostomus (Pallas, 1814)), the red mullet ( Mullus barbatus ponticus Essipov, 1927), the whiting ( Merlangius merlangus (Linnaeus, 1758)), the flounder ( Platichthys flesus (Linnaeus, 1758)), the sole ( Solea solea (Linnaeus, 1758)), the turbot ( Psetta maeotica (Pallas, 1814)) and the starry sturgeon ( Acipenser stellatus Pallas, 1771) from the north-western Black Sea. Gut content coupled with stable isotope analysis allowed describing food web variations according to species, in two seasons and at two areas located seawards the Danube River. Present results showed that most fishes have likely changed their feeding behaviour compared to past studies from the same area. Trophic niches were reduced and dietary overlap was common, as different fish species consumed the same dominant prey types. Fishes probably adapted their feeding behaviour to the increasingly low biodiversity of the Black Sea communities.

  16. Fish pollution with anthropogenic 137Cs in the southern Baltic Sea.

    PubMed

    Zalewska, Tamara; Suplińska, Maria

    2013-02-01

    This paper presents the results of a study on changes in (137)Cs activity concentrations in three fish species from the southern Baltic Sea: cod (Gadus morhua), herring (Clupea harengus) and flounder (Platichtys flesus), in the period 2000-2010. During the study period a marked decline in cesium activity concentration in fish muscle tissue was observed, which reflected changes in radionuclide activity concentration in seawater. No statistically significant temporal trends were determined in changes of concentration factors (CF(fish/seawater)) calculated for the examined fish species. The analysis of (137)Cs activity as a function of ichthyological parameters revealed the lack of a relationship between radionuclide activity concentrations in herring muscle tissue and the fish age in an narrow age range (2-4 years). However, a reverse proportionality of total fish mass, as well as body length, against (137)Cs activity concentrations in muscles was well documented. The latter observation can be the direct result of the dilution effect related to the increase of fish body weight. (137)Cs activity concentration in muscle tissue of the five fish species forms a declining sequence: Gadus morhua, Platichthys flesus, Clupea harengus, Perca fluviatilis and Neogobius melanostomus.

  17. Toxic metals in tissues of fishes from the Black Sea and associated human health risk exposure.

    PubMed

    Plavan, Gabriel; Jitar, Oana; Teodosiu, Carmen; Nicoara, Mircea; Micu, Dragos; Strungaru, Stefan-Adrian

    2017-01-27

    The anthropogenic activities in the Black Sea area are responsible for toxic metal contamination of sea food products. In this study, several toxic metals: cadmium, lead, nickel, chromium, and copper were quantified in different tissues (digestive tract, muscle, skeleton, skin) of nine fish species (Neogobius melanostomus, Belone belone, Solea solea, Trachurus mediterraneus ponticus, Sardina pilchardus, Engraulis encrasicolus, Pomatomus saltatrix, Sprattus sprattus, Scorpaena porcus) by using atomic absorption spectrometer with a high-resolution continuum source and graphite furnace technique (HR-CS GF-AAS), and the risk of fish meat consumption by the young human population was evaluated. These metals are used in high amounts in industries located near the coastline such as shipyard construction and industrial plants. Toxic metal accumulation depends on fish feeding behavior, abiotic conditions, metal chemistry, and animal physiology. For instance, cadmium was measured in the muscle of the investigated species and average values of 0.0008-0.0338 mg kg(-1) were obtained. The lowest average value of this metal was measured at benthic species N. melanostomus and the highest at the pelagic predator T. mediterraneus ponticus. Generally, the highest metal concentration was measured in the digestive tract that has the role of biofilter for these contaminants. The risk of contamination is significantly reduced by avoiding the consumption of certain fish tissues (digestive tract and skin for copper and skeleton for nickel). An estimation of the dietary metal intake to young consumers was realized for each of the studied species of fish from Romanian, Bulgarian, and Turkish waters, during the period 2001-2014 in order to evaluate the risks of chronic exposure in time due to metal toxicity. This estimation is important for the prevention of chronic exposure due to metal toxicity. Food exposure to studied metals showed a negative trend for Romania, Turkey, and Bulgaria

  18. 78 FR 8745 - Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for Tidewater Goby

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-06

    ... determinable. We are required to base the designation on the best available scientific data after taking into... maintenance. Thus, definitions of the term metapopulation within the scientific literature often incorporate... and procedures include, but are not limited to, all activities associated with scientific...

  19. Globalising Assessment: An Ethnography of Literacy Assessment, Camels and Fast Food in the Mongolian Gobi

    ERIC Educational Resources Information Center

    Maddox, Bryan

    2014-01-01

    What happens when standardised literacy assessments travel globally? The paper presents an ethnographic account of adult literacy assessment events in rural Mongolia. It examines the dynamics of literacy assessment in terms of the movement and re-contextualisation of test items as they travel globally and are received locally by Mongolian…

  20. A new cembrane glycoside in Asterothamnus centrali-asiaticus from Gobi Desert.

    PubMed

    Todorova, Milka; Trendafilova, Antoaneta; Javsmaa, Namshir; Altantsetseg, Shatarin; Shatar, Sanduin

    2013-09-01

    A new cembrane glycoside, nephthenol 15-O-β-d-quinovoside, was isolated from the aerial parts of Asterothamnus centrali-asiaticus. Its structure was elucidated by 1D and 2D NMR spectroscopic analysis, as well as by mass spectrometry. This is the first report of the occurrence of a cembrane glycoside in vascular plants.

  1. Cryptic species and historical biogeography of eel gobies (Gobioidei: Odontamblyopus) along the northwestern Pacific coast.

    PubMed

    Tang, Weixing; Lshimatsu, Atsushi; Fu, Cuizhang; Yin, Wei; Li, Guo; Chen, Hui; Wu, Qianhong; Li, Bo

    2010-01-01

    Cryptic species are common in gobioid fishes, as revealed by recent molecular studies. This study collected molecular and morphological data to delimit species boundaries and to reveal the historical biogeography of Odontamblyopus lacepedii sensu lato by sampling 87 specimens from 16 locations in the northwestern Pacific. Phylogenetic trees based on mitochondrial NADH dehydrogenase subunit 5 sequences identified three major clades. Clear morphological separations among these clades were detected by examining morphological characters used in taxonomic diagnosis. Therefore, these clades were delineated as three separate species: O. lacepedii sensu stricto (in the East China Sea, Yellow Sea, Gulf of Bohai, and Ariake Bay); O. sp. (in the southern East China Sea and southern Yellow Sea); and O. rebecca (in the Gulf of Tonkin, northern South China Sea, and southern East China Sea). Estimated divergence times were 0.61 +/- 0.15 Ma between O. lacepedii and O. sp., and 2.31+/-0.36 Ma between O. rebecca and O. lacepedii+O. sp. These findings indicate that isolation of marginal seas and habitat fragmentation during major falls in sea level in the late Pliocene and Pleistocene may have been responsible for genetic breaks among Odontamblyopus species in the northwestern Pacific.

  2. Dentition of eight species of Mediterranean Sea Gobiidae: do dentition characters of gobies reflect phylogenetic relationships?

    PubMed

    Kramer, A; Kovačić, M; Patzner, R A

    2012-01-01

    Oral and pharyngeal dentition was analysed in eight Mediterranean species of five different genera using scanning electron microscopy (SEM). Number, position, shape and size of teeth in the jaws and the pharyngeal tooth plates were used as a basis for comparison among taxa. Three different groups could be established based on the dental morphology among the species investigated and homoplasy due to feeding ecology cannot be considered the reason for similarity among them. The established groups are suggested to reflect phylogenetic relationships and correspond with the scarce published data on the topic.

  3. An Anthropologist among the Psychometricians: Assessment Events, Ethnography, and Differential Item Functioning in the Mongolian Gobi

    ERIC Educational Resources Information Center

    Maddox, Bryan; Zumbo, Bruno D.; Tay-Lim, Brenda; Qu, Demin

    2015-01-01

    This article explores the potential for ethnographic observations to inform the analysis of test item performance. In 2010, a standardized, large-scale adult literacy assessment took place in Mongolia as part of the United Nations Educational, Scientific and Cultural Organization Literacy Assessment and Monitoring Programme (LAMP). In a novel form…

  4. SEROTONIN, SOCIAL STATUS AND SEX CHANGE IN THE BLUEBANDED GOBY LYTHRYPNUS DALLI

    PubMed Central

    Lorenzi, Varenka; Carpenter, Russ E.; Summers, Cliff H.; Earley, Ryan L.; Grober, Matthew S.

    2009-01-01

    In a variety of vertebrates, highly aggressive individuals tend to have high social status and low serotonergic function. In the sex changing fish Lythrypnus dalli, serotonin (5-HT) may be involved as a mediator between the social environment and the reproductive system because social status is a critical cue in regulating sex change. Subordination inhibits sex change in L. dalli, and it is associated with higher serotonergic activity in other species. We tested the hypothesis that high serotonergic activity has an inhibitory effect on sex change. In a social situation permissive to sex change, we administered to the dominant female implants containing the serotonin precursor 5-hydroxytryptophan (5-HTP). In a social situation not conducive to sex change, we administered either the serotonin synthesis inhibitor p-chlorophenylalanine (PCPA) or the 5-HT1A receptor antagonist p-MPPI. After three weeks we used HPLC to measure brain levels of 5-HT and its metabolite 5-hydroxyindoleacetic acid (5-HIAA). We also performed PCPA, p-MPPI and fluoxetine injections in size-matched pairs of females to assess its effect on dominance status. Males and newly sex changed fish showed a trend for higher levels of 5-HIAA and 5-HT/5-HIAA ratio than females. The different implants treatments did not affect the probability of sex change. Interestingly, this species does not seem to fit the pattern seen in other vertebrates where dominant individuals have lower serotonergic activity than subordinates. PMID:19345236

  5. Overlapping patterns of morphometric and genetic differentiation in the Mediterranean goby Pomatoschistus tortonesei Miller, 1968 (Perciformes, Gobiidae) in Tunisian lagoons.

    PubMed

    Mejri, Randa; Lo Brutto, Sabrina; Hassine, Nesrine; Arculeo, Marco; Ben Hassine, Oum Kalthoum

    2012-08-01

    The genetic and morphological variations of Pomatoschistus tortonesei Miller, 1968 were studied in samples collected from three Tunisian lagoons. The morphological analysis included 18 morphometric measurements and was based on linear discriminant analysis (LDA), whereas the genetic analysis was based on the 16S-rRNA and COI mitochondrial genes. Both analyses differentiated the populations and demonstrated consistently a well-supported differentiation between the western Mediterranean samples (Bizerta and Tunis South lagoons) and the eastern Mediterranean sample (El Bibane lagoon). The observed differentiation could be explained in terms of the geographic isolation of the various populations and the influence of environmental factors, which differ greatly between the different sites. The molecular results revealed that the populations are characterised by unique haplotypes which are well defined in relation to limited gene flow and restricted dispersal abilities. Additionally, it seems that local selective pressures have modelled biometrical variation. Morphological results can reflect a differential habitat use revealed in the cephalic features and a different response to hydrodynamic constraints developed in dissimilar dorsal and pelvic fin lengths.

  6. Feeding kinematics and performance of Hawaiian stream gobies, Awaous guamensis and Lentipes concolor: linkage of functional morphology and ecology.

    PubMed

    Maie, Takashi; Wilson, Megan P; Schoenfuss, Heiko L; Blob, Richard W

    2009-03-01

    Distributions of Hawaiian stream fishes are typically interrupted by waterfalls that divide streams into multiple segments. Larvae hatch upstream, are flushed into the ocean, and must climb these waterfalls to reach adult habitats when returning back to freshwater as part of an amphidromous life cycle. Stream surveys and studies of climbing performance show that Lentipes concolor Gill can reach fast-flowing upper stream segments but that Awaous guamensis Valenciennes reaches only slower, lower stream segments. Gut content analyses for these two species indicate considerable overlap in diet, suggesting that feeding kinematics and performance of these two species might be comparable. Alternatively, feeding kinematics and performance of these species might be expected to differ in relation to the different flow regimes in their habitat (feeding in faster stream currents for L. concolor versus in slower currents for A. guamensis). To test these alternative hypotheses, we compared food capturing kinematics and performance during suction feeding behaviors of A. guamensis and L. concolor using morphological data and high-speed video. Lentipes concolor showed both a significantly larger gape angle and faster jaw opening than A. guamensis. Geometric models calculated that despite the inverse relationship of gape size and suction pressure generation, the fast jaw motions of L. concolor allow it to achieve higher pressure differentials than A. guamensis. Such elevated suction pressure would enhance the ability of L. concolor to successfully capture food in the fast stream reaches it typically inhabits. Differences in jaw morphology may contribute to these differences in performance, as the lever ratio for jaw opening is about 10% lower in L. concolor compared with A. guamensis, suiting the jaws of L. concolor better for fast opening.

  7. Evolutionary novelty versus exaptation: oral kinematics in feeding versus climbing in the waterfall-climbing Hawaiian Goby Sicyopterus stimpsoni.

    PubMed

    Cullen, Joshua A; Maie, Takashi; Schoenfuss, Heiko L; Blob, Richard W

    2013-01-01

    Species exposed to extreme environments often exhibit distinctive traits that help meet the demands of such habitats. Such traits could evolve independently, but under intense selective pressures of extreme environments some existing structures or behaviors might be coopted to meet specialized demands, evolving via the process of exaptation. We evaluated the potential for exaptation to have operated in the evolution of novel behaviors of the waterfall-climbing gobiid fish genus Sicyopterus. These fish use an "inching" behavior to climb waterfalls, in which an oral sucker is cyclically protruded and attached to the climbing surface. They also exhibit a distinctive feeding behavior, in which the premaxilla is cyclically protruded to scrape diatoms from the substrate. Given the similarity of these patterns, we hypothesized that one might have been coopted from the other. To evaluate this, we filmed climbing and feeding in Sicyopterus stimpsoni from Hawai'i, and measured oral kinematics for two comparisons. First, we compared feeding kinematics of S. stimpsoni with those for two suction feeding gobiids (Awaous guamensis and Lentipes concolor), assessing what novel jaw movements were required for algal grazing. Second, we quantified the similarity of oral kinematics between feeding and climbing in S. stimpsoni, evaluating the potential for either to represent an exaptation from the other. Premaxillary movements showed the greatest differences between scraping and suction feeding taxa. Between feeding and climbing, overall profiles of oral kinematics matched closely for most variables in S. stimpsoni, with only a few showing significant differences in maximum values. Although current data cannot resolve whether oral movements for climbing were coopted from feeding, or feeding movements coopted from climbing, similarities between feeding and climbing kinematics in S. stimpsoni are consistent with evidence of exaptation, with modifications, between these behaviors. Such comparisons can provide insight into the evolutionary mechanisms facilitating exploitation of extreme habitats.

  8. Aerosol dynamics above the water area of the Peter the Great Bay during the dust storm in the Gobi desert

    NASA Astrophysics Data System (ADS)

    Bukin, O. A.; Pavlov, A. N.; Kulchin, J. N.; Shmirko, K. A.; Salyuk, P. A.; Stoluarchuk, S. Y.

    2006-11-01

    This article presents aerosol dynamic monitoring over the Peter the Great bay during dust storms in continental areas of the China and Mongolia. Both satellite and lidar data was analyzed. Vertical profiles of aerosol backscattering coefficient and aerosol optical thickness were calculated. Aerosol optical thickness in different layers were retrieved and compared with the satellite ones. Correlation coefficient between satellite and lidar data was calculated. Aerosol layer location was compared to Brent-Vaisal criterion of stability. Aerosol layer stratification during spring - summer (April - June 2006) period was analyzed.

  9. A surface-wave investigation of the rupture mechanism of the Gobi-Altai (4 December 1957) earthquake

    NASA Technical Reports Server (NTRS)

    Okal, E. A.

    1975-01-01

    Long period records of multiple Love waves from the 1957 earthquake in Mongolia at Pasadena are analyzed and compared to synthetic seismograms, generated by the method of Kanamori. A fit in the time domain shows that the records are not consistent with the previous solution, achieved through a frequency domain analysis of directivity. The solution asks for a shorter rupture of 270 km at a velocity of 3.5 km/s. The focal parameters are constrained by updating all the reported first motion and are found to be: Strike = 103 deg, Dip = 53 deg, Slip = 32 deg. A seismic moment of 1.8 10 to the 28th power dynes-cm is obtained. These figures are also consistent with a time domain analysis of Love waves at Palisades and Strasbourg, and of Rayleigh waves at Pasadena, with a directivity study of Love waves at Pasadena, and with static deformation and isoseismal data. A discussion is given of the relation between moment, magnitude and rupture area, and a comparison is made with other events in the same region: It is concluded that this earthquake does not exhibit an intra-plate behavior, but rather compares better with inter-plate events, such as the great Assam earthquake.

  10. The role of steroid hormones in protogynous sex change in the Blackeye goby, Coryphopterus nicholsii (Teleostei: Gobiidae).

    PubMed

    Kroon, F J; Liley, N R

    2000-05-01

    To detect and describe correlations between steroid concentrations and sexual function in the protogynous Coryphopterus nicholsii, we examined whole-body concentrations of the gonadal steroids testosterone (T), 11-ketotestosterone (11-KT), and 17beta-estradiol (17beta-E2). Our results show that T, 11-KT, and 17beta-E2 are naturally occurring steroids in both female and male C. nicholsii. Further, mean whole-body concentrations of T and 11-KT in males were approximately twice those in females, whereas mean whole-body concentration of 17beta-E2 in females was almost twice that in males. Second, we tested hypotheses on the causation of sex change arising from these correlations between steroid concentrations and sexual function. We examined the effects of administration of 11-KT, 11-KA, 17alpha-methyltestosterone, and an aromatase inhibitor (Fadrozole) on gonadal structures of mature females. Complete sex change was induced by 11-KT, 11-KA, and Fadrozole. Our results strongly suggest that an increase in 11-KT concentration and perhaps also a decrease in 17beta-E2 concentration are involved in mediating natural sex change in C. nicholsii.

  11. Complete Mitochondrial Reveals a New Phylogenetic Perspective on the Brackish Water Goby Mugilogobius Group (Teleostei: Gobiidae: Gobionellinae).

    PubMed

    Huang, Shih-Pin; Chen, I-Shiung; Jang-Liaw, Nian-Hong; Shao, Kwang-Tsao; Yung, Mana M N

    2016-10-01

    The Mugilogobius group consists of brackish water gobionellines widely distributed in the Indo-West Pacific region. Complete mitochondrial genome and morphological evidence was collected to estimate their phylogenetic relationship and taxonomic status. A total of 11 genera were sampled, including Brachygobius, Calamiana, Hemigobius, Mugilogobius, Pandaka, Pseudogobiopsis, Pseudogobius, Redigobius, Rhinogobius, Stigmatogobius, and Wuhanlinigobius, five of which were sequenced for the first time. A morphological phylogenetic tree was also reconstructed based on 35 characters. The molecular phylogenetic trees reveal that the Mugilogobius group contains four major clades. The present study also reveals that the adult male mouth size and forked sensory papillae row d can be considered as synapomorphies, and that the head pores on inter-orbital, anterior oculoscapular, and preopercular regions can be regarded as derived features among the Mugilogobius group. Furthermore, the absence of posterior oculoscapular pores may provide a clue for understanding the evolutionary history of the Mugilogobius group.

  12. Stairway to heaven: evaluating levels of biological organization correlated with the successful ascent of natural waterfalls in the Hawaiian stream goby Sicyopterus stimpsoni.

    PubMed

    Schoenfuss, Heiko L; Maie, Takashi; Moody, Kristine N; Lesteberg, Kelsey E; Blob, Richard W; Schoenfuss, Tonya C

    2013-01-01

    Selective pressures generated by locomotor challenges act at the level of the individual. However, phenotypic variation among individuals that might convey a selective advantage may occur across any of multiple levels of biological organization. In this study, we test for differences in external morphology, muscle mechanical advantage, muscle fiber type and protein expression among individuals of the waterfall climbing Hawaiian fish Sicyopterus stimpsoni collected from sequential pools increasing in elevation within a single freshwater stream. Despite predictions from previous laboratory studies of morphological selection, few directional morphometric changes in body shape were observed at successively higher elevations. Similarly, lever arm ratios associated with the main pelvic sucker, central to climbing ability in this species, did not differ between elevations. However, among climbing muscles, the adductor pelvicus complex (largely responsible for generating pelvic suction during climbing) contained a significantly greater red muscle fiber content at upstream sites. A proteomic analysis of the adductor pelvicus revealed two-fold increases in expression levels for two respiratory chain proteins (NADH:ubiquinone reductase and cytochrome b) that are essential for aerobic respiration among individuals from successively higher elevations. Assessed collectively, these evaluations reveal phenotypic differences at some, but not all levels of biological organization that are likely the result of selective pressures experienced during climbing.

  13. A new, mesophotic Coryphopterus goby (Teleostei, Gobiidae) from the southern Caribbean, with comments on relationships and depth distributions within the genus.

    PubMed

    Baldwin, Carole C; Robertson, D Ross

    2015-01-01

    A new species of western Atlantic Coryphopterus is described from mesophotic depths off Curaçao, southern Caribbean. Coryphopteruscurasub sp. n., is similar to Coryphopterusdicrus in, among other features, having two prominent pigment spots of roughly equal intensity on the pectoral-fin base, the pelvic fins fused to form a disk, and no pelvic frenum. The two species can be differentiated by body depth (shallower in Coryphopteruscurasub at origin of dorsal fin and caudal peduncle); differences in the pigmentation on the head, trunk, and basicaudal region; and usually by total number of rays (spinous plus soft) in the second dorsal fin (10-11, usually 11, in Coryphopteruscurasub, 10 in Coryphopterusdicrus). Coryphopteruscurasub differs from other Coryphopterus species that have a prominent pigment spot on the lower portion of the pectoral-fin base (Coryphopteruspunctipectophorus and Coryphopterusvenezuelae) in, among other features, lacking a pelvic frenum. Coryphopteruscurasub was collected between 70 and 80 m, the deepest depth range known for the genus. Collections of Coryphopterusvenezuelae at depths of 65-69 m extend the depth range of that species by approximately 50 m. Mitochondrial cytochrome c oxidase subunit I (COI) data corroborate the recognition of Coryphopteruscurasub as a distinct species but do not rigorously resolve its relationships within the genus. A revised key to the western Atlantic species of Coryphopterus is presented.

  14. Arterial pH and Blood Lactate Levels of Anesthetized Mongolian Khulan ( Equus hemionus hemionus) in the Mongolian Gobi Correlate with Induction Time.

    PubMed

    Gerritsmann, Hanno; Stalder, Gabrielle L; Kaczensky, Petra; Buuveibaatar, Bayarbaatar; Payne, John; Boldbaatar, Sukhbaatar; Walzer, Chris

    2016-07-01

    Research and conservation of wide-ranging wild equids in most cases necessitate capture and handling of individuals. For free-roaming Mongolian khulan ( Equus hemionus hemionus), also known as the khulan, capture involves a strenuous, high-speed chase, and physiologic responses have yet to be elucidated. We analyzed sequential arterial blood gas (ABG) samples as a proxy for respiratory and metabolic status of khulan during capture-related anesthesia. We recorded precise chase and induction times and monitored vital parameters and ABG from free-ranging khulan during anesthesia performed for GPS collaring. At the initiation of anesthesia, animals had ABG values similar to those recorded for thoroughbred horses ( Equus caballus ) after maximal exercise. Longer induction times resulted in higher arterial pH (P<0.001) and lower blood lactate (P<0.002). This trend of improvement continued over the course of anesthesia. The most important factor explaining pH and lactate was the time that elapsed between cessation of the chase and obtaining the first ABG sample, which, under field conditions, is tightly linked to induction time. All animals recovered uneventfully. Our data show that khulan recover and shift their metabolic status back toward expected normal values during opioid-based field anesthesia.

  15. The role of mounds in promoting water-exchange in the egg-tending burrows of monogamous goby, Valenciennea longipinnis (Lay et Bennett).

    PubMed

    Takegaki; Nakazono

    2000-10-25

    Valenciennea longipinnis spawns monogamously in a burrow. After spawning, the paired female constructs a conspicuous mound on the burrow by carrying and piling up substratum-derived materials while the male tends eggs in the burrow until hatching occurs. In this study, the mounds of V. longipinnis were tested in the field to confirm their function of promoting water-exchange in the burrow, and their ecological role was examined in relation to egg care by the male. The mound of V.longipinnis promoted water-exchange in the burrow, contributing to the provision of external oxygenated sea water into the burrow. Therefore, dissolved oxygen (DO) concentrations in the burrow with a mound were significantly higher than those without a mound. Although male egg-tending behaviour (e.g., fanning) may also promote water-exchange in the burrow, the water-exchange appeared to depend mainly on the hydrodynamic effect. Removals of the mound and paired female on the day of spawning led to high rates of egg-desertion by males. Since the frequency and time of fanning increase with a decrease of DO concentration in the burrow, the egg-desertion may result from an increased parental cost to males due to the decrease of water-exchange without a mound. This was supported by the fact that the DO concentrations on the day after mound removal were significantly lower in the egg-deserted burrows (measured before desertions) than in burrows not deserted by the male. Moreover, removals of paired females only also led to higher desertion rates. After removal of the female, the mound gradually collapsed by wave action and other factors, and the surface of the mound was covered with planktonic materials. Such a mound of poor quality may provide little water-exchange, which may lead to the egg-desertion by males. These results indicated that mound maintenance by females during the egg-tending period has an important role in the success of parental care by males.

  16. Stairway to Heaven: Evaluating Levels of Biological Organization Correlated with the Successful Ascent of Natural Waterfalls in the Hawaiian Stream Goby Sicyopterus stimpsoni

    PubMed Central

    Schoenfuss, Heiko L.; Maie, Takashi; Moody, Kristine N.; Lesteberg, Kelsey E.; Blob, Richard W.; Schoenfuss, Tonya C.

    2013-01-01

    Selective pressures generated by locomotor challenges act at the level of the individual. However, phenotypic variation among individuals that might convey a selective advantage may occur across any of multiple levels of biological organization. In this study, we test for differences in external morphology, muscle mechanical advantage, muscle fiber type and protein expression among individuals of the waterfall climbing Hawaiian fish Sicyopterus stimpsoni collected from sequential pools increasing in elevation within a single freshwater stream. Despite predictions from previous laboratory studies of morphological selection, few directional morphometric changes in body shape were observed at successively higher elevations. Similarly, lever arm ratios associated with the main pelvic sucker, central to climbing ability in this species, did not differ between elevations. However, among climbing muscles, the adductor pelvicus complex (largely responsible for generating pelvic suction during climbing) contained a significantly greater red muscle fiber content at upstream sites. A proteomic analysis of the adductor pelvicus revealed two-fold increases in expression levels for two respiratory chain proteins (NADH:ubiquinone reductase and cytochrome b) that are essential for aerobic respiration among individuals from successively higher elevations. Assessed collectively, these evaluations reveal phenotypic differences at some, but not all levels of biological organization that are likely the result of selective pressures experienced during climbing. PMID:24386424

  17. A new, mesophotic Coryphopterus goby (Teleostei, Gobiidae) from the southern Caribbean, with comments on relationships and depth distributions within the genus

    PubMed Central

    Baldwin, Carole C.; Robertson, D. Ross

    2015-01-01

    Abstract A new species of western Atlantic Coryphopterus is described from mesophotic depths off Curaçao, southern Caribbean. Coryphopterus curasub sp. n., is similar to Coryphopterus dicrus in, among other features, having two prominent pigment spots of roughly equal intensity on the pectoral-fin base, the pelvic fins fused to form a disk, and no pelvic frenum. The two species can be differentiated by body depth (shallower in Coryphopterus curasub at origin of dorsal fin and caudal peduncle); differences in the pigmentation on the head, trunk, and basicaudal region; and usually by total number of rays (spinous plus soft) in the second dorsal fin (10–11, usually 11, in Coryphopterus curasub, 10 in Coryphopterus dicrus). Coryphopterus curasub differs from other Coryphopterus species that have a prominent pigment spot on the lower portion of the pectoral-fin base (Coryphopterus punctipectophorus and Coryphopterus venezuelae) in, among other features, lacking a pelvic frenum. Coryphopterus curasub was collected between 70 and 80 m, the deepest depth range known for the genus. Collections of Coryphopterus venezuelae at depths of 65–69 m extend the depth range of that species by approximately 50 m. Mitochondrial cytochrome c oxidase subunit I (COI) data corroborate the recognition of Coryphopterus curasub as a distinct species but do not rigorously resolve its relationships within the genus. A revised key to the western Atlantic species of Coryphopterus is presented. PMID:26257572

  18. Complete mitochondrial genome of the urohaze-goby Glossogobius olivaceus (Perciformes, Gobiidae) and structure comparison of light strand replication origin in Gobioidei.

    PubMed

    Sun, Yuena; Wei, Tao; Jin, Xiaoxiao; Qin, Yu; Xu, Tianjun

    2015-01-01

    The genome of Glossogobius olivaceus (G. olivaceus) was 16,568 bp in length with a standard set of 13 protein-coding genes, 22 transfer RNA genes (tRNAs), 2 ribosomal RNA genes (rRNAs) and 2 non-coding region (the control region and origin of the light strand replication). The conserved motif 5'-GCCGG-3' was determined in the origin of light strand replication of G. olivaceus. The G. olivaceus mitogenome base composition was: T 25.65%, C 29.82% A 27.17% and G 17.36%, with a slight A+T bias of 52.82%, which was similar to most of the vertebrate mitogenomes. The mitochondrial genome of G. olivaceus had common features regarding gene arrangement and tRNA structures compared with those of other bony fishes.

  19. Effects of microplastics on juveniles of the common goby (Pomatoschistus microps): confusion with prey, reduction of the predatory performance and efficiency, and possible influence of developmental conditions.

    PubMed

    Carlos de Sá, Luís; Luís, Luís G; Guilhermino, Lúcia

    2015-01-01

    Microplastics (MP) are ubiquitous contaminants able to cause adverse effects on organisms. Three hypotheses were tested here: early Pomatoschistus microps juveniles can ingest MP; the presence of MP may reduce fish predatory performance and efficiency; developmental conditions may influence the preyselection capability of fish. Predatory bioassays were carried out with juveniles from two estuaries with differences in environmental conditions: Minho (M-est) and Lima (L-est) Rivers (NW Iberian coast). Polyethylene MP spheres (3 types) alone and in combination with Artemia nauplii were offered as prey.All the MP types were ingested, suggesting confusion with food. Under simultaneous exposure to MP and Artemia, L-est fish showed a significant reduction of the predatory performance (65%) and efficiency (upto 50%), while M-est fish did not, suggesting that developmental conditions may influence the preyselection capability of fish. The MP-induced reduction of food intake may decrease individual and population fitness.

  20. 77 FR 43222 - Endangered and Threatened Wildlife and Plants; Designation of Critical Habitat for the Tidewater...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-24

    ...; Designation of Critical Habitat for the Tidewater Goby AGENCY: Fish and Wildlife Service, Interior. ACTION... habitat for the tidewater goby (Eucyclogobius newberryi) under the Endangered Species Act of 1973, as... revised designation of critical habitat for tidewater goby and an amended required determinations...

  1. Temperature rise and microplastics interact with the toxicity of the antibiotic cefalexin to juveniles of the common goby (Pomatoschistus microps): Post-exposure predatory behaviour, acetylcholinesterase activity and lipid peroxidation.

    PubMed

    Fonte, Elsa; Ferreira, Pedro; Guilhermino, Lúcia

    2016-11-01

    The goal of this study was to investigate the toxicity of cefalexin to Pomatoschistus microps juveniles in relation to the presence of microplastics in the water and temperature rise. After acclimatization, groups of wild juveniles were exposed for 96h to artificial salt water (control), microplastics alone (0.184mg/l), cefalexin alone (1.3-10mg/l) and in mixture with microplastics (cefalexin: 1.3-10mg/l; microplastics: 0.184mg/l) at 20 and 25°C. Effect criteria were mortality, post-exposure predatory performance (PEPP), acetylcholinesterase activity (AChE) and lipid peroxidation levels (LPO). At 20°C, concentrations of cefalexin alone≥5mg/l significantly reduced PEPP (up to 56%; 96h-EC50=8.4mg/l), indicating toxicity of the antibiotic to juveniles after short-term exposure to water concentrations in the low ppm range. At 20°C, fish exposed to microplastics alone did not have significant differences in any of the parameters tested relative to the control group but tended to have an inhibition of the PEPP (23%) and AChE (21%); at 25°C, microplastics alone caused mortality (33%) and PEPP inhibition (28%). Thus, microplastics are toxic to P. microps juveniles. At 20°C, under simultaneous exposure to cefalexin and microplastics, the PEPP was significantly reduced (at cefalexin concentrations≥1.25mg/l). Moreover, at 25°C, the toxicity curves of cefalexin (PEPP based), alone and in mixture with microplastics, were significantly different (p<0.05; 96h-EC50 of 3.8 and 5.2mg/l, respectively), and the integrated data analysis indicated significant interactions between the two substances for all biomarkers. Thus, the presence of microplastics in the water influenced the toxicity of cefalexin. The rise of water temperature (from 20°C to 25°C), increased the microplastics-induced mortality (from 8 to 33%), and the inhibitory effects of cefalexin on the PEPP (up to 70%). Significant differences (p<0.05) between the toxicity curves of cefalexin alone at distinct temperatures were found, with a lower 96h-EC50 at 25°C (3.8mg/l) than at 20°C (8.4mg/l). Moreover, at 25°C, increases of AChE activity (14%) and LPO (72%) in fish exposed to the mixture treatment containing the highest cefalexin concentration were found, and the integrated analysis of data indicated significant interactions between cefalexin and temperature for PEPP, and among all stressors for LPO. Thus, the temperature rise increased the toxicity of microplastics and of cefalexin, alone and in mixture with microplastics, to P. microps juveniles. These findings raise concern on the long-term exposure of wild populations to complex mixtures of pollutants, likely decreasing their fitness, and highlight the need of more research on the combined effects of widely used pharmaceuticals, microplastics and temperature increase on wild species to improve environmental and human risk assessments of chemicals and their safe use under a global warming scenario.

  2. Does the presence of microplastics influence the acute toxicity of chromium(VI) to early juveniles of the common goby (Pomatoschistus microps)? A study with juveniles from two wild estuarine populations.

    PubMed

    Luís, Luís G; Ferreira, Pedro; Fonte, Elsa; Oliveira, Miguel; Guilhermino, Lúcia

    2015-07-01

    Toxicological interactions between microplastics (MP) and other environmental contaminants are of grave concern. Here, the potential influence of MP in the short-term toxicity of chromium to early juveniles of Pomatoschistus microps was investigated. Three null hypotheses were tested: (1) exposure to Cr(VI) concentrations in the low ppm range does not induce toxic effects on juveniles; (2) the presence of microplastics in the water does not influence the acute toxicity of Cr(VI) to juveniles; (3) the environmental conditions of the natural habitat where fish developed do not influence their sensitivity to Cr(VI)-induced acute stress. Fish were collected in the estuaries of Minho (M-est) and Lima (L-est) Rivers (NW Iberian Peninsula) that have several abiotic differences, including in the water and sediment concentrations of various environmental contaminants. After acclimatization to laboratory conditions, two 96h acute bioassays were carried out with juveniles from both estuaries to: (i) investigate the effects of Cr(VI) alone; (ii) investigate the effects of Cr(VI) in the presence of MP (polyethylene spheres 1-5μm ∅). Cr(VI) alone induced mortality (96h-LC50s: 14.4-30.5mg/l) and significantly decreased fish predatory performance (≤74%). Thus, in the range of concentrations tested (5.6-28.4mg/l) Cr(VI) was found to be toxic to P. microps early juveniles, therefore, we rejected hypothesis 1. Under simultaneous exposure to Cr(VI) and MP, a significant decrease of the predatory performance (≤67%) and a significant inhibition of AChE activity (≤31%) were found. AChE inhibition was not observed in the test with Cr(VI) alone and MP alone caused an AChE inhibition ≤21%. Mixture treatments containing Cr(VI) concentration ≥3.9mg/l significantly increased LPO levels in L-est fish, an effect that was not observed under Cr(VI) or MP single exposures. Thus, toxicological interactions between Cr(VI) and MP occurred, therefore, we rejected hypothesis 2. In the presence of MP, the negative effect caused by high concentrations of Cr(VI) on the predatory performance was significantly reduced in L-est fish but not in M-est fish, and Cr(VI) concentrations higher than 3.9mg/l caused oxidative damage in L-est fish but not in M-est fish. The acclimatization and test conditions were similar for fish from the two estuaries and these ecosystems have environmental differences. Thus, long-term exposure to distinct environmental conditions in the natural habitat during previous developmental phases influenced the sensitivity and responses of juveniles to Cr(VI), therefore, we rejected hypothesis 3. Overall, the results of this study indicate toxicological interactions between MP and Cr(VI) highlighting the importance of further investigating the combined effects of MP and other common contaminants.

  3. Regional Seismic Wave Propagation

    DTIC Science & Technology

    1979-07-31

    Baikal to the Pamirs, earthquakes occuring in the Baikal region, Sinkiang , the Gobi desert, southwest China and the Himalayas generated Lg/P ratios...data were obtained from stations within the USSR from earthquake events occuring in Baikal, Sinkiang , the Gobi desert, Southwest China and the...earthquakes originating in the Sinkiang province and recorded by seismo- graphic stations along the Pamir-Lena River profile [25] 0 - recorded by short

  4. Satellite Observations of Aerosol Variations in the Central North Pacific Ocean

    DTIC Science & Technology

    1989-12-01

    which wvere the Gobi desert dust storms and the eruption of Kilauea volcano . By cormparing shipboard and satellite data, satellite retrieval technique...the Gobi desert dust storms and the eruption of Kilauea volcano . By comparing shipboard and satellite data, satellite retrieval techniques were...the Kilauea volcano . Positive correlation between the two data sets verifies the satellite retrieval techniques. Contrary to the Northern region, the CN

  5. Prey-specific determination of arsenic bioaccumulation and transformation in a marine benthic fish.

    PubMed

    Zhang, Wei; Zhang, Li; Wang, Wen-Xiong

    2017-02-06

    The sediments from Chinese coastal waters contain relatively high concentrations of arsenic (As), mainly arsenate As(V), which may be transferred along the marine benthic food chain. The prey-specific determination of As bioaccumulation and transformation in marine benthic fish remains little known. In this study, we focused on a typical marine benthic food chain comprising of sediments, deposit-feeding invertebrates (polychaete Nereis succinea and clam Gafrarium tumidum) and goby fish Mugilogobius chulae. Graded exposed experiments using different As exposure durations and concentrations were conducted to examine their transformation rate and efficiency. Radiotracer techniques were used to determine the rates of As uptake (as arsenate) from seawater, assimilation from two prey and its subsequent efflux in the goby fish. We demonstrated that the two prey (polychates and clams) displayed different As biotransformation in the goby fish. Biotransformation rate was higher in the goby fish fed on the clams than on the polychaetes, and biotransformation efficiency was lower with increasing inorganic As concentration in the prey. The As overall bioaccumulation in the goby fish was very low, mainly because of the low dissolved uptake and dietary assimilation and high efflux. Combining the biotransformation and biokinetics measurements, our findings highlighted that different prey containing different As concentrations and As species resulted in the comparable As bioaccumulation in the goby fish.

  6. Separation of gonadotropic fractions with different species specificities from tuna pituitaries

    SciTech Connect

    Ando, H.; Ishii, S.

    1988-05-01

    Eight different gonadotropic glycoprotein fractions were separated from the acetone-dried powder of yellow fin tuna pituitary glands by successive chromatographies on Superose 12 for gel filtration and Mono Q for anion exchange using the Pharmacia fast protein liquid chromatography system. This was preceded by preliminary separations using an ammonium sulfate precipitation method and affinity chromatography on concanavalin A-Sepharose. For biological characterization, we employed two radioreceptor assay systems, one using goby testis plasma membranes and silver carp GTH as the receptor and radioligand, respectively, and the other using testis plasma membranes of the yellow fin tuna and gonadotropin of the same species, respectively. We also employed two testicular cyclic AMP accumulation bioassay methods in vitro, one with the goby testis and the other with the mackerel testis. The least acidic fraction after Mono Q was further separated into four subfractions by rechromatography with Mono Q. They were strongly active in the tuna and mackerel assays but almost inactive in the goby assays. They were referred to as tuna-type tuna gonadotropin. In contrast, the most acidic fraction obtained after the first Mono Q was active in the goby assays but almost inactive in the tuna and mackerel assays. It was referred to as goby-type tuna gonadotropin. The intermediate fractions were active on both assays and are considered to be mixtures of tuna-type and goby-type gonadotropins. The reason for the presence of gonadotropin inactive to homologous species is discussed from the evolutionary viewpoint.

  7. The distribution of 4-nonylphenol in marine organisms of North American Pacific Coast estuaries.

    PubMed

    Diehl, Jennifer; Johnson, Sarah E; Xia, Kang; West, Amy; Tomanek, Lars

    2012-04-01

    One of the chemical breakdown products of nonylphenol ethoxylates, 4-nonylphenol (4-NP), accumulates in organisms and is of concern as an environmental pollutant due to its endocrine disrupting effects. We measured 4-NP levels in the seawater, sediment, and twelve organisms within the California estuary, Morro Bay, and examined biomagnification of 4-NP using stable isotope abundances (δ(15)N and δ(13)C) to quantify trophic position. 4-NP concentrations in organisms from Morro Bay included 25000±8600 ng g(-1) lw in liver of California sea lion, 14000±5600 ng g(-1) lw in liver of harbor porpoise, 138000±55000 ng g(-1) lw in liver of sea otters, 15700±3600 ng g(-1) lw in liver of seabirds, 36100±6100 ng g(-1) lw in arrow goby fish, 62800±28400 ng g(-1) lw in oysters, and 12700±1300 ng g(-1) lw in mussels. 4-NP levels generally showed a pattern of trophic dilution among organisms in Morro Bay, with exceptions of biomagnification observed between three trophic links: mussel to sea otter (BMF 10.9), oyster to sea otter (BMF 2.2), and arrow goby to staghorn sculpin (BMF 2.7). Our examination of other west coast estuaries of USA and Canada revealed that mean 4-NP concentrations in gobies and mussels from Morro Bay were significantly higher than those from a more urbanized estuary, San Francisco Bay (goby: 11100±3800 ng g(-1) lw) and from a remote estuary, Bamfield Inlet, Canada (goby: 9000±900 ng g(-1) lw, mussel: 6100±700 ng g(-1) lw). Relative to other estuaries worldwide, 4-NP levels in seawater (0.42±0.16 μg L(-1)) and sediment (53±14 ng g(-1) dw) of Morro Bay are low, but gobies and oysters have higher 4-NP levels than comparable fauna.

  8. The first record of Gyrodactylus corleonis Paladini, Cable, Fioravanti, Faria & Shinn, 2010 (Monogenea: Gyrodactylidae) from the wild.

    PubMed

    Dmitrieva, Evgenija V; Gerasev, Pavel I; Garippa, Giovanni; Piras, M Cristina; Merella, Paolo

    2015-09-01

    Specimens of Gyrodactylus corleonis Paladini, Cable, Fioravanti, Faria & Shinn, 2010 (Monogenea: Gyrodactylidae) were collected from the body and fins of Gobius cobitis Pallas in the western Mediterranean Sea off northwestern Sardinia. This is the first finding of this species in the wild and also represents a new host record. A morphological comparison of the new material with the type description of G. corleonis is presented. Since G. corleonis was found in the wild on representatives of the Gobiidae, a comparison with species of Gyrodactylus von Nordmann, 1832 parasitising gobies is included. The occurrence of G. corleonis on different host species and its phylogenetic relationships with gyrodactylids from sand gobies are discussed.

  9. NATIVE AND INTRODUCED LARVAL FISHES IN SUISAN MARSH, CALIFORNIA,: THE EFFECTS OF FRESHWATER FLOW

    EPA Science Inventory

    We sampled ichthyoplankton weekly in Suisun Marsh in the San Francisco Estuary from February to June each year from 1994 to 1999. We collected approximately 227,900 fish, predominantly shimofuri goby Tridentiger bifasciatus (60%) and prickly sculpin Cottus asper (33%). Principal ...

  10. 76 FR 64995 - Endangered and Threatened Wildlife and Plants; Designation of Revised Critical Habitat for the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-19

    ...We, the U.S. Fish and Wildlife Service (Service), propose to revise critical habitat for the tidewater goby (Eucyclogobius newberryi) under the Endangered Species Act of 1973, as amended (Act). In total, approximately 12,157 acres (4,920 hectares) are being proposed for designation as critical habitat. The proposed revised critical habitat is located in Del Norte, Humboldt, Mendocino, Sonoma,......

  11. Shifting material source of Chinese loess since ~2.7 Ma reflected by Sr isotopic composition

    PubMed Central

    Zhang, Wenfang; Chen, Jun; Li, Gaojun

    2015-01-01

    Deciphering the sources of eolian dust on the Chinese Loess Plateau (CLP) is fundamental to reconstruct paleo-wind patterns and paleo-environmental changes. Existing datasets show contradictory source evolutions of eolian dust on the CLP, both on orbital and tectonic timescales. Here, the silicate Sr and Nd isotopic compositions of a restricted grain size fraction (28–45 μm) were measured to trace the source evolution of the CLP since ~2.7 Ma. Our results revealed an unchanged source on orbital timescales but a gradual source shift from the Qilian Mountains to the Gobi Altay Mountains during the past 2.7 Ma. Both tectonic uplift and climate change may have played important roles for this shift. The later uplift of the Gobi Altay Mountains relative to the Qilian Mountains since 5 ± 3 Ma might be responsible for the increasing contribution of Gobi materials to the source deserts in Alxa arid lands. Enhanced winter monsoon may also facilitate transportation of Gobi materials from the Alxa arid lands to the CLP. The shifting source of Asian dust was also reflected in north Pacific sediments. The finding of this shifting source calls for caution when interpreting the long-term climate changes based on the source-sensitive proxies of the eolian deposits. PMID:25996645

  12. A Mesoscale Model Analysis of Sea Fog Formation and Dissipation Near Kunsan Air Base

    DTIC Science & Technology

    2012-03-01

    early spring. Yellow wind is dust that originates in the Gobi Desert and is carried south by cold fronts that move from the northwest. The dust ...5 II. REGIONAL BACKGROUND AND LITERATURE REVIEW .............................7 A. GEOGRAPHICAL AND CLIMATOLOGICAL DESCRIPTION OF THE YELLOW SEA...7 2. The Yellow Sea Bathymetry ................................................................8 3. Climatology of

  13. Ecological Evaluation of a Beach Nourishment Project at Hallandale (Broward County), Florida. Volume I. Evaluation of Fish Populations Adjacent to Borrow Areas of Beach Nourishment Project, Hallandale (Broward County), Florida.

    DTIC Science & Technology

    1980-02-01

    variabilis), bluehead (ThaZassoma iw_’Izsciatn), red- tail parrotfish (Sparisoma chrysoptern), and doo orfish (Acanthuus chirurgus) were also abundant...Sizable aggregatlons of grunts (Pomadasyidae), angelfishes, and parrotfishes (Scaridae) occurred at specific locations on the first reef...doctorfish were also abundant. Gobies (Gobiidae), parrotfishes , angelfishes, grunts, and sea basses (Serranidae) were also well represented on this

  14. Using occupancy modelling to compare environmental DNA to traditional field methods for regional-scale monitoring of an endangered aquatic species.

    PubMed

    Schmelzle, Molly C; Kinziger, Andrew P

    2016-07-01

    Environmental DNA (eDNA) monitoring approaches promise to greatly improve detection of rare, endangered and invasive species in comparison with traditional field approaches. Herein, eDNA approaches and traditional seining methods were applied at 29 research locations to compare method-specific estimates of detection and occupancy probabilities for endangered tidewater goby (Eucyclogobius newberryi). At each location, multiple paired seine hauls and water samples for eDNA analysis were taken, ranging from two to 23 samples per site, depending upon habitat size. Analysis using a multimethod occupancy modelling framework indicated that the probability of detection using eDNA was nearly double (0.74) the rate of detection for seining (0.39). The higher detection rates afforded by eDNA allowed determination of tidewater goby occupancy at two locations where they have not been previously detected and at one location considered to be locally extirpated. Additionally, eDNA concentration was positively related to tidewater goby catch per unit effort, suggesting eDNA could potentially be used as a proxy for local tidewater goby abundance. Compared to traditional field sampling, eDNA provided improved occupancy parameter estimates and can be applied to increase management efficiency across a broad spatial range and within a diversity of habitats.

  15. An Unsuccessful Experiment in Acclimatizing Grey Mullets.

    DTIC Science & Technology

    2007-11-02

    workers from the Aral Ichthyological Division managed to catch a rather large number of Bubyr caucasicus Kowalewsky and Leander squilla in the... Ichthyological Division, Ye. L. Markova, discovered many gobies and shrimps at the mouth of the Syr Dar’yei and in the last half of August

  16. Complete mitochondrial genome sequence of Tridentiger bifasciatus and Tridentiger barbatus (Perciformes, Gobiidae): a mitogenomic perspective on the phylogenetic relationships of Gobiidae.

    PubMed

    Jin, Xiaoxiao; Wang, Rixin; Wei, Tao; Tang, Da; Xu, Tianjun

    2015-01-01

    The fishes of suborder Gobioidei is the largest group of those in present living Perciformes, which contains about 2,200 species belonging to 270 genera of 9 families in the world. The monophyly and phylogenetic relationships of gobies have been controversial and disputable for a long time. In the present study, the complete mitochondrial genome of the shimofuri goby Tridentiger bifasciatus (T. bifasciatus) and shokihaze goby Tridentiger barbatus (T. barbatus) were firstly determined. The two mitochondrial genomes were both consisted of 2 ribosomal RNA (rRNA) genes, 13 protein-coding genes, 22 transfer RNA (tRNA) genes, and one major control region (CR). They shared similar features with those of other gobies in terms of gene arrangement, base composition, and tRNA structures. The CR was absence of typical conserved blocks (CSB-E, and CSB-F) respectively for the T. bifasciatus and T. barbatus. Phylogenomic analyses, which based on 12 concatenated protein-coding genes and complete mitochondrial genome sequences, revealed that there were two groups within the Gobiidae. A large group consisted of the Amblyopinae, Gobionellinae, Oxudercinae and Sicydiinae, and Amblyopinae was nested in Oxudercinae and they were both paraphyletic to Sicydiinae. The other group was the Gobiinae. As a whole, our phylogenetic data was different from the traditionally classification of Gobiidae, but supported the new phylogenetic taxonomy view of Thacker (Copeia 2009:93-104, 2009).

  17. Impact of long-range desert dust transport on hydrometeor formation over coastal East Asia

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenxi; Zhou, Wen; Wenig, Mark; Yang, Liangui

    2017-01-01

    Model simulations and hydrological reanalysis data for 2007 are applied to investigate the impact of long-range desert dust transport on hydrometeor formation over coastal East Asia. Results are analyzed from Hong Kong and Shanghai, which are two representative coastal cities of East Asia. Long-range desert dust transport impacts mainly spring and summer clouds and precipitation over coastal East Asia. In spring, clouds and precipitation come mainly from large-scale condensation and are impacted mainly by dust from the Gobi, Sahara, and Thar deserts. These desert dusts can participate in the precipitation within and below the clouds. At lower latitudes, the dust particles act mainly as water nuclei. At higher latitudes, they act as both water nuclei and ice nuclei. The effect of Gobi, Sahara, and Thar dust on large-scale clouds and precipitation becomes stronger at higher latitudes. In summer, clouds and precipitation over coastal East Asia come mainly from convection and are impacted mainly by dust from the Taklamakan, Arabian, and Karakum-Kavir deserts. Most Taklamakan dust particles can participate in precipitation within convective clouds as ice nuclei, while Arabian and Karakum-Kavir dust particles participate only as water nuclei in precipitation below the clouds. The effect of Taklamakan dust on convective clouds and precipitation becomes stronger at lower latitudes. Of all the desert dusts, that from the Gobi and Taklamakan deserts has the relatively largest impact. Gobi dust impacts climate change in coastal East Asia by affecting spring water clouds at higher latitudes.

  18. Quantitative estimation of the contribution of dust sources to Chinese loess using detrital zircon U-Pb age patterns

    NASA Astrophysics Data System (ADS)

    Zhang, Hanzhi; Lu, Huayu; Xu, Xisheng; Liu, Xiaoming; Yang, Tao; Stevens, Thomas; Bird, Anna; Xu, Zhiwei; Zhang, Tian; Lei, Fang; Feng, Han

    2016-11-01

    The origin and provenance of the loess deposits of the Chinese Loess Plateau (CLP) are still debated. In order to pinpoint the dust sources, surface samples from the piedmont of the Northeastern Tibetan Plateau, the Gobi Altai Mountains, and modern eolian dunes from the Tengger desert and Mu Us sand field were analyzed by using the detrital zircon dating technique. In order to quantitatively discriminate the content of different potential sources, zircon grains of different ages were grouped according to their tectonic origin. Zircon grains aged from 1300 to 550 Ma were assigned to the Northeastern Tibetan Plateau, and grains aged from 550 to 0 Ma to the Northeastern Tibetan Plateau or the Gobi Altai Mountains, or to a combination of the two. Zircon ages of around 2.8 Ga to 1.3 Ga may be a mixture of sources from the Northeastern Tibetan Plateau, Gobi Altai Mountains, or North China Craton. Sediments from the Tengger desert and Mu Us sand field consist of a mixture of the three sources and exhibit a high degree of spatial variability in terms of their source. In the northern part of the two deserts, 43-83% of the sediments are derived from the Gobi Altai Mountains, while in the south, material from the Northeastern Tibetan Plateau comprises 51-98% of the sediments. Loess deposits from the CLP also comprise a mixture of the three different sources, with material from the Northeastern Tibetan Plateau making the dominant contribution (65-100%), with material from the North China Craton and the Gobi Altai Mountains comprising 0-35% and 0-40% of the loess deposits, respectively. The contributions from the three sources to the loess deposits on CLP vary spatially. Application of the novel statistical method of provenance group analysis demonstrates that the loess deposits comprise a mixture of material from a broad region of northern China and that the Northeastern Tibetan Plateau material makes the dominant contribution.

  19. Bucephalus polymorphus Baer, 1827 - a new fish parasite in Austria?

    PubMed

    Michael Mühlegger, J; Jirsa, Franz; Konecny, Robert; Sattmann, Helmut; Frank, Christa

    2009-10-01

    During parasitological studies of the invasive round goby fish species Apollonia melanostoma (Pallas, 1814) from the Danube River in 2007 the digenean Bucephalus polymorphus Baer, 1827 was detected for the first time in Austria. Encysted metacercariae of the parasite were found on the fins, skin and gills of the fish. The occurrence of the parasite is strictly dependant on the zebra mussel Dreissena polymorpha (Pallas, 1771), which acts as the obligatory first intermediate host in its life cycle. The mussel has also invaded Austrian waters, but has appeared in 1870 already. It will not be possible to establish whether the parasite was introduced to Austria with the gobies, or has arrived earlier, but it should be the subject of future investigations to ascertain whether the parasite will be able to establish a firm population in Austria, and whether this introduction puts additional pressure on the native fish populations.

  20. Digestive Physiological Characteristics of the Gobiidae

    PubMed Central

    Hur, Sang-Woo; Kim, Shin-Kwon; Kim, Dae-Jung; Lee, Bae-Ik; Park, Su-Jin; Hwang, Hyung-Gyu; Jun, Je-Cheon; Myeong, Jeong-In; Lee, Chi-Hoon; Lee, Young-Don

    2016-01-01

    In this study, we investigated the characteristics of CCK-producing cells and mucus-secreting goblet cells with respect to stomach fish and stomachless fish of the Gobiidae in order to provide a basis for understanding the digestive physiology. Hairychin goby (Sagamia geneionema), which is stomachless fish, the numbers of mucus-secreting goblet cells is highest in the posterior intestine portion (P<0.05), while CCK-producing cells are scattered throughout the intestine. Gluttonous goby (Chasmichthys gulosus), which is stomach fish, mucus-secreting goblet cells are most abundant in the mid intestine portion (P<0.05), whereas CCK-producing cells are observed only in the anterior and mid intestine portion. Trident goby (Tridentiger obscurus) which is stomach fish, mucus-secreting goblet cells were most abundant in the mid intestine portion (P<0.05). CCK-producing cells are found in the anterior and mid intestine portion. Giurine goby, Rhinogobius giurinus which is also stomach fish, the largest number of mucus-secreting goblet cells showed in anterior intestine portion except for esophagus (P<0.05). CCK-producing cells are present only in the anterior and mid intestine portion. In S. geneionema, digestive action occurs in the posterior intestine portion to protect and functions to activate digestion. In contrast, in C. gulosus, T. obscurus and R. giurinus, their digestive action occurs in the anterior and mid intestine portion to protect and functions to activate digestion. Further studies of the modes of food ingestion by these fish, the contents of their digestive tracts, and the staining characteristics of the goblet cells need to be carried out. PMID:27796002

  1. Operational Lessons Learned in the Korean War

    DTIC Science & Technology

    2011-12-01

    entire peninsula, however, suffers from cold in the winter, Yellow Dust from the Gobi Desert choking the air in the spring, monsoons in midsummer...Republic of Korea in an effort to deter further North Korean aggression. The purpose of this monograph is capture operational lessons learned during the...considers North Korea as a buffer protecting its region of Manchuria. Encroachment of this border by foreign forces is a threat to Chinese sovereignty

  2. Chinese Ambition

    DTIC Science & Technology

    2000-04-01

    City. In 1271 Kublai Khan adopted a Chinese dynastic name, giving birth to the Yuan Dynasty. The Chinese culture was strong enough to survive the...leader, Timuchin, who was to become known as Genghis Khan , established the Yuan Dynasty. The Mongols were a loosely connected ethnic tribal community...that lived on the edge of the Gobi Desert in an area now known as Outer Mongolia. Genghis Khan organized a small ruthless army of only about 120

  3. Vertical Variation of Dust and Its Impact on the Top of the Atmosphere Brightness Temperature in the Midwave Infrared

    DTIC Science & Technology

    2007-03-01

    Figure 7. Gobi Dust Storm and Resultant Dust Plume Over The Korean Peninsula ......28 Figure 8. Southern Iraq and Persian Gulf Dust Event...spectrum. Many other regions of the world exhibit significant dust storm events. For the sake of scale, military significance, and data collection...overwhelming majority of Asian Dust storms occur in the spring as the polar jet retreats to the north and brings mid-latitude cyclones through

  4. Oxygen isotope signatures of quartz from major Asian dust sources: Implications for changes in the provenance of Chinese loess

    NASA Astrophysics Data System (ADS)

    Yan, Yan; Sun, Youbin; Chen, Hongyun; Ma, Long

    2014-08-01

    We present a systematic investigation of the oxygen isotopic composition of quartz in both fine and coarse fractions (<16 and 16-63 μm) from major dust source regions in East Asia, including the Mongolian Gobi, the northern Chinese deserts, the Taklimakan desert, and the Qaidam Basin. The results demonstrate that the quartz oxygen isotope ratios of the Taklimakan desert and the Mongolian Gobi are more heterogeneous compared with the other areas. The quartz δ18O values of both the fine and coarse fractions from the various sources are overlapped to varying degrees, thus making it difficult to differentiate them. Nevertheless, the quartz δ18O values of both fractions exhibit an increasing trend from the Mongolian Gobi, to the northern Chinese deserts, and then to the Taklimakan desert. This implies that the geological settings of the source areas are different, which in turn results in differing contributions of high-temperature igneous rocks. The combination of quartz δ18O results with other quartz-based provenance tracers can clearly differentiate the three major source areas, i.e., the Taklimakan desert, the Mongolian Gobi, and the northern Chinese deserts. In addition, comparison of our results with previous δ18O measurements of fine-grained quartz from the Luochuan loess sequence suggests the likely glacial-interglacial fluctuations in dust provenance. Finally, we suggest that the combination of quartz δ18O signatures and other dust provenance tracers can potentially improve the recognition of long-term fluctuations in the provenance of Chinese loess-red clay deposits.

  5. Life cycle of Genarchopsis goppo (Trematoda: Derogenidae) from Nara, Japan.

    PubMed

    Urabe, M

    2001-12-01

    A cystophorous cercaria obtained from Semisulcospira libertina (Gould) from Tobihino, Nara, Honshu, Japan, was used to experimentally infect a freshwater goby Rhinogobius sp. OR via the copepods Mesocyclops leuckarti (Claus), Thermocyclops hyalinus (Rehberg), and Eucyclops sarrulatus (Fisher). It was shown to grow into Genarchopsis goppo Ozaki, 1925. The parasite was found to occur as a natural infection in the stomach of Rhinogobius sp. OR and Odontobutis obscura (Temminck and Schlegel) from Tobihino.

  6. Quantitative analysis on windblown dust concentrations of PM10 (PM2.5) during dust events in Mongolia

    NASA Astrophysics Data System (ADS)

    Jugder, Dulam; Shinoda, Masato; Kimura, Reiji; Batbold, Altangerel; Amarjargal, Danzansambuu

    2014-09-01

    Dust concentration, wind speed and visibility, measured at four sites in the Gobi Desert and at a site in the steppe zone of Mongolia over a period of 4.5 years (January 2009 to May 2013), have been analyzed for their relationships, their effects on visibility, and for an estimate of the threshold wind necessary for dust emission in the region. Based on quantitative analysis on measurements, we evaluated that dust emission concentrations of 41-61 (20-24) μg m-3 of PM10 (PM2.5) are as the criterion between normal and hazy atmospheric conditions. With the arrival of dust events, wind-borne soil particulate matter (PM10, PM2.5) that originates in the Gobi Desert is changed dramatically. PM10 (PM2.5) concentrations increase by at least double or by several tens of times during severe dust events in comparison with the normal atmospheric condition. Ratio (PM2.5/PM10) between monthly means of PM10 and PM2.5 concentrations showed that anthropogenic particles were dominant in the ambient air of province centers in cool months (November to February). Threshold values of the onset of dust events were determined for PM10 (PM2.5) concentrations. According to the definition of dust storms, dust concentrations of PM10 corresponding to visibility of 1 km or less were determined at sites in the Gobi Desert and the steppe region. The threshold wind speeds during days with dust events were estimated at four sites in the Gobi Desert and compared each other. The threshold wind was higher at Sainshand and its cause might be due to smaller silt and clay fractions of soil.

  7. Remote sensing-based analysis on temporal and spatial changes about environmental elements in the northwest of Junggar basin, China

    NASA Astrophysics Data System (ADS)

    Yang, Liu; Nannan, Zhang; Wentong, Dong; Liqun, Zou; Shanghong, Huang

    2016-11-01

    This paper presents a study of revealing the environmental elements change during the process of local industrialization based on remote sensing technique in the western part of China. Spatio-temporal evolution of vegetation cover derived from NDVI and land surface water distribution was analyzed by time-series analysis of MSS and Landsat data from 1977 to 2011. Results show that remote sensing provide a way for monitoring the influence of local industrialization on regional environment elements in gobi region.

  8. Evolution of microhabitat association and morphology in a diverse group of cryptobenthic coral reef fishes (Teleostei: Gobiidae: Eviota).

    PubMed

    Tornabene, Luke; Ahmadia, Gabby N; Berumen, Michael L; Smith, Dave J; Jompa, Jamaluddin; Pezold, Frank

    2013-01-01

    Gobies (Teleostei: Gobiidae) are an extremely diverse and widely distributed group and are the second most species rich family of vertebrates. Ecological drivers are key to the evolutionary success of the Gobiidae. However, ecological and phylogenetic data are lacking for many diverse genera of gobies. Our study investigated the evolution of microhabitat association across the phylogeny of 18 species of dwarfgobies (genus Eviota), an abundant and diverse group of coral reef fishes. In addition, we also explore the evolution of pectoral fin-ray branching and sensory head pores to determine the relationship between morphological evolution and microhabitat shifts. Our results demonstrate that Eviota species switched multiple times from a facultative hard-coral association to inhabiting rubble or mixed sand/rubble habitat. We found no obvious relationship between microhabitat shifts and changes in pectoral fin-ray branching or reduction in sensory pores, with the latter character being highly homoplasious throughout the genus. The relative flexibility in coral-association in Eviota combined with the ability to move into non-coral habitats suggests a genetic capacity for ecological release in contrast to the strict obligate coral-dwelling relationship commonly observed in closely related coral gobies, thus promoting co-existence through fine scale niche partitioning. The variation in microhabitat association may facilitate opportunistic ecological speciation, and species persistence in the face of environmental change. This increased speciation opportunity, in concert with a high resilience to extinction, may explain the exceptionally high diversity seen in Eviota compared to related genera in the family.

  9. Top-down Estimate of Dust Emissions Through Integration of MODIS and MISR Aerosol Retrievals With the Geos-chem Adjoint Model

    NASA Technical Reports Server (NTRS)

    Wang, Jun; Xu, Xiaoguang; Henze, Daven K.; Zeng, Jing; Ji, Qiang; Tsay, Si-Chee; Huang, Jianping

    2012-01-01

    Predicting the influences of dust on atmospheric composition, climate, and human health requires accurate knowledge of dust emissions, but large uncertainties persist in quantifying mineral sources. This study presents a new method for combined use of satellite-measured radiances and inverse modeling to spatially constrain the amount and location of dust emissions. The technique is illustrated with a case study in May 2008; the dust emissions in Taklimakan and Gobi deserts are spatially optimized using the GEOSChem chemical transport model and its adjoint constrained by aerosol optical depth (AOD) that are derived over the downwind dark-surface region in China from MODIS (Moderate Resolution Imaging Spectroradiometer) reflectance with the aerosol single scattering properties consistent with GEOS-chem. The adjoint inverse modeling yields an overall 51% decrease in prior dust emissions estimated by GEOS-Chem over the Taklimakan-Gobi area, with more significant reductions south of the Gobi Desert. The model simulation with optimized dust emissions shows much better agreement with independent observations from MISR (Multi-angle Imaging SpectroRadiometer) AOD and MODIS Deep Blue AOD over the dust source region and surface PM10 concentrations. The technique of this study can be applied to global multi-sensor remote sensing data for constraining dust emissions at various temporal and spatial scales, and hence improving the quantification of dust effects on climate, air quality, and human health.

  10. Trophic niche partitioning of littoral fish species from the rocky intertidal of Helgoland, Germany

    NASA Astrophysics Data System (ADS)

    Hielscher, N. N.; Malzahn, A. M.; Diekmann, R.; Aberle, N.

    2015-12-01

    During a 3-year field study, interspecific and interannual differences in the trophic ecology of littoral fish species were investigated in the rocky intertidal of Helgoland island (North Sea). We investigated trophic niche partitioning of common coexisting littoral fish species based on a multi-tracer approach using stable isotope and fatty acids in order to show differences and similarities in resource use and feeding modes. The results of the dual-tracer approach showed clear trophic niche partitioning of the five target fish species, the goldsinny wrasse Ctenolabrus rupestris, the sand goby Pomatoschistus minutus, the painted goby Pomatoschistus pictus, the short-spined sea scorpion Myoxocephalus scorpius and the long-spined sea scorpion Taurulus bubalis. Both stable isotopes and fatty acids showed distinct differences in the trophic ecology of the studied fish species. However, the combined use of the two techniques added an additional resolution on the interannual scale. The sand goby P. minutus showed the largest trophic plasticity with a pronounced variability between years. The present data analysis provides valuable information on trophic niche partitioning of fish species in the littoral zones of Helgoland and on complex benthic food webs in general.

  11. [Independence of the Central Asian faunistic region (according to the distribution of lizards (Reptilia, Sauria))].

    PubMed

    Bobrov, V V

    2005-01-01

    Central Asian area above 2000 m was studied to test the independence of the Central Asian Mountain region in the herpetogeographical map of the Palearctic Region and the neighboring Sahara-Gobi Desert region. According to the range and origin similarity, all species inhabiting this area were assigned to several groups: mountain Central Asian species (the bulk of the range lies within the studied area), Western Asian upland species (the bulk of the range lies in the Near Eastern uplands), plain desert species (the bulk of the range is below 2000 m), Indo-Malayan species (the bulk of the range lies within the Indo-Malayan Kingdom), European species (the bulk of the range lies in the forest and steppe zones of Europe and West Siberia), and mountain desert species (equal parts of the range lie in the deserts and mountains of Central Asia). The distribution of species density was mapped by range superposition for each group. The dominance (over 50% of the total number of species) of mountain Central Asian or other species groups allowed us to assign the studied area to either the Central Asian mountain region or Sahara-Gobi desert region. The areas where neither of the specified groups exceeded the 50% threshold were recognized as transitional. Considering a large number of endemic species (28% of the total fauna), the Central Asian mountain area should be recognized as an independent region rather than a subregion of the Sahara-Gobi Desert region.

  12. Musculoskeletal determinants of pelvic sucker function in Hawaiian stream gobiid fishes: interspecific comparisons and allometric scaling.

    PubMed

    Maie, Takashi; Schoenfuss, Heiko L; Blob, Richard W

    2013-07-01

    Gobiid fishes possess a distinctive ventral sucker, formed from fusion of the pelvic fins. This sucker is used to adhere to a wide range of substrates including, in some species, the vertical cliffs of waterfalls that are climbed during upstream migrations. Previous studies of waterfall-climbing goby species have found that pressure differentials and adhesive forces generated by the sucker increase with positive allometry as fish grow in size, despite isometry or negative allometry of sucker area. To produce such scaling patterns for pressure differential and adhesive force, waterfall-climbing gobies might exhibit allometry for other muscular or skeletal components of the pelvic sucker that contribute to its adhesive function. In this study, we used anatomical dissections and modeling to evaluate the potential for allometric growth in the cross-sectional area, effective mechanical advantage (EMA), and force generating capacity of major protractor and retractor muscles of the pelvic sucker (m. protractor ischii and m. retractor ischii) that help to expand the sealed volume of the sucker to produce pressure differentials and adhesive force. We compared patterns for three Hawaiian gobiid species: a nonclimber (Stenogobius hawaiiensis), an ontogenetically limited climber (Awaous guamensis), and a proficient climber (Sicyopterus stimpsoni). Scaling patterns were relatively similar for all three species, typically exhibiting isometric or negatively allometric scaling for the muscles and lever systems examined. Although these scaling patterns do not help to explain the positive allometry of pressure differentials and adhesive force as climbing gobies grow, the best climber among the species we compared, S. stimpsoni, does exhibit the highest calculated estimates of EMA, muscular input force, and output force for pelvic sucker retraction at any body size, potentially facilitating its adhesive ability.

  13. Performance and scaling of a novel locomotor structure: adhesive capacity of climbing gobiid fishes.

    PubMed

    Maie, Takashi; Schoenfuss, Heiko L; Blob, Richard W

    2012-11-15

    Many species of gobiid fishes adhere to surfaces using a sucker formed from fusion of the pelvic fins. Juveniles of many amphidromous species use this pelvic sucker to scale waterfalls during migrations to upstream habitats after an oceanic larval phase. However, adults may still use suckers to re-scale waterfalls if displaced. If attachment force is proportional to sucker area and if growth of the sucker is isometric, then increases in the forces that climbing fish must resist might outpace adhesive capacity, causing climbing performance to decline through ontogeny. To test for such trends, we measured pressure differentials and adhesive suction forces generated by the pelvic sucker across wide size ranges in six goby species, including climbing and non-climbing taxa. Suction was achieved via two distinct growth strategies: (1) small suckers with isometric (or negatively allometric) scaling among climbing gobies and (2) large suckers with positively allometric growth in non-climbing gobies. Species using the first strategy show a high baseline of adhesive capacity that may aid climbing performance throughout ontogeny, with pressure differentials and suction forces much greater than expected if adhesion were a passive function of sucker area. In contrast, large suckers possessed by non-climbing species may help compensate for reduced pressure differentials, thereby producing suction sufficient to support body weight. Climbing Sicyopterus species also use oral suckers during climbing waterfalls, and these exhibited scaling patterns similar to those for pelvic suckers. However, oral suction force was considerably lower than that for pelvic suckers, reducing the ability for these fish to attach to substrates by the oral sucker alone.

  14. Temporal, spatial and tidal influences on benthic and demersal fish abundance in the Forth estuary

    NASA Astrophysics Data System (ADS)

    Greenwood, M. F. D.; Hill, A. S.

    2003-10-01

    The 10 most common demersal and benthic fish species collected during a 1982-2001 Agassiz trawling programme in the mid/lower Forth estuary, east Scotland, were assessed for possible influences of trawl site, month of sampling and tide height on abundance. All species were seasonal in their occurrence in the study area, with trends generally similar to those shown in other temperate European estuaries. Six species (whiting ( Merlangius merlangus), dab ( Limanda limanda), pogge ( Agonus cataphractus), fatherlasher ( Myoxocephalus scorpius), 'gobies' ( Pomatoschistus spp.) and sea snail ( Liparis liparis)) exhibited high winter and low summer abundance while plaice ( Pleuronectes platessa), flounder ( Platichthys flesus) and eelpout ( Zoarces viviparous) were least numerous in winter and mostly present in summer. Cod ( Gadus morhua) were low in abundance in late spring, but did not show pronounced peaks of abundance. Trawl station significantly influenced fish abundance in all but one case ('gobies'). There was relatively low abundance of most species at the middle trawl location, Tancred; only plaice, dab and whiting were numerous at this site. The majority of species were abundant at Port Edgar, adjacent to the estuary mouth, which may have reflected the relatively stable salinity conditions at this station. Flounder was most abundant at the mid-estuarine site of Longannet, and this was likely to have been in order to feed on the large mudflats nearby. Dispersal of fish onto inundated intertidal areas is suggested as a possible mechanism explaining the significant decrease in abundance of several species (flounder, pogge, eelpout and 'gobies') at high water (HW). The significant increase in abundance of whiting in the study area at HW may have been attributable to immigration of individuals from inshore regions of the Firth of Forth by the action of the flood tide. Interactions of location, month and tide height significantly influenced abundance of most species

  15. Does the invasive plant Elymus athericus modify fish diet in tidal salt marshes?

    NASA Astrophysics Data System (ADS)

    Laffaille, P.; Pétillon, J.; Parlier, E.; Valéry, L.; Ysnel, F.; Radureau, A.; Feunteun, E.; Lefeuvre, J.-C.

    2005-12-01

    The invasion of Mont-Saint-Michel Bay salt marshes (France) by a grass species ( Elymus athericus) has led to important changes in vegetation cover, which is likely to modify the habitat for many invertebrates. Some of them constitute the main food items for several fish species, such as young sea bass ( Dicentrarchus labrax) and sand goby ( Pomatoschistus minutus), that feed in salt marsh creeks during high tides. As a result, fish nursery functions of salt marshes could be modified by the E. athericus invasion. In order to test this hypothesis, gut contents of the two most abundant fish species (sea bass and sand goby) were compared before and after E. athericus invasion in the same salt marsh creek and using the same methodology. The accessibility and availability of the main food item, the semi-terrestrial amphipod Orchestia gammarella, were estimated and compared between invaded (dominated by E. athericus) and original areas (dominated by Atriplex portulacoides). Gut content analysis showed a significantly greater percentage of fish leaving with empty guts from E. athericus areas than from A. portulacoides areas. The sea bass diet composition study showed a major shift in the relative importance of the main food items: before E. athericus invasion, diets were dominated by the semi-terrestrial species O. gammarella, whereas after the E. athericus invasion they were dominated by a marine mysid Neomysis integer. The same trend was found for sand gobies, with a shift of the main food item from O. gammarella before invasion to the polychaete Hediste diversicolor after invasion. These trophic changes may be explained by the lower accessibility and availability of O. gammarella in invaded communities than in natural ones. The E. athericus invasion, observed throughout northern Europe, is thus likely to disturb trophic function of natural salt marshes for fish. This preliminary study of the E. athericus invasion is also an illustration that invasive species are an

  16. Repeated invasions into the twilight zone: evolutionary origins of a novel assemblage of fishes from deep Caribbean reefs.

    PubMed

    Tornabene, Luke; Van Tassell, James L; Robertson, D Ross; Baldwin, Carole C

    2016-08-01

    Mesophotic and deeper reefs of the tropics are poorly known and underexplored ecosystems worldwide. Collectively referred to as the 'twilight zone', depths below ~30-50 m are home to many species of reef fishes that are absent from shallower depths, including many undescribed and endemic species. We currently lack even a basic understanding of the diversity and evolutionary origins of fishes on tropical mesophotic reefs. Recent submersible collections in the Caribbean have provided new specimens that are enabling phylogenetic reconstructions that incorporate deep-reef representatives of tropical fish genera. Here, we investigate evolutionary depth transitions in the family Gobiidae (gobies), the most diverse group of tropical marine fishes. Using divergence-time estimation coupled with stochastic character mapping to infer the timing of shallow-to-deep habitat transitions in gobies, we demonstrate at least four transitions from shallow to mesophotic depths. Habitat transitions occurred in two broad time periods (Miocene, Pliocene-Pleistocene), and may have been linked to the availability of underutilized niches, as well as the evolution of morphological/behavioural adaptations for life on deep reefs. Further, our analysis shows that at least three evolutionary lineages that invaded deep habitats subsequently underwent speciation, reflecting another unique mode of radiation within the Gobiidae. Lastly, we synthesize depth distributions for 95 species of Caribbean gobies, which reveal major bathymetric faunal breaks at the boundary between euphotic and mesophotic reefs. Ultimately, our study is the first rigorous investigation into the origin of Caribbean deep-reef fishes and provides a framework for future studies that utilize rare, deep-reef specimens.

  17. Seismic velocity variations beneath central Mongolia: Evidence for upper mantle plumes?

    NASA Astrophysics Data System (ADS)

    Zhang, Fengxue; Wu, Qingju; Grand, Stephen P.; Li, Yonghua; Gao, Mengtan; Demberel, Sodnomsambuu; Ulziibat, Munkhuu; Sukhbaatar, Usnikh

    2017-02-01

    Central Mongolia is marked by wide spread recent volcanism as well as significant topographic relief even though it is far from any plate tectonic boundaries. The cause of the recent magmatism and topography remains uncertain partially because little is known of the underlying mantle seismic structure due to the lack of seismic instrumentation in the region. From August 2011 through August 2013, 69 broadband seismic stations were deployed in central Mongolia. Teleseismic traveltime residuals were measured using waveform correlation and were inverted to image upper mantle P and S velocity variations. Significant lateral variations in seismic velocity are imaged in the deep upper mantle (100 to 800 km depth). Most significant are two continuous slow anomalies from the deep upper mantle to near the surface. One slow feature has been imaged previously and may be a zone of deep upwelling bringing warm mantle to beneath the Hangay Dome resulting in uplift and magmatism including the active Khanuy Gol and Middle Gobi volcanoes. The second, deep low velocity anomaly is seen in the east from 800 to 150 km depth. The anomaly ends beneath the Gobi Desert that is found to have fast shallow mantle indicating a relatively thick lithosphere. We interpret the second deep slow anomaly as a mantle upwelling that is deflected by the thick Gobi Desert lithosphere to surrounding regions such as the Hentay Mountains to the north. The upwellings are a means of feeding warmer than normal asthenospheric mantle over a widely distributed region beneath Mongolia resulting in distributed volcanic activity and uplift. There is no indication that the upwellings are rooted in the deep lower mantle i.e. classic plumes. We speculate the upwellings may be related to deep subduction of the Pacific and Indian plates and are thus plumes anchored in the upper mantle.

  18. Porpoises: From predators to prey

    NASA Astrophysics Data System (ADS)

    Leopold, Mardik F.; Begeman, Lineke; Heße, Eileen; van der Hiele, Jaap; Hiemstra, Sjoukje; Keijl, Guido; Meesters, Erik H.; Mielke, Lara; Verheyen, Dorien; Gröne, Andrea

    2015-03-01

    Along the Dutch shores hundreds of harbour porpoises Phocoena phocoena are stranded each year. A recurrent phenomenon in the Netherlands is a surge of strandings in late winter and early spring of severely mutilated porpoises, that are mostly in good nutritional body condition (thick blubber layer). These mutilated porpoises have parts of the skin and blubber, and sometimes of the muscle tissue missing. By reviewing photographs of stranded animals taken at the stranding sites as well as autopsy results we found 273 mutilated animals from 2005 to 2012. Mutilations could be classified into several categories, but wounds had been mostly inflicted to the sides of these animals, in a zigzag fashion, or to the throat/cheek region. The stomach contents of 31 zigzags, 12 throats/cheeks and 31 control animals that were not mutilated, from the same age and blubber thickness categories were compared; all these animals had stranded between December and April, 2006-2012. The diet of individuals with zigzag lesions to their sides consisted for a large part of gobies, while animals that had wounds at the throat/cheek had been feeding predominately on clupeids. In comparison, animals without mutilations had a more varied diet, including gobies and clupeids, but also a large proportion of sandeels and gadoids. The finding that the type of mutilation corresponds to a certain diet suggests that porpoises that were feeding on different prey, or in different micro-habitats, were hit in different ways. Animals feeding at the sea floor (on gobies) apparently run a risk of being hit from the side, while animals supposedly feeding higher in the water column (on schooling clupeids), were predominantly hit from below, in the throat region. The wider variation in the diets of non-mutilated porpoises is suggestive of them using a larger variety of micro-habitats.

  19. 3D Anisotropic structure of the south-central Mongolia from Rayleigh and Love wave tomography

    NASA Astrophysics Data System (ADS)

    Yu, D.; Wu, Q.; Montagner, J. P.

    2014-12-01

    A better understanding of the geodynamics of the crust and mantle below Baikal-Mongolia is required to identify the role of mantle processes versus that of far-field tectonic effects from India-Asia collision. Anisotropy tomography can provide new perspective to the continental growth mechanism. In order to study the 3D anisotropic structure of the upper mantle in the south-central Mongolia, we collected the vertical and transverse components of seismograms recorded at 69 broadband seismic stations. We have measured inter-station phase velocities of 7181 Rayleigh waves and 901 Love waves using the frequency-time analysis of wavelet transformation method for the fundamental mode at period range 10~80s. The lateral phase velocity variations are computed by using a regionalization method. These phase velocities have been inverted to obtain the first anisotropic model including Sv velocities, azimuthal and radial anisotropy. The Middle Gobi is associated with low velocity. Based on the distribution of the Cenozoic basalts in the Middle Gobi, it refers that the low velocity anomaly is related to the Cenozoic volcanism. In the northern domain, near to Baikal zone, the azimuthal anisotropy is normal to the Baikal rift and consistent with the fast direction of previous SKS splitting measurements. In the South Gobi, north to Main Mongolian Lineament, the azimuthal anisotropy is NEE-SWW in the crust and NW-SE in the mantle. It indicates that the crust and mantle are decoupled. We propose that the crustal deformation is related to the far-field effects of India-Asia collision and that the mantle flow is correlated with the Baikal rift activity. Further study in process will provide more evidence and insight to better understand the geodynamics in this region.

  20. Origin of desert loess from some experimental observations

    NASA Technical Reports Server (NTRS)

    Whalley, W. B.; Smith, B. J.; Marshall, J. R.

    1982-01-01

    The aeolian attrition of angular quartz grains previously produced by weathering in deserts has been simulated, yielding abrasion products which show that both coarse and fine silt sizes are produced by this process. These results suggest that desert aeolian processes can produce loess, and it is speculated that while much of this material from many deserts has been deposited in the sea, the Chinese loess could have been produced in the Gobi desert. The finest of the particles produced by such attrition may serve as a source of silica for silcrete formation.

  1. A theropod dinosaur embryo and the affinities of the flaming cliffs dinosaur eggs.

    PubMed

    Norell, M A; Clark, J M; Demberelyin, D; Rhinchen, B; Chiappe, L M; Davidson, A R; McKenna, M C; Altangerel, P; Novacek, M J

    1994-11-04

    An embryonic skeleton of a nonavian theropod dinosaur was found preserved in an egg from Upper Cretaceous rocks in the Gobi Desert of Mongolia. Cranial features identify the embryo as a member of Oviraptoridae. Two embryo-sized skulls of dromaeosaurids, similar to that of Velociraptor, were also recovered in the nest. The eggshell microstructure is similar to that of ratite birds and is of a type common in the Djadokhta Formation at the Flaming Cliffs (Bayn Dzak). Discovery of a nest of such eggs at the Flaming Cliffs in 1923, beneath the Oviraptor philoceratops holotype, suggests that this dinosaur may have been a brooding adult.

  2. Asthenospheric counterflows beneath the moving lithosphere of Central and East Asia in the past 90 Ma: volcanic and tomographic evidence

    NASA Astrophysics Data System (ADS)

    Rasskazov, Sergei; Chuvashova, Irina; Kozhevnikov, Vladimir

    2015-04-01

    Asthenospheric counterflows, accompanied motions of the lithosphere in Central and East Asia, are defined on basis of spatial-temporal activity of mantle sources [Rasskazov et al., 2012; Rasskazov, Chuvashova, 2013; Chuvashova, Rasskazov, 2014] and the tomographic model of the Rayleigh wave group velocities [Kozhevnikov et al., 2014]. The opposite fluxes are defined relative to centers of convective instability (low-velocity anomalies), expressed by thinning of the mantle transition layer under Southwestern Gobi (44 °N, 95 °E) and Northern Baikal (52 °N, 108 °E). Cretaceous-Paleogene volcanic fields in Southern Gobi are shifted eastwards relative to the former anomaly over 600 km with the opposite sub-lithospheric flux at depths of 150-300 km. Likewise, the Late Tertiary Vitim volcanic field is shifted relative to the latter anomaly over 100-200 km. We suggest that the Gobi and Baikal asthenospheric counterflows contributed to the rollback mechanism of downgoing slab material from the Pacific under the eastern margin of Asia in the Cretaceous-Paleogene and Early-Middle Miocene. The east-west Gobi reverse flux, caused by differential block motions in front of the Indo-Asian convergence, resulted in the oblique Honshu-Korean flexure of the Pacific slab that propagated beneath the continental margin, while the Japan Sea was quickly opening at about 15 Ma. The Baikal N60°W reverse flux, originated due to oncoming traffic between Eurasia and the Pacific plate, entailed the formation of the Baikal Rift Zone and direct Hokkaido Amur slab flexure [Rasskazov et al., 2004]. The study is supported by the Russian Foundation for Basic Research (Grant 14-05-31328). References Chuvashova I.S., Rasskazov S.V. Magmatic sources in the mantle of the evolving Earth. Irkutsk: Publishing House of the Irkutsk State University, 2014. 310 p. (in Russian) Kozhevnikov V.M., Seredkina A.I., Solovei O.A. 3D mantle structure of Central Asia from Rayleigh wave group velocity dispersion

  3. Transfer of Invasive Species Associated with the Movement of Military Equipment and Personnel

    DTIC Science & Technology

    2007-07-01

    Examples include fire ants, Asian gypsy moth, zebra mussels, round goby, knapweed, leafy spurge , various thistles, water hyacinth, purple loosestrife, and...Capt Herbert T. Bolton, USN) ERDC/EL TR-07-8 105 Trapani, Italy, 1999 Figure C10. Snail eradication at Trapani, Italy, p. 1 of 3 (Source: Capt Mark...A. Pomerinke) ERDC/EL TR-07-8 106 Figure C11. Snail eradication at Trapani, Italy, p. 2 of 3 (Source: Capt Mark A. Pomerinke) ERDC/EL TR-07-8

  4. Evaluation of parasite fauna in Fish of Alborz Dam.

    PubMed

    Shokrolahi, Soodeh; Hosseinifard, Seyed Mehdi; Youssefi, Mohammad Raza; Sadough, Mina

    2016-03-01

    In this study on fish parasites of Alborz Dam in Iran, 202 fish were caught in years 2010-2011. Caught fish include Leucissus cephalus, Alburnoides bipunctatus, Neogobius flaviatilis. Samples transferred alive to Babol University lab and after investigate, these parasites were identified. One species of Protozoan (Icthyophithirious), 4 genus of Monogen (Gyrodoctylus. Sp, Dactylogyrus. sp, Diplozoon. sp, Paradiplozoon. Sp), one species of Cestode (Bothriocephalus gow kongensis) and one genus of nematode (Rhabdochona. Sp). All of these above parasites were found for first time from Alborz Dam in Iran. Rhabdochona genus was reported from Alburnoides bipunctatus and Bothriocephalus gowkongensis species was reported from all 2 fish species for the first time. Percentage of Pollution was higher on spring season on fish species (79.2 %). Pollution percentage was higher in Leuciscus cephalus than other fish species (28.7 %). Besides the fish were examined in this study had lower species diversity but a high percentage of parasites was seen in investigated fish.

  5. Comparative metabolomic and ionomic approach for abundant fishes in estuarine environments of Japan

    PubMed Central

    Yoshida, Seiji; Date, Yasuhiro; Akama, Makiko; Kikuchi, Jun

    2014-01-01

    Environmental metabolomics or ionomics is widely used to characterize the effects of environmental stressors on the health of aquatic organisms. However, most studies have focused on liver and muscle tissues of fish, and little is known about how the other organs are affected by environmental perturbations and effects such as metal pollutants or eutrophication. We examined the metabolic and mineral profiles of three kinds of abundant fishes in estuarine ecosystem, yellowfin goby, urohaze-goby, and juvenile Japanese seabass sampled from Tsurumi River estuary, Japan. Multivariate analyses, including nuclear magnetic resonance-based metabolomics and inductively coupled plasma optical emission spectrometry-based ionomics approaches, revealed that the profiles were clustered according to differences among body tissues rather than differences in body size, sex, and species. The metabolic and mineral profiles of the muscle and fin tissues, respectively, suggest that these tissues are most appropriate for evaluating environmental perturbations. Such analyses will be highly useful in evaluating the environmental variation and diversity in aquatic ecosystems. PMID:25387575

  6. Tactic-specific differences in seminal fluid influence sperm performance.

    PubMed

    Locatello, Lisa; Poli, Federica; Rasotto, Maria B

    2013-03-22

    Seminal fluid often makes up a large part of an ejaculate, yet most empirical and theoretical studies on sperm competition have focused on how sperm characteristics (number and quality) affect fertilization success. However, seminal fluid influences own sperm performance and may potentially influence the outcome of sperm competition, by also affecting that of rivals. As a consequence males may be expected to allocate their investment in both sperm and seminal fluid in relation to the potential level of competition. Grass goby (Zosterisessor ophiocephalus) is an external fertilizer with guard-sneaker mating tactics, where sperm competition risk varies according to the tactic adopted. Here, we experimentally manipulated grass goby ejaculates by separately combining sperm and seminal fluid from territorial and sneaker males. While sperm of sneaker and territorial males did not differ in their performance when they interacted with their own seminal fluid only, sperm of sneakers increased their velocity and fertilization rate in the presence of territorial males' seminal fluid. By contrast, sneaker males' seminal fluid had a detrimental effect on the performance of territorial males' sperm. Sperm velocity was unaffected by the seminal fluid of males employing the same tactic, suggesting that seminal fluid's effect on rival-tactic sperm is not based on a self/non-self recognition mechanism. Our findings show that cross interactions of sperm and seminal fluid may influence the fertilization success of competing ejaculates with males investing in both sperm and seminal fluid in response to sperm competition risk.

  7. Mutualism or parasitism? The variable outcome of cleaning symbioses

    PubMed Central

    Cheney, Karen L; Côté, Isabelle M

    2005-01-01

    The exact nature of many interspecific interactions remains unclear, with some evidence suggesting mutualism and other evidence pointing to parasitism for the same pair of interacting species. Here, we show spatial variation in the outcome of the cleaning relationship between Caribbean cleaning gobies (Elacatinus evelynae) and longfin damselfish (Stegastes diencaeus) over the distribution range of these species, and link this variation to the availability of ectoparasites. Cleaning interactions at sites with more ectoparasites were characterized by greater reductions in ectoparasite loads on damselfish clients and lower rates of removal of scales and mucus (i.e. cheating) by cleaning gobies, whereas the opposite was observed at sites where ectoparasite abundance was lower. For damselfish clients, cleaning was therefore clearly mutualistic in some locations, but sometimes neutral or even parasitic in others. Seasonal variability in ectoparasite abundance may ensure that locally low parasite availability, which promotes cleanerfish cheating, may be a transient condition at any given site. Conflicting conclusions about the nature of cleaning symbioses may, therefore, be explained by variation in ectoparasite abundance. PMID:17148155

  8. Community shelter use in response to two benthic decapod predators in the Long Island Sound

    PubMed Central

    Reagan, Dugan; Crivello, Joseph F.

    2016-01-01

    To investigate community shelter effects of two invasive decapod species, Hemigrapsus sanguineus and Carcinus maenas, in the Long Island Sound (LIS), we deployed artificial shelters in the intertidal and immediate subtidal zones. These consisted of five groups during the summer: a control, a resident H. sanguineus male or female group, and a resident C. maenas male or female group. We quantified utilization of the shelters at 24 h by counting crabs and fish present. We found significant avoidance of H. sanguineus in the field by benthic hermit crabs (Pagurus spp.) and significant avoidance of C. maenas by the seaboard goby (Gobiosoma ginsburgi). The grubby (Myoxocephalus aenaeus) avoided neither treatment, probably since it tends to be a predator of invertebrates. H. sanguineus avoided C. maenas treatments, whereas C. maenas did not avoid any treatment. Seasonal deployments in the subtidal indicated cohabitation of a number of benthic species in the LIS, with peak shelter use corresponding with increased predation and likely reproductive activity in spring and summer for green crabs (C. maenas), hermit crabs (Pagurus spp.), seaboard gobies (G. ginsburgi), and grubbies (Myoxocephalus aenaeus). PMID:27547570

  9. Community shelter use in response to two benthic decapod predators in the Long Island Sound.

    PubMed

    Hudson, David M; Reagan, Dugan; Crivello, Joseph F

    2016-01-01

    To investigate community shelter effects of two invasive decapod species, Hemigrapsus sanguineus and Carcinus maenas, in the Long Island Sound (LIS), we deployed artificial shelters in the intertidal and immediate subtidal zones. These consisted of five groups during the summer: a control, a resident H. sanguineus male or female group, and a resident C. maenas male or female group. We quantified utilization of the shelters at 24 h by counting crabs and fish present. We found significant avoidance of H. sanguineus in the field by benthic hermit crabs (Pagurus spp.) and significant avoidance of C. maenas by the seaboard goby (Gobiosoma ginsburgi). The grubby (Myoxocephalus aenaeus) avoided neither treatment, probably since it tends to be a predator of invertebrates. H. sanguineus avoided C. maenas treatments, whereas C. maenas did not avoid any treatment. Seasonal deployments in the subtidal indicated cohabitation of a number of benthic species in the LIS, with peak shelter use corresponding with increased predation and likely reproductive activity in spring and summer for green crabs (C. maenas), hermit crabs (Pagurus spp.), seaboard gobies (G. ginsburgi), and grubbies (Myoxocephalus aenaeus).

  10. Community structure of soft sediment pool fishes in Moreton Bay, Australia.

    PubMed

    Chargulaf, C A; Townsend, K A; Tibbetts, I R

    2011-02-01

    A survey of soft sediment tide pools was conducted to assess the occupation and assemblage of fishes on three different intertidal shores in Moreton Bay, Australia, between January and December 2009. Tide-pool volume ranged from 0· 30 to 29· 75 l and varied significantly between months and sites. A total of 1364 individuals representing 15 species and nine families of fishes were observed. At Dunwich, fish assemblages were dominated by the sand goby Favonigobius lentiginosus (89%) and whiting, Sillago spp. (10%). At Manly, the gobies Favonigobius exquisitus (37%), Pseudogobius sp. (31%) and the blenny Omobranchus punctatus (19%) dominated the shores while at Godwin Beach, F. lentiginosus (15%), F. exquisitus (45%) and Sillago spp. (25%) were the most abundant species. The mean ±s.e. density of fishes ranged from 0· 29 ± 0· 13 to 5· 04 ± 1· 74 fishes l(-1) and abundance of fish correlated with pool volume. Juveniles (75%) dominated assemblages suggesting that soft sediment pools may act as nurseries. The persistent and recurrent fish assemblages found in soft sediment tide pools in Moreton Bay suggest that these shores are behaving more like a tropical than a temperate climate shore, as there was no significant difference of fish abundances between seasons.

  11. Acanthocephaloides irregularis n. sp. (Acanthocephala: Arhythmacanthidae) from marine fishes off the Ukrainian Black Sea coast.

    PubMed

    Amin, Omar M; Oğuz, Mehmet C; Heckmann, Richard A; Tepe, Yahya; Kvach, Yuriy

    2011-10-01

    Acanthocephaloides irregularis n. sp. (Arhythmacanthidae) is described from four species of marine fishes in the Gulf of Odessa and Sukhyi Lyman, Ukrainan Black Sea waters, making it the tenth species of the genus. The hosts are the combtooth blenny Parablennius zvonimiri (Kolombatovic) (Blenniidae), the mushroom goby Ponticola eurycephalus (Kessler) (Gobiidae), the tubenose goby Proterorhinus marmoratus (Pallas) (Gobiidae) and the black-striped pipefish Syngnathus abaster Risso (Syngnathidae). The new species is most similar to its closest relative, Acanthocephaloides propinquus (Dujardin, 1845), in proboscis shape and armature (12 longitudinal rows of 5 hooks) and the shape of the trunk, reproductive system and lemnisci, but differs in having randomly distributed trunk spines. These trunk spines are organised in circular rings of individual spines separated by aspinose zones. The new species is also unique in having an anterior trunk collar, a very large triangular cephalic ganglion, nucleated pouches at the posterior end of the proboscis receptacle, and hooks and spines with roots bearing anterior manubria. Valid and invalid species of Acanthocephaloides Meyer, 1932 are listed and a key to all ten species is included.

  12. Morphological and molecular evidence for a new species of the genus Dichelyne Jägerskiöld, 1902 (Ascaridida: Cucullanidae) from marine perciform fishes in the South China Sea.

    PubMed

    Li, Liang; Xu, Zhen; Zhang, Lu-Ping

    2014-10-01

    A new cucullanid nematode, Dichelyne (Dichelyne) breviculus n. sp., collected from the intestine of the goatee croaker Dendrophysa russelii (Cuvier) (Perciformes: Sciaenidae), the burrowing goby Trypauchen vagina (Bloch & Schneider) and the tropical sand goby Acentrogobius caninus (Valenciennes) (Perciformes: Gobiidae) in the South China Sea, is described using both light and scanning electron microscopy. The new species differs from its congeners in the size of body (2.16-2.96 mm in male), the position of the excretory pore and deirids, the length of the spicules (0.90-1.32 mm, representing 32.4-51.9% of body length), the arrangement of the caudal papillae and the morphology of the tail. In addition, in order to primarily assess the validity of the new species genetically, the specimens of D. breviculus n. sp. collected from the three different hosts were also characterised using molecular methods by sequencing and analysing ribosomal [small ribosomal subunit (18S rDNA) and internal transcribed spacer (ITS)] and mitochondrial [cytochrome c oxidase subunit 1 (cox1)] target regions. The molecular analyses support the validity of the new species based on the morphological observations.

  13. Predation risk assessment by olfactory and visual cues in a coral reef fish

    NASA Astrophysics Data System (ADS)

    McCormick, M. I.; Manassa, R.

    2008-03-01

    Assessment of predation risk is vital for the success of an individual. Primary cues for the assessment include visual and olfactory stimuli, but the relative importance of these sources of information for risk assessment has seldom been assessed for marine fishes. This study examined the importance of visual and chemical cues in assessing risk for the star goby, Asterropteryx semipunctatus. Visual and chemical cue intensities were used that were indicative of a high threat situation. The behavioural response elicited by both the visual cues of a predator (the rock cod, Cephalopholis boenak) and the chemical alarm cues from conspecifics were similar in magnitude, with responses including a decrease in feeding strikes and moves. A bobbing behaviour was exhibited when the predator was visible and not when only exposed to the chemical alarm cue. When visual and chemical cues were presented together they yielded a stronger antipredator response than when gobies were exposed solely to conspecific alarm cues. This suggests additivity of risk assessment information at the levels of threat used, however, the goby’s response is also likely to depend on the environmental and social context of the predator-prey encounter. This study highlights the importance of chemical cues in the assessment of predation risk for a coral reef fish.

  14. Otolith microchemistry of tropical diadromous fishes: spatial and migratory dynamics

    USGS Publications Warehouse

    Smith, William E.; Kwak, Thomas J.

    2014-01-01

    Otolith microchemistry was applied to quantify migratory variation and the proportion of native Caribbean stream fishes that undergo full or partial marine migration. Strontium and barium water chemistry in four Puerto Rico, U.S.A., rivers was clearly related to a salinity gradient; however, variation in water barium, and thus fish otoliths, was also dependent on river basin. Strontium was the most accurate index of longitudinal migration in tropical diadromous fish otoliths. Among the four species examined, bigmouth sleeper Gobiomorus dormitor, mountain mullet Agonostomus monticola, sirajo goby Sicydium spp. and river goby Awaous banana, most individuals were fully amphidromous, but 9-12% were semi-amphidromous as recruits, having never experienced marine or estuarine conditions in early life stages and showing no evidence of marine elemental signatures in their otolith core. Populations of one species, G. dormitor, may have contained a small contingent of semi-amphidromous adults, migratory individuals that periodically occupied marine or estuarine habitats (4%); however, adult migratory elemental signatures may have been confounded with those related to diet and physiology. These findings indicate the plasticity of migratory strategies of tropical diadromous fishes, which may be more variable than simple categorization might suggest.

  15. Effect of outflow on spring and summertime distribution and abundance of larval and juvenile fishes in the upper San Francisco Estuary

    USGS Publications Warehouse

    Dege, M.; Brown, L.R.

    2004-01-01

    We analyzed data on spring and summertime larval and juvenile fish distribution and abundance in the upper San Francisco Estuary (SFE), California between 1995 and 2001. The upper SFE includes the tidal freshwater areas of the Sacramento-San Joaquin Delta downstream to the euryhaline environment of San Pablo Bay. The sampling period included years with a variety of outflow conditions. Fifty taxa were collected using a larval tow net. Two common native species, delta smelt Hypomesus transpacifucus and longfin smelt Spirinchus thaleichthys, and four common alien taxa, striped bass Morone saxatilis, threadfin shad Dorosoma petenense, gobies of the genus Tridentiger, and yellowfin goby Acanthogobins flavimanus, were selected for detailed analysis. Outflow conditions had a strong influence on the geographic distribution of most of the species, but distribution with respect to the 2 psu isohaline (X2) was not affected. The distribution patterns of delta smelt, longfin smelt, and striped bass were consistent with larvae moving from upstream freshwater spawning areas to down-stream estuarine rearing areas. There were no obvious relationships of outflow with annual abundance indices. Our results support the idea of using X2 as an organizing principle in understanding the ecology of larval fishes in the upper SFE. Additional years of sampling will likely lead to additional insights into the early life history of upper SFE fishes. ?? Copyright by the American Fisheries Society 2004.

  16. Hypoxia increases the risk of egg predation in a nest-guarding fish

    PubMed Central

    Kvarnemo, Charlotta; Andrén, Maria Norevik; Larsson, Therése

    2016-01-01

    For fish with parental care, a nest should meet both the oxygenation needs of the eggs and help protect them against predators. While a small nest opening facilitates the latter, it impedes the former and vice versa. We investigated how the presence of potential egg predators in the form of shore crabs Carcinus maenas affects nest building, egg fanning, defensive displays and filial cannibalism of egg-guarding male sand gobies Pomatoschistus minutus under two levels of dissolved oxygen. In the high oxygen treatment, males retained their nest opening size in the presence of crabs, while males in low oxygen built large nest openings both in the absence and presence of crabs, despite the fact that crabs were more likely to successfully intrude into nests with large entrances. Males in low oxygen also fanned more. In the presence of crabs males increased their defensive displays, but while males in high oxygen reduced fanning, males in low oxygen did not. Filial cannibalism was unaffected by treatment. Sand gobies thus prioritize egg ventilation over the protection afforded by small nest openings under hypoxia and adopt defensive behaviour to avert predator attention, even though this does not fully offset the threat from the egg predators. PMID:27853611

  17. Dual impact of temperature on growth and mortality of marine fish larvae in a shallow estuarine habitat

    NASA Astrophysics Data System (ADS)

    Arula, Timo; Laur, Kerli; Simm, Mart; Ojaveer, Henn

    2015-12-01

    High individual growth and mortality rates of herring Clupea harengus membras and goby Pomatoschistus spp. larvae were observed in the estuarine habitat of the Gulf of Riga, Baltic Sea. Both instantaneous mortality (0.76-1.05) as well as growth rate (0.41-0.82 mm day-1) of larval herring were amongst highest observed elsewhere previously. Mortality rates of goby larvae were also high (0.57-1.05), while first ever data on growth rates were provided in this study (0.23-0.35 mm day-1). Our study also evidenced that higher growth rate of marine fish larvae did not result in lower mortalities. We suggest that high growth and mortality rates primarily resulted from a rapidly increasing and high (>18 °C) water temperature that masked potential food-web effects. The explanation for observed patterns lies in the interactive manner temperature contributed: i) facilitating prey production, which supported high growth rate and decreased mortalities; ii) exceeding physiological thermal optimum of larvae, which resulted in decreased growth rate and generally high mortalities. Our investigation suggests that the projected climate warming may have significant effect on early life history stages of the dominating marine fish species inhabiting shallow estuaries.

  18. Inheritance patterns of morphological laterality in mouth opening of zebrafish, Danio rerio.

    PubMed

    Hata, Hiroki; Hori, Michio

    2012-01-01

    The inheritance patterns of asymmetry in mouth opening in zebrafish were investigated using crossing experiments. Zebrafish exhibit asymmetric laterality in mouth opening, with each individual having either a leftward (righty) or rightward (lefty) bias. All righty incrosses produced only righty F(1), whereas all lefty incrosses resulted in an F(1) L:R ratio of 2:1. All test crosses between lefty and righty individuals resulted in an F(1) L:R=1:1. These results were consistent with the hereditary pattern for Japanese medaka, three Tanganyikan cichlids, and a Japanese riverine goby. The pattern suggests a one-locus two-allele Mendelian model of inheritance, with the lefty allele being dominant over righty and the dominant homozygote being lethal. To determine the reason for the absence of lefty homozygotes, the survival rates of the offspring were examined according to developmental stage. Survival did not differ among combinations of parent laterality. Thus the mechanism underlying the lethality of the dominant homozygote remains unclear. This study showed that the mouth-opening laterality of zebrafish is genetically determined and that the direction follows a Mendelian inheritance pattern that is shared among cypriniform zebrafish, beloniform medaka, perciform cichlids, and a goby, suggesting a common genetic background in mouth-opening laterality among these species.

  19. Hf-Nd isotopic variability in mineral dust from Chinese and Mongolian deserts: implications for sources and dispersal

    PubMed Central

    Zhao, Wancang; Sun, Youbin; Balsam, William; Lu, Huayu; Liu, Lianwen; Chen, Jun; Ji, Junfeng

    2014-01-01

    Mineral dust provenances are closely related to the orogenic processes which may have distinct Hf-Nd isotopic signatures. Here we report the clay-sized (<2 μm) Hf-Nd isotope data from Asian dust sources to better constrain the source and transport dynamics of dust deposition in the North Pacific. Our results show that there is a more positive radiogenic Hf isotopic composition with clay-sized fractions than the corresponding bulk sample and a decoupling of the Hf-Nd couplets in the clay formation during the weathering process. The clay-sized Hf-Nd isotopic compositions of the desert samples from the Sino-Korean-Tarim Craton (SKTC) are different from those of the Gobi and deserts from the Central Asian Orogeny Belt (CAOB) due to varying tectonic and weathering controls. The Hf-Nd isotopic compositions of dust in the North Pacific central province (NPC) match closely with those from the Taklimakan, Badain Jaran and adjacent Tengger deserts, implying that the NPC dust was mainly transported from these potential sources by the westerly jet. Our study indicates that dusts from the CAOB Gobi deserts either didn't arrive in NPC or were quantitatively insignificant, but they were likely transported to the North Pacific margin province (NPM) by East Asian winter monsoon. PMID:25060781

  20. Contributions of sandy lands and stony deserts to long-distance dust emission in China and Mongolia during 2000 2006

    NASA Astrophysics Data System (ADS)

    Zhang, Baolin; Tsunekawa, Atsushi; Tsubo, Mitsuru

    2008-02-01

    More than 400 Moderate Resolution Imaging Spectroradiometer (MODIS) images of dust storm events were collected and analyzed, and individual events were tracked back to their origins. Dust tracks were determined from color composite images, brightness temperature difference (BTD) and the NOAA Hybrid Single-Particle Lagrangian Integrated Trajectory model. The results showed that five regions (sandy lands in central Inner Mongolia and the adjacent area of Mongolia; the Gobi Desert in Xinjiang and Gansu provinces, western Inner Mongolia, and the adjacent southwestern area of Mongolia; the Gobi Desert in southern Mongolia and the adjoining area of northern Inner Mongolia; sandy lands and deserts around the middle reaches of the Yellow River; and the area rimming the Taklimakan Desert) were the main contributors to long-lived mineral dusts in northern China and Mongolia. Of these dust production areas, sandy lands and stony deserts, rather than the sandy deserts of Inner Mongolia and Mongolia, were found to be the dominant dust sources, accounting for more than 75% of regional dust emission events. Dust events in the Taklimakan Desert were often local phenomena, although they could also be transported eastward if they were uplifted high enough to escape the enclosing topographic highs. Dust sources in northwestern China are mainly alluvial fans and dry lake and river beds. Success in identifying the sources and trajectories of Asian dust storms would guide future ground-based research and steppe degradation countermeasures and help reduce the uncertainties in modern modeling of Asian dust.

  1. Slip rate and slip magnitudes of past earthquakes along the Bogd left-lateral strike-slip fault (Mongolia)

    USGS Publications Warehouse

    Rizza, M.; Ritz, J.-F.; Braucher, R.; Vassallo, R.; Prentice, C.; Mahan, S.; McGill, S.; Chauvet, A.; Marco, S.; Todbileg, M.; Demberel, S.; Bourles, D.

    2011-01-01

    We carried out morphotectonic studies along the left-lateral strike-slip Bogd Fault, the principal structure involved in the Gobi-Altay earthquake of 1957 December 4 (published magnitudes range from 7.8 to 8.3). The Bogd Fault is 260 km long and can be subdivided into five main geometric segments, based on variation in strike direction. West to East these segments are, respectively: the West Ih Bogd (WIB), The North Ih Bogd (NIB), the West Ih Bogd (WIB), the West Baga Bogd (WBB) and the East Baga Bogd (EBB) segments. Morphological analysis of offset streams, ridges and alluvial fans-particularly well preserved in the arid environment of the Gobi region-allows evaluation of late Quaternary slip rates along the different faults segments. In this paper, we measure slip rates over the past 200 ka at four sites distributed across the three western segments of the Bogd Fault. Our results show that the left-lateral slip rate is ~1 mm yr-1 along the WIB and EIB segments and ~0.5 mm yr-1 along the NIB segment. These variations are consistent with the restraining bend geometry of the Bogd Fault. Our study also provides additional estimates of the horizontal offset associated with the 1957 earthquake along the western part of the Bogd rupture, complementing previously published studies. We show that the mean horizontal offset associated with the 1957 earthquake decreases progressively from 5.2 m in the west to 2.0 m in the east, reflecting the progressive change of kinematic style from pure left-lateral strike-slip faulting to left-lateral-reverse faulting. Along the three western segments, we measure cumulative displacements that are multiples of the 1957 coseismic offset, which may be consistent with a characteristic slip. Moreover, using these data, we re-estimate the moment magnitude of the Gobi-Altay earthquake at Mw 7.78-7.95. Combining our slip rate estimates and the slip distribution per event we also determined a mean recurrence interval of ~2500-5200 yr for past

  2. Slip rate and slip magnitudes of past earthquakes along the Bogd left-lateral strike-slip fault (Mongolia)

    USGS Publications Warehouse

    Prentice, Carol S.; Rizza, M.; Ritz, J.F.; Baucher, R.; Vassallo, R.; Mahan, S.

    2011-01-01

    We carried out morphotectonic studies along the left-lateral strike-slip Bogd Fault, the principal structure involved in the Gobi-Altay earthquake of 1957 December 4 (published magnitudes range from 7.8 to 8.3). The Bogd Fault is 260 km long and can be subdivided into five main geometric segments, based on variation in strike direction. West to East these segments are, respectively: the West Ih Bogd (WIB), The North Ih Bogd (NIB), the West Ih Bogd (WIB), the West Baga Bogd (WBB) and the East Baga Bogd (EBB) segments. Morphological analysis of offset streams, ridges and alluvial fans—particularly well preserved in the arid environment of the Gobi region—allows evaluation of late Quaternary slip rates along the different faults segments. In this paper, we measure slip rates over the past 200 ka at four sites distributed across the three western segments of the Bogd Fault. Our results show that the left-lateral slip rate is∼1 mm yr–1 along the WIB and EIB segments and∼0.5 mm yr–1 along the NIB segment. These variations are consistent with the restraining bend geometry of the Bogd Fault. Our study also provides additional estimates of the horizontal offset associated with the 1957 earthquake along the western part of the Bogd rupture, complementing previously published studies. We show that the mean horizontal offset associated with the 1957 earthquake decreases progressively from 5.2 m in the west to 2.0 m in the east, reflecting the progressive change of kinematic style from pure left-lateral strike-slip faulting to left-lateral-reverse faulting. Along the three western segments, we measure cumulative displacements that are multiples of the 1957 coseismic offset, which may be consistent with a characteristic slip. Moreover, using these data, we re-estimate the moment magnitude of the Gobi-Altay earthquake at Mw 7.78–7.95. Combining our slip rate estimates and the slip distribution per event we also determined a mean recurrence interval of∼2500

  3. Dust Propagation and Radiation In the Presence of a Low-level Jet in Central China on March 17, 2010

    NASA Astrophysics Data System (ADS)

    McDowell, B. K.; Chen, S. H.

    2014-12-01

    Suspended dust in the air can directly change the energy budget in the atmosphere and at the surface through scattering and absorption of radiation. Thus, dust can potentially modify the development of weather systems. To explore the dust-radiation effects on weather systems, a dust model was developed based on the Weather Research and Forecasting (WRF) model. The calculations of dust processes in the WRF dust model include emission, advection, boundary layer mixing, cumulus mixing, dust-radiation interaction, wet scavenging, and sedimentation. Due to a high vertical spatial resolution near the surface a time splitting method was applied to the calculation of dust sedimentation to relax the numerical time step. The "Hexi Corridor" is the historical name given to a string of oases along the northern slope of the Tibetan Plateau that formed a relatively easy transportation route between eastern China and central Asia. As trade developed over the centuries, this route became known as the Silk Road. This corridor also marks the transition from the relatively flat Gobi desert area in northern China to the elevated mountains of the Tibetan Plateau. These mountains present a southern barrier to the paths of dust storms that develop during spring outbreaks of the Mongolian Cyclone. In March of 2010, a series of dust storms developed in the Gobi Desert north of the Hexi Corridor that transported massive amounts of dust eastward to central and northeastern China, Korea and Japan. On March 17 during this event, a low-level jet developed along the northern perimeter of the Plateau, in alignment with upper level winds and the Hexi Corridor. Over the course of the day, a well-defined short-duration dust plume was emitted in the southern Gobi desert area and was transported over 1300 km in a southeast direction, over the Loess Plateau and into the Gansu Province. In this study, the interactions of synoptic conditions with regional topography that led to the development of the low

  4. Large-scale distribution of surface ozone mixing ratio in southern Mongolia: A survey

    NASA Astrophysics Data System (ADS)

    Meixner, F. X.; Behrendt, T.; Ermel, M.; Hempelmann, N.; Andreae, M. O.; Jöckel, P.

    2012-04-01

    For the first time, measurements of surface ozone mixing ratio have been performed from semi-arid steppe to arid/hyper-arid southern Mongolian Gobi desert. During 12-29 August 2009, ozone mixing ratio was continuously measured from a mobile platform (4x4 Furgon SUV). The survey (3060 km / 229171km2) started at the Mongolian capital Ulaan-Baatar (47.9582° N, 107.0190° E ), heading to south-west (Echin Gol, 43.2586° N, 99.0255° E), eastward to Dalanzadgad (43.6061° N, 104.4445° E), and finally back to Ulaan-Baatar. Ambient air was sampled (approx. 1 l/min) through a 4 m long PTFE-intake line along a forward facing boom mounted on the roof of a 4x4 Furgon SUV. Ozone mixing ratio has been measured by UV-spectroscopy using a mobile dual-cell ozone analyzer (model 205, 2BTechnologies, Boulder, U.S.A.). While ozone signals were measured every 5 seconds, 1 minute averages and standard deviations have been calculated on-line and stored into the data logger. The latter are used to identify and to discriminate against unrealistic low or high ozone mixing ratios which have been due to occasionally passing plumes of vehicle exhaust and/or biomass burning gases, as well as gasoline (at gas filling stations). Even under desert conditions, the temporal behaviour of ozone mixing ratio was characterized by considerable and regular diel variations. Minimum mixing ratios (15-25 ppb) occurred early in the morning (approx. 06:00 local), when surface depletion of ozone (by dry deposition) can not be compensated by supply from the free troposphere due to thermodynamic stability of the nocturnal boundary layer. Late in the afternoon (approx. 17:00 local), under conditions of a turbulently well mixed convective boundary layer, maximum ozone mixing ratios (45-55 ppb) were reached. Daily amplitudes of the diel cycle of ozone mixing ratio were in the order of 30 ppb (steppe), 20 ppb (arid desert), to approx. 5 ppb (hyper-arid Gobi desert (Shargyn Gobi)). Ozone surface measurements were

  5. Seasonal Variation, Export Dynamics and Consumption of Freshwater Invertebrates in an Estuarine Environment

    NASA Astrophysics Data System (ADS)

    Williams, D. D.; Williams, N. E.

    1998-03-01

    sections but resumed a benthic existence by virtue of varying degrees of salt tolerance. Of the three fish species common in the estuary, eel, common goby and flounder, the last two preyed measurably on freshwater taxa. Whereas gobies tended to be opportunistic feeders, depending on the section of estuary that they occupied, flounder were more restricted to the upper estuary where they fed selectively on chironomid larvae. On the latter diet, between March and September, the mean wet weight of flounders increased by more than 100 times (from 5 to 540 mg). Gobies were more numerous in the estuary from September to February, and although they ate insects their primary prey was G. zaddachi.

  6. Complex interactions in Lake Michigan’s rapidly changing ecosystem

    USGS Publications Warehouse

    Vanderploeg, Henry A.; Bunnell, David B.; Carrick, Hunter J.; Hook, Tomas O.

    2015-01-01

    For over 30 years, Lake Michigan’s food web has been in a constant state of transition from reductions in nutrient loading and proliferation of invasive species at multiple trophic levels. In particular, there has been concern about impacts from the invasive predatory cercopagids (Bythotrephes longimanus and Cercopagis pengoi) and expanding dreissenid mussel and round goby populations. This special issue brings together papers that explore the status of the Lake Michigan food web and the factors responsible for these changes, and suggests research paths that must be taken for understanding and predicting system behavior. This introductory paper describes the special issue origin, presents an overview of the papers, and draws overarching conclusions from the papers.

  7. Feeding ecology and trophic relationships of fish species in the lower Guadiana River Estuary and Castro Marim e Vila Real de Santo António Salt Marsh

    NASA Astrophysics Data System (ADS)

    Sá, Rita; Bexiga, Constança; Veiga, Pedro; Vieira, Lina; Erzini, Karim

    2006-10-01

    In this study we analyze the feeding ecology and trophic relationships of some of the main fish species (Soleidae, Moronidae, Mullidae, Sparidae, Mugilidae, and Batrachoididae) of the lower Estuary of the Guadiana River and the Castro Marim e Vila Real de Santo António Salt Marsh. We examined the stomachs of 1415 fish caught monthly between September 2000 and August 2001. Feeding indices and coefficients were determined and used along with the results of multivariate analysis to develop diagrams of trophic interactions (food webs). Results show that these species are largely opportunistic predators. The most important prey items are amphipods, gobies (Gobiidae), shrimps ( Palaemon serratus and Crangon crangon), and polychaete worms. The lower Estuary and associated salt marshes are important nurseries and feeding grounds for the species studied. In this area, it is therefore important to monitor the effects of changes in river runoff, nutrient input, and temperature that result from construction of the Alqueva Dam upstream.

  8. Odour cues from suitors' nests determine mating success in a fish.

    PubMed

    Lehtonen, Topi K; Kvarnemo, Charlotta

    2015-05-01

    Animals use a range of sensory cues for finding food, avoiding predators and choosing mates. In this regard, the aquatic environment is particularly suitable for the use of olfactory and other chemical cues. Nevertheless, mate choice research, even on aquatic organisms, has focused on visual signals, while chemical cues relevant in sexual selection have been assumed to be 'intrinsic' excretions of mate candidates. Here, using the sand goby Pomatoschistus minutus, a small fish with paternal egg care, we investigated the possibility that 'extrinsic' chemical cues in the males' nests could also have a significant contribution to mating success. We found that females strongly avoided laying eggs into nests subject to the odour of Saprolegnia water moulds (an egg infection) and that this effect was independent of the females' initial, visually based preference for males. To the best of our knowledge, this is the first study to show that chemical cues related to parental failure can play a large role in sexual selection.

  9. Aquatic Nuisance Species Locator

    EPA Pesticide Factsheets

    Data in this map has been collected by the United States Geological Survey's Nonindigenous Aquatic Species program located in Gainesville, Florida (http://nas.er.usgs.gov/default.aspx). This dataset may have some inaccuracies and is only current to June 15, 2012. The species identified in this dataset are not inclusive of all aquatic nuisance species, but rather a subset identified to be at risk for transport by recreational activities such as boating and angling. Additionally, the locations where organisims have been identified are also not inclusive and should be treated as a guide. Organisms are limited to the following: American bullfrog, Asian clam, Asian shore crab, Asian tunicate, Australian spotted jellyfish, Chinese mitten crab, New Zealand mudsnail, Colonial sea squirt, Alewife, Bighead carp, Black carp, Flathead catfish, Grass carp, Green crab, Lionfish, Northern snakehead, Quagga mussel, Round Goby, Ruffe, Rusty crayfish, Sea lamprey, Silver carp, Spiny water flea, Veined rapa whelk, Zebra mussel

  10. Compression of FASTQ and SAM format sequencing data.

    PubMed

    Bonfield, James K; Mahoney, Matthew V

    2013-01-01

    Storage and transmission of the data produced by modern DNA sequencing instruments has become a major concern, which prompted the Pistoia Alliance to pose the SequenceSqueeze contest for compression of FASTQ files. We present several compression entries from the competition, Fastqz and Samcomp/Fqzcomp, including the winning entry. These are compared against existing algorithms for both reference based compression (CRAM, Goby) and non-reference based compression (DSRC, BAM) and other recently published competition entries (Quip, SCALCE). The tools are shown to be the new Pareto frontier for FASTQ compression, offering state of the art ratios at affordable CPU costs. All programs are freely available on SourceForge. Fastqz: https://sourceforge.net/projects/fastqz/, fqzcomp: https://sourceforge.net/projects/fqzcomp/, and samcomp: https://sourceforge.net/projects/samcomp/.

  11. Estimates of riparian evapotranspiration using diurnal monitoring of groundwater regime in desert environments

    NASA Astrophysics Data System (ADS)

    Wang, P.; Pozdniakov, S. P.; Grinevsky, S.; Yu, J.

    2013-12-01

    Shallow groundwater is mainly discharged by phreatophytes in many riparian ecosystems of arid and semiarid environment, while estimation of groundwater evapotranspiration in these regions still remains a challenge for regional water resources assessment. In this study, a simple relationship between the average standard deviation of diurnal groundwater level fluctuations and the daily evapotranspiration over relatively short periods (days or weeks) was developed for estimating groundwater consumption by phreatophytes in arid/semi-arid areas. Our approach allows estimating groundwater evapotranspiration using stable statistical characteristics of diurnal groundwater fluctuation, and it is useful for analyzing large amounts of data obtained from digital groundwater level monitoring sensors. The developed methodology was applied to two phreatophyte-dominated riparian areas (Populus euphratica and Tamarix ramosissima) in a typical Gobi desert region of northwest China to demonstrate the usefulness of the technique.

  12. Deserts of China

    USGS Publications Warehouse

    Walker, Alta S.

    1982-01-01

    Improving arid land quality requires an understanding of the original state of the land and its relationship to wind, water, and plant regimes, as well as understanding of interactions within the present ecosystem.  Chinese scientists and local residents have made significant advances in improving arid environments in gobi and sandy deserts and in less arid sandy lands.  Wind patterns are being changed by planting forest belts to protect oases and sandy lands, and on a smaller scale by planting grasses and shrubs or constructing straw grids.  Research on reclamation of deserts is now focusing on how sand-fixing plants may be adapted to local environments, and how the resources of grazing land and water may be effectively exploited without being overused.

  13. Climatic factors impact on the bio-optical sea water features

    NASA Astrophysics Data System (ADS)

    Salyuk, P. A.; Akmaykin, D. A.; Bukin, O. A.; Golik, S. S.; Baulo, E. N.; Lastovskaya, I. A.; Schmirko, K. A.

    2006-11-01

    The estimation of the two most intensive climatic factors impacting on phytoplankton communities was carried out for marginal seas of western Pacific. Influences of some tropical cyclones on chlorophyll "A" concentrations (obtained by SeaWiFS) in 2001 were considered. It is shown that tropical cyclones cause local algae blooming at some regions. Also influence of dust storms from Gobi desert on phytoplankton at the area of the Sea of Japan was analyzed for the spring of 2006. Vladivostok lidar station data and MODIS data were applied for the analysis. Ground lidar data have shown that the most aerosol mass was in lower atmosphere layer (0-3 km). So dust storm could influence on the element composition of surface seawater layer. The high correlation coefficient between time series of chlorophyll A concentration and of aerosol optical thickness (at the 869 nm) was detected.

  14. Spatial extent and dynamics of dam impacts on tropical island freshwater fish assemblages

    USGS Publications Warehouse

    Cooney, Patrick B.; Kwak, Thomas J.

    2013-01-01

    Habitat connectivity is vital to the persistence of migratory fishes. Native tropical island stream fish assemblages composed of diadromous species require intact corridors between ocean and riverine habitats. High dams block fish migration, but low-head artificial barriers are more widespread and are rarely assessed for impacts. Among all 46 drainages in Puerto Rico, we identified and surveyed 335 artificial barriers that hinder fish migration to 74.5% of the upstream habitat. We also surveyed occupancy of native diadromous fishes (Anguillidae, Eleotridae, Gobiidae, and Mugilidae) in 118 river reaches. Occupancy models demonstrated that barriers 2 meters (m) high restricted nongoby fish migration and extirpated those fish upstream of 4-m barriers. Gobies are adapted to climbing and are restricted by 12-m barriers and extirpated upstream of 32-m barriers. Our findings quantitatively illustrate the extensive impact of low-head structures on island stream fauna and provide guidance for natural resource management, habitat restoration, and water development strategies.

  15. Atmospheric Movement of Microorganisms in Clouds of Desert Dust and Implications for Human Health

    PubMed Central

    Griffin, Dale W.

    2007-01-01

    Billions of tons of desert dust move through the atmosphere each year. The primary source regions, which include the Sahara and Sahel regions of North Africa and the Gobi and Takla Makan regions of Asia, are capable of dispersing significant quantities of desert dust across the traditionally viewed oceanic barriers. While a considerable amount of research by scientists has addressed atmospheric pathways and aerosol chemistry, very few studies to determine the numbers and types of microorganisms transported within these desert dust clouds and the roles that they may play in human health have been conducted. This review is a summary of the current state of knowledge of desert dust microbiology and the health impact that desert dust and its microbial constituents may have in downwind environments both close to and far from their sources. PMID:17630335

  16. A monogenean fish parasite, Gyrodactylus chileani n. sp., belonging to a novel marine species lineage found in the South-Eastern Pacific and the Mediterranean and North Seas.

    PubMed

    Ziętara, Marek S; Lebedeva, Dar'ya; Muñoz, Gabriela; Lumme, Jaakko

    2012-10-01

    Gyrodactylus chileani n. sp. is the first Gyrodactylus species reported from Chile. It is an ectoparasite living on fins and skin of a small fish, the Chilean tidal pond dweller Helcogrammoides chilensis (Cancino) (Perciformes: Tripterygiidae). A phylogenetic analysis based on 5.8S+ITS2 of rDNA placed the new species close to marine Gyrodactylus species found in Europe: G. orecchiae Paladini, Cable, Fioravanti, Faria, Cave & Shinn, 2009 on gilthead seabream Sparus aurata L. from the Adriatic and Tyrrhenian Sea fish farms (Perciformes: Sparidae), and an undescribed species on the black goby Gobius niger L. from the North Sea (Perciformes: Gobiidae). A morphological description of the latter species is unavailable. These geographically distant parasite samples on different host families form a new well supported Gyrodactylus orecchiae lineage. Using molecular phylogenetics, it is shown that the marine species groups of Gyrodactylus may have a worldwide distribution.

  17. Effects of altered offshore food webs on coastal ecosystems emphasize the need for cross-ecosystem management.

    PubMed

    Eriksson, Britas Klemens; Sieben, Katrin; Eklöf, Johan; Ljunggren, Lars; Olsson, Jens; Casini, Michele; Bergström, Ulf

    2011-11-01

    By mainly targeting larger predatory fish, commercial fisheries have indirectly promoted rapid increases in densities of their prey; smaller predatory fish like sprat, stickleback and gobies. This process, known as mesopredator release, has effectively transformed many marine offshore basins into mesopredator-dominated ecosystems. In this article, we discuss recent indications of trophic cascades on the Atlantic and Baltic coasts of Sweden, where increased abundances of mesopredatory fish are linked to increased nearshore production and biomass of ephemeral algae. Based on synthesis of monitoring data, we suggest that offshore exploitation of larger predatory fish has contributed to the increase in mesopredator fish also along the coasts, with indirect negative effects on important benthic habitats and coastal water quality. The results emphasize the need to rebuild offshore and coastal populations of larger predatory fish to levels where they regain their control over lower trophic levels and important links between offshore and coastal systems are restored.

  18. Terrestrial analogs of the hellespontus dunes, Mars

    USGS Publications Warehouse

    Breed, C.S.

    1977-01-01

    Geomorphic features in the Hellespontus region, Mars, were compared with dunes of the crescentic ridge type in numerous terrestrial sand seas quantitatively by dimensional analysis of dune lengths, widths, and wavelengths. Mean values for the Hellespontus dunes are close to mean values derived from measurements of all sampled terrestrial sand seas. Terrestrial analogs of form and areal distribution of the Hellespontus dunes are shown by comparison of scale ratios derived from the measurements. Dunes of similar form occur in South West Africa, in Pakistan, in the southeastern Arabian peninsula, in the Sahara, in eastern USSR and northern China, and in western North America. Terrestrial analogs closest to form and areal distribution of the Hellespontus dunes are in the Kara Kum Desert, Turkmen SSR, and in the Ala Shan (Gobi) Desert, China. ?? 1977.

  19. Atmospheric movement of microorganisms in clouds of desert dust and implications for human health

    USGS Publications Warehouse

    Griffin, Dale W.

    2007-01-01

    Billions of tons of desert dust move through the atmosphere each year. The primary source regions, which include the Sahara and Sahel regions of North Africa and the Gobi and Takla Makan regions of Asia, are capable of dispersing significant quantities of desert dust across the traditionally viewed oceanic barriers. While a considerable amount of research by scientists has addressed atmospheric pathways and aerosol chemistry, very few studies to determine the numbers and types of microorganisms transported within these desert dust clouds and the roles that they may play in human health have been conducted. This review is a summary of the current state of knowledge of desert dust microbiology and the health impact that desert dust and its microbial constituents may have in downwind environments both close to and far from their sources.

  20. Columbus State University Global Observation and Outreach for the 2012 Transit of Venus

    NASA Astrophysics Data System (ADS)

    Perry, Matthew; McCarty, C.; Bartow, M.; Hood, J. C.; Lodder, K.; Johnson, M.; Cruzen, S. T.; Williams, R. N.

    2013-01-01

    Faculty, staff and students from Columbus State University’s (CSU’s) Coca-Cola Space Science Center presented a webcast of the 2012 Transit of Venus from three continents to a global audience of 1.4 million unique viewers. Team members imaged the transit with telescopes using white-light, hydrogen-alpha, and calcium filters, from Alice Springs, Australia; the Gobi Desert, Mongolia; Bryce Canyon, UT; and Columbus, GA. Images were webcast live during the transit in partnership with NASA’s Sun-Earth Day program, and Science Center staff members were featured on NASA TV. Local members of the public were brought in for a series of outreach initiatives, in both Georgia and Australia, before and during the transit. The data recorded from the various locations have been archived for use in demonstrating principles such as the historical measurement of the astronomical unit.

  1. Nitrate, ascorbic acid, mineral and antioxidant activities of Cosmos caudatus in response to organic and mineral-based fertilizer rates.

    PubMed

    Hassan, Siti Aishah; Mijin, Salumiah; Yusoff, Umi Kalsom; Ding, Phebe; Wahab, Puteri Edaroyati Megat

    2012-06-28

    The source and quantity of nutrients available to plants can affect the quality of leafy herbs. A study was conducted to compare quality of Cosmos caudatus in response to rates of organic and mineral-based fertilizers. Organic based fertilizer GOBI (8% N:8% P₂O₅:8% K₂O) and inorganic fertilizer (15% N, 15% P₂O₅, 15% K₂O) were evaluated based on N element rates at 0, 30, 60, 90, 120 kg h⁻¹. Application of organic based fertilizer reduced nitrate, improved vitamin C, antioxidant activity as well as nitrogen and calcium nutrients content. Antioxidant activity and chlorophyll content were significantly higher with increased fertilizer application. Fertilization appeared to enhance vitamin C content, however for the maximum ascorbic acid content, regardless of fertilizer sources, plants did not require high amounts of fertilizer.

  2. LOSA-M2 aerosol Raman lidar

    SciTech Connect

    Balin, Yu S; Bairashin, G S; Kokhanenko, G P; Penner, I E; Samoilova, S V

    2011-10-31

    The scanning LOSA-M2 aerosol Raman lidar, which is aimed at probing atmosphere at wavelengths of 532 and 1064 nm, is described. The backscattered light is received simultaneously in two regimes: analogue and photon-counting. Along with the signals of elastic light scattering at the initial wavelengths, a 607-nm Raman signal from molecular nitrogen is also recorded. It is shown that the height range of atmosphere probing can be expanded from the near-Earth layer to stratosphere using two (near- and far-field) receiving telescopes, and analogue and photon-counting lidar signals can be combined into one signal. Examples of natural measurements of aerosol stratification in atmosphere along vertical and horizontal paths during the expeditions to the Gobi Desert (Mongolia) and Lake Baikal areas are presented.

  3. Hurry-up and hatch: selective filial cannibalism of slower developing eggs.

    PubMed

    Klug, Hope; Lindström, Kai

    2008-04-23

    Filial cannibalism (the consumption of one's own offspring) is thought to represent an adaptive strategy in many animals. However, little is known about the details of which offspring are consumed when a parent cannibalizes. Here, we examined patterns of within-brood filial cannibalism in the sand goby (Pomatoschistus minutus). Males spawned sequentially with two females, and we asked whether males cannibalized selectively with regard to egg size or the order in which eggs were received. Males preferentially consumed the larger eggs of the second female they spawned with. Because larger eggs took longer to hatch, and because female 2's eggs were up to 1 day behind those of female 1, such preferential cannibalism might allow males to decrease the time spent caring for the current brood and re-enter the mating pool sooner. More work is needed to understand the fitness consequences of such selective cannibalism.

  4. Integrated trend assessment of ecosystem changes in the Limfjord (Denmark): Evidence of a recent regime shift?

    NASA Astrophysics Data System (ADS)

    Tomczak, Maciej T.; Dinesen, Grete E.; Hoffmann, Erik; Maar, Marie; Støttrup, Josianne G.

    2013-01-01

    An integrated ecosystem assessment was carried out for the Limfjord over the period from 1984 to 2008 to describe changes in ecosystem structure and potentially important drivers. The Limfjord is a eutrophic transitional Danish fjord system with the main inflow from the North Sea in the west and main outflow to the Kattegat in the east. We showed that from 1990 to 1995, the ecosystem structure shifted from dominance by demersal fish species (eelpout, whiting, flounder, plaice) to that of pelagic fish species (sprat, herring, sticklebacks), small-bodied fish species (black goby, pipefish), jellyfish, common shore crab, starfish and blue mussels. We interpret this change as a regime shift that showed a similar temporal pattern to regime shifts identified in adjacent seas. The observed changes in trophic interactions and food web reorganisation suggested a non-linear regime shift. The analyses further showed the regime shift to be driven by a combination of anthropogenic pressures and possible interplay with climatic disturbance.

  5. Hydrology and water resources in Caspian Sea

    NASA Astrophysics Data System (ADS)

    Haddadi Moghaddam, Kourosh

    2016-10-01

    Precipitation is the main driver of the water balance variability of the water over space and time, and changes in precipitation have very important implications for hydrology and water resources. Variations in precipitation over daily, seasonal, annual, and decadal time scales influence hydrological variability over time in a catchment. Flood frequency is affected by changes in the year-to-year variability in precipitation and by changes in short-term rainfall properties. Desiccation of the Caspian Sea is one of the world's most serious ecosystem catastrophes. The Persian Sturgeon (Acipenser persicus) caught under 10 m depth using bottom trawl net by research vessel during winter 2012, summer and winter 2013 and spring 2014 in east, central and west of southern parts of Caspian Sea, then, their diets were investigated. During 136 trawling in the aimed seasons, Persian sturgeon with 1 to 2 years old and 179.67 × 0.2 g (body weight) and 29.97 ± 0.4 cm (Total length) captured. Examination of stomach contents in the sturgeon specimens revealed that the food spectrum was composed of bony fishes (Neogobius sp., Atherina sp. and Clupeonella delicatula), invertebrates belonging to the family Ampharetidae polychaeta worms including (Hypanai sp. and Nereis diversicolor), various crustaceans (Gammarus sp. and Paramysis sp.). Investigation on stomach contents of sturgeon Acipenser persicus caught under 10 m depth in 2012 to 2013 surveys showed that there is significant difference in the consumed food. The most food diversity have been observed in winter 2013, also Polychaeta is the primary consumed food and crustacean is the secondary one (P > 0.05), no new types of food (such as bony fishes or benthics) have been observed on food chain of Acipenser persicus and shows no significant difference (P > 0.05).

  6. Browning in desert boundaries in Asia in recent decades

    NASA Astrophysics Data System (ADS)

    Jeong, Su-Jong; Ho, Chang-Hoi; Brown, Molly E.; Kug, Jong-Seong; Piao, Shilong

    2011-01-01

    In this study, the changes in desert boundaries in Asia (Gobi, Karakum, Lut, Taklimakan, and Thar deserts) during the growing season (April-October) in the years 1982-2008 were investigated by analyzing the normalized difference vegetation index (NDVI), precipitation, and temperature. In the desert boundary regions, the domain mean NDVI values increased by 7.2% per decade in 1982-1998 but decreased by 6.8% per decade thereafter. Accordingly, the bare soil areas (or nonvegetated areas) of the inside of the desert boundaries contracted by 9.8% per decade in the 1990s and expanded by 8.7% per decade in the 2000s. It is noted that the five deserts experience nearly simultaneous NDVI changes although they cover a very diverse area of Asia. In contrast, changes in temperature and precipitation in the deserts show rather diverse results. In desert boundaries located along 40°N (Gobi, Taklimakan, and Karakum), the decadal changes in vegetation greenness were mainly related to regional climate during the entire analysis period. Precipitation increased in the 1990s, providing favorable conditions for vegetation growth (i.e., greening), but precipitation reduced (19 mm per decade) and warming intensified (0.7°C per decade) in the 2000s, causing less moisture to be available for vegetation growth (i.e., browning). In desert boundaries below 40°N (Lut and Thar), although an increase in precipitation (8 mm per decade) led to greening in the 1990s, local changes in precipitation and temperature did not necessarily cause browning in the 2000s. Observed multidecadal changes in vegetation greenness in the present study suggest that under significant global and/or regional warming, changes in moisture availability for vegetation growth in desert boundaries are an important factor when understanding decadal changes in areas vulnerable to desertification over Asia.

  7. A study of Asian dust plumes using satellite, surface, and aircraft measurements during the INTEX-B field experiment

    NASA Astrophysics Data System (ADS)

    Logan, Timothy; Xi, Baike; Dong, Xiquan; Obrecht, Rebecca; Li, Zhanqing; Cribb, Maureen

    2010-04-01

    Asian dust events occur frequently during the boreal spring season. Their optical properties have been analyzed by using a combination of source region (ground-based and satellite) and remote Pacific Ocean (aircraft) measurements during the Intercontinental Chemical Transport Experiment-Phase B (INTEX-B) field campaign which lasted from 7 April to 15 May 2006. A strong dust event originating from the Gobi Desert and passing over the Xianghe surface site on 17 April 2006 has been extensively analyzed. The surface averaged aerosol optical depth (AOD) values increased from 0.17 (clear sky) to 4.0 (strong dust), and the Angström exponent (α) dropped from 1.26 (clear sky) to below 0.1. Its total downwelling SW flux over the Xianghe site (thousands of kilometers away from the dust source region) is only 46% of the clear-sky value with almost no direct transmission and nearly double the diffuse SW clear-sky value. This event was also captured 6 days later by satellite observations as well as the UND/NASA DC-8 aircraft over the eastern Pacific Ocean. The DC-8 measurements in the remote Pacific region further classified the plumes into dust dominant, pollution dominant, and a mixture of dust and pollution events. HYSPLIT backward trajectories not only verified the origins of each case we selected but also showed (1) two possible origins for the dust: the Gobi and Taklimakan deserts; and (2) pollution: urban areas in eastern China, Japan, and other industrialized cities east of the two deserts. Based on the averaged satellite retrieved AOD data (0.5° × 0.5° grid box), declining AOD values with respect to longitude demonstrated the evolution of the transpacific transport pathway of Asian dust and pollution over the period of the field campaign.

  8. Four-year monitoring of parasite communities in gobiid fishes of the southwest Baltic: III. parasite species diversity and applicability of monitoring.

    PubMed

    Zander, C Dieter

    2005-01-01

    The parasite infrapopulations of five goby species (Pomatoschistus minutus, P. pictus, P.microps, Gobiusculus flavescens and Gobius niger) were investigated during spring, summer and autumn of the years 1997-2000. In total, 34 parasite species were found: 17 Digenea, 6 Nematoda, 5 Cestoda, 3 Acanthocephala, 2 Protozoa, and 1 Monogenea. The dominant parasites were the digeneans Podocotyle atomon and Cryptocotyle concavum, which represent different ecological groups in terms of their modes of transmission, either indirectly by prey or directly by larvae. The relationship between the parasite Cryptocotyle concavum and the host P. microps is a special one which results in a mean intensity of several hundred cysts (max. 1,329) which settle in the kidney. The diversity of the parasite component community was highest in autumn, but low in spring and summer, with the exception of P. microps for which high values were already found in spring when direct parasites were disregarded. These results depend on the respective seasonal variation in species, some of which occur in huge numbers in some hosts. The diversity of the prey parasite assemblage is higher in Pomatoschistus microps and Gobius niger than in the whole parasite spectrum; the other hosts present the opposite trend. A combination of the island theory of biogeography as modified for parasite infection with the theory of screens and filters leads to a model which considers three handicaps or distances for parasite colonisation: genetic, phylogenetic and ecological. Long-term investigations, as performed here over a time-span of 4 years, can detect more than 80% of parasite species in single hosts after 3 years, and in the whole goby guild after 2 years. Long-term investigations can be useful for finding rare parasites, in analysing parasite diversity, and for determining the seasonality of parasites.

  9. Heterophyid metacercarial infections in brackish water fishes from Jinju-man (Bay), Kyongsangnam-do, Korea

    PubMed Central

    Kim, Do Gyun; Kim, Tong-Soo; Cho, Shin-Hyeong; Song, Hyeon-Je

    2006-01-01

    Heterophyid metacercarial infections in brackish water fishes, i.e., perch, shad, mullet, redlip mullet, and goby, of Jinju-man (Bay), Kyongsangnam-do, Korea, were investigated using a digestion technique. Among 45 perch (Lateolabrax japonicus), the metacercariae of Heterophyopsis continua were found in 55.6% (18.5 metacercariae per fish), Stictodora spp. in 28.9% (3.6), and Metagonimus takahashii in 6.7% (17.0). The metacercariae of H. continua were detected in 23 (65.7%) of 35 shad (Konosirus punctatus). Among 15 mullet (Mugil cephalus), the metacercariae of Pygidiopsis summa were found in 100% (105.9 metacercariae per fish), Heterophyes nocens in 40.0% (8.5), H. continua in 13.3%, and Stictodora spp. in 6.7%. Among 12 redlip mullet (Chelon haematocheilus), the metacercariae of P. summa were detected in 91.7% (1,299 metacercariae per fish), H. nocens in 16.7%, and Stictodora spp. in 16.7%. Among 35 gobies (Acanthogobius flavimanus), the metacercariae of Stictodora spp. were found in 82.9% (44.5 metacercariae per fish), and H. continua in 25.7% (2.8). The adult flukes recovered from a cat experimentally infected with metacercariae from perches were compatible with M. takahashii. The results confirm that the estuarine fish in Jinju-man (Bay) are heavily infected with heterophyid metacercariae. Furthermore, it was found for the first time that the perch acts as a second intermediate host for M. takahashii. PMID:16514276

  10. Feeding ecology of the early life-history stages of two dominant gobiid species in the headwaters of a warm-temperate estuary

    NASA Astrophysics Data System (ADS)

    Wasserman, Ryan J.

    2012-08-01

    The diet and population structure of larval and early juvenile Glossogobius callidus and Redigobius dewaali (Gobiidae) were examined from the headwater region of the permanently open Great Fish Estuary along the south-east coast of southern Africa. Stomach contents of five selected size classes were sorted and identified to the lowest possible taxonomic level for each goby species. Using % Index of Relative Importance values, ontogenic shifts and dietary breadth were determined for each species as was dietary overlap between species. Numerically, both gobiid species showed similar temporal and spatial trends. Seasonal differences in catches were evident, although no numerical differences across sampled sites were found. A large degree of dietary overlap was found between the two species. The zooplanktonic diet showed a greater degree of ontogenic shift in R. dewaali than G. callidus, although similar trends were found for both. In both goby species, Calanoid sp. (Copepoda) generally decreased in importance across size classes, being the most important in the smallest size class whilst Corophium sp. (Amphipoda) increased in importance across size classes, being the least important at the smallest size classes. For both G. callidus and R. dewaali, Insecta contributed significantly to at least one of the five size classes. The larger size classes showed the least dietary overlap and the highest niche breadth. In addition, as is the case in many gobiids worldwide, the larger size classes of both sampled gobiid species consumed a broader prey size range. In conclusion, dietary overlap was largely similar between the young gobiids, suggesting that either food resources are not limiting, or niche separation is attributed to differences in foraging strategies. Ontogenic dietary shifts were however present for both gobiids with regard to prey items and prey size, suggesting a greater degree of foraging niche separation in adults of the species.

  11. Model development of dust emission and heterogeneous chemistry within the Community Multiscale Air Quality modeling system and its application over East Asia

    NASA Astrophysics Data System (ADS)

    Dong, X.; Fu, J. S.; Huang, K.; Tong, D.

    2015-12-01

    The Community Multiscale Air Quality (CMAQ) model has been further developed in terms of simulating natural wind-blown dust in this study, with a series of modifications aimed at improving the model's capability to predict the emission, transport, and chemical reactions of dust aerosols. The default parameterization of threshold friction velocity constants in the CMAQ are revised to avoid double counting of the impact of soil moisture based on the re-analysis of field experiment data; source-dependent speciation profiles for dust emission are derived based on local measurements for the Gobi and Taklamakan deserts in East Asia; and dust heterogeneous chemistry is implemented to simulate the reactions involving dust aerosol. The improved dust module in the CMAQ was applied over East Asia for March and April from 2006 to 2010. Evaluation against observations has demonstrated that simulation bias of PM10 and aerosol optical depth (AOD) is reduced from -55.42 and -31.97 % in the original CMAQ to -16.05 and -22.1 % in the revised CMAQ, respectively. Comparison with observations at the nearby Gobi stations of Duolun and Yulin indicates that applying a source-dependent profile helps reduce simulation bias for trace metals. Implementing heterogeneous chemistry is also found to result in better agreement with observations for sulfur dioxide (SO2), sulfate (SO42-), nitric acid (HNO3), nitrous oxides (NOx), and nitrate (NO3-). Investigation of a severe dust storm episode from 19 to 21 March 2010 suggests that the revised CMAQ is capable of capturing the spatial distribution and temporal variations of dust aerosols. Model evaluation indicates potential uncertainties within the excessive soil moisture fraction used by meteorological simulation. The mass contribution of fine mode aerosol in dust emission may be underestimated by 50 %. The revised revised CMAQ provides a useful tool for future studies to investigate the emission, transport, and impact of wind-blown dust over East

  12. Model development of dust emission and heterogeneous chemistry within the Community Multiscale Air Quality modeling system and its application over East Asia

    NASA Astrophysics Data System (ADS)

    Dong, Xinyi; Fu, Joshua S.; Huang, Kan; Tong, Daniel; Zhuang, Guoshun

    2016-07-01

    The Community Multiscale Air Quality (CMAQ) model has been further developed in terms of simulating natural wind-blown dust in this study, with a series of modifications aimed at improving the model's capability to predict the emission, transport, and chemical reactions of dust. The default parameterization of initial threshold friction velocity constants are revised to correct the double counting of the impact of soil moisture in CMAQ by the reanalysis of field experiment data; source-dependent speciation profiles for dust emission are derived based on local measurements for the Gobi and Taklamakan deserts in East Asia; and dust heterogeneous chemistry is also implemented. The improved dust module in the CMAQ is applied over East Asia for March and April from 2006 to 2010. The model evaluation result shows that the simulation bias of PM10 and aerosol optical depth (AOD) is reduced, respectively, from -55.42 and -31.97 % by the original CMAQ to -16.05 and -22.1 % by the revised CMAQ. Comparison with observations at the nearby Gobi stations of Duolun and Yulin indicates that applying a source-dependent profile helps reduce simulation bias for trace metals. Implementing heterogeneous chemistry also results in better agreement with observations for sulfur dioxide (SO2), sulfate (SO42-), nitric acid (HNO3), nitrous oxides (NOx), and nitrate (NO3-). The investigation of a severe dust storm episode from 19 to 21 March 2010 suggests that the revised CMAQ is capable of capturing the spatial distribution and temporal variation of dust. The model evaluation also indicates potential uncertainty within the excessive soil moisture used by meteorological simulation. The mass contribution of fine-mode particles in dust emission may be underestimated by 50 %. The revised CMAQ model provides a useful tool for future studies to investigate the emission, transport, and impact of wind-blown dust over East Asia and elsewhere.

  13. Effects of season, sex and body size on the feeding ecology of turtle-headed sea snakes ( Emydocephalus annulatus) on IndoPacific inshore coral reefs

    NASA Astrophysics Data System (ADS)

    Goiran, C.; Dubey, S.; Shine, R.

    2013-06-01

    In terrestrial snakes, many cases of intraspecific shifts in dietary habits as a function of predator sex and body size are driven by gape limitation and hence are most common in species that feed on relatively large prey and exhibit a wide body-size range. Our data on sea snakes reveal an alternative mechanism for intraspecific niche partitioning, based on sex-specific seasonal anorexia induced by reproductive activities. Turtle-headed sea snakes ( Emydocephalus annulatus) on coral reefs in the New Caledonian Lagoon feed entirely on the eggs of demersal-spawning fishes. DNA sequence data (cytochrome b gene) on eggs that we palpated from stomachs of 37 snakes showed that despite this ontogenetic stage specialization, the prey comes from a taxonomically diverse array of species including damselfish (41 % of samples, at least 5 species), blennies (41 %, 4 species) and gobies (19 %, 5 species). The composition of snake diets shifted seasonally (with damselfish dominating in winter but not summer), presumably reflecting seasonality of fish reproduction. That seasonal shift affects male and female snakes differently, because reproduction is incompatible with foraging. Adult female sea snakes ceased feeding when they became heavily distended with developing embryos in late summer, and males ceased feeding while they were mate searching in winter. The sex divergence in foraging habits may be amplified by sexual size dimorphism; females grow larger than males, and larger snakes (of both sexes) feed more on damselfish (which often lay their eggs in exposed sites) than on blennies and gobies (whose eggs are hidden within narrow crevices). Specific features of reproductive biology of coral reef fish (seasonality and nest type) have generated intraspecific niche partitioning in these sea snakes, by mechanisms different from those that apply to terrestrial snakes.

  14. A protocol to correct for intra- and interspecific variation in tail hair growth to align isotope signatures of segmentally cut tail hair to a common time line

    PubMed Central

    Burnik Šturm, Martina; Pukazhenthi, Budhan; Reed, Dolores; Ganbaatar, Oyunsaikhan; Sušnik, Stane; Haymerle, Agnes; Voigt, Christian C; Kaczensky, Petra

    2015-01-01

    Rationale In recent years, segmental stable isotope analysis of hair has been a focus of research in animal dietary ecology and migration. To correctly assign tail hair segments to seasons or even Julian dates, information on tail hair growth rates is a key parameter, but is lacking for most species. Methods We (a) reviewed the literature on tail hair growth rates in mammals; b) made own measurements of three captive equid species; (c) measured δ2H, δ13C and δ15N values in sequentially cut tail hairs of three sympatric, free-ranging equids from the Mongolian Gobi, using isotope ratio mass spectrometry (IRMS); and (d) collected environmental background data on seasonal variation by measuring δ2H values in precipitation by IRMS and by compiling pasture productivity measured by remote sensing via the normalized difference vegetation index (NDVI). Results Tail hair growth rates showed significant inter- and intra-specific variation making temporal alignment problematic. In the Mongolian Gobi, high seasonal variation of δ2H values in precipitation results in winter lows and summer highs of δ2H values of available water sources. In water-dependent equids, this seasonality is reflected in the isotope signatures of sequentially cut tails hairs. Conclusions In regions which are subject to strong seasonal patterns we suggest identifying key isotopes which show strong seasonal variation in the environment and can be expected to be reflected in the animal tissue. The known interval between the maxima and minima of these isotope values can then be used to correctly temporally align the segmental stable isotope signature for each individual animal. © 2015 The Authors. Rapid Communications in Mass Spectrometry published by John Wiley & Sons Ltd. PMID:26044272

  15. Levels and profiles of PCBs and OCPs in marine benthic species from the Belgian North Sea and the Western Scheldt Estuary.

    PubMed

    Voorspoels, Stefan; Covaci, Adrian; Maervoet, Johan; De Meester, Ingrid; Schepens, Paul

    2004-09-01

    Various benthic invertebrates (flying crab, common shrimp, and red starfish), small fish (sand goby), benthic flatfish (dab, plaice, and sole) and gadoids (bib and whiting) were collected in the Belgian North Sea and along the Scheldt Estuary, both representing areas impacted by various contaminants to different degrees. The levels of 25 polychlorinated biphenyls (PCBs) and 15 organochlorine pesticides (OCPs), which included penta- and hexachlorobenzene, alpha-, beta-, and gamma-hexachlorocyclohexane isomers, chlordanes, and DDT and metabolites, were determined. Sum of PCBs and OCPs in benthic invertebrates and goby ranged from 1.5 to 280 ng/g wet weight (ww) and from 0.27 to 23 ng/g ww, respectively. The fish livers revealed total PCB and OCP levels ranging from 20 to 3200 ng/g ww and from 6.0 to 410 ng/g ww, respectively. Levels of both contaminant groups were significantly higher in samples from the Scheldt Estuary compared to the Belgian North Sea. For most species a highly inverse correlation was found between the concentration of contaminants and the distance to Antwerp (r between 0.812 and 0.901, p < 0.05), pointing to a higher degree of exposure further upstream. PCB and OCP exposures are highly correlated (r between 0.836 and 1.000, p < 0.05), which suggests that the pollution can be classified as historical. However, because urban and industrial centres may still be emitting these compounds, more recent point and non-point sources cannot be ruled out.

  16. Changes along the male reproductive axis in response to social context in a gonochoristic gobiid, Zosterisessor ophiocephalus (Teleostei, Gobiidae), with alternative mating tactics.

    PubMed

    Scaggiante, Marta; Grober, Matthew S; Lorenzi, Varenka; Rasotto, Maria B

    2004-12-01

    Sexual selection has given rise, in several taxa, to intrasexual variation in male phenotype. While evolutionary studies have provided explanations of the adaptive function of this dramatic male phenotypic diversity, the proximate control of its expression has still to be completely understood. Several observations, primarily from sex-changing species, indicated a major role of social interactions in reproductive axis regulation and consequently in the expression of alternative male phenotypes. Here we documented changes along the male reproductive axis in response to social context in a gonochoristic species, the grass goby Zosterisessor ophiocephalus, where fully functional alternative male mating tactics appear to be expressed as an ontogenetic gradient. In the grass goby, larger and older males dig a nest and perform parental care, while smaller males sneak fertilization during territorial male spawning. Territorial males are characterized by a higher number of gonadotropin-releasing hormone (GnRH) neurons in forebrain preoptic area, smaller testes, larger seminal vesicles, and viscous ejaculates that last longer and contain fewer sperm than those of sneakers. To experimentally investigate the role of social factors in inducing changes along the male reproductive axis, sneakers were tested in two different situations: nesting alone or with ripe females. Sneakers that mated and performed parental care showed dramatic changes in brain, reproductive apparatus morphology, and ejaculate traits. GnRH-immunoreactive cells in forebrain preoptic area increased in number, reaching values typical of wild-caught parental males. Testes size decreased while seminal vesicle size increased and ejaculates showed lower sperm densities. These results were discussed within the framework of the social transduction hypothesis, which predicts that social experience should mediate, through a cascade of internal processes, shifts between morphs throughout life.

  17. Diurnal and seasonal variations in carbon dioxide exchange in ecosystems in the Zhangye oasis area, Northwest China.

    PubMed

    Zhang, Lei; Sun, Rui; Xu, Ziwei; Qiao, Chen; Jiang, Guoqing

    2015-01-01

    Quantifying carbon dioxide exchange and understanding the response of key environmental factors in various ecosystems are critical to understanding regional carbon budgets and ecosystem behaviors. For this study, CO2 fluxes were measured in a variety of ecosystems with an eddy covariance observation matrix between June 2012 and September 2012 in the Zhangye oasis area of Northwest China. The results show distinct diurnal variations in the CO2 fluxes in vegetable field, orchard, wetland, and maize cropland. Diurnal variations of CO2 fluxes were not obvious, and their values approached zero in the sandy desert, desert steppe, and Gobi ecosystems. Additionally, daily variations in the Gross Primary Production (GPP), Ecosystem Respiration (Reco) and Net Ecosystem Exchange (NEE) were not obvious in the sandy desert, desert steppe, and Gobi ecosystems. In contrast, the distributions of the GPP, Reco, and NEE show significant daily variations, that are closely related to the development of vegetation in the maize, wetland, orchard, and vegetable field ecosystems. All of the ecosystems are characterized by their carbon absorption during the observation period. The ability to absorb CO2 differed significantly among the tested ecosystems. We also used the Michaelis-Menten equation and exponential curve fitting methods to analyze the impact of Photosynthetically Active Radiation (PAR) on the daytime CO2 flux and impact of air temperature on Reco at night. The results show that PAR is the dominant factor in controlling photosynthesis with limited solar radiation, and daytime CO2 assimilation increases rapidly with PAR. Additionally, the carbon assimilation rate was found to increase slowly with high solar radiation. The light response parameters changed with each growth stage for all of the vegetation types, and higher light response values were observed during months or stages when the plants grew quickly. Light saturation points are different for different species. Nighttime

  18. Genetic diversity of invasive species in the Great Lakes versus their Eurasian source populations: insights for risk analysis.

    PubMed

    Stepien, Carol A; Brown, Joshua E; Neilson, Matthew E; Tumeo, Mark A

    2005-08-01

    Combining DNA variation data and risk assessment procedures offers important diagnostic and monitoring tools for evaluating the relative success of exotic species invasions. Risk assessment may allow us to understand how the numbers of founding individuals, genetic variants, population sources, and introduction events affect successful establishment and spread. This is particularly important in habitats that are "hotbeds" for invasive species--such as the North American Great Lakes. This study compares genetic variability and its application to risk assessment within and among three Eurasian groups and five species that successfully invaded the Great Lakes during the mid 1980s through early 1990s; including zebra and quagga mussels, round and tubenose gobies, and the ruffe. DNA sequences are compared from exotic and native populations in order to evaluate the role of genetic diversity in invasions. Close relatives are also examined, since they often invade in concert and several are saline tolerant and are likely to spread to North American estuaries. Results show that very high genetic diversity characterizes the invasions of all five species, indicating that they were founded by very large numbers of propagules and underwent no founder effects. Genetic evidence points to multiple invasion sources for both dreissenid and goby species, which appears related to especially rapid spread and widespread colonization success in a variety of habitats. In contrast, results show that the ruffe population in the Great Lakes originated from a single founding population source from the Elbe River drainage. Both the Great Lakes and the Elbe River populations of ruffe have similar genetic diversity levels--showing no founder effect, as in the other invasive species. In conclusion, high genetic variability, large numbers of founders, and multiple founding sources likely significantly contribute to the risk of an exotic species introduction's success and persistence.

  19. Meiofauna as food source for small-sized demersal fish in the southern North Sea

    NASA Astrophysics Data System (ADS)

    Schückel, Sabine; Sell, Anne F.; Kihara, Terue C.; Koeppen, Annemarie; Kröncke, Ingrid; Reiss, Henning

    2013-06-01

    Meiofauna play an essential role in the diet of small and juvenile fish. However, it is less well documented which meiofaunal prey groups in the sediment are eaten by fish. Trophic relationships between five demersal fish species (solenette, goby, scaldfish, dab <20 cm and plaice <20 cm) and meiofaunal prey were investigated by means of comparing sediment samples and fish stomach contents collected seasonally between January 2009 and January 2010 in the German Bight. In all seasons, meiofauna in the sediment was numerically dominated by nematodes, whereas harpacticoids dominated in terms of occurrence and biomass. Between autumn and spring, the harpacticoid community was characterized by Pseudobradya minor and Halectinosoma canaliculatum, and in summer by Longipedia coronata. Meiofaunal prey dominated the diets of solenette and gobies in all seasons, occurred only seasonally in the diet of scaldfish and dab, and was completely absent in the diet of plaice. For all fish species (excluding plaice) and in each season, harpacticoids were the most important meiofauna prey group in terms of occurrence, abundance and biomass. High values of Ivlev's index of selectivity for Pseudobradya spp. in winter and Longipedia spp. in summer provided evidence that predation on harpacticoids was species-selective, even though both harpacticoids co-occurred in high densities in the sediments. Most surficial feeding strategies of the studied fish species and emergent behaviours of Pseudobradya spp. and Longipedia spp. might have caused this prey selection. With increasing fish sizes, harpacticoid prey densities decreased in the fish stomachs, indicating a diet change towards larger benthic prey during the ontogeny of all fish species investigated.

  20. Three-dimensional structure of aerosol in China: A perspective from multi-satellite observations

    NASA Astrophysics Data System (ADS)

    Guo, Jianping; Liu, Huan; Wang, Fu; Huang, Jingfeng; Xia, Feng; Lou, Mengyun; Wu, Yerong; Jiang, Jonathan H.; Xie, Tao; Zhaxi, Yangzong; Yung, Yuk L.

    2016-09-01

    Using eight years (2006-2014) of passive (MODIS/Aqua and OMI/Aura) and active (CALIOP/CALIPSO) satellite measurements of aerosols, we yield a three-dimensional (3D) distribution of the frequency of occurrence (FoO) of aerosols over China. As an indicator of the vertical heterogeneity of aerosol layers detected by CALIOP, two types of Most Probable Height (MPH), including MPH_FoO and MPH_AOD, are deduced. The FoO of "Total Aerosol" reveals significant geographical dependence. Eastern China showed much stronger aerosol FoD than northwestern China. The FoO vertical structures of aerosol layer are strongly dependent on altitudes. Among the eight typical ROIs analyzed, aerosol layers over the Gobi Desert have the largest occurrence probability located at an altitude as high as 2.83 km, as compared to 1.26 km over Beijing-Tianjin-Hebei. The diurnal variation (nighttime-daytime) in MPH_AOD varies from an altitude as low as 0.07 km over the Sichuan basin to 0.27 km over the Gobi Desert, whereas the magnitude of the diurnal variation in terms of MPH_AOD is six times as large as the MPH_FoO, mostly attributable to the day/night lidar SNR difference. Also, the 3D distribution of dust and smoke aerosols was presented. The multi-sensor synergized 3D observations of dust aerosols, frequently observed in the zonal belt of 38°N-45°N, is markedly different from that of smoke aerosols that are predominantly located in the eastern and southern parts. The 3D FoO distribution of dust indicates a west-to-east passageway of dust originating from the westernmost Taklimakan Desert all the way to North China Plain (NCP). The findings from the multi-sensor synergetic observations greatly improved our understanding on the long-range aerosol dispersion, transport and passageway over China.

  1. Influence of marine reserves on reef fish recruitment in the upper Florida Keys

    NASA Astrophysics Data System (ADS)

    Sponaugle, S.; Walter, K. D.; Grorud-Colvert, K.; Paddack, M. J.

    2012-09-01

    Coral reef fish recruitment to the upper Florida Keys was monitored monthly for 7 years (2003-2009) to establish a baseline and test whether recruitment varied between reserve and non-reserve sites. Recruits <30 days old were surveyed in two primary habitat types (reef and rubble) in each of two replicate reserve and non-reserve sites. Recruitment of all fish species peaked in the summer and early fall; winter recruitment was consistently low. Some interannual recruitment patterns were roughly similar among species, with recruitment generally lower in 2004 for several taxa, possibly reflecting a system-wide process. During 7 peak recruitment months each year, overall recruitment to reef habitat was significantly higher in non-reserve sites in 2 of 7 years. In contrast, recruitment to rubble habitat was significantly higher in reserves in 3 of 7 years. Specific fish taxa had variable patterns of recruitment to reserves and non-reserves: Despite high interannual variation in recruitment magnitude, Scaridae (parrotfish) densities were significantly higher in reserves than in non-reserves. Densities of two abundant goby taxa ( Gnatholepis thompsoni and Coryphopterus spp.) were also higher in reserves than in non-reserves, but the magnitude varied among years. Recruitment of the bicolor damselfish, Stegastes partitus, did not differ consistently between reserves and non-reserves. Densities of Thalassoma bifasciatum had an opposite trend relative to other taxa, with densities typically higher in non-reserves than in reserves (in 6 of 7 years; significant in only 2 years). Higher recruit densities (scarids, gobies, and all rubble taxa together) within reserves were coupled with significantly lower densities of intermediate-sized piscivores and significantly greater cover of Dictyota spp. macroalgae and turfs relative to non-reserves. Reserves may be areas of relative refuge from predation for some fish recruits due to a combination of reduced predator abundance and

  2. Contrasting Genetic Structure among Populations of Two Amphidromous Fish Species (Sicydiinae) in the Central West Pacific

    PubMed Central

    Taillebois, Laura; Castelin, Magalie; Ovenden, Jennifer R.; Bonillo, Céline; Keith, Philippe

    2013-01-01

    Both present-day and past processes can shape connectivity of populations. Pleistocene vicariant events and dispersal have shaped the present distribution and connectivity patterns of aquatic species in the Indo-Pacific region. In particular, the processes that have shaped distribution of amphidromous goby species still remain unknown. Previous studies show that phylogeographic breaks are observed between populations in the Indian and Pacific Oceans where the shallow Sunda shelf constituted a geographical barrier to dispersal, or that the large spans of open ocean that isolate the Hawaiian or Polynesian Islands are also barriers for amphidromous species even though they have great dispersal capacity. Here we assess past and present genetic structure of populations of two amphidromous fish (gobies of the Sicydiinae) that are widely distributed in the Central West Pacific and which have similar pelagic larval durations. We analysed sections of mitochondrial COI, Cytb and nuclear Rhodospine genes in individuals sampled from different locations across their entire known range. Similar to other Sicydiinae fish, intraspecific mtDNA genetic diversity was high for all species (haplotype diversity between 0.9–0.96). Spatial analyses of genetic variation in Sicyopus zosterophorum demonstrated strong isolation across the Torres Strait, which was a geologically intermittent land barrier linking Australia to Papua New Guinea. There was a clear genetic break between the northwestern and the southwestern clusters in Si. zosterophorum (φST = 0.67502 for COI) and coalescent analyses revealed that the two populations split at 306 Kyr BP (95% HPD 79–625 Kyr BP), which is consistent with a Pleistocene separation caused by the Torres Strait barrier. However, this geographical barrier did not seem to affect Sm. fehlmanni. Historical and demographic hypotheses are raised to explain the different patterns of population structure and distribution between these species. Strategies

  3. Modeling the processing of mineral iron during dust transport

    NASA Astrophysics Data System (ADS)

    Vogelsberg, Ulrike; Wolke, Ralf; Tilgner, Andreas; Tegen, Ina; Herrmann, Hartmut

    2014-05-01

    The Saharan desert and the Gobi desert are the main contributors to Aeolian desert dust, which is a major source of micronutrients to the remote ocean regions. Micronutrients, such as transition metals like iron or copper, are regarded essential for biological processes of different marine species. In this context recent studies have shown that soluble iron, since it is generally the most abundant transition metal in dust particles, has the ability to control marine productivity and thereby likely influence the CO2- budget. Nevertheless, the processing of desert dust leading to the release of soluble iron still lacks sufficient understanding since several factors control the solubilization process. Especially anthropogenic emissions are regarded to significantly add to the amount of soluble iron by acidification of dust particles or by the direct emission of soluble iron comprised, e.g. in coal fly ash. For the investigation of the dissolution process of iron that takes place during dust transportation the spectral air parcel model SPACCIM is used. A mechanism describing the precipitation and dissolution of mineral particles by heterogeneous surface reactions has been implemented. Trajectory properties were derived from COSMO-MUSCAT simulations or from re-analysis data by HYSPLIT. Differences in the chemical composition and the amount of anthropogenic and naturally emitted species on the North African continent and the highly industrialized region of South-East Asia have considerable impact on the acidification of the desert dust. Under this aspect, special cases of dust outbreaks of the Saharan desert and the Gobi desert are investigated and compared with focus on soluble iron produced.

  4. Do Community-based Institutions Build Resilience to Climate Change in Mongolia?

    NASA Astrophysics Data System (ADS)

    Fernandez-Gimenez, M.

    2012-12-01

    Climate change impacts are inherently local, yet relatively little is known about the role of local people and institutions in adapting to climate change. Mongolia has experienced one of the strongest warming trends on Earth over the past 40 years, associated declines in streamflow, and increases in the frequency of extreme winter weather events. Environmental changes are compounded by rapid political, economic and social transformations beginning in 1990. We investigate the complex interactions of social, ecological and climate changes across multiple levels from local to regional to national. We hypothesize that community-based institutions increase resilience by strengthening self-regulating feedbacks between social and ecological systems through development and enforcement of formal management rules, implementation of innovative management practices, strengthening of social networks and information exchange within and across levels of social organization, and enhanced monitoring. These result in better ecological and socio-economic conditions and greater adaptive capacity in areas under formal community-based management compared to adjacent areas without formal community management institutions. Evaluation of this hypothesis involves integrated collection and analysis of quantitative and qualitative ecological, social and hydro-climatic data at household, community and regional levels of spatial and social organization. Here, we present preliminary results evaluating these hypotheses from 10 counties (soum) in 3 provinces (aimag) in the Gobi desert-steppe of southern Mongolia based on household-level social data and plot-level ecological data representing. Our initial findings support the hypothesis that community-based institutions are associated with greater household adaptive capacity and healthier pasture ecological conditions, characterized by greater perennial vegetation cover and biomass, especially in the functional group most important for livestock

  5. Threshold wind speed for dust emission in east Asia and its seasonal variations

    NASA Astrophysics Data System (ADS)

    Kurosaki, Y.; Mikami, M.

    2007-09-01

    We present maps of threshold wind speed for dust emission in east Asia, which are statistically evaluated from synoptic surface meteorological data. We define threshold wind speeds as ut5% and ut50%, which can be identified as threshold wind speeds at close to the most favorable land surface condition for dust emission and under normal land surface conditions, respectively. Spatial distributions of ut5% and ut50% are similar and roughly correspond to the land cover type. The threshold wind speed is low in desert regions such as the Taklimakan Desert (ut5% = 4.4 ± 0.6 m s-1 and ut50% = 6.7 ± 1.5 m s-1) and the Loess Plateau (ut5% = 6.9 ± 1.2 m s-1 and ut50% = 9.4 ± 1.6 m s-1). On the other hand, the highest is seen in northern Mongolia (ut5% = 9.8 ± 2.2 m s-1 and ut50% = 16.2 ± 2.5 m s-1), whose land cover type is grassland. One exception is the high threshold wind speed recorded in the Gobi Desert (ut5% = 8.9 ± 2.2 m s-1 and ut50% = 13.8 ± 2.0 m s-1). Seasonal variations in the threshold wind speed are narrow in desert regions such as the Taklimakan Desert, the Gobi Desert and Loess Plateau, but wide in grassland regions such as northern Mongolia. This suggests that land surface conditions are the similar throughout the year in desert regions, but seasonally variable in grassland regions.

  6. Unexpected patterns of genetic structuring among locations but not colour morphs in Acropora nasuta (Cnidaria; Scleractinia).

    PubMed

    Mackenzie, J B; Munday, P L; Willis, B L; Miller, D J; van Oppen, M J H

    2004-01-01

    Symbiotic relationships have contributed greatly to the evolution and maintenance of biological diversity. On the Great Barrier Reef, species of obligate coral-dwelling fishes (genus Gobiodon) coexist by selectively recruiting to colonies of Acropora nasuta that differ in branch-tip colour. In this study, we investigate genetic variability among sympatric populations of two colour morphs of A. nasuta ('blue-tip' and 'brown-tip') living in symbiosis with two fish species, Gobiodon histrio and G. quinquestrigatus, respectively, to determine whether gobies are selecting between intraspecific colour polymorphisms or cryptic coral species. We also examine genetic differentiation among coral populations containing both these colour morphs that are separated by metres between local sites, tens of kilometres across the continental shelf and hundreds of kilometres along the Great Barrier Reef. We use three nuclear DNA loci, two of which we present here for the first time for Acropora. No significant genetic differentiation was detected between sympatric colour morphs at these three loci. Hence, symbiotic gobies are selecting among colour morphs of A. nasuta, rather than cryptic species. Significant genetic geographical structuring was observed among populations, independent of colour, at regional (i.e. latitudinal separation by < 500 km) and cross-shelf (< 50 km) scales, alongside relative homogeneity between local populations on within reef scales (< 5 km). This contrasts with the reported absence of large-scale genetic structuring in A. valida, which is a member of the same species group as A. nasuta. Apparent differences in biogeographical structuring between species within the A. nasuta group emphasize the need for comparative sampling across both spatial (i.e. within reefs, between reefs and between regions) and taxonomic scales (i.e. within and between closely related species).

  7. Mongolia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    With winds that constantly whip dust across high plains, a nomadic population that mostly lives in felt tents, and a local cuisine that consists of fermented goat milk and stewed meats, Mongolia is not a place for the pampered. This true-color image of Mongolia was acquired on March 27, 2000, by the Moderate-resolution Imaging Spectroradiometer (MODIS), flying aboard NASA's Terra spacecraft. Most of the 2.3 million Mongolians live on the vast, rolling, semi-arid, grass-covered plateaus that stretch across eastern and northern Mongolia. In the image, these areas are a dark reddish-brown. The faint herringbone pattern running through eastern Mongolia is formed by the Kerulen and Orhon Gol rivers and their tributaries. The lighter reddish-brown areas covering most of southern Mongolia is the Gobi Desert. Vast and largely uncharted, the Gobi has become a favorite of fossil hunters from around the world. Here ideal fossil specimens of Velociraptor and Protoceratops have been unearthed. (See Finding Fossils from Space for more details.) Moving to the southwest corner of the country, one can see the defined ridges that make up the sparsely vegetated Altai Mountain Range, the highest mountains in Mongolia. A number of lakes can be spotted to the northwest and the far north. The drumstick-shaped lake at the northern tip of Mongolia is Hovsgol Nuur, which is considered a national treasure in Mongolia with its picturesque alpine surroundings and pristine water. Further north in Russia, the long lake that is half surrounded by snow is the great Lake Baykal. Reaching 1,620 meters (nearly one mile) in depth, Lake Baykal is the deepest freshwater lake in the world and holds as much fresh water as the shallower lakes Superior, Huron, Ontario, Michigan, and Erie combined. Image courtesy MODIS Science Team

  8. Extreme gender flexibility: using a phylogenetic framework to infer the evolution of variation in sex allocation, phylogeography, and speciation in a genus of bidirectional sex changing fishes(Lythrypnus, Gobiidae).

    PubMed

    Maxfield, Jessica M; Van Tassell, James L; St Mary, Colette M; Joyeux, Jean-Christophe; Crow, Karen D

    2012-09-01

    The genus Lythrypnus is a group of marine gobies that exhibit extreme gender flexibility as bidirectional sex changers. The genus consists of 20 described species and several undescribed species that are distributed in the Americas. Five species have been characterized with respect to sex allocation and gonad morphology. The hormonal, morphological, and behavioral aspects of sex change have been studied extensively for one species, L. dalli. These data, however, have not been interpreted in an evolutionary context because a phylogenetic hypothesis has not previously been proposed for the genus Lythrypnus. We propose the first phylogenetic hypothesis for the genus based on molecular data from three mitochondrial genes (12s, ND2, and Cytb), one nuclear gene (Rag1) and one nuclear intron (S7). We also include three previously undescribed Lythrypnus species. Our results support the monophyly of the genus with L. heterochroma, an Atlantic species, as the basal taxon. After the divergence of L. heterochroma, there are two main clades, one comprised of species distributed in the Atlantic, the other comprised of species distributed in the Pacific. These data indicate an Atlantic origin for the genus, followed by divergence after the closure of the Isthmus of Panama. Our data also support the monophyly of three previously described species complexes, the L. rhizophora complex and L. dalli complex in the Pacific, and the L. mowbrayi complex in the Atlantic. We mapped patterns of sex allocation within this genus onto the fully resolved and supported topology, and found that sexual plasticity and gender flexibility is likely a synapomorphy for the genus. Overall our results create a well-supported framework to understand the phylogeography of the genus, and to interpret the evolution of sex allocation in Lythrypnus gobies.

  9. Browning in Desert Boundaries in Asia in Recent Decades

    NASA Technical Reports Server (NTRS)

    Jeong, Su-Jong; Ho, Chang-Hoi; Brown, Molly E.; Kug, Jong-Seong; Piao, Shilong

    2011-01-01

    In this study, the changes in desert boundaries in Asia (Gobi, Karakum, Lut, Taklimakan, and Thar deserts) during the growing season (April October) in the years 1982 2008 were investigated by analyzing the normalized difference vegetation index (NDVI), precipitation, and temperature. In the desert boundary regions, the domain mean NDVI values increased by 7.2% per decade in 1982 1998 but decreased by 6.8% per decade thereafter. Accordingly, the bare soil areas (or nonvegetated areas) of the inside of the desert boundaries contracted by 9.8% per decade in the 1990s and expanded by 8.7% per decade in the 2000s. It is noted that the five deserts experience nearly simultaneous NDVI changes although they cover a very diverse area of Asia. In contrast, changes in temperature and precipitation in the deserts show rather diverse results. In desert boundaries located along 40 N (Gobi, Taklimakan, and Karakum), the decadal changes in vegetation greenness were mainly related to regional climate during the entire analysis period. Precipitation increased in the 1990s, providing favorable conditions for vegetation growth (i.e., greening), but precipitation reduced (19 mm per decade) and warming intensified (0.7 C per decade) in the 2000s, causing less moisture to be available for vegetation growth (i.e., browning). In desert boundaries below 40 N (Lut and Thar), although an increase in precipitation (8 mm per decade) led to greening in the 1990s, local changes in precipitation and temperature did not necessarily cause browning in the 2000s. Observed multidecadal changes in vegetation greenness in the present study suggest that under significant global and/or regional warming, changes in moisture availability for vegetation growth in desert boundaries are an important factor when understanding decadal changes in areas vulnerable to desertification over Asia.

  10. Major and trace elements documented paleoenvironmental and provenance signatures as inferred from the lacustrine sequence of Orog Nuur, southern Mongolia

    NASA Astrophysics Data System (ADS)

    Yu, Kaifeng; Lehmkuhl, Frank; Diekmann, Bernhard; Nottebaum, Veit; Stauch, Georg

    2016-04-01

    In arid realm, due to scarce of continuous terrestrial archives, lacustrine sequences were more often employed as the paleoenvironmental repository. However, there exist numerous spatial and temporal heterogeneities concerning existing studied sites. In the Gobi Desert of southern Mongolia, only two records i.e., Bayan Tohomin Nuur and Ulaan Nuur, were previously reported, neither of them, however, provided records older than ~15 ka. A record that spans longer time period is therefore indispensable to better understand the thermal and hydrologic pattern and their driving mechanisms. Among the suite of the multidisciplinary studies on lacustrine archive, geochemistry appears most likely the promising tool to decipher the interplay between the environmental change, source lithotype and sediment bulk-composition. Considering the late Quaternary lacustrine sediments, the bulk-geochemistry may be controlled by source terranes, authigenic or allothigenic input, which can be altered by the past environment conditions. Knowledge of the bulk-geochemistry downcore variance along with the field investigation and carefully examined geologic mapping will thereby allow us to gain a better understanding of the climate-induced provenance changes throughout the deposition process. On the other hand, surveys considering the bulk-geochemistry and corresponding environmental interpretations in the pelagic realm have been systematically conducted and reviewed, while their counterpart explanations in the lacustrine sediments still need more investigations. Two parallel cores (ONW I, 6.00 m; ONW II, 13.36 m) was retrieved from Orog Nuur, Gobi Desert of southern Mongolia. A suite of high resolution element abundances were examined based on core ONW II in an attempt to gain a better understanding of the paleoenvironment and provenance history of the catchment system over the last ~50 ka. Due to the predominant clay or silty-clay fractions in the lacustrine sediments, Al and Si display

  11. Observation of atmospheric aerosols at Mt. Hua and Mt. Tai in central and east China during spring 2009 - Part 2: Impact of dust storm on organic aerosol composition and size distribution

    NASA Astrophysics Data System (ADS)

    Wang, G. H.; Li, J. J.; Cheng, C. L.; Zhou, B. H.; Xie, M. J.; Hu, S. Y.; Meng, J. J.; Sun, T.; Ren, Y. Q.; Cao, J. J.; Liu, S. X.; Zhang, T.; Zhao, Z. Z.

    2012-05-01

    PM10 and size-resolved particles (9-stage) were simultaneously collected at Mt. Hua and Mt. Tai in central and east China during the spring of 2009 including a massive dust storm occurring on 24 April (named as DS II), and determined for organic compounds to investigate the impact of dust storm on organic aerosols. High molecular weight (HMW) n-alkanes, fatty acids, and fatty alcohols and trehalose sharply increased and almost entirely stayed in coarse particles when dust storm was present, suggesting that high level of organic aerosols in the mountain atmospheres during the event largely originated from Gobi desert plants. However, most anthropogenic aerosols (e.g. PAHs, and aromatic and dicarboxylic acids) during the event significantly decreased due to a dilution effect, indicating that anthropogenic aerosols in the mountain atmospheres during the nonevent period largely originated from local/regional sources rather than from long-range transport. Trehalose, a metabolism product enriched in biota in dry conditions, was 62 ± 78 and 421 ± 181 ng m-3 at Mt. Hua and Mt. Tai during DS II, 10-30 times higher than that in the nonevent time, indicating that trehalose may be a tracer for dust emissions from Gobi desert regions. Molecular compositions of organic aerosols in the mountain samples demonstrate that domestic coal burning is still the major source of PAHs in China. n-Alkanes and fatty acids showed a bimodal size distribution during the nonevent with a major peak in fine mode (<2.1 μm) and a small peak in coarse mode (>2.1 μm). The coarse mode significantly increased and even dominated over the whole size range when dust was present. Glucose and trehalose were also dominant in the coarse mode especially in the DS II time. PAHs and levoglucosan concentrated in fine particles with no significant changes in size distribution when dust storm occurred. However, phthalic and succinic acids showed bimodal size distribution pattern with an increase in coarse mode

  12. Evolution of high-performance swimming in sharks: transformations of the musculotendinous system from subcarangiform to thunniform swimmers.

    PubMed

    Gemballa, Sven; Konstantinidis, Peter; Donley, Jeanine M; Sepulveda, Chugey; Shadwick, Robert E

    2006-04-01

    In contrast to all other sharks, lamnid sharks perform a specialized fast and continuous "thunniform" type of locomotion, more similar to that of tunas than to any other known shark or bony fish. Within sharks, it has evolved from a subcarangiform mode. Experimental data show that the two swimming modes in sharks differ remarkably in kinematic patterns as well as in muscle activation patterns, but the morphology of the underlying musculotendinous system (red muscles and myosepta) that drives continuous locomotion remains largely unknown. The goal of this study was to identify differences in the musculotendinous system of the two swimming types and to evaluate these differences in an evolutionary context. Three subcarangiform sharks (the velvet belly lantern shark, Etmopterus spinax, the smallspotted catshark, Scyliorhinus canicula, and the blackmouth catshark, Galeus melanostomus) from the two major clades (two galeans, one squalean) and one lamnid shark, the shortfin mako, Isurus oxyrhinchus, were compared with respect to 1) the 3D shape of myomeres and myosepta of different body positions; 2) the tendinous architecture (collagenous fiber pathways) of myosepta from different body positions; and 3) the association of red muscles with myoseptal tendons. Results show that the three subcarangiform sharks are morphologically similar but differ remarkably from the lamnid condition. Moreover, the "subcarangiform" morphology is similar to the condition known from teleostomes. Thus, major features of the "subcarangiform" condition in sharks have evolved early in gnathostome history: Myosepta have one main anterior-pointing cone and two posterior-pointing cones that project into the musculature. Within a single myoseptum cones are connected by longitudinally oriented tendons (the hypaxial and epaxial lateral and myorhabdoid tendons). Mediolaterally oriented tendons (epineural and epipleural tendons; mediolateral fibers) connect vertebral axis and skin. An individual lateral

  13. Succession of the ecosystems of the Aral Sea during its transition from oligohaline to polyhaline water body

    NASA Astrophysics Data System (ADS)

    Mirabdullayev, Iskandar M.; Joldasova, Iliya M.; Mustafaeva, Zuri A.; Kazakhbaev, Saparbay; Lyubimova, Svetlana A.; Tashmukhamedov, Bekdjan A.

    2004-06-01

    During 22 field trips from 1990 to 2002 (mainly the western basin of the Large Aral) data on salinity, phytoplankton, zooplankton, zoobenthos and fish fauna have been collected. In 2002, the salinity of the western basin reached 75 ppt, while that in the eastern basin, 150 ppt. In 1999-2002, 159 species of planktonic algae have been recorded. This is approximately twice as low as recorded before. The diversity of Cyanophyta, Pyrrhophyta and Chlorophyta in particular has dropped in the past few years. As before, currently Bacillariophyta is the most diverse plankton. However, the composition of dominants has changed. Once previously dominant species, Actinocyclus ehrenbergii, vanished from the plankton of the Aral Sea and was replaced by such diatoms as Amphora coffeaformis, A. coffeaformis var. acutiuscula and Synedra tabulata var. parva. Since 1970s, a gradual decrease in the diversity of zooplankton has been taking place. Since 1997, the formerly dominant Calanipeda aquaedulcis vanished, which apparently was the reason for the emergence of Moina salina and Artemia parthenogenetica. Since 2000, artemia has been dominant in the plankton of the Aral Sea, constituting 99% of the zooplankton biomass. In the 1970-1980s, a rapid decrease in the biodiversity of the zoobenthos was observed. In the 1990s, most aboriginal and introduced species became extinct. Currently, the bivalve mollusk Syndosmya segmentum, the ostracod Cyprideis torosa and larvae of the dipteran Chironomus salinarius can still be recorded in the western basin. In the eastern basin no benthos is observed. By 1998, in the Large Aral, only five fish species survived: baltic herring Clupea harengus membras, flounder Platichthys flesus luscus, atherine Atherina boyeri caspia and bullheads Neogobius fluviatilis and Potamoschistus caucasicus. Since 2002, only flounder and atherina have been recorded in the western basin of the Large Aral. No fish have been recorded in the eastern part of the Aral Sea in 2002

  14. Morphological selection in an extreme flow environment: body shape and waterfall-climbing success in the Hawaiian stream fish Sicyopterus stimpsoni.

    PubMed

    Blob, Richard W; Bridges, William C; Ptacek, Margaret B; Maie, Takashi; Cediel, Roberto A; Bertolas, Morgan M; Julius, Matthew L; Schoenfuss, Heiko L

    2008-12-01

    Flow characteristics are a prominent factor determining body shapes in aquatic organisms, and correlations between body shape and ambient flow regimes have been established for many fish species. In this study, we investigated the potential for a brief period of extreme flow to exert selection on the body shape of juvenile climbing Hawaiian gobiid fishes. Because of an amphidromous life history, juvenile gobies that complete an oceanic larval phase return to freshwater habitats, where they become adults. Returning juveniles often must scale waterfalls (typically with the use of a ventral sucker) in order to reach the habitats they will use as adults, thereby exposing these animals to brief periods of extreme velocities of flow. Hydrodynamic theory predicts that bodies with larger suckers and with lower heights that reduce drag would have improved climbing success and, thus, be well suited to meet the demands of the flows in waterfalls. To test the potential for the flow environment of waterfalls to impose selection that could contribute to differences in body shape between islands, we subjected juvenile Sicyopterus stimpsoni to climbing trials up artificial waterfalls (∼100 body lengths) and measured differences in body shape between successful and unsuccessful climbers. Waterfalls appear to represent a significant selective barrier to these fishes, as nearly 30% failed our climbing test. However, the effects of selection on morphology were not straightforward, as significant differences in shape between successful and unsuccessful climbers did not always match hydrodynamic predictions. In both selection experiments and in adult fish collected from habitats with different prevailing conditions of flow (the islands of Hawai'i versus Kaua'i), lower head heights were associated with exposure to high-flow regimes, as predicted by hydrodynamic theory. Thus, a premium appears to be placed on the reduction of drag via head morphology throughout the ontogeny of this

  15. Mongolian Almond (Prunus mongolica Maxim): The Morpho-Physiological, Biochemical and Transcriptomic Response to Drought Stress.

    PubMed

    Wang, Jǖgang; Zheng, Rong; Bai, Shulan; Gao, Xiaomin; Liu, Min; Yan, Wei

    2015-01-01

    Prunus mongolica Maxim, which is widely established in the Gobi Desert, shows extreme tolerance to drought. However, there is a lack of available transcriptomic resources for this species related to its response to water deficiency. To investigate the mechanisms that allow P. mongolica to maintain growth in extremely arid environments, the response of P. mongolica seedlings to drought stress was analyzed using morphological, physiological, biochemical and high-throughput sequencing approaches. We generated 28,713,735 and 26,650,133 raw reads from no-stress control and drought-stressed P. mongolica seedlings, respectively. In total, we obtained 67,352 transcripts with an average length of 874.44 bp. Compared with the no-stress control, 3,365 transcripts were differentially expressed in the drought-stressed seedlings, including 55.75% (1,876 transcripts) up-regulated and 44.25% (1,489 transcripts) down-regulated transcripts. The photosynthesis response showed a decreasing tendency under drought stress, but the changes in the levels of hormones (auxins, cytokinins and abscisic acid) resulted in the closing of stomata and decreased cell enlargement and division; these changes were effective for promoting P. mongolica survival in Gobi Desert. Next, we analyzed the aquaporin and superoxide dismutase gene families due to their importance in plant resistance to drought stress. We found that all of the plasma membrane intrinsic protein transcripts were down-regulated in the drought-stressed treatment, whereas drought did not affect the expression of nodulin intrinsic protein or small basic intrinsic protein transcripts in P. mongolica seedlings. In addition, activation of iron superoxide dismutase transcription and enhanced transcription of manganese superoxide dismutase were observed in P. mongolica to promote tolerance of drought stress. This study identified drought response genes in P. mongolica seedlings. Our results provide a significant contribution to the

  16. Spatio-temporal and interspecific variation in otolith trace-elemental fingerprints in a temperate estuarine fish assemblage

    NASA Astrophysics Data System (ADS)

    Swearer, Stephen E.; Forrester, Graham E.; Steele, Mark A.; Brooks, Andrew J.; Lea, David W.

    2003-04-01

    We tested whether estuarine fishes have site-specific differences in the concentrations of trace elements in their otoliths that can be used as 'fingerprints' to identify them to their estuary of origin. To evaluate the robustness of this approach, we tested whether elemental fingerprints were consistent among individuals of five species that were collected in 1996 from three temperate estuaries in southern California. We also tested whether elemental fingerprints were consistent between spring and autumn 1996 for three species in one of the sites, Carpinteria Marsh. The species evaluated comprised a mid-water-dwelling smelt ( Atherinops affinis), two benthic gobies ( Clevelandia ios and Ilypnus gilberti), and two flatfish ( Paralichthys californicus and Hypsopsetta guttulata). The concentrations of six elements (Mn, Cu, Zn, Sr, Ba, and Pb) were determined in the otoliths using inductively coupled plasma-mass spectrometry (ICP-MS). Within estuaries, the five species exhibited strong variation in elemental concentration, indicating substantial interspecific differences in otolith environmental history. When the five fish species were considered separately, multivariate (MANOVA) and univariate (ANOVA) analyses of variance indicated that the elemental composition of otoliths differed significantly among the estuaries in four of the five species. Based on linear discriminant function analyses (DFA), differences were strong enough that trace element composition could be used to accurately assign fish to their site of origin [mean (range): 93.5% (74-100%)]. However, elemental signatures within Carpinteria Marsh were not consistent between spring and autumn 1996, and this was reflected in a substantial reduction in the accuracy of assigning fish to their true site of origin. When we compared site differences between fish species (site×species interactions), the elemental fingerprints were most similar between closely related species (e.g. the two gobies and the two

  17. Atmospheric circulation patterns and geochemistry time series from ice/firn cores and snow samples of central Asian glaciers (Pamir, Tien Shan and Altai).

    NASA Astrophysics Data System (ADS)

    Aizen, E. M.; Aizen, V. B.; Joswiak, D. R.; Mayewski, P. A.

    2008-12-01

    Combination of high mountain ice-core isotope-geochemistry, ground based aerosol monitoring, NASA remote sensed and a NOAA atmospheric pressure distribution data were used to receive information on sources of dust/loess transport, their time and spatial extension in modern and pre-industrial time. Hundreds of samples from snow pits and ice/firn cores obtained from central Asian glaciers were collected, processed and analyzed. The NASA RS products address the gap in interpretation of available snow, firn and ice records by providing the spatial resolution necessary for identifying possible local and regional-scale dust sources, transport routes and depositions. NOAA Hypslit program modeled the air back-trajectories allowed to found association between the ice core geochemistry records and aerosol sources. To find the circulation patterns, which are closely associated with geochemistry ice core/snow pit records, the correlation coefficients between the Empirical Orthogonal Functions of the atmospheric circulation patterns and geochemistry time coefficients for first two unrotated scores were computed. The loess / dust storm sources with corresponding geo-chemical composition (trace elements, major ions and dust particles) in western, central and northern Asia were identified: 1. Tajik loess deposition and Iran, Afghanistan /Turkmenistan sands are for the Pamir. For example, the Pamir ice core records that associated with Tajikistan loess deposition are characterized by high concentrations of REEs and Al, high or median content of Ca, and a background S concentration. Samples from the Pamir Mountains differed in having low concentrations of Gadolinium. Occasional intrusions of Chinese loess to Pamir glaciers are not excluded. REE profile of pilot Pamir cores documented one of the most extreme droughts of 2001 and 2002 that developed in south-west Asia. 2. Chinese loess deposition in the Takla Makhan, sands in the Tajikistan Deserts and western Gobi, and dust aerosols

  18. Mantle plume related Paleozoic riftogenic alkaline magmatism of Mongolia: isotope and geocemical evidence.

    NASA Astrophysics Data System (ADS)

    Yarmolyuk, V.; Savatenkov, V.; Kozlovsky, A.

    2003-04-01

    Paleozoic alkaline magmatic activity in Mongolia associates with series of W-E trending rifts, ranged from south to north. The rifts system was evolved northward at three stages beginning from later Carboniferous-earlier Permian to later Permian. The isotopic-geochemical composition of the rocks from five volcano-plutonic bimodal complexes was studied. These complexes belong to the Gobi-Tien Shan Zone (GTZ) 310-290 Ma and the Gobi-Altai Zone (GAZ) 270 Ma of riftogenic alkaline magmatism. The studied volcano-plutonic complexes are formed by mafic rocks alkaline basalts and felsic rocks alkaline riolites (comendite and pantelerite) with subordinate rocks of intermedial composition (trachidacites, trachiandesites) and associated plutons of alkaline granites. Basaltic rocks of GTZ are characterized by positive eNd(T) values (+4.2 +7.0), 87Sr/86Sr(T) value ranged from 0.7036 to 0.7049, enrichment in Th, LREE, Sr, P, Zr, Hf, Ti and pronounced depletion in Nb and Ta. GTZ felsic rocks have general enrichment in most incompatible trace element (K, Rb, Th, Zr, Hf and REE) and depletion in Nb, Ta, Sr, P, Eu and Ti. The range of eNd(T) of alkaline riolites demonstrates general shift to more positive values (+5.8 +7.3) comparatively to that of basalts. Generally rocks of GAZ and GTZ volcano-plutonic complexes have similar geochemical features. However the GAZ alkaline riolites have more differentiated character (higher silica content, more strong depletion in Ti, Sr and Eu, enrichment in Rb and REE). Furthermore eNd(T) and 87Sr/86Sr(T) values of GAZ basalts demonstrate more wide scatter from +0.2 to +8.1 and from 0.7037 to 0.7054 respectively. Geochemical trends in the trace elements (REE, Y, Th, Nb, Ta) and in Sr-Nd isotope composition suggest that basaltic rocks were derived from OIB-like mantle sourse and underwent contamination during of fraction crystallization by material of subduced oceanic crust (Neoproterozoic ?). Felsic rocks were generated from OIB-like basaltic melt

  19. Mongolian Hangay Uplift Recorded in Vesicular Basalts

    NASA Astrophysics Data System (ADS)

    Sahagian, D. L.; Proussevitch, A. A.; Ancuta, L. D.; Idleman, B. D.; Zeitler, P. K.

    2014-12-01

    Epeirogenic histories of highland areas have confounded geophysicists for decades, as there are few records of paleoelevation in eroding highlands. However, preserved basaltic lava flows record paleoelevation in the size distributions of vesicles at the tops and bottoms of flow units. Although the bubbles have identical mass distributions at top and base, they are subject to different total pressures (sizes) due to differences in overburden. Two factors control the size of bubbles at the base of the flow: atmospheric pressure and lava weight. Thus, the atmospheric pressure-dependence of vesicle size can be expressed by the ratio of vesicle size modes at the top and bottom of a flow. The atmosphere's paleopressure can thus be determined and a paleoelevation can then be calculated. Knowing the elevation at which the rock formed, its age, and its present elevation, the amount of uplift or subsidence can be determined, providing a history of tectonic uplift or subsidence of the locality. The total error bounds of the method are estimated to be ±400 m, which is sufficient only for major epeirogenic trends, such as that seen previously on the Colorado Plateau, and now in Mongolia. The mechanisms that led to the high elevations of the Hangay Plateau in central Mongolia are not clear. As part of a broader collaborative project to better understand the tectonics of this part of Asia, we collected samples from several flows from throughout the Hangay Plateau. Results suggest that the Hangay Plateau experienced uplift of over 1 km in the last 10 Ma., corresponding to an average uplift rate of about 140 m/Ma (see graph below, with intercept within error bounds of 0,0). A flow sampled from the adjacent northern Gobi Desert indicates a paleoelevation of only a few hundred meters (no significant recent uplift), suggesting that the Gobi has experienced a different recent tectonic history from the Hangay Plateau. The uplift history of the Hangay, in addition to the composition of

  20. Mongolian Almond (Prunus mongolica Maxim): The Morpho-Physiological, Biochemical and Transcriptomic Response to Drought Stress

    PubMed Central

    Bai, Shulan; Gao, Xiaomin; Liu, Min; Yan, Wei

    2015-01-01

    Prunus mongolica Maxim, which is widely established in the Gobi Desert, shows extreme tolerance to drought. However, there is a lack of available transcriptomic resources for this species related to its response to water deficiency. To investigate the mechanisms that allow P. mongolica to maintain growth in extremely arid environments, the response of P. mongolica seedlings to drought stress was analyzed using morphological, physiological, biochemical and high-throughput sequencing approaches. We generated 28,713,735 and 26,650,133 raw reads from no-stress control and drought-stressed P. mongolica seedlings, respectively. In total, we obtained 67,352 transcripts with an average length of 874.44 bp. Compared with the no-stress control, 3,365 transcripts were differentially expressed in the drought-stressed seedlings, including 55.75% (1,876 transcripts) up-regulated and 44.25% (1,489 transcripts) down-regulated transcripts. The photosynthesis response showed a decreasing tendency under drought stress, but the changes in the levels of hormones (auxins, cytokinins and abscisic acid) resulted in the closing of stomata and decreased cell enlargement and division; these changes were effective for promoting P. mongolica survival in Gobi Desert. Next, we analyzed the aquaporin and superoxide dismutase gene families due to their importance in plant resistance to drought stress. We found that all of the plasma membrane intrinsic protein transcripts were down-regulated in the drought-stressed treatment, whereas drought did not affect the expression of nodulin intrinsic protein or small basic intrinsic protein transcripts in P. mongolica seedlings. In addition, activation of iron superoxide dismutase transcription and enhanced transcription of manganese superoxide dismutase were observed in P. mongolica to promote tolerance of drought stress. This study identified drought response genes in P. mongolica seedlings. Our results provide a significant contribution to the

  1. Basaltic Martian analogues from the Baikal Rift Zone and Mongolian terranes

    NASA Astrophysics Data System (ADS)

    Gurgurewicz, J.; Kostylew, J.

    2007-08-01

    In order to compare the results of studies of the western part of the Valles Marineris canyon on Mars there have been done field works on terrestrial surface areas similar with regard to geological setting and environmental conditions. One of the possible terrestrial analogues of the Valles Marineris canyon is the Baikal Rift Zone [1]. Field investigations have been done on the south end of the Baikal Lake, in the Khamar-Daban massif, where the outcrops of volcanic rocks occur. The second part of the field works has been done in the Mongolian terranes: Mandalovoo, Gobi Altay and Bayanhongor, because of environmental conditions being similar to those on Mars. The Mandalovoo terrane comprises a nearly continuous Paleozoic islandarc sequence [2]. In the Gobi Altay terrane an older sequence is capped by younger Devonian-Triassic volcanic-sedimentary deposits [2]. The Bayanhongor terrane forms a northwest-trending, discontinuous, narrow belt that consists of a large ophiolite allochton [3]. The collected samples of basalts derive from various geologic environments. The CORONA satellite-images have been used for the imaging of the Khamar-Daban massif and the Mandalovoo terrane. These images have the same spatial resolution and range as the Mars Orbiter Camera images of the Mars Global Surveyor mission. In the Mandalovoo terrane these images allowed to find an area with large amounts of tectonic structures, mainly faults (part of the Ongi massif), similar to the studied area on Mars. Microscopic observations in thin sections show diversification of composition and structures of basalts. These rocks have mostly a porphyric structure, rarely aphyric. The main components are plagioclases, pyroxenes and olivines phenocrysts, in different proportions. The groundmass usually consist of plagioclases, pyroxenes and opaques. The most diversified are basalts from the Mandalovoo terrane. Infrared spectroscopy has been used to analyse the composition of the rock material and compare

  2. Diurnal and Seasonal Variations in Carbon Dioxide Exchange in Ecosystems in the Zhangye Oasis Area, Northwest China

    PubMed Central

    Zhang, Lei; Sun, Rui; Xu, Ziwei; Qiao, Chen; Jiang, Guoqing

    2015-01-01

    Quantifying carbon dioxide exchange and understanding the response of key environmental factors in various ecosystems are critical to understanding regional carbon budgets and ecosystem behaviors. For this study, CO2 fluxes were measured in a variety of ecosystems with an eddy covariance observation matrix between June 2012 and September 2012 in the Zhangye oasis area of Northwest China. The results show distinct diurnal variations in the CO2 fluxes in vegetable field, orchard, wetland, and maize cropland. Diurnal variations of CO2 fluxes were not obvious, and their values approached zero in the sandy desert, desert steppe, and Gobi ecosystems. Additionally, daily variations in the Gross Primary Production (GPP), Ecosystem Respiration (Reco) and Net Ecosystem Exchange (NEE) were not obvious in the sandy desert, desert steppe, and Gobi ecosystems. In contrast, the distributions of the GPP, Reco, and NEE show significant daily variations, that are closely related to the development of vegetation in the maize, wetland, orchard, and vegetable field ecosystems. All of the ecosystems are characterized by their carbon absorption during the observation period. The ability to absorb CO2 differed significantly among the tested ecosystems. We also used the Michaelis-Menten equation and exponential curve fitting methods to analyze the impact of Photosynthetically Active Radiation (PAR) on the daytime CO2 flux and impact of air temperature on Reco at night. The results show that PAR is the dominant factor in controlling photosynthesis with limited solar radiation, and daytime CO2 assimilation increases rapidly with PAR. Additionally, the carbon assimilation rate was found to increase slowly with high solar radiation. The light response parameters changed with each growth stage for all of the vegetation types, and higher light response values were observed during months or stages when the plants grew quickly. Light saturation points are different for different species. Nighttime

  3. Phylogeny and tempo of diversification in the superradiation of spiny-rayed fishes

    PubMed Central

    Near, Thomas J.; Dornburg, Alex; Eytan, Ron I.; Keck, Benjamin P.; Smith, W. Leo; Kuhn, Kristen L.; Moore, Jon A.; Price, Samantha A.; Burbrink, Frank T.; Friedman, Matt; Wainwright, Peter C.

    2013-01-01

    Spiny-rayed fishes, or acanthomorphs, comprise nearly one-third of all living vertebrates. Despite their dominant role in aquatic ecosystems, the evolutionary history and tempo of acanthomorph diversification is poorly understood. We investigate the pattern of lineage diversification in acanthomorphs by using a well-resolved time-calibrated phylogeny inferred from a nuclear gene supermatrix that includes 520 acanthomorph species and 37 fossil age constraints. This phylogeny provides resolution for what has been classically referred to as the “bush at the top” of the teleost tree, and indicates acanthomorphs originated in the Early Cretaceous. Paleontological evidence suggests acanthomorphs exhibit a pulse of morphological diversification following the end Cretaceous mass extinction; however, the role of this event on the accumulation of living acanthomorph diversity remains unclear. Lineage diversification rates through time exhibit no shifts associated with the end Cretaceous mass extinction, but there is a global decrease in lineage diversification rates 50 Ma that occurs during a period when morphological disparity among fossil acanthomorphs increases sharply. Analysis of clade-specific shifts in diversification rates reveal that the hyperdiversity of living acanthomorphs is highlighted by several rapidly radiating lineages including tunas, gobies, blennies, snailfishes, and Afro-American cichlids. These lineages with high diversification rates are not associated with a single habitat type, such as coral reefs, indicating there is no single explanation for the success of acanthomorphs, as exceptional bouts of diversification have occurred across a wide array of marine and freshwater habitats. PMID:23858462

  4. Seasonal changes in community composition and trophic structure of fish populations of five salt marshes along the Essex coastline, United Kingdom

    NASA Astrophysics Data System (ADS)

    Green, Benjamin C.; Smith, David J.; Earley, Sarah E.; Hepburn, Leanne J.; Underwood, Graham J. C.

    2009-11-01

    European intertidal salt marshes are important nursery sites for juvenile fish and crustaceans. Due to the increasing threat of habitat loss, the seasonal changes of salt marsh fish communities need to be understood in order to appreciate the ecological and economic importance of the saltmarsh habitat. This study was the first in Great Britain to investigate the seasonal changes of salt marsh fish communities and the variation in community structure between closely located marsh habitats. Between February 2007 and March 2008, five marshes on three estuaries of the Essex coastline were sampled using flume nets to block off intertidal creeks at high tide. Fourteen fish species were caught. The community overall was dominated by three species that made up 91.6% of the total catch: the common goby Pomatoschistus microps (46.2% of the total catch), juvenile herring Clupea harengus (24.3%), and juvenile and larval sea bass Dicentrarchus labrax (21.2%). Cluster analysis demonstrated clear seasonal patterns, with some community structures unique to specific marshes or estuaries. The marsh fish community shifts from a highly diverse community during spring, to a community dominated by D. labrax and P. microps in autumn, and low diversity during winter months. Gravimetric stomach content analysis of fish community identified three main trophic guilds; macroinvertivores, planktivores and omnivores. The macroinvertivore feeding guild contained D. labrax and P. microps, the two most frequently occurring species. This investigation demonstrates the importance of British salt marshes as nursery habitats for commercial fish species.

  5. Nursery function of an estuarine tidal marsh for the brown shrimp Crangon crangon

    NASA Astrophysics Data System (ADS)

    Cattrijsse, André; Dankwa, Hederick R.; Mees, Jan

    1997-12-01

    The brown shrimp Crangon crangon migrates into the brackish part of the Westerschelde estuary (southwest Netherlands) shortly after metamorphosis and uses the tidal marsh habitat as a nursery until reaching a total length of about 15 mm. The importance of the marsh as a nursery was evaluated by estimating foraging activity, predation mortality and residence time. In early postlarval stages, C. crangon utilised the intertidal creeks of an estuarine tidal marsh from early spring (March-April) until late autumn (October-November). Postlarval shrimp leaving the marsh with the ebb tide always had significantly more food in their stomachs than shrimp entering the marsh with the incoming flood water. Predation upon the shrimp population was relatively low during most months, but in increased between August and October when common gobies, Pomatoschistus microps, were present in high densities. There was also predation by the small seabass Dicentrarchus labrax. The marsh creeks function both as foraging areas and as predation refuge. Depending on temperature, postlarval shrimp stayed in the marsh for a period of two to three weeks. Quantitatively, the value of the marsh as a nursery area had changed drastically during a second year of sampling, illustrating high natural year-to-year variability. However, the seasonal pattern remained. Recruitment to the subtidal adult population represents an export of animals from the marsh to the estuary. This export is negligible in terms of biomass (as compared to the total biomass of the estuarine population) but it may be important in terms of numbers of individuals.

  6. Depth distribution and abundance of a coral-associated reef fish: roles of recruitment and post-recruitment processes

    NASA Astrophysics Data System (ADS)

    Smallhorn-West, Patrick F.; Bridge, Tom C. L.; Munday, Philip L.; Jones, Geoffrey P.

    2017-03-01

    The abundance of many reef fish species varies with depth, but the demographic processes influencing this pattern remain unclear. Furthermore, while the distribution of highly specialized reef fish often closely matches that of their habitat, it is unclear whether changes in distribution patterns over depth are the result of changes in habitat availability or independent depth-related changes in population parameters such as recruitment and mortality. Here, we show that depth-related patterns in the distribution of the coral-associated goby, Paragobiodon xanthosoma, are strongly related to changes in recruitment and performance (growth and survival). Depth-stratified surveys showed that while the coral host, Seriatopora hystrix, extended into deeper water (>20 m), habitat use by P. xanthosoma declined with depth and both adult and juvenile P. xanthosoma were absent below 20 m. Standardization of S. hystrix abundance at three depths (5, 15 and 30 m) demonstrated that recruitment of P. xanthosoma was not determined by the availability of its habitat. Reciprocal transplantation of P. xanthosoma to S. hystrix colonies among three depths (5, 15 and 30 m) then established that individual performance (survival and growth) was lowest in deeper water; mortality was three times higher and growth greatly reduced in individuals transplanted to 30 m. Individuals collected from 15 m also exhibited growth rates 50% lower than fish from shallow depths. These results indicate that the depth distribution of this species is limited not by the availability of its coral habitat, but by demographic costs associated with living in deeper water.

  7. Biomass of deepwater demersal forage fishes in Lake Huron, 1994-2007: Implications for offshore predators

    USGS Publications Warehouse

    Roseman, E.F.; Riley, S.C.

    2009-01-01

    We estimated the biomass of deepwater demersal forage fishes (those species common in the diets of lake trout and Chinook salmon) in Lake Huron during the period 1994-2007. The estimated total lake-wide biomass of deepwater demersal fishes in 2007 was reduced by 87 percent of that observed in 1994. Alewife biomass remained near the record low observed in 2004. Biomass of young-of-the-year rainbow smelt was at a record high in 2005, but little recruitment appears to have occurred in 2006 or 2007. Record-high estimates of young-of-the-year bloater biomass were observed in 2005 and 2007, and an increase in the biomass of adult bloater in 2007 suggests that some recruitment may be occurring. The biomass of other potential deepwater demersal forage fish species (sculpins, ninespine stickleback, trout-perch and round goby) has also declined since 1994 and remained low in 2007. The forage fish community in 2007 was dominated by small (< 120 mm) bloater and rainbow smelt. These results suggest that lake trout and Chinook salmon in Lake Huron may face nutritional stress in the immediate future.

  8. Trophic transfer of metals along freshwater food webs: Evidence of cadmium biomagnification in nature

    USGS Publications Warehouse

    Croteau, M.-N.; Luoma, S.N.; Stewart, A.R.

    2005-01-01

    We conducted a study with cadmium (Cd) and copper (Cu) in the delta of San Francisco Bay, using nitrogen and carbon stable isotopes to identify trophic position and food web structure. Cadmium is progressively enriched among trophic levels in discrete epiphyte-based food webs composed of macrophyte-dwelling invertebrates (the first link being epiphytic algae) and fishes (the first link being gobies). Cadmium concentrations were biomagnified 15 times within the scope of two trophic links in both food webs. Trophic enrichment in invertebrates was twice that of fishes. No tendency toward trophic-level enrichment was observed for Cu, regardless of whether organisms were sorted by food web or treated on a taxonomic basis within discrete food webs. The greatest toxic effects of Cd are likely to occur with increasing trophic positions, where animals are ingesting Cd-rich prey (or food). In Franks Tract this occurs within discrete food chains composed of macrophyte-dwelling invertebrates or fishes inhabiting submerged aquatic vegetation. Unraveling ecosystem complexity is necessary before species most exposed and at risk can be identified. ?? 2005, by the American Society of Limnology and Oceanography, Inc.

  9. Epibenthic colonization of concrete and steel pilings in a cold-temperate embayment: a field experiment

    NASA Astrophysics Data System (ADS)

    Andersson, Mathias H.; Berggren, Matz; Wilhelmsson, Dan; Öhman, Marcus C.

    2009-09-01

    With large-scale development of offshore wind farms, vertical structures are becoming more common in open water areas. To examine how vertical structures of different materials may be colonized by epibenthic organisms, an experiment was carried out using steel and concrete pilings constructed to resemble those commonly used in wind farm constructions as well as in bridges, jetties and oil platforms. The early recruitment and succession of the epibenthic communities were sampled once a month for the first 5 months and then again after 1 year. Further, the fish assemblages associated with the pillars were sampled and compared to natural areas. The main epibenthic species groups, in terms of coverage, differed between the two materials at five out of six sampling occasions. Dominant organisms on steel pillars were the barnacle Balanus improvisus, the calcareous tubeworm Pomatoceros triqueter and the tunicate Ciona intestinalis. On the concrete pillars, the hydroid Laomedea sp. and the tunicates Corella parallelogramma and Ascidiella spp. dominated. However, there was no different in coverage at different heights on the pillars or in biomass and species abundance at different directions (north-east or south-west) 5 months after submergence. Fish showed overall higher abundances and species numbers on the pillars (but no difference between steel and concrete) compared to the surrounding soft bottom habitats but not compared to natural vertical rock walls. Two species were attracted to the pillars, indicating a reef effect; Gobiusculus flavescens and Ctenolabrus rupestris. The bottom-dwelling gobies, Pomatoschistus spp., did not show such preferences.

  10. Zonation and spatial distribution of littoral fish communities from the southwestern Finnish coast (Archipelago and Bothnian Sea, Northern Baltic Sea)

    NASA Astrophysics Data System (ADS)

    Vahteri, Petri; O'Brien, Kevin; Vuorinen, Ilppo

    2009-03-01

    The aim of our study was to test whether the distribution of littoral fish assemblages would reflect both their immediate environment with reference to local underwater vegetation, including larger scale geographic archipelagial zonation. A total of 62 locations were sampled using beach seine and underwater video along the southwestern Finnish coastline in summer 2001. At all locations, water temperature, water transparency and benthic vegetation patterns (depth ranges of plant species or taxa) were recorded. Using correspondence analysis, our results showed a clear division of the Archipelago Sea into three separate zones based on littoral fish species assemblages. Overall, fish assemblages formed three distinct site groups, being dominated by pike and cyprinids, by percids and gobies, or by gasterosteids, and showed clear inner, middle and outer archipelago zones respectively, within the study area. Our results suggest that while vegetation in the study sites was diverse, it failed to express the zonation reflected by the littoral fish assemblages, which showed a definite zonation pattern which broadly reflected previous reports using both physical and biological parameters. We interpret our results to show that littoral vegetation is better in expressing small-scale differences between study sites, while littoral fish communities are more robust in detecting changes over a larger geographical scale.

  11. Small-sized euryhaline fish as intermediate hosts of the digenetic trematode Cryptocotyle concavum

    NASA Astrophysics Data System (ADS)

    Zander, C. D.; Kollra, H.-G.; Antholz, B.; Meyer, W.; Westphal, D.

    1984-03-01

    Cercariae of the trematode Cryptocotyle concavum, which encyst in skin and/or kidney of sticklebacks and gobies, were studied in the Schlei Fjord (western Baltic Sea). Mean incidence of dermal cysts was 48 % in Gasterosteus aculeatus and 37 % in Pungitius pungitius. No cysts were found in the kidneys of sticklebacks. While 97 % of Pomatoschistus microps had encysted metacercariae in the kidneys, only 2 % had cysts in the skin. Pomatoschistus minutus, however, showed hardly any cyst infestation of either skin or kidney. In P. microps the intensity of infestation by metacercariae was frequently more than 50 cysts; in contrast, sticklebacks rarely exhibited more than 5 dermal cysts. Infested fish were larger than 10 mm in total length, the incidence rate increasing with growth. Parasitic infestation depends on ambient salinity: C. concavum was not found at salinities below 4 ‰. In contrast to the high incidence in fish, the first hosts — the snails Hydrobia stagnalis and H. neglecta — showed remarkably low infection rates (3 to 5 %). The findings reported are related to the distribution of C. concavum, the mode of life of infested fish, the feeding habits of the final hosts and the infestation of P. microps by other parasites. Evidently, P. microps represents an optimal second host for C. concavum.

  12. Clay-sized Hf-Nd-Sr isotopic composition of Mongolian dust as a fingerprint for regional to hemispherical transport

    NASA Astrophysics Data System (ADS)

    Zhao, Wancang; Sun, Youbin; Balsam, William; Zeng, Lin; Lu, Huayu; Otgonbayar, Khureldavaa; Ji, Junfeng

    2015-07-01

    Hf-Nd-Sr isotopic fingerprinting has been employed as a powerful method for distinguishing dust sources. However, the Hf and Sr isotopic compositions of dust are highly dependent on particle size to accurately identify dust provenance. Here we compare the Hf-Nd-Sr isotopic compositions of clay-sized fractions from dust sources (the Mongolian Plateau) to sinks (Beijing and Greenland). Our results document that clay-sized Hf-Nd-Sr isotopic compositions of Mongolian dust are controlled by two isotopic/geochemical provinces: Southern Mongolian Gobi (SMG) and Northern Mongolian Plateau (NMP). Our data indicate that the SMG is potentially an important dust source to the loess in Beijing and Hulun Buir and could be a contributing source of dust to Greenland, whereas the NMP contributes little dust to the Chinese loess and the Greenland. Furthermore, we demonstrate that the deserts of northwest China are one of the main dust contributors to Beijing and Greenland, but not to Hulun Buir.

  13. Snow and Dust over Inner Mongolia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A severe snow-and-sand storm hit an 80,000 square-mile (205,000-square-km) stretch of the Chinese province of Mongolia on New Year's Eve, killing 21 people and leaving thousands of people to face possible starvation. The affected area is located about 250 miles (400 km) northwest of Beijing. It is the worst snowstorm to hit the region in more than 50 years. Lasting about 3 days, the storm dumped 24 inches (60 cm) of snow mixed with sand from the Gobi Desert, stranding many residents in deep drifts. The Chinese Red Cross reports that almost 1 million people were affected by the storm and at least 10,000 head of livestock are confirmed dead. As many as 120,000 residents are in need of food and other supplies. The Sea-viewing Wide Field-of-view Sensor (SeaWiFS), flying aboard the OrbView-2 satellite, acquired this image of the storm on January 2, 2001, as it approached China's eastern provinces. You can see storm clouds (white pixels) and windblown dust (brownish pixels) crossing the Yellow Sea and East China Sea toward Japan and the western Pacific. Provided by the SeaWiFS Project, NASA/Goddard Space Flight Center, and ORBIMAGE

  14. Solar spectral irradiance and atmospheric transmission at Mauna Loa Observatory

    SciTech Connect

    Shaw, G.E.

    1982-06-01

    A radiometer was operated at the Mauna Loa Observatory during calendar year 1980 to estimate the spectral irradiance of the sun and its possible fluctuation in time near the peak of solar activity. Data were also acquired on seasonal trends of atmospheric transmissivity above the marine mixing layer in the central Pacific. Spectral irradiance remained c constant to at least 1/2% at all wavelengths monitored. Furthermore its absolute magnitude was in agreement with the Labs and Neckel values to +- 2% except at blue wavelengths where the Mauna Loa values are from 4 to 12% higher and at lambda = 850 nm where the Mauna Loa value is 9% lower. The residual aerosol optical depth above Mauna Loa Observatory during 1980 averaged tau/sub 0/ = 0.020. An intrusion of dust into the central Pacific from the Gobi Desert (as deduced by the composition of collected particles) invaded the Central Pacific from Mar. to May 19890 and caused a perturbation in optical depth (at lambda = 500 nm) of ..delta..tau/sub 0/approx.0.01--0.02. The optical depth increment caused by the Mt. St. Helens volcano was <0.005 in the 2-month period following the eruption.

  15. Solar spectral irradiance and atmospheric transmission at Mauna Loa Observatory.

    PubMed

    Shaw, G E

    1982-06-01

    A radiometer was operated at the Mauna Loa Observatory during calendar year 1980 to estimate the spectral irradiance of the sun and its possible fluctuation in time near the peak of solar activity. Data were also acquired on seasonal trends of atmospheric transmissivity above the marine mixing layer in the central Pacific. Spectral irradiance remained constant to at least (1/2)% at all wavelengths monitored. Furthermore its absolute magnitude was in agreement with the Labs and Neckel values to +/-2% except at blue wavelengths where the Mauna Loa values are from 4 to 12% higher and at lambda = 850 nm where the Mauna Loa value is 9% lower. The residual aerosol optical depth above Mauna Loa Observatory during 1980 averaged tau(0) = 0.020. An intrusion of dust into the central Pacific from the Gobi Desert (as deduced by the composition of collected particles) invaded the Central Pacific from Mar. to May 1980 and caused a perturbation in optical depth (at lambda = 500 nm) of Deltatau(0) ~ 0.01-0.02. The optical depth increment caused by the Mt. St. Helens volcano was <0.005 in the 2-month period following the eruption.

  16. Tidal, diel and semi-lunar changes in the faunal assemblage of an intertidal salt marsh creek

    NASA Astrophysics Data System (ADS)

    Hampel, Henrietta; Cattrijsse, Andre; Vincx, Magda

    2003-03-01

    The utilisation of a brackish estuarine marsh by nekton was investigated over a semi-lunar cycle in August 1994. Nekton migrating in and out of the intertidal creeks of the marsh 'Het Verdronken Land van Saeftinghe' in the Westerschelde estuary, SW Netherlands, was sampled passively during seven complete tidal cycles. Sampling one tidal cycle yielded three consecutive flood samples and four consecutive ebb samples. Sampling occurred every 2-3 days, covering diel, tidal and semi-lunar situations, thus allowing comparison of tidal, diel and semi-lunar influences on the composition of the intertidal fauna. Two different tidal-migration modes were observed. The mysid shrimp, Mesopodopsis slabberi, showed maximum abundance around high tide. For the remaining common species, the mysid ( Neomysis integer), the shrimp ( Palaemonetes varians), the crab ( Carcinus maenas) and the goby ( Pomatoschistus microps) and the amphipod ( Corophium volutator), highest densities were recorded during lower water heights. The faunal assemblage shifts between the different tidal stages. On two occasions, consecutive day and night samples were taken. Total densities were higher during the night samples. During spring tide, difference in community composition was noticed between the night and the day samples. During neap tide, day-night differences were less clear. Recorded total densities were highest during spring tide and lowest during neap tide. At maximum water levels, a drop in total density was observed. A shift in community composition occurred between spring and neap tides.

  17. Seasonal Variation of the Macrozoobenthic Community Structure at Low Salinities in a Mediterranean Lagoon (Monolimni Lagoon, Northern Aegean)

    NASA Astrophysics Data System (ADS)

    Kevrekidis, Theodoros

    2004-09-01

    The macrozoobenthic community structure and dynamics at low salinities (0.3-6 psu) in a Mediterranean lagoon (Monolimni lagoon) were investigated. Samples were collected monthly from February 1998 to February 1999 at two sampling stations. Community structure was analyzed by means of uni- and multivariate methods. 21 taxa were collected; the amphipod Corophium orientale and the gastropod Ventrosia maritima dominated the assemblages. Total abundance peaked (50,000-60,000 individuals m-2) in mid or late autumn. Community structure showed an almost even seasonal periodicity; seasonal changes were mainly derived from the intense variation in abundance of most species and the non-occurrence of a few ones (e.g. Corophium insidiosum, Polydora ciliata) in spring and summer. Non- occurrence, which led to a depression of the most diversity indices, was possibly the only direct impact of the extremely low salinities (~0.3 psu) on community structure. The main structuring factors of the community in the deeper outer part of the lagoon were water temperature and depth, and in the innermost part, where a Ruppia maritima meadow occurred, were water temperature and predation pressure by crabs (Carcinus aestuarii) and gobies (Knipowitchia caucasica). A temporary decline in total abundance in summer followed an increase in abundance of these predators. (

  18. Muscle fiber type distribution in climbing Hawaiian gobioid fishes: ontogeny and correlations with locomotor performance.

    PubMed

    Cediel, Roberto A; Blob, Richard W; Schrank, Gordon D; Plourde, Robert C; Schoenfuss, Heiko L

    2008-01-01

    Three species of Hawaiian amphidromous gobioid fishes are remarkable in their ability to climb waterfalls up to several hundred meters tall. Juvenile Lentipes concolor and Awaous guamensis climb using rapid bursts of axial undulation, whereas juvenile Sicyopterus stimpsoni climb using much slower movements, alternately attaching oral and pelvic sucking disks to the substrate during prolonged bouts of several cycles. Based on these differing climbing styles, we hypothesized that propulsive musculature in juvenile L. concolor and A. guamensis would be dominated by white muscle fibers, whereas S. stimpsoni would exhibit a greater proportion of red muscle fibers than other climbing species. We further predicted that, because adults of these species shift from climbing to burst swimming as their main locomotor behavior, muscle from adult fish of all three species would be dominated by white fibers. To test these hypotheses, we used ATPase assays to evaluate muscle fiber type distribution in Hawaiian climbing gobies for three anatomical regions (midbody, anal, and tail). Axial musculature was dominated by white muscle fibers in juveniles of all three species, but juvenile S. stimpsoni had a significantly greater proportion of red fibers than the other two species. Fiber type proportions of adult fishes did not differ significantly from those of juveniles. Thus, muscle fiber type proportions in juveniles appear to help accommodate differences in locomotor demands among these species, indicating that they overcome the common challenge of waterfall climbing through both diverse behaviors and physiological specializations.

  19. Influence of salinity, competition and food supply on the growth of Gobiosoma robustum and Microgobius gulosus from Florida Bay, U. S. A.

    USGS Publications Warehouse

    Schofield, P.J.

    2004-01-01

    The code Gobiosoma robustum and clown Microgobius gulosus gobies were grown in the laboratory over 27 days at two salinities (5 and 35), two food levels [low (a fixed proportion of initial mass) and high (saturation)] and both with and without the presence of the other species. Both species exhibited greatest growth at the high food level and the low (5) salinity. Neither species was affected by the presence of the other species, and there were no overall differences in growth between the two species. Thus, the observed competitive superiority of G. robustum over M. gulosus does not seem to confer an advantage relative to feeding success. Furthermore, as growth of G. robustum was greater at the lower salinity, it is clear that some factor other than salinity is restricting this species from north-eastern Florida Bay. Additional work on the importance of predation and food resources in various regions of Florida Bay is needed to further evaluate the underlying mechanisms responsible for the bay-wide distribution of these species. ?? 2004 The Fisheries Society of the British Isles.

  20. Feeding habits of juvenile flatfish in relation to habitat characteristics in the Baltic Sea

    NASA Astrophysics Data System (ADS)

    Florin, Ann-Britt; Lavados, Gaston

    2010-03-01

    To investigate feeding habits of juvenile flounder ( Platichthys flesus) and turbot ( Psetta maxima) in relation to habitat characteristics a field survey with push net sampling was conducted in nursery areas with different ecological characteristics in the northern Baltic proper. Sampling sites were stratified to cover several different habitat types defined by substrate and wave exposure. Apart from flatfishes and epifauna, samples of macrofauna, meiofauna and hyperbenthic planktons were collected from each site together with data on vegetation, depth, salinity, temperature and turbidity. The diet differed between species where flounder diet was dominated by chironomids, copepods and oligochaetes while turbot apart from chironomids had a high incidence of amphipods, gobies and mysids. In both species there was a shift in diet with size, although this shift was influenced by the habitat. Among the environmental variables investigated, wave exposure was found to significantly influence flounder diet. Food preference in the most exposed areas was dominated by oligochaetes and copepods instead of chironomids, which dominated in sheltered areas. This study shows that habitat characteristics can have a major influence on feeding habits of juvenile flatfish.

  1. Preliminary raptor surveys in western Mongolia

    USGS Publications Warehouse

    Ellis, D.H.; Ellis, M.H.; Tsengeg, P.

    1995-01-01

    Raptors were observed on a 5200 km expedition from Ulaan Baatar through the Hangay Mountains to the Russian Altay Mountains with return through the Gobi Altay Mountains. The focus of the expedition was on nesting ecology of the Saker (Falco cherrug) and Altay falcons (F. altaicus) (25 eyries were located), but nests were also found for seven other species including more than 30 nests found of the upland buzzard (Buteo hemilasius). We conducted 21 day-long counts and 10 more formal raptor road counts. Raptors were concentrated in areas where perches were common and where food was most abundant. Western Mongolia remains a vast undeveloped land where camel trains and yak carts are normal. No developed highway network exists. Raptor work in the interior must be supported by four-wheel drive vehicles traveling cross country. Food and fuel for a research team are difficult to procure, but raptor populations are largely unexploited. Raptors frequently nest on the ground or on very low cliffs and tress, and often nest in close proximity of pairs of their own and other species. Several areas of special significance to raptors are discussed including the Taleen Ulaan (Red Steppe) areas of granite dells which we recommend for status as an international reserve.

  2. Iron mobilization in mineral dust: Can anthropogenic SO2 emissions affect ocean productivity?

    NASA Astrophysics Data System (ADS)

    Meskhidze, N.; Chameides, W. L.; Nenes, A.; Chen, G.

    2003-11-01

    For Fe contained in long-range transported aeolian dust to act as a micronutrient for oceanic phytoplankton it must be first dissolved or mobilized. We propose that Fe-mobilization can occur in mineral dust from East Asia by the incorporation of SO2 into the advecting dust plumes and subsequent acidification of the dust through heterogeneous SO2 oxidation. To test this hypothesis, we consider a dust plume that originated from the gobi-deserts and advected over the Pacific Ocean. Data collected over the Yellow Sea confirm that this plume contained high concentrations of dust and SO2. Significant gaseous HNO3 concentrations indicate that the dust particles were acidified (i.e., pH < 2). At these pH's, 1-2% of the Fe contained in a deliquescent mineral dust particle would be mobilized within 3-5 days. These results suggest a possible link between the rate of C-fixation in so-called High-Nitrate-Low-Chlorophyll regions of the Pacific Ocean and SO2 emissions from East Asia.

  3. Agonistic reciprocity is associated with reduced male reproductive success within haremic social networks

    PubMed Central

    Solomon-Lane, Tessa K.; Pradhan, Devaleena S.; Willis, Madelyne C.; Grober, Matthew S.

    2015-01-01

    While individual variation in social behaviour is ubiquitous and causes social groups to differ in structure, how these structural differences affect fitness remains largely unknown. We used social network analysis of replicate bluebanded goby (Lythrypnus dalli) harems to identify the reproductive correlates of social network structure. In stable groups, we quantified agonistic behaviour, reproduction and steroid hormones, which can both affect and respond to social/reproductive cues. We identified distinct, optimal social structures associated with different reproductive measures. Male hatching success (HS) was negatively associated with agonistic reciprocity, a network structure that describes whether subordinates ‘reciprocated’ agonism received from dominants. Egg laying was associated with the individual network positions of the male and dominant female. Thus, males face a trade-off between promoting structures that facilitate egg laying versus HS. Whether this reproductive conflict is avoidable remains to be determined. We also identified different social and/or reproductive roles for 11-ketotestosterone, 17β-oestradiol and cortisol, suggesting that specific neuroendocrine mechanisms may underlie connections between network structure and fitness. This is one of the first investigations of the reproductive and neuroendocrine correlates of social behaviour and network structure in replicate, naturalistic social groups and supports network structure as an important target for natural selection. PMID:26156769

  4. Customizing a rangefinder for community-based wildlife conservation initiatives

    USGS Publications Warehouse

    Ransom, Jason I.

    2011-01-01

    Population size of many threatened and endangered species is relatively unknown because estimating animal abundance in remote parts of the world, without access to aircraft for surveying vast areas, is a scientific challenge with few proposed solutions. One option is to enlist local community members and train them in data collection for large line transect or point count surveys, but financial and sometimes technological constraints prevent access to the necessary equipment and training for accurately quantifying distance measurements. Such measurements are paramount for generating reliable estimates of animal density. This problem was overcome in a survey of Asiatic wild ass (Equus hemionus) in the Great Gobi B Strictly Protected Area, Mongolia, by converting an inexpensive optical sporting rangefinder into a species-specific rangefinder with visual-based categorical labels. Accuracy trials concluded 96.86% of 350 distance measures matched those from a laser rangefinder. This simple customized optic subsequently allowed for a large group of minimally-trained observers to simultaneously record quantitative measures of distance, despite language, education, and skill differences among the diverse group. The large community-based effort actively engaged local residents in species conservation by including them as the foundation for collecting scientific data.

  5. Alterations in the airborne bacterial community during Asian dust events occurring between February and March 2015 in South Korea

    PubMed Central

    Cha, Seho; Lee, Dongwook; Jang, Jun Hyeong; Lim, Sora; Yang, Dahye; Seo, Taegun

    2016-01-01

    During Asian dust events, a relatively high concentration of particulate matter is transported by wind from arid and semi-arid regions, such as the Gobi and Taklamakan deserts, to nearby countries, including China, Korea, and Japan. The dust particles contain various microorganisms, which can affect human health as well as the environmental microbe population. In the current study, we investigated the characteristics of the airborne bacterial community during Asian dust events between February and March 2015 in South Korea. Bacterial diversity indexes such as operational taxonomic units, Chao1 and Inverse Simpson index were increased, along with total 16S rRNA gene copy number during Asian dust events. The bacterial community structure during Asian dust events was clearly distinguishable from that during non-Asian dust days. The genera Bacillus and Modestobacter were increased 3.9- and 2.7-fold, respectively, while Escherichia-Shigella was decreased by 89.8%. A non-metric multidimensional scaling plot with metadata analysis revealed association of particulate matter concentration, but not temperature, humidity or wind speed, with bacterial community structure, suggesting that the newly transported dust particles contain various microorganisms that influence the airborne bacterial environment. PMID:27849049

  6. The right place for the right job in the photovoltaic life cycle.

    PubMed

    Kawajiri, Kotaro; Genchi, Yutaka

    2012-07-03

    The potential for photovoltaic power generation (PV) to reduce primary energy consumption (PEC) and CO(2) emissions depends on the physical locations of each stage of its life cycle. When stages are optimally located, CO(2) emissions are reduced nearly ten times as much as when each stage is located in the country having the largest current market share. The usage stage contributes the most to reducing CO(2) emissions and PEC, and total CO(2) emissions actually increase when PV is installed in countries having small CO(2) emissions from electricity generation. Global maps of CO(2) reduction potential indicate that Botswana and Gobi in Mongolia are the optimal locations to install PV due to favorable conditions for PV power generation and high CO(2) emissions from current electricity generation. However, the small electricity demand in those countries limits the contribution to global CO(2) reduction. The type of PVs has a small but significant effect on life cycle PEC and CO(2) emissions.

  7. Next-generation freshwater bioassessment: eDNA metabarcoding with a conserved metazoan primer reveals species-rich and reservoir-specific communities

    PubMed Central

    Tay, Ywee Chieh; Srivathsan, Amrita; Tan, Jonathan W. T.; Kwik, Jeffrey T. B.; Baloğlu, Bilgenur; Yeo, Darren C. J.

    2016-01-01

    Freshwater habitats are of high conservation value and provide a wide range of ecosystem services. Effective management requires regular monitoring. However, conventional methods based on direct observation or specimen collection are so invasive, expensive and labour-intensive that frequent monitoring is uncommon. Here, we test whether the evaluation of environmental DNA (eDNA) from water based on a simple protocol can be used for assessing biodiversity. We use universal metazoan primers for characterizing water eDNA across horizontal and vertical spatial dimensions in two reservoirs with known species diversity for two key taxa. eDNA obtained directly from 42 samples × 15 ml water (total = 630 ml) per reservoir yielded DNA signatures for more than 500 metazoan species, of which 105 could be identified to species/genus based on DNA barcodes. We show that eDNA can be used to assign each water sample to its reservoir of origin, and that eDNA outperforms conventional survey methods in single-sample richness comparisons, while revealing evidence for hundreds of unknown species that are undetected by conventional bioassessment methods. eDNA also confirms the presence of a recently discovered invasive snail species and provides evidence for the continued survival of a rare native species of goby not sighted in that habitat since 2007. eDNA thus promises to be a useful addition to the bioassessment toolbox for freshwater systems. PMID:28018653

  8. Acoustics of fish shelters: frequency response and gain properties.

    PubMed

    Lugli, Marco

    2012-11-01

    Many teleosts emit sounds from cavities beneath stones and other types of submerged objects, yet the acoustical properties of fish shelters are virtually unexplored. This study examines the gain properties of shelters commonly used by Mediterranean gobies as hiding places and/or nest sites in the field (flat stones, shells belonging to five bivalve species), or within aquarium tanks (tunnel-shaped plastic covers, concrete blocks, concrete cylinder pipe, halves of terracotta flower pots). All shelters were acoustically stimulated using a small underwater buzzer, placed inside or around the shelter to mimic a fish calling from the nest site, and different types of driving stimuli (white noise, pure tones, and artificial pulse trains). Results showed the presence of significant amplitude gain (3-18 dB) at frequencies in the range 100-150 Hz in all types of natural shelters but one (Mytilus), terracotta flower pots, and concrete blocks. Gain was higher for stones and artificial shelters than for shells. Gain peak amplitude increased with the weight of stones and shells. Conclusions were verified by performing analogous acoustical tests on flat stones in the stream. Results draw attention to the use of suitable shelters for proper recording of sounds produced by fishes kept within laboratory aquaria.

  9. Links between type E botulism outbreaks, lake levels, and surface water temperatures in Lake Michigan, 1963-2008

    USGS Publications Warehouse

    Lafrancois, Brenda Moraska; Riley, Stephen C.; Blehert, David S.; Ballmann, Anne E.

    2011-01-01

    Relationships between large-scale environmental factors and the incidence of type E avian botulism outbreaks in Lake Michigan were examined from 1963 to 2008. Avian botulism outbreaks most frequently occurred in years with low mean annual water levels, and lake levels were significantly lower in outbreak years than in non-outbreak years. Mean surface water temperatures in northern Lake Michigan during the period when type E outbreaks tend to occur (July through September) were significantly higher in outbreak years than in non-outbreak years. Trends in fish populations did not strongly correlate with botulism outbreaks, although botulism outbreaks in the 1960s coincided with high alewife abundance, and recent botulism outbreaks coincided with rapidly increasing round goby abundance. Botulism outbreaks occurred cyclically, and the frequency of outbreaks did not increase over the period of record. Climate change scenarios for the Great Lakes predict lower water levels and warmer water temperatures. As a consequence, the frequency and magnitude of type E botulism outbreaks in the Great Lakes may increase.

  10. An exquisitely preserved troodontid theropod with new information on the palatal structure from the Upper Cretaceous of Mongolia

    NASA Astrophysics Data System (ADS)

    Tsuihiji, Takanobu; Barsbold, Rinchen; Watabe, Mahito; Tsogtbaatar, Khishigjav; Chinzorig, Tsogtbaatar; Fujiyama, Yoshito; Suzuki, Shigeru

    2014-02-01

    Troodontidae is a clade of small-bodied theropod dinosaurs. A new troodontid, Gobivenator mongoliensis gen. et sp. nov., is described based on the most complete skeleton of a Late Cretaceous member of this clade presently known, from the Campanian Djadokhta Formation in the central Gobi Desert. G. mongoliensis is different from other troodontids in possessing a pointed anterior end of the fused parietal and a fossa on the surangular in front of the posterior surangular foramen. The skull was superbly preserved in the specimen and provides detailed information of the entire configuration of the palate in Troodontidae. Overall morphology of the palate in Gobivenator resembles those of dromaeosaurids and Archaeopteryx, showing an apparent trend of elongation of the pterygoid process of the palatine and reduction of the pterygopalatine suture toward the basal Avialae. The palatal configuration suggests that the skull of Gobivenator would have been akinetic but had already acquired prerequisites for later evolution of cranial kinesis in birds, such as the loss of the epipterygoid and reduction in contact areas among bones.

  11. Occurrence of the Great Lake's most recent invader, Hemimysis anomala, in the diet of fishes in southeastern Lake Ontario

    USGS Publications Warehouse

    Lantry, B.F.; Walsh, M.G.; Johnson, J.H.; McKenna, J.E.

    2010-01-01

    The Ponto-Caspian mysid, Hemimysis anomala, was first observed in southeastern Lake Ontario in May 2006. During July and August 2007, gill nets were fished in 6 to 8 m of water at two locations of known Hemimysis colonization in southeastern Lake Ontario to determine if fish that consume macroinvertebrates were beginning to include this new invasive mysid in their diets. Of nine fish species captured in August, September, and October 2007, three species had consumed Hemimysis: alewife (Alosa pseudoharengus), rock bass (Ambloplites rupestris), and yellow perch (Perca flavescens); and six species had not: round goby Apollonia melanostoma, smallmouth bass Micropterus dolomieu, spottail shiner Notropis hudsonius, gizzard shad Dorosoma cepedianum, white perch Morone americana and log perch Percina caprodes. Diets of alewives from all samples were composed predominantly of Hemimysis (69.6% -100% frequency of occurrence, 46.0%–74.5% dry weight diet composition). Two of 6 rock bass stomachs sampled in August contained ≥ 98.9% Hemimysis (10 and 40 individuals each) and one of 61 yellow perch stomachs sampled in September contained 10.0% Hemimysis (6 individuals) and 90.0% fish. While Hemimysis were observed only sparsely in the diet of most nearshore fish, their predominance in alewife diets and their omnivorous feeding behavior indicated that they have the potential to alter energy flow in Great Lakes' foodwebs.

  12. The Change of Land Cover/Land Use in Ejina Oasis over 20 Years

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoyou; Men, Tongtong; Zhou, Maoxian

    Land use and land cover change have been of great concern in global change research in recent years. Base on comparison with the remote sensing data in1982 and 2000 and field investigation, the results of land cover and land use change were obtained by the method of landscape analysis. Ten types of land use were identified: riparian woods, riparian shrubbery, desert shrubbery, desert grassland, river-way and water area, salinised land, town, Gobi, shift sand dune, denudative upland. The results show that, (1) there were obvious Changes in land cover structure. The area of riparian woods decreased 0.97% and the number of patch decrease 376; The area of riparian shrubbery increased 0.92% and the number of patch decreased 1316. Meanwhile, the index of %LAND of desert shrubbery increased from 4.49% to 5.65%; patch of river-way and water area decreased from 40 to 6. The index of % dune increased 0.42%. (2) the area of riparian woods dominated by Populus euphratica and desert grassland decreased to 45.02% and 14.55%. However, the areas of riparian shrubbery dominated by Tamarix SPP and desert shrubbery increase to 35.03% and 25.88%. The transition probability is shrubbery and desert grassland. The succession trend of ecosystem was obtained: riparian woods riparian shrubbery and grassland desert grassland. Meanwhile, the succession velocity becomes higher and higher.

  13. [Imagination and creation: 1-hydroxyindole chemistry and the dream challenge].

    PubMed

    Somei, Masanori

    2008-04-01

    We have had five dreams to challenge through our life. To meet our end, we needed imaginary compounds, 1-hydroxytryptophans. This review describes how we had conceived the 1-hydroxyindole hypothesis, how we created a general synthetic method for 1-hydroxyindoles after 20 years' research, and how we have developed the chemistry of 1-hydroxytryptophans with full of new findings and discoveries. During the period, we defined "the efficient synthesis" and "the ideal synthesis" consisting of originality rate (OR), intellectual property factor (IPF), and application potential factor (APF). For evaluating the originality and the efficiency of the synthetic research, these indexes are more effective than both citation index and impact factor. Taking advantage of our 1-hydroxyindole chemistry, we have achieved three "ideal syntheses" approximately with high OR, IPF, and APF values. The methods employ only conventional reagents and reaction conditions without using any protecting groups. These methods made possible to produce such intellectual properties as leads for an alpha(2)-blocker, an inhibitor of platelet aggregation, an anti-osteoporosis agent, and a promising medicine for combating desertification, changing Gobi desert to the tract with full of green plants. These would be suitable for realizing our five dreams. Chemical conversion of enmein to gibberellin A(15), four-step total synthesis of optically active ergot alkaloids, and various new reactions for the synthesis of 4-substituted indoles are also involved.

  14. Kin-Aggregations Explain Chaotic Genetic Patchiness, a Commonly Observed Genetic Pattern, in a Marine Fish.

    PubMed

    Selwyn, Jason D; Hogan, J Derek; Downey-Wall, Alan M; Gurski, Lauren M; Portnoy, David S; Heath, Daniel D

    2016-01-01

    The phenomenon of chaotic genetic patchiness is a pattern commonly seen in marine organisms, particularly those with demersal adults and pelagic larvae. This pattern is usually associated with sweepstakes recruitment and variable reproductive success. Here we investigate the biological underpinnings of this pattern in a species of marine goby Coryphopterus personatus. We find that populations of this species show tell-tale signs of chaotic genetic patchiness including: small, but significant, differences in genetic structure over short distances; a non-equilibrium or "chaotic" pattern of differentiation among locations in space; and within locus, within population deviations from the expectations of Hardy-Weinberg equilibrium (HWE). We show that despite having a pelagic larval stage, and a wide distribution across Caribbean coral reefs, this species forms groups of highly related individuals at small spatial scales (<10 metres). These spatially clustered family groups cause the observed deviations from HWE and local population differentiation, a finding that is rarely demonstrated, but could be more common than previously thought.

  15. Long-term changes in the diet of Gymnogobius isaza from Lake Biwa, Japan: effects of body size and environmental prey availability.

    PubMed

    Briones, Jonathan Carlo; Tsai, Cheng-Han; Nakazawa, Takefumi; Sakai, Yoichiro; Papa, Rey Donne S; Hsieh, Chih-Hao; Okuda, Noboru

    2012-01-01

    Body size and environmental prey availability are both key factors determining feeding habits of gape-limited fish predators. However, our understanding of their interactive or relative effects is still limited. In this study, we performed quantitative dietary analysis of different body sizes of goby (Gymnogobius isaza) specimens collected from Lake Biwa between 1962 and 2004. First, we report that the diet was composed mainly of zooplankton (cladocerans and copepods) before the 1980s, and thereafter, shifted to zoobenthos (gammarids). This foraging shift coincided with, and thus can be linked to, known historical events in the lake at that time: decrease in zooplankton abundance with the alleviation of eutrophication, increase in fish body size resulting from fish population collapse, and increase in gammarid abundance due to reduced fish predation pressure. Supporting this view, our data analyses revealed how the long-term changes in the diet composition would be co-mediated by changes in fish body size and environmental prey availability. Specifically, while zoobenthos abundance strongly affected the fish diet composition, larger (smaller) fish preferred zoobenthos (zooplankton). Furthermore, the body size effects were stronger than those of prey availability. These results provide the best long-term evidence that fish feeding habits vary over decades with its body size and prey community due to anthropogenic disturbances.

  16. Fish mortality by impingement on the cooling-water intake screens of Britain's largest direct-cooled power station.

    PubMed

    Greenwood, M F D

    2008-04-01

    An estimated 5.66 x 10(7) fish (summed quarterly 95% confidence intervals: 3.01 x 10(7)-1.07 x 10(8)) weighing 258.4 t (143.2-467.9 t) were killed on the cooling-water intake screens of the 2400 MW Longannet Power Station (Forth estuary) in January 1999--December 2000. Abundance and number of species (40) collected were close to predictions for a power station of this size and latitude. Potential losses of equivalent adult whiting (Merlangius merlangus), cod (Gadus morhua), and plaice (Pleuronectes platessa) through deaths of juveniles were estimated at 353.1 t (208.0-603.2 t) worth approximately euro 429,266 (euro 246,592-752,765) in 1999--2000. Fish catch-per-trawl in the estuary was generally not noticeably greater during a year of low water withdrawal (coal miners' strike of 1984--1985) when compared to other years from 1982 to 2001, except for gobies (Pomatoschistus spp.). A fish-return system is being tested at Longannet to reduce mortality.

  17. Individual adjustment of sperm expenditure accords with sperm competition theory.

    PubMed

    Pilastro, Andrea; Scaggiante, Marta; Rasotto, Maria B

    2002-07-23

    Sperm competition theory predicts that males should strategically allocate their sperm reserves according to the level of sperm competition, defined as the probability that the sperm of two males compete for fertilizing a given set of ova. Substantial evidence from numerous animal taxa suggests that, at the individual level, sperm expenditure increases when the risk of sperm competition is greater. In contrast, according to the "intensity model" of sperm competition [Parker, G. A., Ball, M. A., Stockley, P. & Gage, M. J. G. (1996) Proc. R. Soc. London Ser. B 263, 1291-1297], when more than two ejaculates compete during a given mating event, sperm expenditure should decrease as the number of competing males increases. Empirical evidence supporting this prediction, however, is still lacking. Here we measured sperm expenditure in two gobiid fishes, the grass (Zosterisessor ophiocephalus) and black goby (Gobius niger), in which up to six sneakers can congregate around the nest of territorial males and release their sperm when females spawn. We show that, in accordance with theory, sneaker males of both species release fewer sperm as the number of competitors increases.

  18. How Has Land Cover Change Affected Precipitation for the Mongolian Plateau Since 2001?

    NASA Astrophysics Data System (ADS)

    Moore, N. J.; John, R.; Chen, J.

    2015-12-01

    Recent trends towards increased grazing pressures on the Mongolian Plateau have placed a premium on grasslands to meet increasing domestic and international demand for animal products. Recent land cover shifts include degradation in ecosystem function and structure of the grasslands, reduction of vegetation cover, particularly in northeastern Inner Mongolia, and urban expansion around Ulanbaatar. Here we examine the impacts of land cover change using the Regional Atmospheric Modeling System (RAMS v. 6.0) to test whether or not the land cover changes from 2001-2010 could significantly impact surface energy fluxes enough to alter convection over the regions where grasslands are dominant. We performed this experiment for two distinct sets of boundary conditions: the growing season of 2001 (a drought/dzud year) and 2003 (a wet year). Preliminary results from the model indicate increased cloud cover and lowered daily temperature ranges for the northeastern Mongolian Plateau accompanying patterns of meadow and forest steppe growth. More broadly, the overall trend towards reduced vegetation cover leads to higher screen height temperatures and reduced soil moisture throughout much of the domain, together with a shift of moisture southward of Inner Mongolia. In the desert steppe regions around the Gobi desert, more complex patterns associated with land degradation will be discussed.

  19. Dinosaur eggshell geochemistry as an indicator of Central Asian Cretaceous paleoenvironments

    NASA Astrophysics Data System (ADS)

    Montanari, S.; Higgins, P.; Norell, M.

    2011-12-01

    The Late Cretaceous fossiliferous beds of Mongolia's Gobi Desert have yielded spectacular articulated remains of an extraordinary diversity of fossil mammals, reptiles, birds, and dinosaurs. Paleoenvironmental interpretations of the deposits at these localities have ranged from arid wind-blown dune fields to more mesic, moist environments. Among the diversity of fossils, dinosaur eggshells are commonly found at these localities and dinosaur embryos, although rare, are also encountered. Dinosaur (including modern bird) eggs are constructed of calcite (CaCO3) allowing carbon and oxygen stable isotopes to be quantified to provide information about the environment the egg-laying animals were living in. Here we show that dinosaur eggshell from the Djadokhta Formation at one locality has not been significantly altered and reflects an environment that of dry-climate adapted C3 plants and isolated, ephemeral water sources during the egg-laying season. Carbonate nodules from the same eggshell-bearing layers also independently reflects a similar environmental signal. This study represents the first geochemical analysis of dinosaur remains from the Cretaceous of Mongolia and illustrates the potential of utilizing dinosaur eggshell geochemistry to reconstruct Mesozoic environments.
    Mean, n, standard deviation, and range for both carbon and oxygen isotope values for all materials sampled

  20. Do pharmaceuticals bioaccumulate in marine molluscs and fish from a coastal lagoon?

    PubMed

    Moreno-González, R; Rodríguez-Mozaz, S; Huerta, B; Barceló, D; León, V M

    2016-04-01

    The bioaccumulation of 20 pharmaceuticals in cockle (Cerastodema glaucum), noble pen shell (Pinna nobilis), sea snail (Murex trunculus), golden grey mullet (Liza aurata) and black goby (Gobius niger) was evaluated, considering their distribution throughout the Mar Menor lagoon and their variations in spring and autumn 2010. The analytical procedure was adapted for the different matrices as being sensitive and reproducible. Eighteen out of the 20 compounds analysed were found at low ngg(-1) in these species throughout the lagoon. Hydrochlorothiazide and carbamazepine were detected in all species considered. The bioaccumulation of pharmaceuticals was heterogeneous in the lagoon, with a higher number of pharmaceuticals being detected in fish (18) than in wild molluscs (8), particularly in golden grey mullet muscle (16). В-blockers and psychiatric drugs were preferentially bioccumulated in fish and hydrochlorothiazide was also confirmed in caged clams. The higher detection frequency and concentrations found in golden grey mullet suggested that mugilids could be used as an indicator of contamination by pharmaceuticals in coastal areas. To the best of our knowledge, this is the first study that shows data about hydrochlorothiazide, levamisole and codeine in wild marine biota.

  1. A late Paleocene probable metatherian (?deltatheroidan) survivor of the Cretaceous mass extinction.

    PubMed

    Ni, Xijun; Li, Qiang; Stidham, Thomas A; Li, Lüzhou; Lu, Xiaoyu; Meng, Jin

    2016-12-07

    Deltatheroidans are primitive metatherian mammals (relatives of marsupials), previously thought to have become extinct during the Cretaceous mass extinction. Here, we report a tiny new deltatheroidan mammal (Gurbanodelta kara gen. et sp. nov.) discovered at the South Gobi locality in China (Xinjiang Province) that is the first Cenozoic record of this clade and renders Deltatheroida a Lazarus taxon (with a new record 10 million years younger than their supposed extinction). The vertebrate fauna associated with Gurbanodelta is most similar to that from the slightly older late Paleocene Subeng locality in Inner Mongolia. The upper molars of Gurbanodelta exhibit a broad stylar shelf with one prominent cusp (stylocone), and a paracone that is sharp and significantly taller than the metacone. The lower molar tentatively assigned to Gurbanodelta has a very small talonid without an entoconid. This combination of these features is known only in deltatheroidans. Phylogenetic analysis places Gurbanodelta as the sister taxon of the North American latest Cretaceous Nanocuris. Gurbanodelta is the smallest-known deltatheroidan, and roughly the same size as the smallest living marsupial. It is likely that the Gurbanodelta lineage dispersed between Asia and North America as part of known intercontinental mammalian dispersals in the late Paleocene, or possibly earlier.

  2. Petrography and Mineralogy of 18 Newly Recovered Ordinary Chondrites in China

    NASA Astrophysics Data System (ADS)

    Li, S. L.

    2015-05-01

    Petrology and mineralogy of 18 newly recovered ordinary chondrites in China are reported in this paper. Fifteen meteorites were found in Xinjiang, among which 13 meteorites were found in the Lop Nur desert, and the other 2 meteorites were found in Kumtag and Aksai Chin, respectively. Three other meteorites are observed falls in Xining, Fuhe, and Dongyang, respectively. All meteorites are equilibrated ordinary chondrites with 8 H group and 10 L group meteorites. Their petrographic types vary from 4 to 6 in the L group meteorites, with most being type 5, while all H group meteorites are classified as type 5. The features of shock metamorphism of most meteorites are moderate though a few have features of ≥S4 stage. Most Lop Nur meteorites underwent intense weathering with only two of which have weathering degree of W1 and W2. Both Kumtag and Aksai Chin meteorite have a weathering degree of W2. The newly discovered tens of meteorites in the gobi deserts east to the Taklimakan Desert indicate that this region may become an important dense meteorite collection area in Eurasia.

  3. Human bronchial epithelial cell injuries induced by fine particulate matter from sandstorm and non-sandstorm periods: Association with particle constituents.

    PubMed

    Wang, Bin; Li, Ning; Deng, Furong; Buglak, Nicholas; Park, George; Su, Shu; Ren, Aiguo; Shen, Guofeng; Tao, Shu; Guo, Xinbiao

    2016-09-01

    Epidemiological studies have demonstrated the exacerbation of respiratory diseases following sandstorm-derived particulate matter (PM) exposure. The presence of anthropogenic and biological agents on the sandstorm PM and the escalation of PM<2.5μm (PM2.5) pollution in China have led to serious concerns regarding the health effects of PM2.5 during Asian sandstorms. We investigated how changes in PM2.5 composition, as the weather transitioned towards a sandstorm, affected human airway epithelial cells. Six PM2.5 samples covering two sandstorm events and their respective background and transition periods were collected in Baotou, an industrial city near the Gobi Desert in China. PM samples from all three periods had mild cytotoxicity in human bronchial epithelial cell line BEAS-2B, which was positively correlated with the contents of polycyclic aromatic hydrocarbons and several metals. All PM samples potently increased the release of interleukin-6 (IL-6) and interleukin-8 (IL-8). Endotoxin in all samples contributed significantly to the IL-6 response, with only a minor effect on IL-8. Cr was positively correlated with both IL-6 and IL-8 release, while Si was only associated with the increase of IL-6. Our study suggests that local agricultural and industrial surroundings in addition to the sandstorm play important roles in the respiratory effects of sandstorm-derived PM.

  4. North-East Asian Super Grid: Renewable energy mix and economics

    NASA Astrophysics Data System (ADS)

    Breyer, Christian; Bogdanov, Dmitrii; Komoto, Keiichi; Ehara, Tomoki; Song, Jinsoo; Enebish, Namjil

    2015-08-01

    Further development of the North-East Asian energy system is at a crossroads due to severe limitations of the current conventional energy based system. For North-East Asia it is proposed that the excellent solar and wind resources of the Gobi desert could enable the transformation towards a 100% renewable energy system. An hourly resolved model describes an energy system for North-East Asia, subdivided into 14 regions interconnected by high voltage direct current (HVDC) transmission grids. Simulations are made for highly centralized, decentralized and country-wide grids scenarios. The results for total system levelized cost of electricity (LCOE) are 0.065 and 0.081 €/(kW·h) for the centralized and decentralized approaches for 2030 assumptions. The presented results for 100% renewable resources-based energy systems are lower in LCOE by about 30-40% than recent findings in Europe for conventional alternatives. This research clearly indicates that a 100% renewable resources-based energy system is THE real policy option.

  5. Infections may select for filial cannibalism by impacting egg survival in interactions with water salinity and egg density.

    PubMed

    Lehtonen, Topi K; Kvarnemo, Charlotta

    2015-07-01

    In aquatic environments, externally developing eggs are in constant contact with the surrounding water, highlighting the significance of water parameters and pathogens for egg survival. In this study we tested the impact of water salinity, egg density and infection potential of the environment on egg viability in the sand goby (Pomatoschistus minutus), a small fish that exhibits paternal egg care and has a marine origin, but which in the Baltic Sea lives in brackish water. To manipulate the infection potential of the environment, we added either a Saprolegnia infection vector into UV-filtered water or a fungicide into natural Baltic Sea water. Saprolegnia are widely spread water moulds that are a key cause of egg mortality in aquatic organisms in fresh- and brackish water. We found that increased water salinity indeed decreased the egg infection rate and had a positive effect on egg viability, while high egg density tended to have the opposite effect. However, the different factors influenced egg viability interactively, with a higher egg density having negative effects at low, but not in high, salinity. Thus, the challenges facing marine organisms adapting to lower salinity levels can be amplified by Saprolegnia infections that reduce egg survival in interaction with other environmental factors. Our results support the hypothesis that suppressing egg infections is an important aspect of parental care that can select for filial cannibalism, a common but poorly understood behaviour, especially in fish with parental care.

  6. Gimme shelter: The importance of crevices to some fish species inhabiting a deeper-water rocky outcrop in Southern California

    USGS Publications Warehouse

    Love, M.S.; Schroeder, D.M.; Lenarz, B.; Cochrane, G.R.

    2006-01-01

    Federal law governing fisheries management recognizes the role habitat plays in structuring fish assemblages and achieving sustainable fisheries. However, in most instances it is not known which aspects of habitat are important to the lives of fish species. In 2004, we examined the importance of sheltering sites (crevices) to fishes living along low ledges in deeper waters off Anacapa Island, southern California. We found that patterns of fish-habitat relationships varied among the eight most abundant species. Three species, bocaccio (Sebastes paucispinis), vermilion (S. miniatus), and flag (S. rubrivinctus) rockfishes, had densities one to three orders of magnitude greater in the deep crevice habitat compared to low relief rock or shallow crevice habitats. Density and mean size of the two most abundant fishes, halfbanded (S. semicinctus) and squarespot (S. hopkinsi) rockfishes, generally increased as complexity of rock habitat increased. Not all species had the highest densities in deep crevice habitat. Greenspotted rockfish (S. chlorostictus) and blackeye goby (Rhinogobiops nicholsii) showed no significant difference in density among rock habitats. Pink seaperch (Zalembius rosaceus) were absent in the deep crevice habitat and abundant only in low relief rock habitats. Our study implies that it is not sufficient to distinguish only between soft and hard bottom types when using habitat to guide fisheries management strategies. Finer-scale investigations of fish-habitat relationships, paired with habitat mapping and groundtruthing, aid in the design and positioning of Marine Park Areas (MPAs) and are necessary to facilitate understanding of how a particular MPA may contribute to fisheries management.

  7. Bioaccumulation characteristics of perfluoroalkyl acids (PFAAs) in coastal organisms from the west coast of South Korea.

    PubMed

    Hong, Seongjin; Khim, Jong Seong; Wang, Tieyu; Naile, Jonathan E; Park, Jinsoon; Kwon, Bong-Oh; Song, Sung Joon; Ryu, Jongseong; Codling, Garry; Jones, Paul D; Lu, Yonglong; Giesy, John P

    2015-06-01

    Year-round monitoring for perfluoroalkyl acids (PFAAs) along the west coast of South Korea targeting long-term changes in water and coastal organisms has been conducted since 2008. In this study, we present the most recent 5-years of accumulated data and scrutinize the relationship between concentrations in water and biota highlighting bioaccumulation characteristics. Twelve individual PFAAs in samples of water (n=43) and biota (n=59) were quantified by use of HPLC-MS/MS after solid phase extraction. In recent years, concentrations of PFAAs in water have been generally decreasing, but profiles of relative concentrations of individual PFAAs vary among location and year. Bioaccumulation of PFAAs in various organisms including fishes, bivalves, crabs, gastropods, shrimps, starfish, and polychaetes varied among species. However, overall bioaccumulation of PFAAs was dependent on corresponding concentrations of PFAAs in water within an area. In organ-specific distributions of PFAAs, greater concentrations of PFAAs were found in intestine of fish (green eel goby). This result suggests that PFAAs are mainly accumulated via dietary exposure, while greater concentrations were found in gill and intestine of bivalve (oyster) which suggests both waterborne and dietary exposures to these organisms. Concentrations of PFAAs in biota did not decrease over time (2008-2010), indicating that continuing bioaccumulation followed by slow degradation or excretion of PFAAs accumulated in biota. Overall, spatio-temporal distributions of PFAAs in water and bioaccumulation characteristics seemed to be associated with recent restrictions of PFOS-based products and uses of PFBS-based substitutes.

  8. Effects of soil dust emissions on air quality over East Asia

    NASA Astrophysics Data System (ADS)

    Koo, Y.; Kim, S.; Cho, J.

    2012-12-01

    Dust emissions from the Gobi Desert, sand desert, Loess Plateau and barren mixed soil in Northern China and Mongolia have a major impact on the air quality in the East Asian region. These mineral aerosols increase PM10 concentration over 1000 μg/m3 during the dust storm event as well as PM10 background concentrations as the fugitive dust during the non-dust period in Korea. The mineral dusts also modifies the formation mechanism of inorganic aerosols via the chemical interactions with atmospheric gas species. The performance of available dust emission schemes to depict not only the high PM10 concentration and onset time for the dust storm period but also the level of background PM10 concentration for the non-dust event were evaluated against the surface measurements of EANET (Acid Deposition Monitoring NETwork in East Asia) and satellite measurements over East Asia. The US EPA Models-3/CMAQ v5.0 by modifying the fugitive dust modules was used to simulate the chemical transport including the mineral aerosols. The results show that the Asian Dust Aerosol Model 2 (ADAM2) and DEAD are relatively good dust emission schemes in this region and influence of mineral dusts on the sulfate and nitrate formations is significant when the dust mixes with anthropogenic emissions over China. Details of modifications of dust emission schemes and annual background PM10 concentrations by the soil fugitive dust in Korea will be discussed in the presentation.

  9. Levels of platinum group metals in selected species (Sarotherodon melanotheron, Chonophorus lateristriga, Macrobrachium vollenhovenii and Crassostrea tulipa) in some estuaries and lagoons along the coast of Ghana.

    PubMed

    Essumang, D K; Adokoh, C K; Boamponsem, L

    2010-10-12

    The use of some biota as bioindicators of heavy metal pollution has been demonstrated as particularly adequate due to their capacity of bioconcentration. This study evaluated the levels of platinum group metals (PGMs) in some selected species along the coastal belt of Ghana, using the neutron activation analysis (NAA) method. The result was processed to evaluate pollution indices in order to map the distribution of the metals in those species in the lagoons and estuaries along the costal belt of Ghana. The analysis showed significant levels of all PGMs in blackchin tilapia (Sarotherodon melanotheron Cichlidae), brown goby (Chonophorus lateristriga Gobiidae), shrimp (Macrobrachium vollenhovenii Palaemonidae), and mangrove oysters (Crassostrea tulipa Ostreidae) in the lagoons and river Pra estuary. However, the oysters showed an elevated mean concentration of 0.13 μg/g (dry weight) Pd. From the pollution indices, most of the sampling sites registered mean contamination factor (CF) values between 1.20 and 3.00 for Pt, Pd, and Rh. The pollution load index (PLI) conducted also gave an average pollution index between 0.79 and 2.37, indicating progressive contamination levels. The results revealed that anthropogenic sources, industrial and hospital effluent, etc., together with vehicular emissions, could be the contributing factors to the deposition of PGMs along the Ghanaian coast.

  10. Existing and emerging high impact invasive species are characterized by higher functional responses than natives.

    PubMed

    Alexander, Mhairi E; Dick, Jaimie T A; Weyl, Olaf L F; Robinson, Tamara B; Richardson, David M

    2014-02-01

    Predicting ecological impacts of invasive species and identifying potentially damaging future invaders are research priorities. Since damage by invaders is characterized by their depletion of resources, comparisons of the 'functional response' (FR; resource uptake rate as a function of resource density) of invaders and natives might predict invader impact. We tested this by comparing FRs of the ecologically damaging 'world's worst' invasive fish, the largemouth bass (Micropterus salmoides), with a native equivalent, the Cape kurper (Sandelia capensis), and an emerging invader, the sharptooth catfish (Clarias gariepinus), with the native river goby (Glossogobius callidus), in South Africa, a global invasion hotspot. Using tadpoles (Hyperolius marmoratus) as prey, we found that the invaders consumed significantly more than natives. Attack rates at low prey densities within invader/native comparisons reflected similarities in predatory strategies; however, both invasive species displayed significantly higher Type II FRs than the native comparators. This was driven by significantly lower prey handling times by invaders, resulting in significantly higher maximum feeding rates. The higher FRs of these invaders are thus congruent with, and can predict, their impacts on native communities. Comparative FRs may be a rapid and reliable method for predicting ecological impacts of emerging and future invasive species.

  11. Life history variation among geographically close populations of the toad-headed lizard (Phrynocephalus przewalskii): Exploring environmental and physiological associations

    NASA Astrophysics Data System (ADS)

    Zeng, Zhi-Gao; Zhao, Jia-Ming; Sun, Bao-Jun

    2013-08-01

    Geographic variation in life history traits has been extensively studied along latitudinal and altitudinal clines, but life history variation among geographically close populations has received much less attention. We collected gravid female toad-headed lizards (Phrynocephalus przewalskii) and environmental data from three localities (Alxa Zuoqi, Alxa Youqi, and Shandan) across the Gobi desert in China, to examine among-population differences in reproductive strategies. The precipitation was significantly lower in Alxa Youqi than Alxa Zouqi and Shandan. Food availability was highest in Shandan, lowest in Alxa Zuoqi, with Alxa Youqi in between. Females from Shandan population were larger and produced more and larger eggs than their counterparts from the other two populations. Incubation period also differed among the populations, with the lowest incubation period in Alxa Youqi population, and the longest incubation period in Alxa Zuoqi population. Our data on the physiological mechanisms of incubation period indicated that the shortened incubation period in Alxa Youqi population was due to advanced embryogenesis completed prior to oviposition rather than higher embryonic heart rates during incubation. Therefore, our data support the hypothesis that geographically close populations can show different reproductive strategies if environmental factors vary among these populations.

  12. Compression of Structured High-Throughput Sequencing Data

    PubMed Central

    Campagne, Fabien; Dorff, Kevin C.; Chambwe, Nyasha; Robinson, James T.; Mesirov, Jill P.

    2013-01-01

    Large biological datasets are being produced at a rapid pace and create substantial storage challenges, particularly in the domain of high-throughput sequencing (HTS). Most approaches currently used to store HTS data are either unable to quickly adapt to the requirements of new sequencing or analysis methods (because they do not support schema evolution), or fail to provide state of the art compression of the datasets. We have devised new approaches to store HTS data that support seamless data schema evolution and compress datasets substantially better than existing approaches. Building on these new approaches, we discuss and demonstrate how a multi-tier data organization can dramatically reduce the storage, computational and network burden of collecting, analyzing, and archiving large sequencing datasets. For instance, we show that spliced RNA-Seq alignments can be stored in less than 4% the size of a BAM file with perfect data fidelity. Compared to the previous compression state of the art, these methods reduce dataset size more than 40% when storing exome, gene expression or DNA methylation datasets. The approaches have been integrated in a comprehensive suite of software tools (http://goby.campagnelab.org) that support common analyses for a range of high-throughput sequencing assays. PMID:24260313

  13. Cardiovascular effects of native and non-native urotensin II and urotensin II-related peptide on rat and salmon hearts.

    PubMed

    Prosser, H C G; Leprince, J; Vaudry, H; Richards, A M; Forster, M E; Pemberton, C J

    2006-12-01

    Urotensin II (UII) was first discovered in the urophyses of goby fish and later identified in mammals, while urotensin II-related peptide (URP) was recently isolated from rat brain. We studied the effects of UII on isolated heart preparations of Chinook salmon and Sprague-Dawley rats. Native rat UII caused potent and sustained, dose-dependent dilation of the coronary arteries in the rat, whereas non-native UII (human and trout UII) showed attenuated vasodilation. Rat URP dilated rat coronary arteries, with 10-fold less potency compared with rUII. In salmon, native trout UII caused sustained dilation of the coronary arteries, while rat UII and URP caused significant constriction. Nomega-nitro-(l)-arginine methyl (l-NAME) and indomethacin significantly attenuated the URP and rat UII-induced vasodilation in the rat heart. We conclude that UII is a coronary vasodilator, an action that is species form specific. We also provide the first evidence for cardiac actions of URP, possibly via mechanisms common with UII.

  14. Dust-infused baroclinic cyclone storm clouds: The evidence, meteorology, and some implications

    NASA Astrophysics Data System (ADS)

    Fromm, Michael; Kablick, George; Caffrey, Peter

    2016-12-01

    Desert mineral dust is a critical yet still poorly understood component of atmospheric composition, weather, and climate. Long-range transport of dust is well known, yet uncertainty persists regarding the pathway from the desert floor to the free troposphere. Here we will show that a recurrent pathway for dust into the uppermost troposphere involves passage through an extratropical baroclinic cyclonic storm. The evidence derives from a synergistic use of satellite-based, multispectral nadir-image data and lidar. The dust-infused baroclinic storm (DIBS) exhibits peculiar cirrus cloud top reflected and emitted radiance from the UV through thermal IR, involving positive UV absorbing aerosol index, muted visible reflectivity, visible cumuliform texture, and systematically intense visible lidar backscatter on a synoptic scale. Proof that the DIBS is microphysically impacted by storm-scale dust infusion is the occurrence of anomalously large daytime 3.9-11μm brightness temperature difference indicative of small ice crystals. We present multispectral snapshots of two DIBS, over two desert source regions, in comparison with a pristine baroclinic storm cloud. Each storm snapshot is presented in the context of the baroclinic cyclone's lifetime and dust source region (the Gobi desert and the Sahara). These and other cases discussed show that the DIBS is a recurring conduit for long-range transport and a natural experiment in dust-related aerosol indirect effects.

  15. Characterization of the current biological communities within the Nanticoke River in the vicinity of the Vienna SES

    SciTech Connect

    Stroup, C.F.; Brindley, A.; Kazyak, P.F.

    1991-07-01

    Pursuant to a utility's intent to file for permission to build a generating station along the Nanticoke River, Maryland, a field program was conducted to update characterizations of major aquatic biota of the river in proximity to the existing power plant and a potential intake/discharge location. This characterization sampled five stations on the Nanticoke River, spanning 14 miles from Chapter Point to Riverton, between July 1988 and October 1989. During the study period, the juvenile and adult fish community was dominated by white perch, Atlantic menhaden, bay anchovy, hogchoker, and spot. Spring ichthyoplankton was composed of white perch, striped bass, yellow perch, and alosids, while summer ichthyoplankton was dominated by naked gobies and bay anchovy. Acartia tonsa, Eurytemora affinis and Bosmina longirostris dominated zooplankton samples. The phytoplankton community was composed primarily of diatoms, green algae, and monads. Polychaetes and crustaceans were the dominant macrobenthic taxa, with molluscs contributing to total abundance primarily during spring recruitment. The final report presents the results of fish, ichthyoplankton, zooplankton, and benthic surveys conducted between July 1988 and October 1989 in the middle portion of the Nanticoke River, Maryland. During the dry conditions of 1988, aquatic communities were dominated by estuarine species, while the lower saline environment of 1989 resulted in the presence of more freshwater species.

  16. Polar Dunes In Summer Exhibit Frost Patches, Wind Streaks

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Mars Global Surveyor passes over the north polar region of the red planet twelve times each day, offering many opportunities to observe how the polar cap frosts and dunes are changing as the days goby. Right now it is summer in the north. This picture, taken the second week of April 1999, shows darks and dunes and remnant patches of bright frost left over from the winter that ended in July 1998. Dark streaks indicate recent movement of sand. The picture covers an area only 1.4 kilometers (0.9 miles)across and is illuminated from the upper right.

    Malin Space Science Systems and the California Institute of Technology built the MOC using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO.

  17. Modeling Mineral Dust and Accessing Its Impact on Radiative Forcing over East Asia

    NASA Astrophysics Data System (ADS)

    Dong, X.

    2015-12-01

    East Asia dust storm has been investigated with revised WRF/CMAQ modeling system in this study. Taklamkan and Gobi deserts in China and Mongolia are the major contributors for East Asia dust storm, which significantly affect air quality and regional climate over downwind areas in China, Japan and Korea. Understanding the mixing of dust and intensive anthropogenic emissions would require a regional chemistry transport model which can simulate both the emission and transport of the natural and anthropogenic particles, and also their chemical interactions as well as the particles evolutions. In this study, we conducted model development of the WRF/CMAQ modeling system by revising the dust emission scheme and implementing source-dependent speciation profiles of dust aerosol and heterogeneous chemistry. With the revised modeling system, East Asia dust impact on atmospheric chemistry and regional climate has been investigated for the period of March and April from 2006 to 2010. The revised modeling system has been demonstrated to greatly improve model's capability of reproducing dust emission and transport over East Asia by comparing with surface measurements and satellite observations.

  18. Aerosol particles at a high-altitude site on the Southeast Tibetan Plateau, China: Implications for pollution transport from South Asia

    NASA Astrophysics Data System (ADS)

    Zhao, Zhuzi; Cao, Junji; Shen, Zhenxing; Xu, Baiqing; Zhu, Chongshu; Chen, L.-W. Antony; Su, Xiaoli; Liu, Suixin; Han, Yongming; Wang, Gehui; Ho, Kinfai

    2013-10-01

    aerosol samples were collected from 16 July 2008 to 26 July 2009 at Lulang, a high-altitude (>3300m above sea level) site on the southeast Tibetan Plateau (TP); objectives were to determine chemical characteristics of the aerosol and identify its major sources. We report aerosol (total suspended particulate, TSP) mass levels and the concentrations of selected elements, carbonaceous species, and water-soluble inorganic ions. Significant buildup of aerosol mass and chemical species (organic carbon, element carbon, nitrate, and sulfate) occurred during the premonsoon, while lower concentrations were observed during the monsoon. Seasonal variations in aerosol and chemical species were driven by precipitation scavenging and atmospheric circulation. Two kinds of high-aerosol episodes were observed: one was enriched with dust indicators (Fe and Ca2+), and the other was enhanced with organic and elemental carbon (OC and EC), SO42-, NO3-, and Fe. The TSP loadings during the latter were 3 to 6 times those on normal days. The greatest aerosol optical depths (National Centers for Environmental Protection/National Center for Atmospheric Research reanalysis) occurred upwind, in eastern India and Bangladesh, and trajectory analysis indicates that air pollutants were transported from the southwest. Northwesterly winds brought high levels of natural emissions (Fe, Ca2+) and low levels of pollutants (SO42-, NO3-, K+, and EC); this was consistent with high aerosol optical depths over the western deserts and Gobi. Our work provides evidence that both geological and pollution aerosols from surrounding regions impact the aerosol population of the TP.

  19. Long-Term Variability of Airborne Asian Dust Observed from TOMS

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Hsu, N. C.; Seftor, C. J.; Holben, B. N.; Holben, B. N.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Recent studies suggest that airborne Asian dust may not only play an important role in the regional radiation budget, but also influence the air quality over North America through long-range transport. In this paper, we use satellite data to investigate the long-term variability of airborne Asian dust as well as the daily variation of the dust aerosol distribution. By combining the Total Ozone Mapping Spectrometer (TOMS) aerosol index with National Centers for Environmental Prediction (NCEP) wind data, our analysis shows a strong correlation between the generation of dust storms in the region and the passage of springtime weather fronts. This is consistent with earlier studies performed by other researchers. According to both the Nimbus-7 and Earth-Probe TOMS data the Takla Makan desert, the Gobi desert, and the and region of Inner Mongolia are major sources of the eastward-flowing airborne Asian dust. Heavily populated areas in eastern China (e.g., Beijing) are often on the primary path of the dust storms originating in these desert regions. The increasing desertification north of the Beijing region has served to exacerbate problems stemming from these storms. The time series derived from 20 years of TOMS aerosol index data shows the first significant satellite evidence of the atmospheric effect of increasing desertification, indicating that the amount of dust blown eastward has increased strongly during the past few years including the year 2000.

  20. Aerobic vs. anaerobic scope: sibling species of fish indicate that temperature dependence of hypoxia tolerance can predict future survival.

    PubMed

    Sørensen, Christina; Munday, Philip L; Nilsson, Göran E

    2014-03-01

    The temperature dependence of aerobic scope has been suggested to be a major determinant of how marine animals will cope with future rises in environmental temperature. Here, we present data suggesting that in some animals, the temperature dependence of anaerobic scope (i.e., the capacity for surviving severe hypoxia) may determine present-day latitudinal distributions and potential for persistence in a warmer future. As a model for investigating the role of anaerobic scope, we studied two sibling species of coral-dwelling gobies, Gobiodon histrio, and G. erythrospilus, with different latitudinal distributions, but which overlap in equal abundance at Lizard Island (14°40'S) on the Great Barrier Reef. These species did not differ in the temperature dependence of resting oxygen consumption or critical oxygen concentration (the lowest oxygen level where resting oxygen consumption can be maintained). In contrast, the more equatorial species (G. histrio) had a better capacity to endure anaerobic conditions at oxygen levels below the critical oxygen concentration at the high temperatures (32-33 °C) more likely to occur near the equator, or in a warmer future. These results suggest that anaerobic scope, in addition to aerobic scope, could be important in determining the impacts of global warming on some marine animals.

  1. Hormonal regulation of colour change in eyes of a cryptic fish.

    PubMed

    Sköld, Helen Nilsson; Yngsell, Daniel; Mubashishir, Muhmd; Wallin, Margareta

    2015-01-16

    Colour change of the skin in lower vertebrates such as fish has been a subject of great scientific and public interest. However, colour change also takes place in eyes of fish and while an increasing amount of data indicates its importance in behaviour, very little is known about its regulation. Here, we report that both eye and skin coloration change in response to white to black background adaptation in live sand goby Pomatoschistus minutes, a bentic marine fish. Through in vitro experiments, we show that noradrenaline and melanocyte concentrating hormone (MCH) treatments cause aggregation of pigment organelles in the eye chromatophores. Daylight had no aggregating effect. Combining forskolin to elevate intracellular cyclic adenosine monophosphate (cAMP) with MCH resulted in complete pigment dispersal and darkening of the eyes, whereas combining prolactin, adrenocorticotrophic hormone (ACTH) or melanocyte stimulating hormone (α-MSH) with MCH resulted in more yellow and red eyes. ACTH and MSH also induced dispersal in the melanophores, resulting in overall darker eyes. By comparing analysis of eyes, skin and peritoneum, we conclude that the regulation pattern is similar between these different tissues in this species which is relevant for the cryptic life strategy of this species. With the exception of ACTH which resulted in most prominent melanophore pigment dispersal in the eyes, all other treatments provided similar results between tissue types. To our knowledge, this is the first study that has directly analysed hormonal regulation of physiological colour change in eyes of fish.

  2. Phylogeny and tempo of diversification in the superradiation of spiny-rayed fishes.

    PubMed

    Near, Thomas J; Dornburg, Alex; Eytan, Ron I; Keck, Benjamin P; Smith, W Leo; Kuhn, Kristen L; Moore, Jon A; Price, Samantha A; Burbrink, Frank T; Friedman, Matt; Wainwright, Peter C

    2013-07-30

    Spiny-rayed fishes, or acanthomorphs, comprise nearly one-third of all living vertebrates. Despite their dominant role in aquatic ecosystems, the evolutionary history and tempo of acanthomorph diversification is poorly understood. We investigate the pattern of lineage diversification in acanthomorphs by using a well-resolved time-calibrated phylogeny inferred from a nuclear gene supermatrix that includes 520 acanthomorph species and 37 fossil age constraints. This phylogeny provides resolution for what has been classically referred to as the "bush at the top" of the teleost tree, and indicates acanthomorphs originated in the Early Cretaceous. Paleontological evidence suggests acanthomorphs exhibit a pulse of morphological diversification following the end Cretaceous mass extinction; however, the role of this event on the accumulation of living acanthomorph diversity remains unclear. Lineage diversification rates through time exhibit no shifts associated with the end Cretaceous mass extinction, but there is a global decrease in lineage diversification rates 50 Ma that occurs during a period when morphological disparity among fossil acanthomorphs increases sharply. Analysis of clade-specific shifts in diversification rates reveal that the hyperdiversity of living acanthomorphs is highlighted by several rapidly radiating lineages including tunas, gobies, blennies, snailfishes, and Afro-American cichlids. These lineages with high diversification rates are not associated with a single habitat type, such as coral reefs, indicating there is no single explanation for the success of acanthomorphs, as exceptional bouts of diversification have occurred across a wide array of marine and freshwater habitats.

  3. A late Paleocene probable metatherian (?deltatheroidan) survivor of the Cretaceous mass extinction

    PubMed Central

    Ni, Xijun; Li, Qiang; Stidham, Thomas A.; Li, Lüzhou; Lu, Xiaoyu; Meng, Jin

    2016-01-01

    Deltatheroidans are primitive metatherian mammals (relatives of marsupials), previously thought to have become extinct during the Cretaceous mass extinction. Here, we report a tiny new deltatheroidan mammal (Gurbanodelta kara gen. et sp. nov.) discovered at the South Gobi locality in China (Xinjiang Province) that is the first Cenozoic record of this clade and renders Deltatheroida a Lazarus taxon (with a new record 10 million years younger than their supposed extinction). The vertebrate fauna associated with Gurbanodelta is most similar to that from the slightly older late Paleocene Subeng locality in Inner Mongolia. The upper molars of Gurbanodelta exhibit a broad stylar shelf with one prominent cusp (stylocone), and a paracone that is sharp and significantly taller than the metacone. The lower molar tentatively assigned to Gurbanodelta has a very small talonid without an entoconid. This combination of these features is known only in deltatheroidans. Phylogenetic analysis places Gurbanodelta as the sister taxon of the North American latest Cretaceous Nanocuris. Gurbanodelta is the smallest-known deltatheroidan, and roughly the same size as the smallest living marsupial. It is likely that the Gurbanodelta lineage dispersed between Asia and North America as part of known intercontinental mammalian dispersals in the late Paleocene, or possibly earlier. PMID:27924847

  4. You eat what you are: personality-dependent filial cannibalism in a fish with paternal care.

    PubMed

    Vallon, Martin; Grom, Christina; Kalb, Nadine; Sprenger, Dennis; Anthes, Nils; Lindström, Kai; Heubel, Katja U

    2016-03-01

    Many animal parents invest heavily to ensure offspring survival, yet some eventually consume some or all of their very own young. This so-called filial cannibalism is known from a wide range of taxa, but its adaptive benefit remains largely unclear. The extent to which parents cannibalize their broods varies substantially not only between species, but also between individuals, indicating that intrinsic behavioral differences, or animal personalities, might constitute a relevant proximate trigger for filial cannibalism. Using a marine fish with extensive paternal care, the common goby (Pomatoschistus microps), we investigated the influence of animal personality on filial cannibalism by assessing (1) behavioral consistency across a breeding and a nonbreeding context; (2) correlations between different breeding (egg fanning; filial cannibalism) and nonbreeding (activity) behaviors, and, in a separate experiment; (3) whether previously established personality scores affect filial cannibalism levels. We found consistent individual differences in activity across contexts. Partial filial cannibalism was independent of egg fanning but correlated strongly with activity, where active males cannibalized more eggs than less active males. This pattern was strong initially but vanished as the breeding season progressed. The incidence of whole clutch filial cannibalism increased with activity and clutch size. Our findings indicate that filial cannibalism cannot generally be adjusted independently of male personality and is thus phenotypically less plastic than typically assumed. The present work stresses the multidimensional interaction between animal personality, individual plasticity and the environment in shaping filial cannibalism.

  5. Parasite transfer from crustacean to fish hosts in the Lübeck Bight, SW Baltic Sea

    NASA Astrophysics Data System (ADS)

    Zander, C. D.; Groenewold, S.; Strohbach, U.

    1994-03-01

    Four helminth parasites out of 19 species found in the Lübeck Bight, Baltic Sea, were chosen for investigations on the transfer from invertebrate to small-sized fish hosts: larvae of the tapeworms Schistocephalus sp. and Bothriocephalus sp. (Cestoda) living in planktonic copepods as primary hosts; Podocotyle atomon (Digenea) and Hysterothylacium sp. (Nematoda) were found in benthic crustaceans, especially Gammarus spp. These hosts were the prey of 3 gobiid fishes, Gobiusculus flavescens (feeding mainly on plankton), Pomatoschistus minutus (preferring benthos), and P. pictus (feeding more on plankton than benthos). Because the fishes selected smaller sizes of crustaceans, they ingested all stages of the copepods but only the smaller-sized groups of gammarids which were often less infested by parasites. In order to evaluate the probability for a fish to be parasitized by a helminth, an infestation potential index (IP) was calculated. Podocotyle atomon and Hysterothylacium sp. revealed an IP which was far lower in gobies than expected when the prevalences of the previous hosts were taken into consideration. The IP of tapeworm larvae was mainly influenced by the feeding pressure of the gobiid predators, which might change with developmental stage and season. It is concluded that parasite transfer to the next host decreases when sizes of prey and predator differ only moderately. This mechanism can reduce the numbers of parasites transferred to less suitable or wrong hosts.

  6. Precambrian crystalline basement in southern Mongolia as revealed by SHRIMP zircon dating

    NASA Astrophysics Data System (ADS)

    Demoux, Antoine; Kröner, Alfred; Liu, Dunyi; Badarch, Gombosuren

    2009-09-01

    Single zircon ages determined by ion microprobe (SHRIMP II) for granitoid gneisses from the southern slope of the Baga Bogd massif (Gobi-Altai, southern Mongolia) reveal several episodes of zircon growth, ranging from late Palaeoproterozoic to late Cambrian. The oldest events are documented by a zircon crystallization age for a gneiss protolith at 1519 ± 11 Ma and by a xenocrystic zircon from a dark grey augen-gneiss yielding an age of c. 1701 Ma. Discrete igneous events are recorded in granite-gneisses with protolith emplacement ages of 983 ± 6, 956 ± 3 and 954 ± 8 Ma. These ages provide the first record of early Neoproterozoic magmatic activity in this region. A much younger and discrete magmatic event is recorded by several dioritic to granitic orthogneisses which are tectonically interlayered with the older gneisses and have protolith emplacement ages between 502 and 498 Ma. These late Cambrian granitoids of calc-alkaline affinity are likely to have been emplaced along an active continental margin and suggest that the Baga Bogd Precambrian crustal fragment was either docked against the southward (present-day coordinates) growing margin of the CAOB or was a large enough crustal entity to develop an arc along its margin. We speculate that the Precambrian gneisses of this massif may be part of a crustal fragment rifted off the Tarim Craton.

  7. The trophic importance of algal turfs for coral reef fishes: the crustacean link

    NASA Astrophysics Data System (ADS)

    Kramer, M. J.; Bellwood, O.; Bellwood, D. R.

    2013-06-01

    On coral reefs, the epilithic algal matrix (EAM) is widely recognised as an important resource for herbivorous and detritivorous fishes. In comparison, little is known of the interaction between benthic carnivores and the EAM, despite the abundance of Crustacea within the EAM. The trophic importance of the EAM to fishes was investigated in Pioneer Bay, Orpheus Island, Great Barrier Reef. Fish densities were quantified using visual and clove oil censuses, and gut content analyses conducted on abundant fish species. Crustaceans were found to be an important dietary category, contributing between 49.5 and 100 % of the gut contents, with harpacticoid copepods being the dominant component. Of the benthic carnivores, the goby Eviota zebrina was found to consume the most harpacticoids with a mean of 249 copepods m-2 day-1. This represents approximately 0.1 % of the available harpacticoid population in the EAM. In a striking comparison, herbivorous parrotfishes were estimated to consume over 12,000 harpacticoids m-2 day-1, over 27 times more than all benthic carnivores surveyed, representing approximately 5.3 % of the available harpacticoid copepod population each day. The high consumption of harpacticoid copepods by benthic carnivores and parrotfishes indicates that harpacticoids form an important trophic link between the EAM and higher trophic levels on coral reefs.

  8. Functional type 2 photosynthetic reaction centers found in the rare bacterial phylum Gemmatimonadetes

    PubMed Central

    Zeng, Yonghui; Feng, Fuying; Medová, Hana; Dean, Jason; Koblížek, Michal

    2014-01-01

    Photosynthetic bacteria emerged on Earth more than 3 Gyr ago. To date, despite a long evolutionary history, species containing (bacterio)chlorophyll-based reaction centers have been reported in only 6 out of more than 30 formally described bacterial phyla: Cyanobacteria, Proteobacteria, Chlorobi, Chloroflexi, Firmicutes, and Acidobacteria. Here we describe a bacteriochlorophyll a-producing isolate AP64 that belongs to the poorly characterized phylum Gemmatimonadetes. This red-pigmented semiaerobic strain was isolated from a freshwater lake in the western Gobi Desert. It contains fully functional type 2 (pheophytin-quinone) photosynthetic reaction centers but does not assimilate inorganic carbon, suggesting that it performs a photoheterotrophic lifestyle. Full genome sequencing revealed the presence of a 42.3-kb–long photosynthesis gene cluster (PGC) in its genome. The organization and phylogeny of its photosynthesis genes suggests an ancient acquisition of PGC via horizontal transfer from purple phototrophic bacteria. The data presented here document that Gemmatimonadetes is the seventh bacterial phylum containing (bacterio)chlorophyll-based phototrophic species. To our knowledge, these data provide the first evidence that (bacterio)chlorophyll-based phototrophy can be transferred between distant bacterial phyla, providing new insights into the evolution of bacterial photosynthesis. PMID:24821787

  9. Ecological conversion efficiency and its influencers in twelve species of fish in the Yellow Sea Ecosystem

    NASA Astrophysics Data System (ADS)

    Tang, Qisheng; Guo, Xuewu; Sun, Yao; Zhang, Bo

    2007-09-01

    The ecological conversion efficiencies in twelve species of fish in the Yellow Sea Ecosystem, i.e., anchovy ( Engraulis japonicus), rednose anchovy ( Thrissa kammalensis), chub mackerel ( Scomber japonicus), halfbeak ( Hyporhamphus sajori), gizzard shad ( Konosirus punctatus), sand lance ( Ammodytes personatus), red seabream ( Pagrus major), black porgy ( Acanthopagrus schlegeli), black rockfish ( Sebastes schlegeli), finespot goby ( Chaeturichthys stigmatias), tiger puffer ( Takifugu rubripes), and fat greenling ( Hexagrammos otakii), were estimated through experiments conducted either in situ or in a laboratory. The ecological conversion efficiencies were significantly different among these species. As indicated, the food conversion efficiencies and the energy conversion efficiencies varied from 12.9% to 42.1% and from 12.7% to 43.0%, respectively. Water temperature and ration level are the main factors influencing the ecological conversion efficiencies of marine fish. The higher conversion efficiency of a given species in a natural ecosystem is acquired only under the moderate environment conditions. A negative relationship between ecological conversion efficiency and trophic level among ten species was observed. Such a relationship indicates that the ecological efficiency in the upper trophic levels would increase after fishing down marine food web in the Yellow Sea ecosystem.

  10. The influence of dry lakebeds, degraded sandy grasslands and abandoned farmland in the arid inlands of northern China on the grain size distribution of East Asian aeolian dust

    NASA Astrophysics Data System (ADS)

    Yang, Li-Rong; Yue, Le-Ping; Li, Zhi-Pei

    2008-02-01

    Dry lakes, degraded sandy grasslands, abandoned farmland and mobile dunes which are widely distributed throughout the arid areas of northern China have been investigated in this work. Gain-size distribution of the surface sediments of Manas lake in Junggar basin, Juyan lake in the Alxa plateau, Zhuye lake in Minqin basin and most deserts (such as Mu Us desert, Otindag desert, Horqin desert and Hulun Buir desert) in China have been analyzed. The results show clay with particle sized <10 μm on the surface sediments of dry lakebed and sandy grassland developed from dry lakebed, respectively, account for >60% and ˜50% of the total mass. Since the tiny particles on the surface of abandoned farmland are blown away easily and rapidly, the content of clay particles in Minqin basin is <14%. The grain-size distribution of mobile dunes in northern China mainly consists of particles >63 μm and few particles <10 μm. Consequently, although sand/dust storms originate primarily in the western deserts, the gobi areas of the Alxa plateau, the north and east of Hexi Corridor and in central Mongolia, the widely distributed dry lakebeds, sandy grasslands and abandoned farmland adjacent to the deserts also contribute to aeolian dusts. Hence, the material sources for sand dust storm in East Asia include inland deserts, but also dry lakes, sandy grasslands and abandoned farmland, which are widely distributed throughout the arid inlands of northern China.

  11. Development of standard weight equations for Caribbean and Gulf of Mexico amphidromous fishes

    USGS Publications Warehouse

    Cooney, Patrick B.; Kwak, Thomas J.

    2010-01-01

    We collected and compiled length and weight information from four countries and one commonwealth to develop standard weight (Ws) equations for three amphidromous fish species native to the Caribbean and Gulf of Mexico regions: mountain mullet Agonostomus monticola (N = 9,768 individuals, 52 populations), river goby Awaous banana (N = 1,847 individuals, 62 populations), and bigmouth sleeper Gobiomorus dormitor (N = 2,983 individuals, 53 populations). Linear and quadratic Ws equations for three quartiles (25%, median, 75%) are presented for these three species. The length-weight relationship from eight lentic bigmouth sleeper populations was significantly different from that of lotic populations, reflecting higher weights of juvenile fish (< 70 mm total length) in lentic environments. Thus, independent W(s) equations were developed for lotic populations of bigmouth sleepers. W(s) equations were not developed from lentic bigmouth sleeper populations alone due to the low number of applicable populations caused by life history constraints; the equation from combined lentic and lotic populations is suggested for application to lentic bigmouth sleeper populations. These morphometric relationships for amphidromous fishes may improve the ability to assess existing and potential sport fisheries and allow ecological assessment based on fish condition.

  12. Kin-Aggregations Explain Chaotic Genetic Patchiness, a Commonly Observed Genetic Pattern, in a Marine Fish

    PubMed Central

    Hogan, J. Derek; Downey-Wall, Alan M.; Gurski, Lauren M.; Portnoy, David S.; Heath, Daniel D.

    2016-01-01

    The phenomenon of chaotic genetic patchiness is a pattern commonly seen in marine organisms, particularly those with demersal adults and pelagic larvae. This pattern is usually associated with sweepstakes recruitment and variable reproductive success. Here we investigate the biological underpinnings of this pattern in a species of marine goby Coryphopterus personatus. We find that populations of this species show tell-tale signs of chaotic genetic patchiness including: small, but significant, differences in genetic structure over short distances; a non-equilibrium or “chaotic” pattern of differentiation among locations in space; and within locus, within population deviations from the expectations of Hardy-Weinberg equilibrium (HWE). We show that despite having a pelagic larval stage, and a wide distribution across Caribbean coral reefs, this species forms groups of highly related individuals at small spatial scales (<10 metres). These spatially clustered family groups cause the observed deviations from HWE and local population differentiation, a finding that is rarely demonstrated, but could be more common than previously thought. PMID:27119659

  13. Underwater television observations of Serpula vermicularis (L.) reefs and associated mobile fauna in Loch Creran, Scotland

    NASA Astrophysics Data System (ADS)

    Poloczanska, E. S.; Hughes, D. J.; Burrows, M. T.

    2004-11-01

    The behaviour of Serpula vermicularis reef worms and associated mobile fauna in Loch Creran, on the west coast of Scotland, was recorded for six weeks using underwater television. The reef worms were extended almost continually, generally only retracting when stimulated by the close proximity of a predator. The length of hiding time varied according to the species triggering the reaction. The mean length of time retracted was 21 s. Fauna associated with the reefs included the corkwing wrasse Crenilabrus melops, ballan wrasse Labrus bergylta, black squat lobster Galathea squamifera and velvet swimming crabs Necora puber. There were few significant associations between tidal cycle and the presence/activity of associated fauna but a number of fish and crustacean species appeared to be influenced by