Sample records for hake merluccius gayi

  1. The impact of overfishing and El Niño on the condition factor and reproductive success of Peruvian hake, Merluccius gayi peruanus

    NASA Astrophysics Data System (ADS)

    Ballón, Michael; Wosnitza-Mendo, Claudia; Guevara-Carrasco, Renato; Bertrand, Arnaud

    2008-10-01

    In this study we examine physiological responses of Peruvian hake ( Merluccius gayi peruanus) to changes in their population structure and physical environment during the period 1971-2004. In particular, we assess the relative investment of energy in growth and/or reproduction of small (20-35 cm) and large (35-50 cm) hake. We calculated the (i) condition (Fulton’s K), (ii) gonad and (iii) gut fullness indices for 42,761 female hakes sampled from commercial landings; these indices indicate fish somatic, reproductive and feeding condition, respectively. Using Generalized Additive Models we then examined potential relationships between these indices and sea surface temperature anomalies and date. Drastic energy exhaustion and a decrease in female hake fecundity were observed during El Niño events. The long-term trend showed a general increase in condition factor and a decrease in gonad index for large hake between 1971 and 2004. Small hake exhibited a different trend with an increase in reproductive activity, which was accompanied by an earlier maturation. We hypothesise that the observed low investment of energy in reproduction by large female hake might be related to the lack of large males, due to a sex-selective fishery and the impact of El Niño. We suggest that fishing diminished hake reproductive capacity, modified the sex ratio in favour of females and increased population vulnerability to environmental stress, in particular to the El Niño. The impact of multidecadal variability and predators like the squid, Dosidicus gigas, remain unresolved until longer time series become available.

  2. Effect of Intestinal Tapeworm Clestobothrium crassiceps on Concentrations of Toxic Elements and Selenium in European Hake Merluccius merluccius from the Gulf of Lion (Northwestern Mediterranean Sea).

    PubMed

    Torres, Jordi; Eira, Catarina; Miquel, Jordi; Ferrer-Maza, Dolors; Delgado, Eulàlia; Casadevall, Margarida

    2015-10-28

    The capacity for heavy metal bioaccumulation by some fish parasites has been demonstrated, and their contribution to decreasing metal concentrations in tissues of parasitized fish has been hypothesized. The present study evaluated the effect of the cestode Clestobothrium crassiceps on the accumulation of trace elements in 30 European hake, Merluccius merluccius, in Spain (half of them infested by C. crassiceps). Tissue samples from all M. merluccius and specimens of C. crassiceps from the infected hakes were collected and stored until element analysis by inductively coupled plasma mass spectrometry (ICP-MS). Arsenic, mercury, and selenium were generally present in lower levels in the cestode than in all hake tissues. The mean value of the muscular Se:Hg molar ratio in the infested subsample was higher than that in hakes without cestodes. Values indicate that the edible part of infested hakes presents a lower amount of Cd and Pb in relation to noninfested hakes.

  3. A dynamic and mechanistic model of PCB bioaccumulation in the European hake ( Merluccius merluccius)

    NASA Astrophysics Data System (ADS)

    Bodiguel, Xavier; Maury, Olivier; Mellon-Duval, Capucine; Roupsard, François; Le Guellec, Anne-Marie; Loizeau, Véronique

    2009-08-01

    Bioaccumulation is difficult to document because responses differ among chemical compounds, with environmental conditions, and physiological processes characteristic of each species. We use a mechanistic model, based on the Dynamic Energy Budget (DEB) theory, to take into account this complexity and study factors impacting accumulation of organic pollutants in fish through ontogeny. The bioaccumulation model proposed is a comprehensive approach that relates evolution of hake PCB contamination to physiological information about the fish, such as diet, metabolism, reserve and reproduction status. The species studied is the European hake ( Merluccius merluccius, L. 1758). The model is applied to study the total concentration and the lipid normalised concentration of 4 PCB congeners in male and female hakes from the Gulf of Lions (NW Mediterranean sea) and the Bay of Biscay (NE Atlantic ocean). Outputs of the model compare consistently to measurements over the life span of fish. Simulation results clearly demonstrate the relative effects of food contamination, growth and reproduction on the PCB bioaccumulation in hake. The same species living in different habitats and exposed to different PCB prey concentrations exhibit marked difference in the body accumulation of PCBs. At the adult stage, female hakes have a lower PCB concentration compared to males for a given length. We successfully simulated these sex-specific PCB concentrations by considering two mechanisms: a higher energy allocation to growth for females and a transfer of PCBs from the female to its eggs when allocating lipids from reserve to eggs. Finally, by its mechanistic description of physiological processes, the model is relevant for other species and sets the stage for a mechanistic understanding of toxicity and ecological effects of organic contaminants in marine organisms.

  4. First Record of Anisakis simplex Third-Stage Larvae (Nematoda, Anisakidae) in European Hake Merluccius merluccius lessepsianus in Egyptian Water

    PubMed Central

    Abou-Rahma, Yasmin; Abdel-Gaber, Rewaida; Kamal Ahmed, Amira

    2016-01-01

    The prevalence of infection and the identification of anisakid larvae in European hake Merluccius merluccius lessepsianus from Hurghada City, Red Sea Governorate, Egypt, were investigated. Fish samples were collected during the period of February and November 2014. Twenty-two (36.66%) out of sixty examined fish specimens were found to be naturally infected with Anisakis type I larvae mostly found as encapsulated larvae in visceral organs. There was a positive relationship between host length/weight and prevalence of infection. Based on morphological, morphometric, and molecular analyses, these nematodes were identified as third-stage larvae of Anisakis simplex. The present study was considered as the first report of anisakid larvae from European hake in the Egyptian water. PMID:26925257

  5. New icing media for quality enhancement of chilled hake (Merluccius merluccius) using a jumbo squid (Dosidicus gigas) skin extract.

    PubMed

    Ezquerra-Brauer, Josafat Marina; Miranda, José M; Chan-Higuera, Jesús Enrique; Barros-Velázquez, Jorge; Aubourg, Santiago P

    2017-08-01

    An advanced strategy for chilled fish preservation, based on the inclusion in ice of an extract of jumbo squid (Dosidicus gigas) skin (JSS), is proposed. Aqueous solutions including acetic acid-ethanol extracts of JSS were tested at two different concentrations as icing media, with the effects on the quality evolution of chilled hake (Merluccius merluccius) being monitored. A significant inhibition (P < 0.05) of microbial activity (aerobes, psychrotrophs, Enterobacteriaceae, proteolytic bacteria; pH, trimethylamine) was obtained in hake corresponding to the icing batch including the highest JSS concentration. Additionally, fish specimens from such icing conditions showed an inhibitory effect (P < 0.05) on lipid hydrolysis development, while no effect (P > 0.05) was depicted for lipid oxidation. Sensory analysis (skin and mucus development; eyes; gills; texture; external odour; raw and cooked flesh odour; flesh taste) indicated a shelf life extension of chilled hake stored in ice including the highest JSS concentration. A profitable use of JSS, an industrial by-product during jumbo squid commercialisation, has been developed in the present work, which leads to a remarkable microbial inhibition and a significant shelf life extension of chilled hake. In agreement with previous research, ommochrome pigments (i.e. lipophilic-type compounds) would be considered responsible for this preservative effect. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  6. Endotoxin and biogenic amine levels in Atlantic mackerel (Scomber scombrus), sardine (Sardina pilchardus) and Mediterranean hake (Merluccius merluccius) stored at 22 degrees C.

    PubMed

    Prester, Ljerka; Macan, Jelena; Varnai, Veda Marija; Orct, Tatjana; Vukusic, Jelena; Kipcic, Dubravka

    2009-03-01

    Whole Atlantic mackerel (Scomber scombrus), sardine (Sardina pilchardus) and Mediterranean hake (Merluccius merluccius) from the Croatian Adriatic were stored at 22 degrees C and changes in histamine, putrescine, tyramine and cadaverine levels were monitored in relation to bacterial endotoxin. After 12 h, histamine levels in sardine were above the legal limit of 50 mg kg(-1), set by the US Food and Drug Administration, and an increase in putrescine content preceded the increase in histamine. After 24 h, histamine contents in mackerel and sardine reached 1090 +/- 101 and 577 +/- 275 mg kg(-1), respectively, which exceeded the toxic threshold of 500 mg kg(-1). At the same time, the putrescine content was also high in both fish (353-420 mg kg(-1)). The time-course of endotoxin production was similar in all fish species stored at 22 degrees C. A high correlation was found between endotoxin and histamine, and between endotoxin and putrescine in mackerel and sardine. On the other hand, high endotoxin levels in hake, after 24 h, were associated with the low histamine and putrescine content (40-60 mg kg(-1)).

  7. Influence of sex, maturity and reproduction on PCB and p,p'DDE concentrations and repartitions in the European hake (Merluccius merluccius, L.) from the Gulf of Lions (N.W. Mediterranean).

    PubMed

    Bodiguel, Xavier; Loizeau, Véronique; Le Guellec, Anne-Marie; Roupsard, François; Philippon, Xavier; Mellon-Duval, Capucine

    2009-12-20

    The main objective of this work was to establish the influence of sex, maturity and reproduction on the contamination of the demersal fish Merluccius merluccius by organochlorine compounds. Polychlorinated biphenyls (PCBs) and p,p'DDE were quantified in muscle, liver and gonads of female and male hakes collected in the Gulf of Lions in 2004 and 2005. Observed levels appeared higher than the population of the Bay of Biscay and lower than the population of the Thyrrenian Sea. Contaminant fingerprints were roughly constant whatever the studied organ and the hake biological condition. Concentrations varied significantly according to the sex and maturity of hakes. Mature specimens were more contaminated than immature, and males presented higher levels than females. This sex effect can be linked to a lower growth rate of males, and a contaminant elimination during female spawning. Gonadal contamination depends on the importance of lipid content and increases with the maturation degree. Although the main organ of energy and PCB storage is the liver, muscle appears as the main contributor to the gonad contamination.

  8. Feeding strategy and cannibalism of the Argentine hake Merluccius hubbsi.

    PubMed

    Ocampo Reinaldo, M; González, R; Romero, M A

    2011-12-01

    The diet composition and feeding strategy of the Argentine hake Merluccius hubbsi in the San Matías Gulf were analysed in order to use this information for the sustainable management of the fishery. Merluccius hubbsi behaved as an opportunistic predator. Small M. hubbsi consumed planktonic crustaceans, whereas medium and large fish ate numerous prey taxa with low frequency of occurrence and variable specific abundance. Intra- and intercohort cannibalism were detected in all size groups and were particularly significant in large M. hubbsi. Medium-sized M. hubbsi consumed small conspecifics and large-sized M. hubbsi consumed both small and medium M. hubbsi. These results indicate that the removal of large M. hubbsi by fishing may increase the risk of overfishing by two combined effects: a direct effect of recruitment-overfishing and an indirect effect of growth-overfishing through an enhanced cannibalism of medium M. hubbsi on small M. hubbsi. Intra- and intercohort cannibalism and other trophic relationships in the M. hubbsi should therefore be considered explicitly in stock assessment models. © 2011 The Authors. Journal of Fish Biology © 2011 The Fisheries Society of the British Isles.

  9. Seasonal and annual variation in Chilean hake Merluccius gayi spawning locations and egg size off central Chile

    NASA Astrophysics Data System (ADS)

    Landaeta, Mauricio F.; Castro, Leonardo R.

    2012-01-01

    Variability in Chilean hake reproductive tactics off central Chile was assessed by analyzing ichthyoplankton samples from nine oceanographic cruises (1996-2005) and through experimental trials with early life stages (eggs, yolk-sac larvae) during the main (austral spring) and secondary (late summer-early autumn) spawning seasons. Abundant eggs in the plankton (1300-2000 eggs per 10 m 2) and historical adult reproductive data showed the highest reproductive activity in austral spring, with large egg aggregations near shelf break (50-100 m depth). Large, recently spawned eggs (1.15-1.20 mm diameter) were advected nearshore by coastward subsurface flows in the spring upwelling season. Experimental trials indicated that recently hatched larvae (3.4-3.5 mm) consumed their yolk-sac (0.17-0.41 mm 3) in 3-4 days at 10-12 °C; plankton sampling indicated that larval hake remained at mid-depth (50-100 m) without showing daily vertical migrations until completing their caudal fin formation (∼15 mm). During the secondary reproductive peak, hake spawned nearshore, when smaller eggs (0.95-1.13 mm) and recently hatched larvae (2.2-2.6 mm notochord length) occurred in surface waters (0-10 m depth). Their relatively large yolk-sac volumes (0.57 ± 0.11 mm 3) provided endogenous nourishment for at least 5 days at 10 °C, according to experiments. In the field, preflexion larvae occurred mainly in the mixed layer (0-25 m) and started ontogenetic daily vertical migrations at 7 mm. A strong decline occurred after 2002 in the adult Chilean hake biomass (estimated by hydroacoustic surveys) and body size, coinciding with variations in spawning locations (more coastward in early spring 2004 and 2005) and decline in egg size. Thus, recent variations in Chilean hake reproductive tactics may reflect an indirect effect of declines in the parental population size.

  10. Changes in the diet and feeding of the hake Merluccius merluccius at the shelf-break of the Balearic Islands: Influence of the mesopelagic-boundary community

    NASA Astrophysics Data System (ADS)

    Cartes, Joan E.; Hidalgo, Manuel; Papiol, Vanesa; Massutí, Enric; Moranta, Joan

    2009-03-01

    Short spatio-temporal variations in the feeding intensity and the diet of the European hake, Merluccius merluccius, together with the abundance of their potential prey were studied between August 2003 and June 2004 at two locations, northwest (Sóller) and south (Cabrera), off the island of Mallorca (Balearic Islands, Western Mediterranean) at depths between 150 and 750 m. The two areas present different oceanographic conditions. Hake was mainly distributed along the shelf-slope break and the upper slope (between 166 and 350 m) where recruits (TL<18 cm) were dominant. The hake's diet varied as a function of size. Recruits fed mainly on micronektonic prey, and the diet was influenced primarily by seasonality, with two dietary patterns (identified by MDS analyses) corresponding to August-September 2003 (summer) and to November 2003/February-April 2004 (autumn-winter). The summer pattern was consistent with a thermally stratified water column, while November and April were consistent with homogenized temperature and salinity throughout all the water column. The main prey of recruits were the euphausiid Meganyctiphanes norvegica and the midwater fish Maurolicus muelleri in autumn-winter and myctophids (mainly Ceratoscopelus maderensis) in summer. In contrast to recruits, the geographic factor (NW vs. S) was the main factor influencing the diets of post-recruits (TL between 18 and 21.9 cm) and adults (TL⩾22 cm). Hake recruits (and to a lesser extent post-recruits) and their preferred prey occupied different depth ranges during daylight periods. Meganyctiphanes norvegica and Ceratoscopelus maderensis were, for instance, distributed as much as 500 m deeper than hake that had eaten them. All these trends were especially obvious at NW, an area with a more abrupt slope and with a greater influence by northern winter intermediate water (WIW) inflow in early spring than the S area. These factors probably enhanced micronekton aggregation in April, when feeding intensity

  11. Morphological and molecular characterisation of Aporocotyle margolisi Smith, 1967 (Digenea: Aporocotylidae) from the North Pacific hake Merluccius productus (Ayres) (Gadiformes: Merlucciidae) off Oregon, USA.

    PubMed

    Hernández-Orts, Jesus S; Hernández-Mena, David I; Alama-Bermejo, Gema; Kuchta, Roman; Jacobson, Kym C

    2017-09-01

    Aporocotylid blood flukes conspecific with Aporocotyle margolisi Smith, 1967 were collected from the bulbus arteriosus of the North Pacific hake Merluccius productus (Ayres). This study revisits the morphology of A. margolisi, including drawings, measurements and scanning electron microscopy images, and provides for the first time molecular data for the large subunit of the ribosomal RNA (28S rDNA) and the mitochondrial cytochrome c oxidase subunit 1 (cox1) genes for this species. A 28S rDNA phylogenetic study of A. margolisi, and all available Aporocotyle spp., was also performed. The distribution range of A. margolisi is extended to the Pacific coast of the USA. We provide a morphological comparison of Aporocotyle spp. from the Pacific coast in North America as well as other Aporocotyle spp. infecting hake. Comparisons with the original description revealed that the new specimens of A. margolisi were considerably larger with respect to all morphological features, except for shorter spines. Molecular results showed a close relationship between A. margolisi and A. argentinensis Smith, 1969 from the Argentine hake Merluccius hubbsi Marini. The phylogenetic relationships of Aporocotyle spp. point to a possible co-speciation of hakes species and these blood fluke parasites.

  12. A multitracer approach to assess the spatial contamination pattern of hake (Merluccius merluccius) in the French Mediterranean.

    PubMed

    Cresson, Pierre; Bouchoucha, Marc; Morat, Fabien; Miralles, Francoise; Chavanon, Fabienne; Loizeau, Veronique; Cossa, Daniel

    2015-11-01

    Chemical contamination levels and stable isotope ratios provide integrated information about contaminant exposure, trophic position and also biological and environmental influences on marine organisms. By combining these approaches with otolith shape analyses, the aim of the present study was to document the spatial variability of Hg and PCB contamination of the European hake (Merluccius merluccius) in the French Mediterranean, hypothesizing that local contaminant sources, environmental conditions and biological specificities lead to site-specific contamination patterns. High Hg concentrations discriminated Corsica (average: 1.36 ± 0.80 μg g(-1) dm) from the Gulf of Lions (average values<0.5 μg g(-1) dm), where Rhône River input caused high PCB burdens. CB 153 average concentrations ranged between 4.00 ± 0.64 and 18.39 ± 12.38 ng g(-1) dm in the Gulf of Lions, whatever the sex of the individuals, whereas the highest values in Corsica were 6.75 ± 4.22 ng g(-1) dm. Otolith shape discriminated juveniles and adults, due to their different habitats. The use of combined ecotracers was revealed as a powerful tool to discriminate between fish populations at large and small spatial scale, and to enable understanding of the environmental and biological influences on contamination patterns. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. The biology and fisheries of European hake, Merluccius merluccius, in the north-east Atlantic.

    PubMed

    Murua, Hilario

    2010-01-01

    The aim of this chapter is to review the biology and fishery, including the management, of European hake in the north-east Atlantic. The European hake is widely distributed throughout the north-east Atlantic, from Norway in the north to the Guinea Gulf in the south, and throughout the Mediterranean and Black Sea, being more abundant from the British Isles to the south of Spain. In this area, ICES (International Council for the Exploration of the Sea) recognises the existence of two stocks: the northern stock and the southern stock. Both stocks have been extensively and intensively harvested and since the beginning of the 90s have been considered to be outside safe biological limits. The northern stock, however, is currently considered to lie within safe biological limits. In any case, recovery plans were implemented for the northern stock in 2004 and for the southern stock in 2006. Despite its commercial importance, knowledge of the biology and ecology of the European hake in the North Atlantic is still quite scarce. For example, recent investigations suggest that European hake grows much faster, by a factor of two, than was considered previously. This faster growth also affects the maturity-at-age pattern of hake and the agreed maturity-at-age ogive used in the assessments. European hake is a top predator in the demersal community in the north-east Atlantic area; mainly preying on blue whiting, horse mackerel and other cupleids. In relation to the reproductive biology, European hake is considered to be a batch spawner species with indeterminate fecundity and spawning activity all year round. All these characteristics could, in turn, be interpreted as European hake adopting a more opportunistic life strategy, which is unusual for a gadoid and demersal species, and raises several questions about hake biology and ecology that require further investigation. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. Dynamics and fishery of the Peruvian hake: Between nature and man

    NASA Astrophysics Data System (ADS)

    Guevara-Carrasco, Renato; Lleonart, Jordi

    Mean length in the catch of Peruvian hake ( Merluccius gayi peruanus) declined drastically by 8 cm in a few months in 1992. The 1991-93 El Niño event marked the beginning of changes in bottom environmental conditions, that along with other changes in the ecosystem, were the cause of the disappearance of large sized old hake from the traditional fishing grounds and the invasion of these areas by high concentrations of small sized young hake, traditionally distributed in the southern areas. A misinterpretation of this change gave an optimistic perception of the state of the stock, leading to a large increase of the fishing fleet and therefore to an increase of the fishing pressure on this resource. Catch increased quickly to very high levels in 1996, the fishery indicators of relative abundance remained stable, while global abundance of hake was diminishing. The resource responded to these natural variations of environment and to the intense fishing pressure with changes in some aspects of its biology and ecology. The most remarkable was the decrease of the length and age at first maturity that led to spawning by 1 year old (19 cm) individuals in a species whose observed longevity was 14 years. In 2002 a total and indefinite fishery closure was established by the Peruvian government and a technical commission for the hake recovery was created, which carried out continuous monitoring of the stock. After a closure of 20 months the indicators showed signs of recovery and the fishery was reopened in 2004. However, after an encouraging beginning during 2004 and the first quarter of 2005, neither abundance nor age structure had improved by the end of 2005, and in fact were deteriorating by the start of 2006. The survival of the age 2 and 3 groups was very low and few 4+ years old individuals were observed. Several factors working at different time scales have been proposed to explain the status of hake. The impact of the fishery, variations in the abiotic environment

  15. Spatial patterns of copepod biodiversity in relation to a tidal front system in the main spawning and nursery area of the Argentine hake Merluccius hubbsi

    NASA Astrophysics Data System (ADS)

    Temperoni, B.; Viñas, M. D.; Martos, P.; Marrari, M.

    2014-11-01

    Copepods play an important role in marine ecosystems as a direct link of energy transfer between primary producers and higher trophic level consumers, such as fish. In the Argentine Sea, the Patagonian stock of Argentine hake Merluccius hubbsi spawns from late austral spring (December) to early autumn (April) in the northern Patagonian shelf region (43°-45°30‧S), in association with a highly productive tidal front system. Since hake larvae prey mainly upon copepods, the objective of this study was to assess the spatial variability in the abundance and diversity of these potential food items in different sectors of the front, as one of the possible factors affecting hake recruitment success. Two complementary mesh sizes (67 and 300 μm) were used to accurately target the entire copepod size spectrum. The copepod community was dominated by developmental stages < 1 mm in total length (eggs, nauplii, copepodites of cyclopoids and calanoids), and adults of the species Oithona helgolandica, Microsetella norvegica, Ctenocalanus vanus and Drepanopus forcipatus. Their spatial distribution was highly influenced by the across-shelf characteristics of the tidal front system, highlighting the impact of environmental features, mainly bottom temperature and salinity, in shaping the community. Abundances were higher in the transitional relative to the stratified sector of the system. Such sector would provide the appropriate conditions to sustain M. hubbsi larval growth resulting from high availability of adequate prey, the suitable thermal ranges, and the existence of retention mechanisms.

  16. Silver hake tracks changes in Northwest Atlantic circulation.

    PubMed

    Nye, Janet A; Joyce, Terrence M; Kwon, Young-Oh; Link, Jason S

    2011-08-02

    Recent studies documenting shifts in spatial distribution of many organisms in response to a warming climate highlight the need to understand the mechanisms underlying species distribution at large spatial scales. Here we present one noteworthy example of remote oceanographic processes governing the spatial distribution of adult silver hake, Merluccius bilinearis, a commercially important fish in the Northeast US shelf region. Changes in spatial distribution of silver hake over the last 40 years are highly correlated with the position of the Gulf Stream. These changes in distribution are in direct response to local changes in bottom temperature on the continental shelf that are responding to the same large scale circulation change affecting the Gulf Stream path, namely changes in the Atlantic meridional overturning circulation (AMOC). If the AMOC weakens, as is suggested by global climate models, silver hake distribution will remain in a poleward position, the extent to which could be forecast at both decadal and multidecadal scales.

  17. Radioactive zinc ( sup 65 Zn), zinc, cadmium, and mercury in the Pacific Hake, Merluccius productus (Ayres), off the West Coast of the United States

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Naidu, J.R.

    1974-06-01

    The Pacific Hake, Merluccius productus (Ayers) was used to monitor the waters off Puget Sound and the West Coast of the US for zinc(Zn), cadmium(Cd), mercury(Hg) and {sup 65}Zn. The Columbia River is not the source of Zn, Cd or Hg contamination, but is the source of {sup 65}Zn, with the concentration in the Hake reflecting the position of the Columbia River plume. Zn and Cd accumulation in the Hake were fit to the equation Y=B{sub 1}+B{sub 2}e{sup B}{sub 3}X where Y is the concentration of the element and X is the length or weight of the fish. Biological attributesmore » were assigned to the other parameters as follows: B{sub 1} is the asymptotic value for Zn or Cd at chemical maturity; B{sub 2} is the location of the curve with respect to the length or weight of the fish; and B{sub 3} is a constant pertaining to the rate of change of Zn or Cd. Although Zn, Cd and Hg are all Group 2B elements, only the concentrations of Zn and Cd were correlated for all locations; Hg concentrations varied as a function of location. Zn and Cd concentrations increase with fish size and approach an asymptotic value at maturity, while Hg concentrations were linear and the slope is a function of sampling location. Zn and Cd levels are regulated in the adult, while Hg continues to increase with age. It may be significant that the age distribution of fish caught commercially coincides with the maximum concentration of Zn and Cd. 195 refs., 30 figs., 10 tabs. (MHB)« less

  18. Acoustical Scattering, Propagation, and Attenuation Caused by Two Abundant Pacific Schooling Species: Humboldt Squid and Hake

    DTIC Science & Technology

    2014-09-30

    exercises, the most abundant species by biomass is Pacific hake, Merluccius productus, a fish with an air-filled swimbladder that averages 50 cm in length...its type of prey) may affect the scattering characteristics of the animal especially if the animal has eaten hard- shelled mollusc prey. Figure 7

  19. Use of sand wave habitats by silver hake

    USGS Publications Warehouse

    Auster, P.J.; Lindholm, J.; Schaub, S.; Funnell, G.; Kaufman, L.S.; Valentine, P.C.

    2003-01-01

    Silver hake Merluccius bilinearis are common members of fish communities in sand wave habitats on Georges Bank and on Stellwagen Bank in the Gulf of Maine. Observations of fish size v. sand wave period showed that silver hake are not randomly distributed within sand wave landscapes. Regression analyses showed a significant positive relationship between sand wave period and fish length. Correlation coefficients, however, were low, suggesting other interactions with sand wave morphology, the range of current velocities, and available prey may also influence their distribution. Direct contact with sand wave habitats varied over diel periods, with more fish resting on the seafloor during daytime than at night. Social foraging, in the form of polarized groups of fish swimming in linear formations during crepuscular and daytime periods, was also observed. Sand wave habitats may provide shelter from current flows and mediate fish-prey interactions. ?? 2003 The Fisheries Society of the British Isles.

  20. Role of oceanography in shaping the genetic structure in the North Pacific hake Merluccius productus

    PubMed Central

    2018-01-01

    Determining the relative influence of biotic and abiotic factors on genetic connectivity among populations remains a major challenge in evolutionary biology and in the management and conservation of species. North Pacific hake (Merluccius productus) inhabits upwelling regions in the California Current ecosystem from the Gulf of California to the Gulf of Alaska. In this study, we examined mitochondrial DNA (mtDNA) and microsatellite variation to estimate levels of genetic differentiation of M. productus in relation to the role of oceanographic features as potential barriers to gene flow. Samples were obtained from nine sites spanning a large part of the geographic range of the species, from Puget Sound, Washington to Costa Rica. The microsatellite results revealed three genetically discrete populations: one spanning the eastern Pacific coast, and two apparently resident populations circumscribed to the Puget Sound and the northern Gulf of California (FST = 0.032, p = 0.036). Cytochrome b sequence data indicated that isolation between the Puget Sound and northern Gulf of California populations from the coastal Pacific were recent phenomena (18.5 kyr for Puget Sound and 40 kyr for the northern Gulf of California). Oceanographic data obtained from the Gulf of California support the hypothesis that permanent fronts within the region, and strong gradients at the entrance to the Gulf of California act as barriers to gene flow. A seascape genetics approach found significant genetic–environment associations, where the daytime sea surface temperature and chlorophyll concentrations were the best predictive variables for the observed genetic differentiation. Considering the potential causes of genetic isolation among the three populations, e.g. spawning areas in different latitudes associated with upwelling processes, oceanographic barriers, asymmetric migration and specialized diet, oceanographic barriers appear to be a likely mechanism restricting gene flow. PMID:29579060

  1. Role of oceanography in shaping the genetic structure in the North Pacific hake Merluccius productus.

    PubMed

    García-De León, Francisco Javier; Galván-Tirado, Carolina; Sánchez Velasco, Laura; Silva-Segundo, Claudia A; Hernández-Guzmán, Rafael; Barriga-Sosa, Irene de Los Angeles; Díaz Jaimes, Píndaro; Canino, Michael; Cruz-Hernández, Pedro

    2018-01-01

    Determining the relative influence of biotic and abiotic factors on genetic connectivity among populations remains a major challenge in evolutionary biology and in the management and conservation of species. North Pacific hake (Merluccius productus) inhabits upwelling regions in the California Current ecosystem from the Gulf of California to the Gulf of Alaska. In this study, we examined mitochondrial DNA (mtDNA) and microsatellite variation to estimate levels of genetic differentiation of M. productus in relation to the role of oceanographic features as potential barriers to gene flow. Samples were obtained from nine sites spanning a large part of the geographic range of the species, from Puget Sound, Washington to Costa Rica. The microsatellite results revealed three genetically discrete populations: one spanning the eastern Pacific coast, and two apparently resident populations circumscribed to the Puget Sound and the northern Gulf of California (FST = 0.032, p = 0.036). Cytochrome b sequence data indicated that isolation between the Puget Sound and northern Gulf of California populations from the coastal Pacific were recent phenomena (18.5 kyr for Puget Sound and 40 kyr for the northern Gulf of California). Oceanographic data obtained from the Gulf of California support the hypothesis that permanent fronts within the region, and strong gradients at the entrance to the Gulf of California act as barriers to gene flow. A seascape genetics approach found significant genetic-environment associations, where the daytime sea surface temperature and chlorophyll concentrations were the best predictive variables for the observed genetic differentiation. Considering the potential causes of genetic isolation among the three populations, e.g. spawning areas in different latitudes associated with upwelling processes, oceanographic barriers, asymmetric migration and specialized diet, oceanographic barriers appear to be a likely mechanism restricting gene flow.

  2. Cooperation between scientists, NGOs and industry in support of sustainable fisheries: the South African hake Merluccius spp. trawl fishery experience.

    PubMed

    Field, J G; Attwood, C G; Jarre, A; Sink, K; Atkinson, L J; Petersen, S

    2013-10-01

    This paper examines the increasingly close interaction between natural and social scientists, non-governmental organizations (NGO) and industry, in pursuit of responsible ecosystem-based management of fisheries. South Africa has committed to implementing an ecosystem approach to fisheries management. Management advice stems from multi-stakeholder representation on government-led scientific and management working groups. In the hake Merluccius capensis and Merluccius paradoxus fishery, the primary management measure is an annual total allowable catch (TAC), the level of which is calculated using a management procedure (MP) that is revised approximately every 4 years. Revision of the MP is a consultative process involving most stakeholders, and is based on simulation modelling of projected probable scenarios of resource and fishery dynamics under various management options. NGOs, such as the Worldwide Fund for Nature in South Africa (WWF-SA), have played an important role in influencing consumers, the fishing industry and government to develop responsible fishing practices that minimize damage to marine ecosystems. Cooperation between industry, government and scientists has helped to improve sustainability and facilitated the meeting of market-based incentives for more responsible fisheries. Research includes ecosystem modelling, spatial analysis and ecosystem risk assessment with increasing research focus on social and economic aspects of the fishery. A four-year cooperative experiment to quantify the effect of trawling on benthic community structure is being planned. The food requirements of top predators still need to be included in the TAC-setting formulae and more social and economic research is needed. This paper also demonstrates how NGO initiatives such as Marine Stewardship Council certification and the Southern African Sustainable Seafood Initiative, a traffic light system of classifying seafood for consumers, have contributed to responsible fishing

  3. Endoparasite fauna of five Gadiformes fish species from the coast of Chile: host ecology versus phylogeny.

    PubMed

    Chávez, R A; González, M T; Oliva, M E; Valdivia, I M

    2012-03-01

    The aims of the present study were to compare, using multivariate analyses, the degree of similarity of the endoparasite fauna of five fish species belonging to the order Gadiformes: Merluccius gayi, Merluccius australis, Macruronus magellanicus (Gadoidei) and Micromesistius australis and Nezumia pulchella (Macrouroidei), from the southern and central Chilean coast, and to evaluate whether the composition of the endoparasite fauna was determined by phylogenetic or ecological relationships. We employed our database of Merluccius australis, M. magellanicus and Micromesistius australis, which was complemented with published information for M. magellanicus, Merluccius australis, Micromesistius australis, M. gayi and N. pulchella. A higher number of endoparasite species was recorded for Merluccius australis, Micromesistius australis and M. magellanicus, namely Anisakis sp. and Hepatoxylon trichiuri, which is the most prevalent parasite among these hosts. Aporocotyle wilhelmi and Hysterothylacium sp. were detected only in M. gayi, whereas Lepidapedon sp. was found exclusively in N. pulchella. These results suggest that fish ecology rather than host phylogeny was the most important factor for the determination of similarity in parasite composition. This result could be explained by the similar trophic patterns of hosts and by the predominance of generalist larval species among these fish parasite communities.

  4. Effects of High-Pressure Treatment on the Muscle Proteome of Hake by Bottom-Up Proteomics.

    PubMed

    Carrera, Mónica; Fidalgo, Liliana G; Saraiva, Jorge A; Aubourg, Santiago P

    2018-05-02

    A bottom-up proteomics approach was applied for the study of the effects of high-pressure (HP) treatment on the muscle proteome of fish. The performance of the approach was established for a previous HP treatment (150-450 MPa for 2 min) on frozen (up to 5 months at -10 °C) European hake ( Merluccius merluccius). Concerning possible protein biomarkers of quality changes, a significant degradation after applying a pressure ≥430 MPa could be observed for phosphoglycerate mutase-1, enolase, creatine kinase, fructose bisphosphate aldolase, triosephosphate isomerase, and nucleoside diphosphate kinase; contrary, electrophoretic bands assigned to tropomyosin, glyceraldehyde-3-phosphate dehydrogenase, and beta parvalbumin increased their intensity after applying a pressure ≥430 MPa. This repository of potential protein biomarkers may be very useful for further HP investigations related to fish quality.

  5. Multi-sensor Oceanographic Correlations for Pacific Hake Acoustic Survey Improvement

    NASA Astrophysics Data System (ADS)

    Brozen, M.; Hillyer, N.; Holt, B.; Armstrong, E. M.

    2010-12-01

    North Pacific hake (Merluccius productus), the most abundant groundfish along the Pacific coast of northwestern America, are an essential source of income for the coastal region from southern California to British Columbia, Canada. However, hake abundance and distribution are highly variable among years, exhibiting variance in both the north-south and east-west distribution as seen in the results from biannual acoustic surveys. This project is part of a larger undertaking, ultimately focused on the prediction of hake distribution to improve the distribution of survey effort and precision of stock assessments in the future. Four remotely sensed oceanographic variables are examined as a first step in improving our understanding the relationship between the intensity of coastal upwelling and other ocean dynamics, and the north-south summer hake distribution. Sea surface height, wind vectors, chlorophyll - a concentrations, and sea surface temperature were acquired from several satellites, including AVHRR, SeaWifs, TOPEX/Poseidon, Jason-1, Jason-2, SSM/I, ASMR-E, and QuikScat. Data were aligned to the same spatial and temporal resolution, and these re-gridded data were then analyzed using empirical orthogonal functions (EOFs). EOFs were used as a spatio-temporally compact representation of the data and to reduce the co-variability of the multiple time series in the dataset. The EOF results were plotted and acoustic survey results were overlaid to understand differences between regions. Although this pilot project used data from only a single year (2007), it demonstrated a methodology for reducing dimensionality of linearly related satellite variables that can used in future applications, and provided insight into multi-dimensional ocean characteristics important for hake distribution.

  6. Acoustical Scattering, Propagation, and Attenuation Caused by Two Abundant Pacific Schooling Species: Humboldt Squid and Hake

    DTIC Science & Technology

    2015-09-30

    an area important for acoustical testing and tactical exercises, the most abundant species by biomass is Pacific hake, Merluccius productus, a fish...scattering characteristics of the animal especially if the animal has eaten hard- shelled mollusc prey. Figure 7. A dorsal scan (similar to an x-ray) of a...kHz echogram. 11 In order to generate abundance and biomass estimates for organisms using active acoustics, one assumption that can be made is

  7. Pacific Hake Characteristics Affecting the Conduct of an Acoustic Clutter Experiment off the West Coast of the United States

    DTIC Science & Technology

    2012-07-04

    Blois , L. C. Hufnagle, A. R. Kronlund, J. A. Holmes, and C. D. Wilson, "The 2003 Integrated Acoustic and Trawl Survey of Pacific Hake, Merluccius...Center, Seattle, WA, 2005. 17. Fleischer, G. W., K. D. Cooke, P. H. Ressler, R. E. Thomas, S. K. de Blois , and L. C. Hufnagle, "The 2005 Integrated...Marine Fisheries Service, Northwest Fisheries Science Center, Seattle, WA, 2008. 18. de Blois , S. K., D. Chu, and K. D. Cooke, "Results of the 2007

  8. [IMPACT OF SIX COOKING TECHNIQUES ON FATTY ACID COMPOSITION OF MARLIN (MAKAIRA NIGRICANS) AND HAKE (MERLUCCIUS PRODUCTUS)].

    PubMed

    Castro-González, María Isabel; Carrillo-Domínguez, Silvia

    2015-09-01

    the regular consumption of fish brings benefits to health due to its content of n-3 fatty acids, but cooking enhances or damages the concentration of fatty acids (FA) since they are susceptible to oxidation by temperatures and cooking times. to analyze the effect of six cooking techniques on total lipids (TL) and (FA) content in marlin and hake and select which one helps the best conservation of health beneficial FA. fillets were subjected to different cooking techniques: steam (ST), foiled-aluminum-paper (FAP), foiled- banana-leaf (FBL), gas-oven (GO), microwave-oven (MO) and fried-lightly (FL). FA were identified by gas chromatography/FID. Marlin: FL increased the concentration of TL and MO decreased it. Statistically, PUFA, SFA and EPA + DHA increased with FAP, MUFA decreased with FBL and increased in FL. Hake: FL increased concentration in all groups of FA while ST decreased it. SFA values and index of atherogenicity (IA), thrombogenicity (IT), peroxidisability and hipocolesterolemic/ hipercolesterolemic fatty acid ratio (HH) found, suggested that hake is a fish with greater health benefits, regardless of the technique you employ. By its EPA + DHA content, marlin seems to be an excellent choice if cooked FAP. FL technique in both species decreased the IA, IT and significantly increased the HH; however n3/n6 ratio decreased. ST seems to be the least desirable cooking technique for both species. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

  9. The influence of oceanographic scenarios on the population dynamics of demersal resources in the western Mediterranean: Hypothesis for hake and red shrimp off Balearic Islands

    NASA Astrophysics Data System (ADS)

    Massutí, Enric; Monserrat, Sebastià; Oliver, Pere; Moranta, Joan; López-Jurado, José Luis; Marcos, Marta; Hidalgo, Manuel; Guijarro, Beatriz; Carbonell, Aina; Pereda, Pilar

    2008-06-01

    The aim of the present paper is to study the relationships between some climatic indices and parental stock, recruitment and accessibility to trawl fishery of hake ( Merluccius merluccius) and red shrimp ( Aristeus antennatus) off Balearic Islands (western Mediterranean). Available annual catch per unit effort, recruitment and spawning stock biomass have been used as biological data. As environmental data, the meso-scale IDEA index and the large-scale North Atlantic Oscillation (NAO) and Mediterranean Oscillation (MO) indices have been used. To analyze possible links between these indices with the population dynamics of demersal resources, two non-linear approaches have been applied: (i) stock-recruitment relationships from Ricker and Beverton-Holt models, by sequentially incorporating environment factors; (ii) generalized additive modelling, both classical general and threshold non-additive models were considered. The latter simulate an abrupt change in explicative variables across different phases (time periods or climatic index values). The results have shown that two oceanographic scenarios around the Balearic Islands, associated with macro and meso-scale climate regimes, can influence the population dynamics of hake and red shrimp. This is especially true for recruitment, which seems to be enhanced during low NAO and IDEA indices periods. During these periods, colder-than-normal winters generate high amounts of cold Western Mediterranean Intermediate Waters (WIW) in the Gulf of Lions, which flow southwards and reach the Balearic Islands channels in spring, increasing the productivity in the area. This oceanographic scenario could also be favourable to the distribution of hake on the fishing grounds where the trawl fleet targets this species, increasing its accessibility to the fishery. Both spawning stock and abundance of red shrimp seems to be also enhanced by high MO index periods, which could reflect the increased presence of the saline and warm Levantine

  10. Food web and fish stock changes in central Chile: comparing the roles of jumbo squid (Dosidicus gigas) predation, the environment, and fisheries

    NASA Astrophysics Data System (ADS)

    Neira, Sergio; Arancibia, Hugo

    2013-10-01

    We analyzed recent food web and fish stock changes in the central Chile marine ecosystem, comparing the roles of jumbo squid (Dosidicus gigas) as predator, the environment, and fishing. To accomplish this we used food web modeling and the Ecopath with Ecosim software (EwE). The principal fish stocks have experienced wide decadal fluctuations in the past 30 years, including stock collapses of horse mackerel (Trachurus murphyi) and hake (Merluccius gayi), and there was a large influx of jumbo squid during the mid-2000s. We used two EwE models representing the food web off central Chile to test the hypothesis that predation by jumbo squid has been significant in explaining the dynamics of the main fishing resources and other species in the study area. Results indicate that predation by jumbo squid on fish stocks is lower than that of other predators (e.g. hake) and the fishery. Long-term fluctuations (1978-2004) in the biomass of the main fish stocks (as well as other components of the food web) seem to be related to fishing and to variation in primary production, rather than to predation by jumbo squid alone. Jumbo squid seems to play a role as predator rather than prey in the system, but its impacts are low when compared with the impacts of other predators and fishing. Therefore, we conclude that jumbo squid predation on its prey was not the primary force behind the collapse of important fish stocks off central Chile. Future efforts should be directed to better understanding factors that trigger sudden increases in jumbo squid abundance off central Chile, as well as modeling its trophic impacts.

  11. Biases in determining the diet of jumbo squid Dosidicus gigas (D' Orbigny 1835) (Cephalopoda: Ommastrephidae) off southern-central Chile (34°S-40°S)

    NASA Astrophysics Data System (ADS)

    Ibáñez, Christian M.; Arancibia, Hugo; Cubillos, Luis A.

    2008-12-01

    The diet of jumbo squid ( Dosidicus gigas) off southern-central Chile is described to examine potential biases in the determination of their main prey. Specimens were collected from catches using different fishing gear (jigging, trawl and purse-seine), from July 2003 to January 2004, and from December 2005 to October 2006. The stomach contents were analyzed in terms of frequency of occurrence, number, and weight of prey items and the diet composition was analyzed using Detrended Correspondence Analysis. In the industrial purse-seine fleet for jack mackerel ( Trachurus murphyi), the dominant prey of D. gigas was T. murphyi. In the industrial mid-trawl fishery for Patagonian grenadier ( Macruronus magellanicus), the dominant species in the diet of D. gigas was M. magellanicus. Similarly, Chilean hake ( Merluccius gayi) was the main prey in the diet of D. gigas obtained in the industrial trawl fishery for Chilean hake; and, in both artisanal fisheries (purse-seine for small pelagics and jigging), small pelagic fish and D. gigas were the main prey in the stomach contents of D. gigas. Cannibalism in D. gigas varied between different fleets and probably is related to stress behavior during fishing. The Detrended Correspondence Analysis ordination showed that the main prey in the diet of D. gigas is associated with the target species of the respective fishery. Consequently, biases are associated with fishing gear, leading to an overestimate in the occurrence of the target species in the diet. We recommend analyzing samples from jigging taken at the same time and place where the trawl and purse-seine fleets are operating to avoid this problem, and the application of new tools like stable isotope, heavy metal, and fatty acid signature analyses.

  12. Antioxidative and angiotensin-I-converting enzyme inhibitory potential of a Pacific Hake ( Merluccius productus ) fish protein hydrolysate subjected to simulated gastrointestinal digestion and Caco-2 cell permeation.

    PubMed

    Samaranayaka, Anusha G P; Kitts, David D; Li-Chan, Eunice C Y

    2010-02-10

    Pacific hake fish protein hydrolysate (FPH) with promising chemical assay based antioxidative capacity was studied for in vitro angiotensin-I-converting enzyme (ACE)-inhibitory potential, intestinal cell permeability characteristics, and intracellular antioxidative potential using the Caco-2 cell model system. FPH showed substrate-type inhibition of ACE with IC(50) of 161 microg of peptides/mL. HPLC analysis revealed that different peptides were responsible for antioxidative and ACE-inhibitory activity. FPH inhibited 2,2'-azobis(2-amidinopropane) dihydrochloride-induced oxidation in Caco-2 cells at noncytotoxic concentrations. In vitro simulated gastrointestinal digestion increased (P < 0.05) antioxidative capacity; ACE-inhibitory activity of FPH remained unchanged, although individual peptide fractions showed decreased or no activity after digestion. Some FPH peptides passed through Caco-2 cells: the permeates showed 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity but no ACE-inhibitory activity. These results suggest the potential for application of Pacific hake FPH to reduce oxidative processes in vivo. Further studies are needed to assess prospective antihypertensive effects.

  13. Modeling warming predicts a physiological threshold for the extinction of the living fossil frog Calyptocephalella gayi.

    PubMed

    Vidal, Marcela A; Novoa-Muñoz, Francisco; Werner, Enrique; Torres, Cristian; Nova, Ricardo

    2017-10-01

    Global climate change will have a greater impact on ectotherms in tropical and subtropical communities than at higher latitudes, because ambient temperatures are closer to the upper thermal limits of species. Amphibian species are highly dependent on external weather conditions, and the effect of global warming on these has been evaluated recently. The Great Chilean frog (Calyptocephalella gayi) is an endemic, monotypic species and genus whose conservation status is considered Vulnerable because of high extraction pressure for human consumption, lack of regulatory measures and comprehension by its consumers. Their populations have also declined due to the loss and destruction of their habitats. C. gayi has not been considered as an object of physiological study, so this large species is not known as one that can adapt to current environmental changes. In this study we analyze the thermoregulatory capacity and thermal efficiency of C. gayi to determine its potential for climatic adaptation. The results indicate that this species is strictly a thermal-conformer; its thermal efficiency and its ability to withstand high temperatures allow it to sustain itself under a climate change scenario, however, it has thermal constraints that do not allow it to withstand temperatures greater than 30°C. By modeling its ontogenetic conditions mathematically, we project that the larvae are not in danger, although there is a group of around 4% which is very close to 30°C, which is the highest temperature recorded for the species. However, about 40% of subadults and approximately 47% of adult frogs will not survive the change of ~7°C projected for the following 85 years, which will affect future generations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. 77 FR 48915 - Fisheries of the Northeastern United States; Northeast Multispecies Fishery; White Hake Trimester...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-15

    ... Fishery; White Hake Trimester Total Allowable Catch Area Closure for the Common Pool Fishery AGENCY... (TAC) Area to all common pool vessels fishing with trawl gear, sink gillnet gear, or longline/hook gear... common pool fishery from exceeding its Trimester 1 TAC or its annual catch limit for white hake. This...

  15. Species- and size-specific variability of mercury concentrations in four commercially important finfish and their prey from the northwest Atlantic.

    PubMed

    Staudinger, Michelle D

    2011-04-01

    Total mercury was analyzed as a function of body length, season, and diet in four commercially and recreationally important marine fish, bluefish (Pomatomus saltatrix), goosefish (Lophius americanus), silver hake (Merluccius bilinearis), and summer flounder (Paralichthys dentatus), collected from continental shelf waters of the northwest Atlantic Ocean. Mercury levels in the dorsal muscle tissue of 115 individuals ranged from 0.006 to 1.217 μg/g (wet weight) and varied significantly among species. The relationship between predator length and mercury concentration was linear for bluefish and summer flounder, while mercury levels increased with size at an exponential rate for silver hake and goosefish. Mercury burdens were the highest overall in bluefish, but increased with size at the greatest rate in silver hake. Seasonal differences were detected for bluefish and goosefish with mercury levels peaking during summer and spring, respectively. Prey mercury burdens and predator foraging habits are discussed as the primary factors influencing mercury accumulation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  16. High level of mislabeling in Spanish and Greek hake markets suggests the fraudulent introduction of African species.

    PubMed

    Garcia-Vazquez, Eva; Perez, Juliana; Martinez, Jose L; Pardiñas, Antonio F; Lopez, Belen; Karaiskou, Nikoletta; Casa, Mary F; Machado-Schiaffino, Gonzalo; Triantafyllidis, Alexander

    2011-01-26

    DNA analysis of hake products commercialized in southern European (Spanish and Greek) market chains have demonstrated more than 30% mislabeling, on the basis of species substitution. Tails and fillets were more mislabeled than other products, such as slices and whole pieces. African species were substitute species for products labeled as American and European species, and we suggest it is a case of deliberate economically profitable mislabeling because real market prices of European and American hake products are higher than those of African in Spanish market chains. The presented results suggest fraud detection that disadvantages African producers. Government-mandated genetic surveys of commercial hakes and the use of subsequent statements of fair trade on labels of seafood products could help to reduce fraud levels in a global market of increasingly conscious consumers sensitive to ethical issues.

  17. A comparison of spring larval fish assemblages in the Strait of Georgia (British Columbia, Canada) between the early 1980s and late 2000s

    NASA Astrophysics Data System (ADS)

    Guan, Lu; Dower, John F.; McKinnell, Skip M.; Pepin, Pierre; Pakhomov, Evgeny A.; Hunt, Brian P. V.

    2015-11-01

    The concentration and composition of the larval fish assemblage in the Strait of Georgia (British Columbia, Canada) has changed between the early 1980s (1980 and 1981) and the late 2000s (2007, 2009 and 2010). During both periods, the spring larval fish assemblages were dominated by pelagic species: Clupea pallasi (Pacific herring), Merluccius productus (Pacific hake), Leuroglossus schmidti (northern smoothtongue) and Theragra chalcogramma (walleye Pollock). The average concentration of Merluccius productus, Theragra chalcogramma, Leuroglossus schmidti, and Sebastes spp. declined between the early 1980s and the late 2000s; in contrast, the absolute concentration and proportion of Pleuronectidae and several demersal fish taxa increased in the spring larval assemblage. Examination of the associations between larval fish assemblages and environmental fluctuations suggests that large-scale climate processes are potential contributors to variations in overall larval concentrations of the dominant taxa and assemblage composition in the Strait of Georgia.

  18. Diet of bottlenose dolphins (Tursiops truncatus) from the Gulf of Cadiz: Insights from stomach content and stable isotope analyses.

    PubMed

    Giménez, Joan; Marçalo, Ana; Ramírez, Francisco; Verborgh, Philippe; Gauffier, Pauline; Esteban, Ruth; Nicolau, Lídia; González-Ortegón, Enrique; Baldó, Francisco; Vilas, César; Vingada, José; G Forero, Manuela; de Stephanis, Renaud

    2017-01-01

    The ecological role of species can vary among populations depending on local and regional differences in diet. This is particularly true for top predators such as the bottlenose dolphin (Tursiops truncatus), which exhibits a highly varied diet throughout its distribution range. Local dietary assessments are therefore critical to fully understand the role of this species within marine ecosystems, as well as its interaction with important ecosystem services such as fisheries. Here, we combined stomach content analyses (SCA) and stable isotope analyses (SIA) to describe bottlenose dolphins diet in the Gulf of Cadiz (North Atlantic Ocean). Prey items identified using SCA included European conger (Conger conger) and European hake (Merluccius merluccius) as the most important ingested prey. However, mass-balance isotopic mixing model (MixSIAR), using δ13C and δ15N, indicated that the assimilated diet consisted mainly on Sparidae species (e.g. seabream, Diplodus annularis and D. bellottii, rubberlip grunt, Plectorhinchus mediterraneus, and common pandora, Pagellus erythrinus) and a mixture of other species including European hake, mackerels (Scomber colias, S. japonicus and S. scombrus), European conger, red bandfish (Cepola macrophthalma) and European pilchard (Sardina pilchardus). These contrasting results highlight differences in the temporal and taxonomic resolution of each approach, but also point to potential differences between ingested (SCA) and assimilated (SIA) diets. Both approaches provide different insights, e.g. determination of consumed fish biomass for the management of fish stocks (SCA) or identification of important assimilated prey species to the consumer (SIA).

  19. Diet of bottlenose dolphins (Tursiops truncatus) from the Gulf of Cadiz: Insights from stomach content and stable isotope analyses

    PubMed Central

    Marçalo, Ana; Ramírez, Francisco; Verborgh, Philippe; Gauffier, Pauline; Esteban, Ruth; Nicolau, Lídia; González-Ortegón, Enrique; Baldó, Francisco; Vilas, César; Vingada, José; G. Forero, Manuela; de Stephanis, Renaud

    2017-01-01

    The ecological role of species can vary among populations depending on local and regional differences in diet. This is particularly true for top predators such as the bottlenose dolphin (Tursiops truncatus), which exhibits a highly varied diet throughout its distribution range. Local dietary assessments are therefore critical to fully understand the role of this species within marine ecosystems, as well as its interaction with important ecosystem services such as fisheries. Here, we combined stomach content analyses (SCA) and stable isotope analyses (SIA) to describe bottlenose dolphins diet in the Gulf of Cadiz (North Atlantic Ocean). Prey items identified using SCA included European conger (Conger conger) and European hake (Merluccius merluccius) as the most important ingested prey. However, mass-balance isotopic mixing model (MixSIAR), using δ13C and δ15N, indicated that the assimilated diet consisted mainly on Sparidae species (e.g. seabream, Diplodus annularis and D. bellottii, rubberlip grunt, Plectorhinchus mediterraneus, and common pandora, Pagellus erythrinus) and a mixture of other species including European hake, mackerels (Scomber colias, S. japonicus and S. scombrus), European conger, red bandfish (Cepola macrophthalma) and European pilchard (Sardina pilchardus). These contrasting results highlight differences in the temporal and taxonomic resolution of each approach, but also point to potential differences between ingested (SCA) and assimilated (SIA) diets. Both approaches provide different insights, e.g. determination of consumed fish biomass for the management of fish stocks (SCA) or identification of important assimilated prey species to the consumer (SIA). PMID:28898268

  20. Juvenile hake predation on Myctophidae and Sternoptychidae: Quantifying an energy transfer between mesopelagic and neritic communities

    NASA Astrophysics Data System (ADS)

    Modica, Larissa; Cartes, Joan E.; Velasco, Francisco; Bozzano, Anna

    2015-01-01

    Seasonal study of the diet and food consumption of juvenile hake has been carried out in the Central Mediterranean Sea (Southern Tyrrhenian Sea). Fish were the most important food resource in terms of weight (ca. 70%). Among the fish, Myctophidae and Sternoptychidae, which are usually distributed deeper than juvenile hake, are most important. During summer, Ceratoscopelus maderensis constituted up to 21% of weight of all prey, and Maurolicus muelleri represented almost 10%. During autumn M. muelleri became the most important food resource. The way in which these more deeply distributed prey enter shallower food webs relates to the daily vertical migrations of lanternfish. In upper water column strata at night or near dawn they become prey of the juvenile hake. Considering that trophic energy flows primarily downward, in the direction of the productivity gradient, the observed flow of energy from deep strata into epipelagic layers could be considered an inverse energy transfer. Daily food consumption of juvenile hake ranged between 4.11 and 4.72% of the body wet-weight (BWW). The application of a square-root model allowed calculation of the fraction of this consumption derived by ingestion of the more deeply distributed mesopelagic fish. Between 11.6% and 17.8% of food consumption was sustained by this energy flow. Such information is useful for understanding the interaction between communities distributed in different depth ranges and to reinforce the idea that marine communities are open systems in which migratory movements can dramatically change the assumptions and results of mass-balance models.

  1. Ecology and genetic structure of zoonotic Anisakis spp. from adriatic commercial fish species.

    PubMed

    Mladineo, Ivona; Poljak, Vedran

    2014-02-01

    Consumption of raw or thermally inadequately treated fishery products represents a public health risk, with the possibility of propagation of live Anisakis larvae, the causative agent of the zoonotic disease anisakidosis, or anisakiasis. We investigated the population dynamics of Anisakis spp. in commercially important fish-anchovies (Anisakis), sardines (Sardina pilchardus), European hake (Merluccius merluccius), whiting (Merlangius merlangus), chub mackerel (Scomber japonicus), and Atlantic bluefin tuna (Thunnus thynnus)-captured in the main Adriatic Sea fishing ground. We observed a significant difference in the numbers of parasite larvae (1 to 32) in individual hosts and between species, with most fish showing high or very high Anisakis population indices. Phylogenetic analysis confirmed that commercial fish in the Adriatic Sea are parasitized by Anisakis pegreffii (95.95%) and Anisakis simplex sensu stricto (4.05%). The genetic structure of A. pegreffii in demersal, pelagic, and top predator hosts was unstructured, and the highest frequency of haplotype sharing (n = 10) was between demersal and pelagic fish.

  2. Trophic structure of pelagic species in the northwestern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Albo-Puigserver, Marta; Navarro, Joan; Coll, Marta; Layman, Craig A.; Palomera, Isabel

    2016-11-01

    Ecological knowledge of food web interactions within pelagic marine communities is often limited, impairing our capabilities to manage these ecologically and economically important marine fish species. Here we used stable isotope analyses to investigate trophic interactions in the pelagic ecosystem of the northwestern Mediterranean Sea during 2012 and 2013. Our results suggest that European sardine, Sardina pilchardus, and anchovy, Engraulis encrasicolus, are consumers located at relatively low levels of the pelagic food web. Unexpectedly, the round sardinella, Sardinella aurita, appeared to be located at a higher trophic level than the other small pelagic fish species, although previous studies found similarity in their diets. Isotope data suggested that trophic niches of species within the genera Trachurus spp. and Scomber spp., were distinct. Atlantic bonito Sarda sarda, European hake Merluccius merluccius and European squid Loligo vulgaris, appeared to feed at higher trophic levels than other species. Despite some intraspecific seasonal variability for some species, community trophic structure appeared relatively stable through the year. These data provide an important step for developing models of food web dynamics in the northwestern Mediterranean Sea.

  3. 77 FR 72242 - Fisheries of the Northeastern United States; Northeast Multispecies Fishery; White Hake Trimester...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-05

    ... Fishery; White Hake Trimester Total Allowable Catch Area Closure for the Common Pool Fishery AGENCY... Allowable Catch (TAC) Area to all common pool groundfish vessels fishing with trawl gear, sink gillnet gear... necessary to prevent the common pool fishery from exceeding its Trimester 2 TAC or its annual catch limit...

  4. Seabird bycatch mitigation trials in artisanal demersal longliners of the Western Mediterranean.

    PubMed

    Cortés, Verónica; González-Solís, Jacob

    2018-01-01

    High numbers of seabirds are killed annually worldwide in longline fisheries. In the Mediterranean, this mortality is seriously affecting the viability of seabird populations, in particular of the three endemic shearwaters. Even so, there is currently no specific seabird mitigation requirements for the longline fleet operating in this area. From 2013 to 2014, we assessed the efficiency and practical applicability of four mitigation measures on artisanal demersal longliners targeting European hake (Merluccius merluccius) in the western Mediterranean: night setting, tori line, weighted lines and artificial baits. We performed fifty-two pairs of experimental (with the tested mitigation measure) and control settings (without any measure), and compared their effects on seabird interactions and fish catches. In addition, we estimated the longline sink rates and the seabird access area to baited hooks in different longline configurations. Night setting reduced bycatch risk without affecting target and non-commercial fish catches. The tori line may have reduced the bycatch risk by displacing bait attacks beyond the end of the line, but at this distance shearwaters could still access to the baits and the streamers did not deter birds under calm wind conditions. Weighted lines increased sink rate, but it resulted in only a minor reduction of the seabird access window to baited hooks and led to some operational problems during the setting. Artificial baits substantially reduced commercial catches. Moreover, the seabird access to the baited hooks was influenced by the longline configuration, the setting speed and the relative position to the floats and weights. So far, night setting stands out as the best mitigation measure for reducing bycatch levels without compromising target catches in demersal longliners. Ideally, these results should be confirmed in longliners targeting species other than European hake.

  5. Effect of cooking on total mercury content in Norway lobster and European hake and public health impact.

    PubMed

    Perugini, Monia; Zezza, Daniela; Tulini, Serena Maria Rita; Abete, Maria Cesarina; Monaco, Gabriella; Conte, Annamaria; Olivieri, Vincenzo; Amorena, Michele

    2016-08-15

    The risk of Hg poisoning by eating seafood is considered real from the several international agencies that recommended, by fish consumption advisories, to pregnant women and young children to avoid or severely limit the consumption of the fish and shellfish with a high-range mercury levels. The analyses of two common species, European hake and Norway lobster, collected from an area of Central Adriatic Sea, reported high mercury levels in crustaceans. For Norway lobster total mercury exceeded, in six out of ten analysed pools, the recommended 0.5mg/kg wet weight European limit. Moreover the increased amount of Hg concentrations in Norway lobster cooked samples suggests the necessity to review current procedures of Hg control in food, considering also consumption habits of consumers. The Hg values found in all European hake samples are below the legal limits and, in this species, the boiling did not modify the concentrations in fish tissues. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Functional and antioxidative properties of protein hydrolysates from Cape hake by-products prepared by three different methodologies.

    PubMed

    Pires, Carla; Clemente, Teresa; Batista, Irineu

    2013-03-15

    The production of fish protein hydrolysates (FPH) is a convenient technology for upgrading fish by-products. The aim of this work was to study three different methods of FPH preparation from Cape hake by-products to improve yield and quality. Functional and antioxidative properties of all FPHs were determined. The protein content of hake FPH was in the range 807-860 g kg(-1) and the degree of hydrolysis was between 19% and 22%. The maximum yield (71.9%) was achieved by methodology B but the hydrolysate was darker. The peptide profile of all FPHs was very similar. FPH prepared by methodology C had significantly higher emulsifying activity index and hydrolysate prepared by methodology B had the highest foaming capacity. The solubility of FPH was in the range 71-76% and increased the water-holding capacity of minced fish by about 9%. The fractionation of FPH obtained by methodologies A and B allowed concentrating peptides with higher radical scavenging activity and reducing power. The properties of the FPH prepared indicated that they can be used in food systems as natural additives, particularly to improve their water-holding capacity. © 2012 Society of Chemical Industry.

  7. Protein gels and emulsions from mixtures of Cape hake and pea proteins.

    PubMed

    Tomé, Ana Sofia; Pires, Carla; Batista, Irineu; Sousa, Isabel; Raymundo, Anabela

    2015-01-01

    Portioning of frozen fish generates by-products such as fish 'sawdust' and cut-offs which can be further processed into protein concentrates and isolates. The objective of the present work was to produce gels and emulsions using recovered Cape hake protein powder (HPP). In previous works, the structures of the gels produced by HPP were found to be strong, with a high rubbery character. In this work, the addition of commercial pea proteins (PPC) to HPP gels and emulsions was studied. Physical properties of gels and emulsions prepared with different proportions of mixtures of PPC and HPP were evaluated. In general, gels and emulsions showed high values for whiteness and, as expected, the higher content of HPP in the protein mixtures led to higher firmness values of the gels. The gel network was rapidly formed upon heating due to the fish protein macromolecules and further reinforced by the pea protein macromolecules when cooled to 5 °C. Both visco-elastic parameters, storage and loss moduli, of the produced gels increased with the HPP proportion in the protein mixtures, corresponding to more structured systems. For the emulsions, two different pH environments were studied: 3.8 and 7.0. At neutral pH a synergy was found between the vegetable and fish protein, which is not so strong when pH is lowered to 3.8, near the isoelectric point of pea proteins (pI = 4.5). This evidence was supported by the results from the texture measurements, viscosity and visco-elastic parameters. Gels made from Cape hake proteins showed a softer texture and were less rubbery with the addition of pea proteins. Emulsions stabilised by these mixtures showed slightly different behaviour when produced at pH 7.0 or pH 3.8. © 2014 Society of Chemical Industry.

  8. Variation in wind and piscivorous predator fields affecting the survival of Atlantic salmon, Salmo salar, in the Gulf of Maine

    USGS Publications Warehouse

    Friedland, K.D.; Manning, J.P.; Link, Jason S.; Gilbert, J.R.; Gilbert, A.T.; O'Connell, A.F.

    2012-01-01

    Observations relevant to the North American stock complex of Atlantic salmon, Salmo salar L., suggest that marine mortality is influenced by variation in predation pressure affecting post-smolts during the first months at sea. This hypothesis was tested for Gulf of Maine (GOM) stocks by examining wind pseudostress and the distribution of piscivorous predator fields potentially affecting post-smolts. Marine survival has declined over recent decades with a change in the direction of spring winds, which is likely extending the migration of post-smolts by favouring routes using the western GOM. In addition to changes in spring wind patterns, higher spring sea surface temperatures have been associated with shifting distributions of a range of fish species. The abundance of several pelagic piscivores, which based on their feeding habits may predate on salmon post-smolts, has increased in the areas that serve as migration corridors for post-smolts. In particular, populations of silver hake, Merluccius bilinearis (Mitchell), red hake, Urophycis chuss (Walbaum), and spiny dogfish, Squalus acanthias L., increased in size in the portion of the GOM used by post-smolts. Climate variation and shifting predator distributions in the GOM are consistent with the predator hypothesis of recruitment control suggested for the stock complex.

  9. The Nature of the In Vivo Sodium and Chloride Uptake Mechanisms through the Epithelium of the Chilean Frog Calyptocephalella gayi (Dum. et Bibr., 1841)

    PubMed Central

    Romeu, Federico García; Salibián, Alfredo; Pezzani-Hernandez, Silvia

    1969-01-01

    The Chilean frog, Calyptocephallela gayi, placed in dilute NaCl solutions may pump Na+ and Cl- at very different rates depending on the kind of bath solutions in which it was preadapted. Furthermore, Na+ and Cl- may be absorbed from solutions in which the accompanying coion, such as sulfate and choline, respectively, is impermeant. In all these cases it is obligatory to postulate the existence of two ionic exchange mechanisms, Cl- and Na+, being exchanged against endogenous anions and cations, respectively. It has been determined that Na+ is exchanged against endogenous H+ and that Cl- is exchanged against HCO3 -. In animals pumping Na+ and Cl- from dilute NaCl solutions Na+ or Cl- uptake may be selectively inhibited, while the flux of the accompanying ion remains unchanged. This is considered to be an additional proof that both Na+ and Cl- fluxes are always independent. The role of the ionic exchange mechanisms in the direct regulation of the Na+ and Cl- levels in the internal medium is discussed as well as their relationship in the regulation of the acid-base equilibrium; other physioecological considerations have been treated. PMID:5822161

  10. Developmental instability as an indicator of natural stress on the Pacific Hake (Merlussius productus)

    USGS Publications Warehouse

    Alados, C.L.; Escos, J.; Emlen, J.M.

    1994-01-01

    Developmental lnstability (DI) has been proposed as an inexpensive, quickly applied, and sensitive indicator of stress that can be utilized in early warning and in monitoring anthropogenic impacts on fish and other animals and plants. A problem arises, however, to the extent that natural stressors confound the effects of human-induced disturbances. Our objective in this work was to investigate whether a natural stressor, in the form of EI Nino conditions, contributed to DI in the Pacific hake. Right-left (fluctuating> asymmetry of otolith length, width, growth rate, and weight, as well as right-left otolith shape differences, were used as measures of DI. Results show that indeed EI Nino disrupts development, indicating stress. This outcome suggests that DI, as an early warning and monitoring tool for stress, must be used with caution.

  11. Hake fish bone as a calcium source for efficient bone mineralization.

    PubMed

    Flammini, Lisa; Martuzzi, Francesca; Vivo, Valentina; Ghirri, Alessia; Salomi, Enrico; Bignetti, Enrico; Barocelli, Elisabetta

    2016-01-01

    Calcium is recognized as an essential nutritional factor for bone health. An adequate intake is important to achieve or maintain optimal bone mass in particular during growth and old age. The aim of the present study was to evaluate the efficiency of hake fish bone (HBF) as a calcium source for bone mineralization: in vitro on osteosarcoma SaOS-2 cells, cultured in Ca-free osteogenic medium (OM) and in vivo on young growing rats fed a low-calcium diet. Lithotame (L), a Ca supplement derived from Lithothamnium calcareum, was used as control. In vitro experiments showed that HBF supplementation provided bone mineralization similar to standard OM, whereas L supplementation showed lower activity. In vivo low-Ca HBF-added and L-added diet similarly affected bone deposition. Physico-chemical parameters concerning bone mineralization, such as femur breaking force, tibia density and calcium/phosphorus mineral content, had beneficial effects from both Ca supplementations, in the absence of any evident adverse effect. We conclude HBF derived from by-product from the fish industry is a good calcium supplier with comparable efficacy to L.

  12. Heavy metal concentrations in commercial deep-sea fish from the Rockall Trough

    NASA Astrophysics Data System (ADS)

    Mormede, S.; Davies, I. M.

    2001-05-01

    Samples of monkfish ( Lophius piscatorius), black scabbard ( Aphanopus carbo), blue ling ( Molva dypterygia), blue whiting ( Micromesistius poutassou) and hake ( Merluccius merluccius) were obtained from 400 to 1150 m depth on the continental slope of Rockall Trough west of Scotland. Muscle, liver, gill and gonad tissue were analysed for arsenic, cadmium, copper, lead, mercury and zinc by various atomic absorption techniques. Median concentrations of arsenic in the muscle tissue ranged from 1.25 to 8.63 mg/kg wet weight; in liver tissue from 3.04 to 5.72 mg/kg wet weight; cadmium in muscle tissue from <0.002 to 0.034 mg/kg wet weight, in liver tissue from 0.11 to 6.98 mg/kg wet weight; copper in the muscle from 0.12 to 0.29 mg/kg wet weight, in the liver from 3.47 to 11.87 mg/kg wet weight; lead levels in muscle from <0.002 to 0.009 mg/kg wet weight, respectively, and in liver tissue <0.05 mg/kg wet weight for all species. In general, the concentrations are similar to those previously published on deep-sea fish, and higher or similar to those published for shallow water counterparts. All metal levels in black scabbard livers are much higher than in the other fish, and between 2 and 30 times higher than the limits of the European Dietary Standards and Guidelines. Differences in accumulation patterns between species and elements, as well as between organs are described using univariate and multivariate statistics (scatterplots, discriminant analysis, triangular plots).

  13. Material properties of zooplankton and nekton from the California current

    NASA Astrophysics Data System (ADS)

    Becker, Kaylyn

    This study measured the material properties of zooplankton, Pacific hake (Merluccius productus), Humboldt squid (Dosidicus gigas), and two species of myctophids (Symbolophorus californiensis and Diaphus theta) collected from the California Current ecosystem. The density contrast (g) was measured for euphausiids, decapods (Sergestes similis), amphipods (Primno macropa, Phronima sp., and Hyperiid spp.), siphonophore bracts, chaetognaths, larval fish, crab megalopae, larval squid, and medusae. Morphometric data (length, width, and height) were collected for these taxa. Density contrasts varied within and between zooplankton taxa. The mean and standard deviation for euphausiid density contrast were 1.059 +/- 0.009. Relationships between zooplankton density contrast and morphometric measurements, geographic location, and environmental conditions were investigated. Site had a significant effect on euphausiid density contrast. Density contrasts of euphausiids collected in the same geographic area approximately 4-10 days apart were significantly higher (p < 0.001). Sound speed contrast (h) was measured for euphausiids and pelagic decapods (S. similis) and it varied between taxa. The mean and standard deviation for euphausiid sound speed were 1.019 +/- 0.009. Euphausiid mass was calculated from density measurements and volume, and a relationship between euphausiid mass and length was produced. We determined that euphausiid from volumes could be accurately estimated two dimensional measurements of animal body shape, and that biomass (or biovolume) could be accurately calculated from digital photographs of animals. Density contrast (g) was measured for zooplankton, pieces of hake flesh, myctophid flesh, and of the following Humboldt squid body parts: mantle, arms, tentacle, braincase, eyes, pen, and beak. The density contrasts varied within and between fish taxa, as well as among squid body parts. Effects of animal length and environmental conditions on nekton density

  14. Determination of the Geographical Origin of All Commercial Hake Species by Stable Isotope Ratio (SIR) Analysis.

    PubMed

    Carrera, Mónica; Gallardo, José M

    2017-02-08

    The determination of the geographical origin of food products is relevant to comply with the legal regulations of traceability, to avoid food fraud, and to guarantee food quality and safety to the consumers. For these reasons, stable isotope ratio (SIR) analysis using an isotope ratio mass spectrometry (IRMS) instrument is one of the most useful techniques for evaluating food traceability and authenticity. The present study was aimed to determine, for the first time, the geographical origin for all commercial fish species belonging to the Merlucciidae family using SIR analysis of carbon (δ 13 C) and nitrogen (δ 15 N). The specific results enabled their clear classification according to the FAO (Food and Agriculture Organization of the United Nations) fishing areas, latitude, and geographical origin in the following six different clusters: European, North African, South African, North American, South American, and Australian hake species.

  15. Benzo[a]pyrene and Benzo[k]fluoranthene in Some Processed Fish and Fish Products

    PubMed Central

    Olatunji, Olatunde S.; Fatoki, Olalekan S.; Opeolu, Beatrice O.; Ximba, Bhekumusa J.

    2015-01-01

    In this study, the concentration levels of the probable carcinogenic PAH fractions, benzo[a]pyrene (BaP) and benzo[k]fluoranthrene (BkF) in fillets of some processed fish species were investigated. Fish species comprising Merluccius poli (hake), Tyrsites atun (snoek), Seriola lalandi (yellow-tail) and Brama brama (angel fish) were bought in fish shops at Gordon’s Bay, Western Cape, South Africa. The fish were gutted, filleted and prepared for edibility by frying, grilling and boiling. Polycyclic aromatic hydrocarbons were extracted from each homogenized fish sample, cleaned-up using solid phase extraction (SPE), and analysed for the PAH fractions, BaP and BkF using a Gas Chromatograph coupled with a Flame Ionization Detector (GC-FID). The sum of the two PAHs (∑2PAH) i.e., BaP and BkF ranged between 0.56 and 1.46 µg/kg, in all boiled, grilled and fried fish species. The fried fish extracts showed significantly higher (p < 0.05) abundance of ∑2PAH, than grilled and boiled fish. Dietary safety and PAHs toxicity was also discussed. PMID:25607603

  16. Strategies to increase the hygienic and economic value of fresh fish: Biopreservation using lactic acid bacteria of marine origin.

    PubMed

    Gómez-Sala, Beatriz; Herranz, Carmen; Díaz-Freitas, Belén; Hernández, Pablo E; Sala, Ana; Cintas, Luis M

    2016-04-16

    In this work we describe the development of a biopreservation strategy for fresh fish based on the use of bacteriocinogenic LAB of marine origin. For this purpose, two multibacteriocinogenic LAB strains, Lactobacillus curvatus BCS35 and Enterococcus faecium BNM58, previously isolated from fish and fish products were selected owing to their capability to inhibit the growth of several fish-spoilage and food-borne pathogenic bacteria. Two commercially important fish species were chosen, young hake (Merluccius merluccius) and megrim (Lepidorhombus boscii), and the specimens were acquired at the Marín (Pontevedra, Spain) retail fish market, after one night in the chilled hold of a near-shore fishing vessel. The biopreservation potential and the application strategies of these two LAB strains were first tested at a laboratory scale, where several batches of fresh fish were inoculated with: (i) the multibacteriocinogenic LAB culture(s) as protective culture(s); and/or (ii) their cell-free culture supernatant(s) as food ingredient(s), and (iii) the lyophilized bacteriocin preparation(s) as lyophilized food ingredient(s). All batches were stored in polystyrene boxes, permanently filled with ice at 0-2 °C, for 14 days. Microbiological analyses, as well as sensorial analyses, were carried out during the biopreservation trials. Subsequently, Lb. curvatus BCS35 was selected to up-scale the trials, and combinations of the three application methods were assayed. For this purpose, this strain was grown in a semi-industrial scale fermentor (150l) in modified MRS broth, and three batches of fresh fish were inoculated with the protective culture and/or food ingredient, and stored on ice in a chilled chamber at 0-2 °C at the Marín retail fish market for 14 days. Microbiological analyses were carried out during the storage period, showing that when Lb. curvatus BCS35 culture or the corresponding cell-free culture supernatant was used as protective culture or food ingredient

  17. Antigenicity and viability of Anisakis larvae infesting hake heated at different time-temperature conditions.

    PubMed

    Vidacek, Sanja; de las Heras, Cristina; Solas, Maria Teresa; Mendizábal, Angel; Rodriguez-Mahillo, Ana I; Tejada, Margarita

    2010-01-01

    Heat treatments (40 to 94 degrees Celsius, 30 s to 60 min) were applied to different batches of Anisakis simplex L3 larvae isolated from hake ovaries and viscera to study the effect of heat on the viability of the larvae measured as mobility, emission of fluorescence under UV light, and changes in color after staining with specific dyes, and on A. simplex antigenic proteins. The aim was to determine the lowest time-temperature conditions needed to kill the larvae to avoid anisakiasis in consumers, and to evaluate whether high temperature modifies the antigenicity of A. simplex extracts. Heating at 60 degrees Celsius for 10 min (recommended by some authors) was considered unsafe, as differences in viability between batches were found, with some larvae presenting spontaneous movements in one batch. At higher temperatures (> or = 70 degrees Celsius for > or = 1 min), no movement of the larvae was observed. Antigenic protein Ani s 4 and A. simplex crude antigens were detected in the larvae heated at 94 + or - 1 degrees Celsius for 3 min. This indicates that allergic symptoms could be provoked in previously sensitized consumers, even if the larvae were killed by heat treatment.

  18. Enzymatic-microwave assisted extraction and high-performance liquid chromatography-mass spectrometry for the determination of selected veterinary antibiotics in fish and mussel samples.

    PubMed

    Fernandez-Torres, R; Lopez, M A Bello; Consentino, M Olias; Mochon, M Callejon; Payan, M Ramos

    2011-04-05

    A new method based on enzymatic-microwave assisted extraction prior to high performance liquid chromatography (HPLC) has been developed for the determination of 11 antibiotics (drugs) and the main metabolites of five of them in fish tissue and mussel samples. The analysed compounds were sulfadiazine (SDI), N(4)-acetylsulfadiazine (NDI), sulfamethazine (SMZ), N(4)-acetylsulfamethazine (NMZ), sulfamerazine (SMR), N(4)-acetylsulfamerazine (NMR), sulfamethoxazole (SMX), trimetroprim (TMP), amoxicillin (AMX), amoxicilloic acid (AMA), ampicillin (AMP), ampicilloic acid (APA), chloramphenicol (CLF), thiamphenicol (TIF), oxytetracycline (OXT) and chlortetracycline (CLT). The main factors affecting the extraction efficiency were optimized in tissue of hake (Merluccius merluccius), anchovy (Engraulis encrasicolus), mussel (Mytilus sp.) and wedge sole (Solea solea). The microwave extraction was carried out using an extraction time of 5 min with 5 mL of water at 50W and posterior clean up with dichloromethane. High-performance liquid chromatography (HPLC)-mass spectrometry was used for the determination of the antibiotics. The separation of the analysed compounds was conducted by means of a Phenomenex® Gemini C(18) (150 mm × 4.6mm I.D., particle size 5 μm) analytical column with LiChroCART® LiChrospher® C(18) (4 mm × 4 mm, particle size 5 μm) guard-column. Analysed drugs were determined using formic acid 0.1% in water and acetonitrile in gradient elution mode as mobile phase. Under the optimal conditions, the average recoveries of all the analysed drugs were in the range 70-100%. The proposed method was applied to samples obtained from Mediterranean sea and also evaluated by a laboratory assay consisting in the determination of the targeted analytes in samples of Cyprinus carpio that had been previously administered the antibiotics. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. Material properties of Pacific hake, Humboldt squid, and two species of myctophids in the California Current.

    PubMed

    Becker, Kaylyn N; Warren, Joseph D

    2015-05-01

    Material properties of the flesh from three fish species (Merluccius productus, Symbolophorus californiensis, and Diaphus theta), and several body parts of the Humboldt squid (Dosidicus gigas) collected from the California Current ecosystem were measured. The density contrast relative to seawater varied within and among taxa for fish flesh (0.9919-1.036), squid soft body parts (mantle, arms, tentacle, braincase, eyes; 1.009-1.057), and squid hard body parts (beak and pen; 1.085-1.459). Effects of animal length and environmental conditions on nekton density contrast were investigated. The sound speed contrast relative to seawater varied within and among taxa for fish flesh (0.986-1.027) and Humboldt squid mantle and braincase (0.937-1.028). Material properties in this study are similar to values from previous studies on species with similar life histories. In general, the sound speed and density of soft body parts of fish and squid were 1%-3% and 1%-6%, respectively, greater than the surrounding seawater. Hard parts of the squid were significantly more dense (6%-46%) than seawater. The material properties reported here can be used to improve target strength estimates from acoustic scattering models, which could increase the accuracy of biomass estimates from acoustic surveys for these nekton.

  20. From discard ban to exemption: How can gear technology help reduce catches of undersized Nephrops and hake in the Bay of Biscay trawling fleet?

    PubMed

    Vogel, Camille; Kopp, Dorothée; Méhault, Sonia

    2017-01-15

    On January 1st, 2016, the French mixed Nephrops and hake fishery of the Grande Vasière, an area located in the Bay of Biscay, fell under the discard ban implemented as part of the new European Common Fisheries Policy. The fleet records historically high levels of discard despite numerous gear selectivity studies. Together with high discards survival, new technological solutions to minimize catches of undersized individuals could justify local exemptions from the discard ban. Our study focuses on the effects of two selective devices, a square mesh cylinder (SMC) and a grid, on the escapement of undersized individuals and discard reduction. Relative catch probability of the modified gear compared with the traditional gear was modelled using the catch comparison method. Potential losses from the commercial fraction of the catch were taken into account to assess their influence on the economic viability of fishing with the modified gears. The two devices had similar effects on undersized Nephrops escapement and on discard reduction, with median values of 26.5% and 23.6% for the SMC and of 30.4% and 21.4% for the grid, respectively. Only the grid was efficient for undersized hake, recording median values of escapement and discard reduction equal to 25.0% and 20.6%, respectively. Some loss from the commercial fraction of the catch was to be expected with both devices, which could be compensated for in the long term by the contribution of undersized individuals to the stock biomass. Our results support the use of selective gears technology as part of an integrated framework including control and management measures to mitigate the effect of the discard ban both for fishers and for the ecosystem. Further work is needed to quantify the effect of additional escapement from the gear on stock dynamics. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Feeding strategies and ecological roles of three predatory pelagic fish in the western Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Navarro, Joan; Sáez-Liante, Raquel; Albo-Puigserver, Marta; Coll, Marta; Palomera, Isabel

    2017-06-01

    Knowing the feeding ecology of marine predators is pivotal to developing an understanding of their ecological role in the ecosystem and determining the trophic relationships between them. Despite the ecological importance of predatory pelagic fish species, research on these species in the Mediterranean Sea is limited. Here, by combining analyses of stomach contents and stable isotope values, we examined the feeding strategies of swordfish, Xiphias gladius, little tunny, Euthynnus alletteratus and Atlantic bonito, Sarda sarda, in the western Mediterranean Sea. We also compared the trophic niche and trophic level of these species with published information of other sympatric pelagic predators present in the ecosystem. Results indicated that, although the diet of the three species was composed mainly by fin-fish species, a clear segregation in their main feeding strategies was found. Swordfish showed a generalist diet including demersal species such as blue whiting, Micromesistius poutassou, and European hake, Merluccius merluccius, and pelagic fin-fish such as barracudina species (Arctozenus risso and Lestidiops jayakari) or small pelagic fish species. Little tunny and Atlantic bonito were segregated isotopically between them and showed a diet basically composed of anchovy, Engraulis encrasicolus, and round sardinella, Sardinella aurita, and sardines, Sardina pilchardus, respectively. This trophic segregation, in addition to potential segregation by depth, is likely a mechanism that allows their potential coexistence within the same pelagic habitat. When the trophic position of these three predatory pelagic fish species is compared with other pelagic predators such as bluefin tuna, Thunnus thynnus, and dolphinfish, Coryphaena hippurus, present in the western Mediterranean Sea, we found that they show similar intermediate trophic position in the ecosystem. In conclusion, the combined stomach and isotopic results highlight, especially for little tunny and Atlantic

  2. Gap analysis on the biology of Mediterranean marine fishes

    PubMed Central

    Dimarchopoulou, Donna; Stergiou, Konstantinos I.

    2017-01-01

    We estimated the current level of knowledge concerning several biological characteristics of the Mediterranean marine fishes by carrying out a gap analysis based on information extracted from the literature, aiming to identify research trends and future needs in the field of Mediterranean fish biology that can be used in stock assessments, ecosystem modeling and fisheries management. Based on the datasets that emerged from the literature review, there is no information on any biological characteristic for 43% (n = 310) of the Mediterranean fish species, whereas for an additional 15% (n = 109) of them there is information about just one characteristic. The gap between current and desired knowledge (defined here as having information on most biological characteristics for at least half of the Mediterranean marine fishes) is smaller in length-weight relationships, which have been studied for 43% of the species, followed by spawning (39%), diet (29%), growth (25%), maturity (24%), lifespan (19%) and fecundity (17%). The gap is larger in natural mortality for which information is very scarce (8%). European hake (Merluccius merluccius), red mullet (Mullus barbatus), annular seabream (Diplodus annularis), common pandora (Pagellus erythrinus), European anchovy (Engraulis encrasicolus), European pilchard (Sardina pilchardus) and bogue (Boops boops) were the most studied species, while sharks and rays were among the least studied ones. Only 25 species were fully studied, i.e. there was available information on all their biological characteristics. The knowledge gaps per characteristic varied among the western, central and eastern Mediterranean subregions. The number of available records per species was positively related to total landings, while no relationship emerged with its maximum reported length, trophic level and commercial value. Future research priorities that should be focused on less studied species (e.g. sharks and rays) and mortality/fecundity instead of length

  3. Gap analysis on the biology of Mediterranean marine fishes.

    PubMed

    Dimarchopoulou, Donna; Stergiou, Konstantinos I; Tsikliras, Athanassios C

    2017-01-01

    We estimated the current level of knowledge concerning several biological characteristics of the Mediterranean marine fishes by carrying out a gap analysis based on information extracted from the literature, aiming to identify research trends and future needs in the field of Mediterranean fish biology that can be used in stock assessments, ecosystem modeling and fisheries management. Based on the datasets that emerged from the literature review, there is no information on any biological characteristic for 43% (n = 310) of the Mediterranean fish species, whereas for an additional 15% (n = 109) of them there is information about just one characteristic. The gap between current and desired knowledge (defined here as having information on most biological characteristics for at least half of the Mediterranean marine fishes) is smaller in length-weight relationships, which have been studied for 43% of the species, followed by spawning (39%), diet (29%), growth (25%), maturity (24%), lifespan (19%) and fecundity (17%). The gap is larger in natural mortality for which information is very scarce (8%). European hake (Merluccius merluccius), red mullet (Mullus barbatus), annular seabream (Diplodus annularis), common pandora (Pagellus erythrinus), European anchovy (Engraulis encrasicolus), European pilchard (Sardina pilchardus) and bogue (Boops boops) were the most studied species, while sharks and rays were among the least studied ones. Only 25 species were fully studied, i.e. there was available information on all their biological characteristics. The knowledge gaps per characteristic varied among the western, central and eastern Mediterranean subregions. The number of available records per species was positively related to total landings, while no relationship emerged with its maximum reported length, trophic level and commercial value. Future research priorities that should be focused on less studied species (e.g. sharks and rays) and mortality/fecundity instead of length

  4. Seafloor habitat mapping of the New York Bight incorporating sidescan sonar data

    USGS Publications Warehouse

    Lathrop, R.G.; Cole, M.; Senyk, N.; Butman, B.

    2006-01-01

    The efficacy of using sidescan sonar imagery, image classification algorithms and geographic information system (GIS) techniques to characterize the seafloor bottom of the New York Bight were assessed. The resulting seafloor bottom type map was compared with fish trawl survey data to determine whether there were any discernable habitat associations. An unsupervised classification with 20 spectral classes was produced using the sidescan sonar imagery, bathymetry and secondarily derived spatial heterogeneity to characterize homogenous regions within the study area. The spectral classes, geologic interpretations of the study region, bathymetry and a bottom landform index were used to produce a seafloor bottom type map of 9 different bottom types. Examination of sediment sample data by bottom type indicated that each bottom type class had a distinct composition of sediments. Analysis of adult summer flounder, Paralichthys dentatus, and adult silver hake, Merluccius bilinearis, presence/absence data from trawl surveys did not show evidence of strong associations between the species distributions and seafloor bottom type. However, the absence of strong habitat associations may be more attributable to the coarse scale and geographic uncertainty of the trawl sampling data than conclusive evidence that no habitat associations exist for these two species. ?? 2006 Elsevier Ltd. All rights reserved.

  5. Thermal ecological physiology of native and invasive frog species: do invaders perform better?

    PubMed

    Cortes, Pablo A; Puschel, Hans; Acuña, Paz; Bartheld, José L; Bozinovic, Francisco

    2016-01-01

    Biological invasions are recognized as an important biotic component of global change that threatens the composition, structure and functioning of ecosystems, resulting in loss of biodiversity and displacement of native species. Although ecological characteristics facilitating the establishment and spread of non-native species are widely recognized, little is known about organismal attributes underlying invasion success. In this study, we tested the effect of thermal acclimation on thermal tolerance and locomotor performance in the invasive Xenopus laevis and the Chilean native Calyptocephalella gayi . In particular, the maximal righting performance (μ MAX ), optimal temperature ( T O ), lower (CT min ) and upper critical thermal limits (CT max ), thermal breadth ( T br ) and the area under the performance curve (AUC) were studied after 6 weeks acclimation to 10 and 20°C. We observed higher values of μ max and AUC in X. laevis in comparison to C. gayi . On the contrary, the invasive species showed lower values of CT min in comparison to the native one. In contrast, CT max , T O and T br showed no inter-specific differences. Moreover, we found that both species have the ability to acclimate their locomotor performance and lower thermal tolerance limit at low temperatures. Our results demonstrate that X. laevis is a better performer than C. gayi . Although there were differences in CT min , the invasive and native frogs did not differ in their thermal tolerance. Interestingly, in both species the lower and upper critical thermal limits are beyond the minimal and maximal temperatures encountered in nature during the coldest and hottest month, respectively. Overall, our findings suggest that both X. laevis and C. gayi would be resilient to climate warming expectations in Chile.

  6. Trophic ecology of yellownose skate Zearaja chilensis, a top predator in the south-western Atlantic Ocean.

    PubMed

    Belleggia, M; Andrada, N; Paglieri, S; Cortés, F; Massa, A M; Figueroa, D E; Bremec, C

    2016-03-01

    The diet and trophic level (TL ) of the yellownose skate Zearaja chilensis in the south-western Atlantic Ocean (35°-54° S), and how these varied in relation to body size, sex, maturity stage, depth and region were determined by analysis of stomach contents. From 776 specimens analysed, 671 (86·5%) ranging from 180 to 1190 mm total length (LT ) had prey in their stomachs. The diet was dominated by fishes, mainly the notothenioid Patagonotothen ramsayi and the Argentine hake Merluccius hubbsi. The consumption of fishes and crabs increased with increasing predator size, and these preys were more important in the north than in the south. Isopods and other crustaceans were consumed more in the south and their consumption decreased as the size of Z. chilensis increased. The TL of Z. chilensis increased with LT from 4·29 to 4·59 (mean 4·53), confirming their ecological role as a top predator. The small and large size classes exhibited a low diet overlap and the highest spatial segregation, whereas medium and large specimens had higher co-occurrence and dietary overlap indices. A clear distinction in tooth shape was noted between sexes in adult specimens, with males having longer cusps. This sexual heterodonty may be related to reproductive behaviour, increasing the grasping ability of males during courtship, because there were no differences in diet between the sexes. © 2016 The Fisheries Society of the British Isles.

  7. Potential risk assessment of metals in edible fish species for human consumption from the Eastern Aegean Sea.

    PubMed

    Pazi, Idil; Gonul, L Tolga; Kucuksezgin, Filiz; Avaz, Gulsen; Tolun, Leyla; Unluoglu, Aydın; Karaaslan, Yakup; Gucver, S Mine; Koc Orhon, Aybala; Siltu, Esra; Olmez, Gulnur

    2017-07-15

    The levels of Hg, Cd, Pb, Cr, Cu and Zn were measured in the tissues of four edible fish species namely: Diplodus annularis, Pagellus erythrinus, Merluccius merluccius and Mullus barbatus, collected from the Turkish Coast of the Aegean Sea. Except for D. annularis, the levels of Cd and Pb in all fish tissues sampled in Aliaga Bay in 2009 were above the tolerable limits according to the Food and Agriculture Organization of the United Nations (FAO). Hg in P. erythrinus and M. barbatus were higher than the maximum permitted limits (FAO), while D. annularis and M. merluccius were lower than the limit for biota in the district of Aliaga. Although the Target Hazard Quotient (THQ) values for Cd, Pb, Cu, Cr, Zn in all fish samples were lower than 1.0, the THQ for Hg levels were higher than 1.0 for most of the samples. According to the THQ values, M. merluccius may be consumed in moderation from Aliaga Bay, while the consumption of M. barbatus and P. erythrinus collected from Aliaga Bay are potentially hazardous to human health due to the Hg concentrations. Fish collected from Izmir Bay can be consumed safely. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. 50 CFR 600.520 - Northwest Atlantic Ocean fishery.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., ocean pout, pollock, red hake, scup, sea turtles, sharks (except dogfish), silver hake, spot, striped... species or species group (e.g., “other finfish”). When vessels of a foreign nation have caught an...

  9. Extending Vulnerability Assessment to Include Life Stages Considerations.

    PubMed

    Hodgson, Emma E; Essington, Timothy E; Kaplan, Isaac C

    2016-01-01

    Species are experiencing a suite of novel stressors from anthropogenic activities that have impacts at multiple scales. Vulnerability assessment is one tool to evaluate the likely impacts that these stressors pose to species so that high-vulnerability cases can be identified and prioritized for monitoring, protection, or mitigation. Commonly used semi-quantitative methods lack a framework to explicitly account for differences in exposure to stressors and organism responses across life stages. Here we propose a modification to commonly used spatial vulnerability assessment methods that includes such an approach, using ocean acidification in the California Current as an illustrative case study. Life stage considerations were included by assessing vulnerability of each life stage to ocean acidification and were used to estimate population vulnerability in two ways. We set population vulnerability equal to: (1) the maximum stage vulnerability and (2) a weighted mean across all stages, with weights calculated using Lefkovitch matrix models. Vulnerability was found to vary across life stages for the six species explored in this case study: two krill-Euphausia pacifica and Thysanoessa spinifera, pteropod-Limacina helicina, pink shrimp-Pandalus jordani, Dungeness crab-Metacarcinus magister and Pacific hake-Merluccius productus. The maximum vulnerability estimates ranged from larval to subadult and adult stages with no consistent stage having maximum vulnerability across species. Similarly, integrated vulnerability metrics varied greatly across species. A comparison showed that some species had vulnerabilities that were similar between the two metrics, while other species' vulnerabilities varied substantially between the two metrics. These differences primarily resulted from cases where the most vulnerable stage had a low relative weight. We compare these methods and explore circumstances where each method may be appropriate.

  10. Self-Passivation of POSS-Kapton-Polyimides in the Presence of Atomic Oxygen (Preprint)

    DTIC Science & Technology

    2007-10-29

    3. Koontz , S. L., Leger, L. J., Visentine, J. T., Hunton, D. E., Cross, J. B., and Hakes, C. L., “EOIM-III Mass Spectroscopy and Polymer Chemistry...1983. 88(A12): p. 170-188. 14. Koontz , S.L., Leger, L. J., Rickman, S. L., Hakes, C. L., Bui, D. T., Hunton, D. E. and Cross, J.B., "Oxygen

  11. Long-term variation in a central California pelagic forage assemblage

    NASA Astrophysics Data System (ADS)

    Ralston, Stephen; Field, John C.; Sakuma, Keith M.

    2015-06-01

    A continuous 23 year midwater trawl survey (1990-2012) of the epipelagic forage assemblage off the coast of central California (lat. 36°30‧-38°20‧ N) is described and analyzed. Twenty taxa occurred in ≥ 10% of the 2037 trawls that were completed at 40 distinct station locations. The dominant taxa sampled by the 9.5 mm mesh net included a suite of young-of-the-year (YOY) groundfish, including rockfish (Sebastes spp.) and Pacific hake (Merluccius productus), two clupeoids (Engraulis mordax and Sardinops sagax), krill (Euphausiacea), cephalopods (Doryteuthis opalescens and Octopus sp.), and a variety of mesopelagic species, i.e., Diaphus theta, Tarltonbeania crenularis, "other" lanternfish (Myctophidae), deep-sea smelts (Bathylagidae), and sergestid shrimp. Annual abundance estimates of the 20 taxa were obtained from analysis of variance models, which included year and station as main effects. Principal components analysis of the abundance estimates revealed that 61% of assemblage variance was explained by the first three components. The first component revealed a strong contrast in the abundance of: (a) YOY groundfish, market squid (D. opalescens), and krill with (b) mesopelagics and clupeoids; the second component was associated with long-term trends in abundance. An evaluation of 10 different published oceanographic data sets and CTD data collected during the survey indicated that seawater properties encountered each year were significantly correlated with abundance patterns, as were annual sea-level anomalies obtained from an analysis of AVISO satellite information. A comparison of our findings with several other recent studies of biological communities occurring in the California Current revealed a consistent structuring of forage assemblages, which we conjecture is primarily attributable to large-scale advection patterns in the California Current ecosystem.

  12. Different Levels of Hypoxia Tolerance during Early Life History Stages of Key Fish Species from the Northern Benguela Upwelling Ecosystem Inferred from the Comparison of Eco-Physiological Traits

    NASA Astrophysics Data System (ADS)

    Geist, S. J.; Imam, R. M.; Kunzmann, A.; Ekau, W.

    2016-02-01

    Global change factors such as a pronounced Oxygen Minimum Zone and the shoaling of hypoxic waters are assumed to play a major role in controlling the recruitment of fish stocks in Upwelling Systems by affecting the planktonic early life history stages. Ecological and ecophysiological traits in the larval stages of five key fish species in the Northern Benguela Upwelling System (Sardine, Sardinops sagax; Anchovy, Engraulis encrasicolus; Cape horse mackerel, Trachurus capensis; Cape hake, Merluccius sp.; Pelagic goby, Sufflogobobius bibarbatus) were investigated during the GENUS (Geochemistry and Ecology of the Namibian Upwelling Ecosystem) research project . Analysis of vertical larval distributions in relation to the depth of hypoxic water layers showed gradual interspecific differences, suggesting lower hypoxia tolerance levels of the small pelagics Sardine and Anchovy. Cape horse mackerel juveniles and larvae exhibited very high tolerance levels to short-term hypoxia in respirometry stress experiments, close to the levels of the extremely hypoxia-tolerant Pelagic goby. In the latter two species, we also measured the highest activities of anaerobic enzymes (pyruvate kinase and lactate dehydrogenase) in early and late larval stages, compared to very low activities in Sardine larvae. A higher amount of anaerobic enzymatic activity is related to a higher capacity to break down metabolites that build up during phases of oxygen debt and thus help the larvae to quickly recover from hypoxia exposure. In consequence, a high hypoxia tolerance during their early life stages allows Cape horse mackerel and Pelagic goby to successfully reproduce in an environment characterized by frequent hypoxic events. The low hypoxia tolerance of Sardine larvae, eventually resulting in higher mortality rates, is likely to be an important factor to understand the poor reproductive success and continuing recruitment failures of this formerly dominant fish species of the NBUS during the last

  13. PREVALENCE OF ANISAKID NEMATODE LARVAE INFECTING SOME MARINE FISHES FROM THE LIBYAN COAST.

    PubMed

    Kassem, Hamed H; Bowashi, Salem Mohamed

    2015-12-01

    This study examined eight hundred ninety six marine fishes belonging to nine different fish species; Synodus saurus; Merluccius merluccius; Trachurus mediterraneus; Serranus cabrilla; Mullus surmuletus; Diplodus annularis; Spicara maena; Siganus rirulatus and Liza ramada. The fishes were bought from fish markets at five different sites on Libyan coast, from January to December 2013, for study the anisakids larvae among them. The results showed that 344/896 fishes (38.4%) were infected with Anisakids larvae. S. saurus was the highly infected (80.9%), followed by T mediterraneus (77.5%) but, S. cabrilla, S. maena, M merluccius, M surmuletus, and D. annularis were least anisakid infected showed rates of 58.2%, 53.8%, 43.7%, 36.7% & 3.6%, respectively. No parasites were in S. rirulatus and L, ramada. Ten species of Anisakids larvae was detected during the present study. Two Pseudoterranova sp. Larvae, two types of Anisakis larvae, Anisakis simplex larva and Anisakis sp. Larva, two types of Contracaecum sp. Larvae and four Hysterothylacium larvae. Females showed higher prevalence than males. The number of anisakid larvae varied according to body length and weight of infected fish, without significant difference between prevalence and seasons, but, a significant difference was between prevalence and regions.

  14. Phenological and distributional shifts in ichthyoplankton associated with recent warming in the northeast Pacific Ocean.

    PubMed

    Auth, Toby D; Daly, Elizabeth A; Brodeur, Richard D; Fisher, Jennifer L

    2018-01-01

    Understanding changes in the migratory and reproductive phenology of fish stocks in relation to climate change is critical for accurate ecosystem-based fisheries management. Relocation and changes in timing of reproduction can have dramatic effects upon the success of fish populations and throughout the food web. During anomalously warm conditions (1-4°C above normal) in the northeast Pacific Ocean during 2015-2016, we documented shifts in timing and spawning location of several pelagic fish stocks based on larval fish samples. Total larval concentrations in the northern California Current (NCC) during winter (January-March) 2015 and 2016 were the highest observed since annual collections first occurred in 1998, primarily due to increased abundances of Engraulis mordax (northern anchovy) and Sardinops sagax (Pacific sardine) larvae, which are normally summer spawning species in this region. Sardinops sagax and Merluccius productus (Pacific hake) exhibited an unprecedented early and northward spawning expansion during 2015-16. In addition, spawning duration was greatly increased for E. mordax, as the presence of larvae was observed throughout the majority of 2015-16, indicating prolonged and nearly continuous spawning of adults throughout the warm period. Larvae from all three of these species have never before been collected in the NCC as early in the year. In addition, other southern species were collected in the NCC during this period. This suggests that the spawning phenology and distribution of several ecologically and commercially important fish species dramatically and rapidly changed in response to the warming conditions occurring in 2014-2016, and could be an indication of future conditions under projected climate change. Changes in spawning timing and poleward migration of fish populations due to warmer ocean conditions or global climate change will negatively impact areas that were historically dependent on these fish, and change the food web structure

  15. Fish scales in sediments from off Callao, central Peru

    NASA Astrophysics Data System (ADS)

    Díaz-Ochoa, J. A.; Lange, C. B.; Pantoja, S.; De Lange, G. J.; Gutiérrez, D.; Muñoz, P.; Salamanca, M.

    2009-07-01

    We study fish scales as a proxy of fish abundance and preservation biases together with phosphorus from fish remains (P fish) in a sediment core retrieved off Callao, Peru (12°1'S, 77°42'W; water depth=179 m; core length=52 cm). We interpret our results as a function of changing redox conditions based on ratios of redox-sensitive trace elements (Cu/Al, Mo/Al, Ni/Al, Zn/Al, V/Al), terrigenous indicators (Fe in clays, Ti, Al), and biogenic proxies (CaCO 3, biogenic opal, total nitrogen, organic carbon, barite Ba). The core covers roughly 700 years of deposition, based on 210Pb activities extrapolated downcore and 14C dating at selected intervals. Our fish-scale record is dominated by anchovy ( Engraulis ringens) scales followed by hake ( Merluccius gayii) scales. The core presented an abrupt lithological change at 17 cm (corresponding to the early 19th century). Above that depth, it was laminated and was more organic-rich (10-15% organic carbon) than below, where the core was partly laminated and less organic-rich (<10%). The lithological shift coincides with abrupt changes in dry bulk density and in the contents of terrigenous and redox-sensitive trace elements, biogenic proxies, and fish scales. The remarkable increase in redox-sensitive trace elements in the upper 17 cm of the core suggests more reducing conditions when compared with deeper and older horizons, and is interpreted as an intensification of the oxygen minimum zone off Peru beginning in the early 19th century. Higher fish-scale contents and higher P fish/P total ratios were also observed within the upper 17 cm of the core. The behavior of biogenic proxies and redox-sensitive trace elements was similar; more reduced conditions corresponded to higher contents of CaCO 3, C org, total nitrogen and fish scales, suggesting that these proxies might convey an important preservation signal.

  16. Concentrations of polybrominated diphenyl ethers, hexachlorobenzene and polycyclic aromatic hydrocarbons in various foodstuffs before and after cooking.

    PubMed

    Perelló, Gemma; Martí-Cid, Roser; Castell, Victoria; Llobet, Juan M; Domingo, José L

    2009-04-01

    The cooking-induced changes in the levels of polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), and 16 polycyclic aromatic hydrocarbons (PAHs) in various foodstuffs were investigated. Foods included fish (sardine, hake and tuna), meat (veal steak, loin of pork, breast and thigh of chicken, and steak and rib of lamb), string bean, potato, rice, and olive oil. For each food item, raw and cooked (fried, grilled, roasted, boiled) samples were analyzed. There were some variations in the concentrations of PBDEs before and after cooking. However, they depended not only on the cooking process, but mainly on the specific food item. The highest HCB concentrations were found in sardine, being lower in cooked samples. All cooking processes enhanced HCB levels in hake, while very scarce differences could be noted in tuna (raw and cooked). In general terms, the highest PAH concentrations were found after frying by being the values especially notable in fish, excepting hake, where the highest total PAH levels corresponded to roasted samples. The results of this study show that, in general, cooking processes are only of a limited value as a means of reducing PBDE, HCB and PAH concentrations in food.

  17. Deep-water fisheries at the Atlantic Frontier

    NASA Astrophysics Data System (ADS)

    Gordon, J. D. M.

    2001-05-01

    ( Micromesistius poutassou). The other semipelagic fishery is on spawning aggregations of the greater silver smelt or argentine ( Argentina silus). Spanish and UK vessels that target mainly hake ( Merluccius merluccius) and a Norwegian fleet that targets ling ( Molva molva), blue ling and tusk ( Brosme brosme) dominate the upper slope longline fishery. West of Shetland, the fishery on the upper slope has some similarities with that of the Hebridean slope, with anglerfish and blue ling being important target species. A quite different fishery occurs in the transition zone between the Atlantic and Norwegian Sea waters. Here the main target species is Greenland halibut ( Reinhardtius hippoglossoides). Below the transition zone biomass decreases rapidly and there is no fishery. It is generally agreed that many deep-water species have slow growth, a high age at first maturity and a low fecundity, which makes them vulnerable to over-exploitation. Other features of these fishes such as high mortality of discards and escapees will add to the problems. Despite this the only management procedures in place are general limitation of effort measures within the area of jurisdiction of the European Union.

  18. Collapse and recovery of forage fish populations prior to commercial exploitation

    NASA Astrophysics Data System (ADS)

    McClatchie, S.; Hendy, I. L.; Thompson, A. R.; Watson, W.

    2017-02-01

    We use a new, well-calibrated 500 year paleorecord off southern California to determine collapse frequency, cross correlation, persistence, and return times of exploited forage fish populations. The paleorecord shows that "collapse" (defined as <10% of the mean peak biomass) is a normal state repeatedly experienced by northern anchovy, Pacific hake, and Pacific sardine which were collapsed 29-40% of the time, prior to commercial fishing exploitation. Mean (± SD) persistence of "fishable biomass" (defined as one third mean peak biomass from the paleorecord) was 19 ± 18, 15 ± 17, and 12 ± 7 years for anchovy, hake, and sardine. Mean return times to the same biomass was 8 years for anchovy but 22 years for sardine and hake. Further, we find that sardine and anchovy are positively correlated over 400 years, consistent with coherent declines of both species off California. Persistence and return times combined with positive sardine-anchovy correlation indicate that on average 1-2 decades of fishable biomass will be followed by 1-2 decades of low forage. Forage populations are resilient on the 500 year time scale, but their collapse and recovery cycle (based on the paleorecord) are suited to alternating periods of high fishing mortality and periods of little or no fishing.

  19. 76 FR 14923 - Endangered and Threatened Species; Take of Anadromous Fish

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-18

    ... (i.e., surface and bottom water temperature, salinity, near bottom dissolved oxygen concentration...-water and bottom trawls) are adequately characterizing schools of hake. The IVC research would take...

  20. 77 FR 51521 - New England Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-24

    ..., Georges Bank yellowtail flounder, witch flounder, plaice, and Georges Bank/Gulf of Maine white hake... meeting is physically accessible to people with disabilities. Requests for sign language interpretation or...

  1. Specific IgE to fish extracts does not predict allergy to specific species within an adult fish allergic population

    PubMed Central

    2014-01-01

    Background Fish is an important cause of food allergy. Studies on fish allergy are scarce and in most cases limited to serological evaluation. Our objective was to study patterns of self-reported allergy and tolerance to different commonly consumed fish species and its correlation to IgE sensitization to the same species. Methods Thirty-eight adult fish allergic patients completed a questionnaire regarding atopy, age of onset and symptoms to 13 commonly consumed fish species in the Netherlands (pangasius, cod, herring, eel, hake, pollock, mackerel, tilapia, salmon, sardine, tuna, plaice and swordfish). Specific IgE to these fish extracts were analyzed by ImmunoCAP. Results Median age of onset of fish allergy was 8.5 years. Severe reactions were reported by the majority of patients (n = 20 (53%) respiratory and of these 20 patients, 6 also had cardiovascular symptoms). After diagnosis, 66% of the patients had eliminated all fish from their diet. Allergy to all species ever tried was reported by 59%. In relation to species ever tried, cod (84%) and herring (79%) were the most frequently reported culprit species while hake (57%) and swordfish (55%) were the least frequent. A positive sIgE (value ≥ 0.35 kUA/L) to the culprit species ranged between 50% (swordfish) and 100% (hake). In tolerant patients, a negative sIgE (value < 0.35 kUA/L) ranged from 0% (hake, pollock and swordfish) to 75% (sardine). For cod, the agreement between sIgE test results and reported allergy or tolerance was 82% and 25%, respectively. Sensitization to cod parvalbumin (Gad c 1) was present in 77% of all patients. Conclusion Serological cross-reactivity between fish species is frequent, but in a significant proportion of patients, clinical relevance appears to be limited to only certain species. A well-taken history or food challenge is required for discrimination between allergy to the different fish species. PMID:25225608

  2. Specific IgE to fish extracts does not predict allergy to specific species within an adult fish allergic population.

    PubMed

    Schulkes, Karlijn Jg; Klemans, Rob Jb; Knigge, Lidy; de Bruin-Weller, Marjolein; Bruijnzeel-Koomen, Carla Afm; Marknell deWitt, Asa; Lidholm, Jonas; Knulst, André C

    2014-01-01

    Fish is an important cause of food allergy. Studies on fish allergy are scarce and in most cases limited to serological evaluation. Our objective was to study patterns of self-reported allergy and tolerance to different commonly consumed fish species and its correlation to IgE sensitization to the same species. Thirty-eight adult fish allergic patients completed a questionnaire regarding atopy, age of onset and symptoms to 13 commonly consumed fish species in the Netherlands (pangasius, cod, herring, eel, hake, pollock, mackerel, tilapia, salmon, sardine, tuna, plaice and swordfish). Specific IgE to these fish extracts were analyzed by ImmunoCAP. Median age of onset of fish allergy was 8.5 years. Severe reactions were reported by the majority of patients (n = 20 (53%) respiratory and of these 20 patients, 6 also had cardiovascular symptoms). After diagnosis, 66% of the patients had eliminated all fish from their diet. Allergy to all species ever tried was reported by 59%. In relation to species ever tried, cod (84%) and herring (79%) were the most frequently reported culprit species while hake (57%) and swordfish (55%) were the least frequent. A positive sIgE (value ≥ 0.35 kUA/L) to the culprit species ranged between 50% (swordfish) and 100% (hake). In tolerant patients, a negative sIgE (value < 0.35 kUA/L) ranged from 0% (hake, pollock and swordfish) to 75% (sardine). For cod, the agreement between sIgE test results and reported allergy or tolerance was 82% and 25%, respectively. Sensitization to cod parvalbumin (Gad c 1) was present in 77% of all patients. Serological cross-reactivity between fish species is frequent, but in a significant proportion of patients, clinical relevance appears to be limited to only certain species. A well-taken history or food challenge is required for discrimination between allergy to the different fish species.

  3. 77 FR 66169 - Fisheries of the Northeastern United States; Northeast Multispecies Fishery Management Plan...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-02

    .... This may not be a true revenue loss, however. Red hake is rarely the primary target species and vessel... appropriate seasonal adjustments for vessels fishing in experimental or exempted fisheries that use small mesh...

  4. Fish Allergy

    MedlinePlus

    ... experience their first allergic reaction as adults. 1 Salmon, tuna and halibut are the most common kinds ... Hake Halibut Herring Mahi mahi Perch Pike Pollock Salmon Scrod Sole Snapper Swordfish Tilapia Trout Tuna Also ...

  5. Spatial overlap of shark nursery areas and the salmon farming industry influences the trophic ecology of Squalus acanthias on the southern coast of Chile.

    PubMed

    Gaitán-Espitia, Juan Diego; Gómez, Daniela; Hobday, Alistair J; Daley, Ross; Lamilla, Julio; Cárdenas, Leyla

    2017-06-01

    Potential interactions between marine predators and humans arise in the southern coast of Chile where predator feeding and reproduction sites overlap with fisheries and aquaculture. Here, we assess the potential effects of intensive salmon aquaculture on food habits, growth, and reproduction of a common predator, the spiny dogfish-identified as Squalus acanthias via genetic barcoding. A total of 102 (89 females and 13 males) individuals were collected during winter and summer of 2013-2014 from the Chiloé Sea where salmon aquaculture activities are concentrated. The low frequency of males in our study suggests spatial segregation of sex, while immature and mature females spatially overlapped in both seasons. Female spiny dogfish showed a functional specialist behavior as indicated by the small number of prey items and the relative high importance of the austral hake and salmon pellets in the diet. Immature sharks fed more on pellets and anchovies than the larger hake-preferring mature females. Our results also indicate that spiny dogfish switch prey (anchovy to hake) to take advantage of seasonal changes in prey availability. Despite differences in the trophic patterns of S. acanthias due to the spatial association with intensive salmon farming, in this region, there appears to be no difference in fecundity or size at maturity compared to other populations. Although no demographic effects were detected, we suggest that a range of additional factors should be considered before concluding that intensive aquaculture does not have any impact on these marine predators.

  6. Heavy metal (As, Cd, Hg, Pb, Cu, Zn, Se) concentrations in muscle and bone of four commercial fish caught in the central Adriatic Sea, Italy.

    PubMed

    Perugini, Monia; Visciano, Pierina; Manera, Maurizio; Zaccaroni, Annalisa; Olivieri, Vincenzo; Amorena, Michele

    2014-04-01

    Heavy metal (As, Cd, Cu, Pb, Zn, Hg and Se) concentrations in the muscle and bone of four fish species (Mullus barbatus, Merluccius merluccius, Micromesistius poutassou, and Scomber scombrus) from the central Adriatic Sea were measured and the relationships between fish size (length and weight) and metal concentrations in the tissues were investigated. Samples were analyzed by inductively coupled plasma-atomic emission spectrophotometry with automatic dual viewing. In the muscle, results of linear regression analysis showed that, except for mercury, significant relationships between metal concentrations and fish size were negative. Only mercury levels were positively correlated with Atlantic mackerel size (p < 0.05). No significant variations of heavy metal concentrations were observed in muscles of the examined species, but a significant difference (p < 0.01) was found for As, Cd, Pb, and Se concentrations in bone. All the investigated metals showed higher values in the muscle than in bone, except for lead and zinc. Regarding cadmium, lead, and mercury maximum levels, set for the edible portion by European legislation, several samples exceeded these values, confirming the heavy metal presence in species caught near the Jabuka Pit.

  7. New gadiform fishes (Teleostei, Gadiformes) from the Miocene of Algeria

    NASA Astrophysics Data System (ADS)

    Carnevale, Giorgio

    2007-02-01

    As part of the completion of studies on the Miocene fishes of the Chelif Basin (north-western Algeria), this paper represents a contribution to the knowledge of the Messinian gadiform diversity of this western Mediterranean, semi-enclosed, Neogene basin. A new genus and species of the family Macrouridae is erected ( Razelainia paradoxa n. gen. et sp.), two specimens are tentatively referred to already existing taxa ( Gadiculus cf. jonas; Merluccius cf. merluccius), and a species formerly assigned to the gadid genus Brosme is transferred to the genus Gaidropsarus ( Gaidropsarus murdjadjensis). The macrourid Razelainia paradoxa n. gen. et sp. is characterized by an unusual combination of: plesiomorphic gadiform features, such as low vertebral number (presumed), well-developed caudal-fin rays, presence of a single continuous dorsal fin originating just posterior to the neurocranium, anal-fin rays slightly longer than dorsal-fin rays; and derived, typically macrourid features, such as the presence of spinoid scales and the anterior anal-fin pterygiophores extending forward over the abdominal wall. A paleoecological analysis reveals that the Messinian gadiform assemblage of the Chelif Basin had a subtropical/warm temperate affinity, with a marked north-eastern Atlantic-Mediterranean biogeographic character.

  8. International Perspectives on Lifelong Learning.

    ERIC Educational Resources Information Center

    Holford, John, Ed.; Jarvis, Peter, Ed.; Griffin, Colin, Ed.

    This book contains 30 papers providing international perspectives on lifelong learning. The following papers are included: "Edgar Faure after 25 Years" (Roger Boshier); "Public Rhetoric and Public Policy" (Colin Griffin); "Lifelong Learning and the European Union" (Barry J. Hake); "Critical Perspectives and New…

  9. 77 FR 47373 - New England Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-08

    ..., Southern New England/Mid-Atlantic yellowtail flounder, Georges Bank yellowtail flounder, witch flounder, plaice and Georges Bank/Gulf of Maine white hake. The committee may not develop all the recommendations... accessible to people with disabilities. Requests for sign language interpretation or other auxiliary aids...

  10. 78 FR 64889 - Fisheries of the Northeastern United States; Northeast Multispecies Fishery; Emergency Rule...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-30

    ..., pursuant to NMFS's emergency authority in the Magnuson-Stevens Fishery Conservation and Management Act... under the Northeast (NE) Multispecies Fishery Management Plan (FMP). These measures were scheduled to... management of white hake. DATES: This rule is effective October 30, 2013, through April 30, 2014. The...

  11. Global assessment of molecularly identified Anisakis Dujardin, 1845 (Nematoda: Anisakidae) in their teleost intermediate hosts.

    PubMed

    Kuhn, Thomas; Hailer, Frank; Palm, Harry W; Klimpel, Sven

    2013-05-01

    Here, we present the ITS ribosomal DNA (rDNA) sequence data on 330 larvae of nematodes of the genus Anisakis Dujardin, 1845 collected from 26 different bony fish species from 21 sampling locations and different climatic zones. New host records are provided for Anisakis simplex (Rudolphi, 1809) sensu stricto (s.s.) and A. pegreffli Campana-Rouget et Biocca, 1955 from Anoplopoma fimbria (Pallas) (Santa Barbara, East Pacific), A. typica (Diesing, 1860) from Caesio cuning (Bloch), Lepturacanthus savala (Cuvier) and Katsuwonus pelamis (Linnaeus) (Indonesia, West Pacific), A. simplex s.s. from Cololabis saira (Brevoort) (Hawaii, Central Pacific), A. simplex C of Nascetti et al. (1986) from Sebastolobus alascanus Bean (Santa Barbara, East Pacific) and A. physeteris Baylis, 1923 from Synaphobranchus kaupii Johnson (Namibia, East Atlantic). Comparison with host records from 60 previous molecular studies of Anisakis species reveals the teleost host range so far recorded for the genus. Perciform (57 species) and gadiform (21) fishes were the most frequently infected orders, followed by pleuronectiforms (15) and scorpaeniforms (15). Most commonly infected fish families were Scombridae (12), Gadidae (10), Carangidae (8) and Clupeidae (7), with Merluccius merluccius (Linnaeus) alone harbouring eight Anisakis species. Different intermediate host compositions implicate differing life cycles for the so far molecularly identified Anisakis sibling species.

  12. Adult Education between Cultures. Encounters and Identities in European Adult Education since 1890. Leeds Studies in Continuing Education. Cross-Cultural Studies in the Education of Adults, Number 2.

    ERIC Educational Resources Information Center

    Hake, Barry J., Ed.; Marriott, Stuart, Ed.

    This book contains the following papers from a European research seminar examining the history and theory of cross-cultural communication in adult education: "Introduction: Encounters and Identities in European Adult Education since 1890" (Barry J. Hake, Stuart Marriott); "The University Extension Movement (1892-1914) in Ghent,…

  13. 78 FR 65888 - Fisheries of the Northeastern United States; Northeast Multispecies Fishery; Trip Limit...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-04

    ... economic impacts to the common pool fishery. There is additional good cause to waive the delayed effective... Fishery; Trip Limit Adjustments for the Common Pool Fishery AGENCY: National Marine Fisheries Service... hake, and pollock for Northeast multispecies common pool vessels for the remainder of the 2013 fishing...

  14. 77 FR 19231 - New England Fishery Management Council; Public Meeting

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-30

    ... ABC recommendations for redfish, Georges Bank haddock, Gulf of Maine/ Georges Bank windowpane flounder... 2013 and 2014 ABC recommendations for Georges Bank cod, Gulf of Maine haddock, Cape Cod/ Gulf of Maine yellowtail flounder, American plaice, witch flounder and Georges Bank/Gulf of Maine white hake. c. Other...

  15. 50 CFR 648.124 - Scup commercial season and commercial fishery area restrictions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... vessels in the Southern Gear Restricted Area that are fishing for or in possession of the following non-exempt species: Longfin squid; black sea bass; and silver hake (whiting). (b) Northern Gear Restricted... are fishing for, or in possession of, the following non-exempt species: Longfin squid squid; black sea...

  16. 50 CFR 648.124 - Scup commercial season and commercial fishery area restrictions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... vessels in the Southern Gear Restricted Area that are fishing for or in possession of the following non-exempt species: Longfin squid; black sea bass; and silver hake (whiting). (b) Northern Gear Restricted... are fishing for, or in possession of, the following non-exempt species: Longfin squid squid; black sea...

  17. 50 CFR 648.124 - Scup commercial season and commercial fishery area restrictions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... vessels in the Southern Gear Restricted Area that are fishing for or in possession of the following non-exempt species: Longfin squid; black sea bass; and silver hake (whiting). (b) Northern Gear Restricted... are fishing for, or in possession of, the following non-exempt species: Longfin squid squid; black sea...

  18. Correcting the Normalized Gain for Guessing

    ERIC Educational Resources Information Center

    Stewart, John; Stewart, Gay

    2010-01-01

    The normalized gain, "g", has been an important tool for the characterization of conceptual improvement in physics courses since its use in Hake's extensive study on conceptual learning in introductory physics. The normalized gain is calculated from the score on a pre-test administered before instruction and a post-test administered…

  19. Youth Attitude Tracking Study. Volume 1. Spring 1979.

    DTIC Science & Technology

    1979-08-01

    2.5 .3 + .5 no " Men with guns . 1 .2 + .1 no m Slogans (e.g., Navy Makes Boys Into Men) .1 .2 + .1 no Men with...survey. Thank you. TO HAKE THIS A VALID INTERVIEW, PLEASE RECORD THE TA, STATE AND COUNTY NUNBER FRON YOUR CALL RECORD PORN . (TA) (STATE

  20. 50 CFR 648.122 - Season and area restrictions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... apply only to vessels in the Southern Gear Restricted Area that are fishing for or in possession of the following non-exempt species: Loligo squid, black sea bass and silver hake (whiting). (b) Northern Gear... section apply only to vessels in the Northern Gear Restricted Area I that are fishing for, or in...

  1. 78 FR 26526 - Magnuson-Stevens Act Provisions; Fisheries off West Coast States; Pacific Coast Groundfish...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-07

    ... base-case model using nine years of an acoustic survey biomass index as well as catches to estimate the scale of the current hake stock. The 2012 acoustic-trawl survey result was a relative biomass 1,380,000... series. The age-composition data from the aggregated fisheries (1975-2012) and the acoustic survey...

  2. Worldwide Natural Gas Supply and Demand and the Outlook for Global LNG Trade

    EIA Publications

    1997-01-01

    This article is adapted from testimony by Jay Hakes, Administrator of the Energy Information Administration, before the Senate Energy and Natural Resources Committee on July 23, 1997. The hearing focused on the examination of certain aspects of natural gas into the next century with special emphasis on world natural gas supply and demand to 2015.

  3. Levels of polychlorinated biphenyls in fish and shellfish from the Adriatic Sea.

    PubMed

    Sagratini, G; Buccioni, M; Ciccarelli, C; Conti, P; Cristalli, G; Giardinà, D; Lambertucci, C; Marucci, G; Volpini, R; Vittori, S

    2008-01-01

    Levels of 18 polychlorinated biphenyl (PCB) congeners were determined by gas chromatography-mass spectrometry (GC-MS) in some marine species, living both in the coastal area and in deeper seawater. In some species analysis was performed separately in edible parts (fillets) and in viscera. The existence and degree of bioaccumulation was assessed studying individual species of very different size, with the smaller being younger. Furthermore, with a multivariate statistical analysis, a correlation between PCB congeners and the feeding habits and habitat of the fish was demonstrated. The results show that fat from edible parts (fish fillets) had total PCB levels in the range 22.6-601.9 µg kg⁻¹ (with 601.9 µg kg⁻¹ in anchovies), while fat from viscera showed much higher concentrations (407.3-916.6 µg kg⁻¹). Bioaccumulation was confirmed, comparing PCB levels between younger and older individual hake, squid, and horned octopus. The total PCB concentration ratio (older/younger individuals) ranges from 2.11 (squid = 292.1/137.8 µg kg⁻¹) to 3.46 (hake = 546.0/158.0 µg kg⁻¹).

  4. Anthropogenic impact in the Santa Maria di Leuca cold-water coral province (Mediterranean Sea): Observations and conservation straits

    NASA Astrophysics Data System (ADS)

    D'Onghia, G.; Calculli, C.; Capezzuto, F.; Carlucci, R.; Carluccio, A.; Grehan, A.; Indennidate, A.; Maiorano, P.; Mastrototaro, F.; Pollice, A.; Russo, T.; Savini, A.; Sion, L.; Tursi, A.

    2017-11-01

    , Merluccius merluccius and Conger conger while those from trawling mostly consisted of Aristeus antennatus, Aristaeomorpha foliacea and M. merluccius. The information collected during the observers' program and VMS data indicated greater impact due to trawling than longlining. The conservation and effective management of this vulnerable marine ecosystem remain difficult.

  5. Military Chapels and Chaplains: A Bibliography of Books and Periodical Articles.

    DTIC Science & Technology

    1982-07-29

    Dave . "Fifteen len of God," AD, 22:47, 48,.Sep 1967. Hake, Janet. "Helping Rands," SOL, 30:44-46, May 1975. _ "Sunday Every Day," SOL, 31:28-31, Oct...Chaplain," LCIM, 27:10-12, Oct 1943. Yates, Julian -. "The Chaplain," ;A:J, 70:550, 1932-33. Zielinski , Constantine Z. "The Chaplain and Stimulation

  6. Silver Hake Tracks Changes in Northwest Atlantic Circulation

    EPA Science Inventory

    Recent studies documenting shifts in spatial distribution of many organisms in response to a warming climate highlight the need to understand the mechanisms underlying species distribution at large spatial scales. Here we present one noteworthy example of remote oceanographic pro...

  7. Will the No Child Left Behind Act Promote Direct Instruction of Science?

    NASA Astrophysics Data System (ADS)

    Hake, Richard

    2005-03-01

    Education research in physics at the high school and undergraduate level strongly suggests that interactive engagement enhances students' conceptual understanding much more than traditional Direct Science Instruction (DSI). Similar conclusions can be drawn from K-8 science-education research. Nevertheless, DSI predominates in CA because of the DSI- orientation of the CA State Board of Education and Curriculum Commission [1]. Likewise the U.S. Dept. of Education's (USDE's): (a) DSI-orientation as demonstrated by its recent national-education summit showcasing of the research of Klahr and Nigam [2]; and (b) science achievement testing starting in 2007; threatens to promote DSI nationwide. It might be hoped that NRC's expert science education committees will steer the USDE away from promoting DSI, the antithesis of the NRC's own recommendations for inquiry methods. [1] R.R. Hake. ``Direct Science Instruction Suffers a Setback in California - Or Does It?" (2004), <ł http://www.physics.indiana.edu/˜hake/DirInstSetback-041104f.pdf>. [2] Klahr, D. & M. Nigam. 2004. ``The equivalence of learning paths in early science instruction: effects of direct instruction and discovery learning" (2004), .

  8. Physical Fitness Symposium, 12-14 October 1970, United States Army Infantry School, Fort Benning, Georgia

    DTIC Science & Technology

    1970-10-14

    Lcadersalp Department, USAIS Fort Uennlng, GA 43 rä^ajaaäaiafeaaaft-ai HAKE Bray, H. F., MAJ Ely the, Ronald , LIC Bussaan, Carl E ., LT Orroll...development of the Army physic*! fitness program. ^ JECTIVESl e objectives of the symposium were: I. To discuss new developments in physical...upon the body. c. Evaluation of physical fitness. d. Motivation in training and tcstinR. e . Running progrsa "RUN FOR YOUR LIFE." f. Contribution of

  9. Characteristics of Fishes with the Potential to Cause Acoustic Clutter off Oregon and Washington during the Summer of 2012

    DTIC Science & Technology

    2014-05-10

    14. Barboza, T., "West Coast sardine crash could radiate throughout ecosystem," Los Angeles Times, January 5, 2014. 15. Enticknap, B., Letter to the...AND SURVEYS Much of the Pacific sardine and Pacific hake stocks undertake annual north-south migrations . They migrate in late spring from off...California to the Pacific Northwest to feed during the summer. In the fall they migrate back to California to spawn during the winter and spring. The

  10. Host location by ichneumonid parasitoids is associated with nest dimensions of the host bee species.

    PubMed

    Flores-Prado, L; Niemeyer, H M

    2012-08-01

    Parasitoid fitness depends on the ability of females to locate a host. In some species of Ichneumonoidea, female parasitoids detect potential hosts through vibratory cues emanating from them or through vibrational sounding produced by antennal tapping on the substrate. In this study, we (1) describe host location behaviors in Grotea gayi Spinola (Hymenoptera: Ichneumonidae) and Labena sp. on nests of Manuelia postica Spinola (Hymenoptera: Apidae), (2) compare nest dimensions between parasitized and unparasitized nests, (3) correlate the length of M. postica nests with the number of immature individuals developing, and (4) establish the relative proportion of parasitized nests along the breeding period of M. postica. Based on our results, we propose that these parasitoids use vibrational sounding as a host location mechanism and that they are able to assess host nest dimensions and choose those which may provide them with a higher fitness. Finally, we discuss an ancestral host-parasitoid relationship between Manuelia and ichneumonid species.

  11. Remedial Investigation Concept Plan for Picatinny Arsenal. Volume 1. Environmental Setting, Applicable Regulations, Summaries of Site Sampling Plans, Sampling Priorities, and Supporting Appendixes.

    DTIC Science & Technology

    1991-03-22

    Aquathoi Pius Aquathoi Plus Capran Ch i p-CaI Copper-Tox Oapsodar Floral dust Lead arsenate Ferrated eyelohexiwide 2.261 Pentachioronitroben?ene...thiram 151 Chloroneb 651 Thiram 751 Thi-am 51, cadmium chloride 0.751 Siduron 501 Potassium salts of endothall 22.H and siIvex 52.61 Potassium ...cans SmoKe« Potassium nitrate (46.21) «a cartridges Moth Hakes Naphthalene (1001) 30 tb Cytn.on maiathion Maiathion (9𔃻) T? gat Pyrethrum

  12. Seasonal changes in composition, fatty acid, cholesterol and mineral content of six highly commercial fish species of Greece.

    PubMed

    Zotos, A; Vouzanidou, M

    2012-04-01

    Changes in lipid, protein, ash and moisture, quantitative distribution of fatty acids, cholesterol and mineral content (Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni and Zn) of six common fish species from Greece were studied. The proximate composition of all samples was significantly influenced by the fishing period, even the cultured ones. The sum of C20:5ω-3 and C22:6ω-3 ranged from 1.18 to 2.76 for sardine, from 0.37 to 1.99 for bogue, from 1.1 to 1.52 for mackerel, from 1.23 to 1.46 for sea bass, from 1.00 to 1.24 for trout and from 0.26 to 0.45 g/100 g edible portion for hake samples. Besides the ratio of ω-3/ω-6 polyunsaturated fatty acids ranged from 6.80 to 19.00 for the wild fish samples and from 1.01 to 3.67 for the cultured ones. Cholesterol of sardine, bogue, mackerel, trout and sea bass ranged from 37 up to 76 mg/100 g edible flesh, while it was varied from 72 to 124 mg/100 g in the flesh of hake. The concentration of minerals was detected at acceptable levels. All fish samples seemed to be quite good sources of Mg, Zn and Fe. Co was not detected in the samples studied.

  13. Active Learning in the Physics Classroom

    NASA Astrophysics Data System (ADS)

    Naron, Carol

    Many students enter physics classes filled with misconceptions about physics concepts. Students tend to retain these misconceptions into their adult lives, even after physics instruction. Constructivist researchers have found that students gain understanding through their experiences. Researchers have also found that active learning practices increase conceptual understanding of introductory physics students. This project study sought to examine whether incorporating active learning practices in an advanced placement physics classroom increased conceptual understanding as measured by the force concept inventory (FCI). Physics students at the study site were given the FCI as both a pre- and posttest. Test data were analyzed using two different methods---a repeated-measures t test and the Hake gain method. The results of this research project showed that test score gains were statistically significant, as measured by the t test. The Hake gain results indicated a low (22.5%) gain for the class. The resulting project was a curriculum plan for teaching the mechanics portion of Advanced Placement (AP) physics B as well as several active learning classroom practices supported by the research. This project will allow AP physics teachers an opportunity to improve their curricular practices. Locally, the results of this project study showed that research participants gained understanding of physics concepts. Social change may occur as teachers implement active learning strategies, thus creating improved student understanding of physics concepts.

  14. Ocean Acoustic Waveguide Remote Sensing (OAWRS) of Marine Ecosystems

    DTIC Science & Technology

    2009-12-03

    Am 124:EL91–EL96 Thompson D, Buck CD, McConnell BJ, Garrett J (1998) For- aging behavior and diet of lactating female southern sea lions in the...surface ( Thorne & Thomas 1990, our Fig. S1). Thorne & Thomas (1990) measured neutral buoyancy depths of up to ~60 m for herring, a physostome, and...scup, hake, black sea bass and alewife (NEFSC Resource Survey Report 2003, Makris et al. 2006b). While dogfish and mackerel are also found in the area

  15. Phytochemical Study of the Genus Salpichroa (Solanaceae), Chemotaxonomic Considerations, and Biological Evaluation in Prostate and Breast Cancer Cells.

    PubMed

    Basso, Ana Valentina; Leiva González, Segundo; Barboza, Gloria Estela; Careaga, Valeria Pilar; Calvo, Juan Carlos; Sacca, Paula A; Nicotra, Viviana Estela

    2017-08-01

    Twelve Salpichroa taxa have been phytochemically analyzed. From the aerial parts of S. scandens, four known salpichrolides A, C, I, S, and an unreported withanolide named salpichrolide V (1), were isolated. In S. dependens, S. gayi, S. glandulosa subsp. glandulosa, S. glandulosa subps. weddellii, S. leucantha, S. micrantha, S. microloba, S. proboscidea, S. ramosissima, S. tristis var. tristis, and S. weberbauerii, no withanolides were found. The chemical content of ca. 85% of the Salpichroa taxa is in agreement with molecular studies, which suggest that Salpichroa and Jaborosa, a genus considered morphologically close to Salpichroa, are distant in the systematic of the Solanoideae subfamily. Moreover, the in vitro cytotoxic activity of a set of natural salpichrolides and derivatives was examined against two prostate carcinoma cell lines (PC3 and LNCaP) and two human breast cancer cell lines (MCF-7 and T47D). Several compounds showed moderate activity (IC 50  = 64.91 - 29.97 μm). © 2017 Wiley-VHCA AG, Zurich, Switzerland.

  16. Persistence and co-occurrence of demersal nurseries in the Strait of Sicily (central Mediterranean): Implications for fishery management

    NASA Astrophysics Data System (ADS)

    Garofalo, G.; Fortibuoni, T.; Gristina, M.; Sinopoli, M.; Fiorentino, F.

    2011-08-01

    This study investigated the nurseries of seven commercially important demersal species of the northern sector of the Strait of Sicily (central Mediterranean): red mullet, European hake, horned octopus, deep-water rose shrimp, greater forkbeard, Norway lobster and giant red shrimp. An eleven-year series of data collected through experimental trawling in the Strait of Sicily during spring and autumn was analyzed. The spatio-temporal persistence of the high-density aggregations (hot spots) of juvenile individuals in their first year of life was investigated to identify habitats that serve as nurseries. The density of recruits within the persistent nurseries was used as a proxy of the unit area contribution of individuals which recruit to the adult population. The spatial distribution patterns of the recruits of most the species were well defined and very stable in the long term. Persistent and potentially highly productive nurseries of European hake, deep-water rose shrimp and greater forkbeard were identified off the southern coast of Sicily. Persistent areas of recruits concentration were also observed for the other species investigated, but their specific potential contribution of individuals to the adult population was not substantial compared to adjacent grounds. The close or overlapped localization of sites which regularly host vulnerable life stages of different exploited species, revealed an area of great ecological significance which probably plays a major role in the dynamics of the fishery resources in the Strait of Sicily. Appropriate spatial protection measures of this area, including marine protected area designation, could complement conventional management approach for ensuring the long-term sustainability of these fisheries and stocks conservation.

  17. White fish reduces cardiovascular risk factors in patients with metabolic syndrome: the WISH-CARE study, a multicenter randomized clinical trial.

    PubMed

    Vázquez, C; Botella-Carretero, J I; Corella, D; Fiol, M; Lage, M; Lurbe, E; Richart, C; Fernández-Real, J M; Fuentes, F; Ordóñez, A; de Cos, A I; Salas-Salvadó, J; Burguera, B; Estruch, R; Ros, E; Pastor, O; Casanueva, F F

    2014-03-01

    Reduction of cardiovascular risk with high consumption of fish in diet is still a matter of debate, and concerns about heavy metal contamination have limited consumption of oily fish. We aimed to evaluate the effect of regular ingestion of white fish on cardiovascular risk factors in patients with metabolic syndrome. Multicenter randomized crossover clinical trial including 273 individuals with metabolic syndrome. An 8-week only-one dietary intervention: 100 g/d of white fish (Namibia hake) with advice on a healthy diet, compared with no fish or seafood with advice on a healthy diet. Outcomes were lipid profile, individual components of the metabolic syndrome, serum insulin concentrations, homeostasis model of insulin resistance, serum C-reactive protein and serum fatty acid levels. We found a significant lowering effect of the intervention with white fish on waist circumference (P < 0.001) and diastolic blood pressure (P = 0.014). A significant lowering effect was also shown after the dietary intervention with fish on serum LDL concentrations (P = 0.048), whereas no significant effects were found on serum HDL or triglyceride concentrations. A significant rise (P < 0.001) in serum EPA and DHA fatty acids was observed following white fish consumption. Overall adherence to the intervention was good and no adverse events were found. In individuals with metabolic syndrome, regular consumption of hake reduces LDL cholesterol concentrations, waist circumference and blood pressure components of the metabolic syndrome. White Fish for Cardiovascular Risk Factors in Patients with Metabolic Syndrome Study, Registered under ClinicalTrials.gov Identifier: NCT01758601. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Tolerability to dogfish in children with fish allergy.

    PubMed

    Calderon-Rodriguez, S; Pineda, F; Perez, R; Muñoz, C

    2016-01-01

    Fish is a potent food allergen. The aim of this work is to demonstrate that dogfish, a small shark, has low allergenicity in both its clinical tolerance as well as its molecular structure. We present a study of 34 paediatric patients with IgE-mediated immediate reactions after eating fish. The diagnosis of several fish allergies was demonstrated by skin prick techniques and determination of specific IgE, in all the cases excluding sensitisation to Anisakis simplex. Open oral challenge test was checked with dogfish. Analysis was by SDS-PAGE of dogfish and other fish (megrim, shark, hake, sole, cod, anchovy and tuna) and Western-blot with "pool" of patients polysensitised sera against extracts of dogfish and other fish, and ELISA - inhibition with the "pool" sera. The prick-prick with raw dogfish was slightly positive in six patients, however cooked was negative in 34 cases. The specific IgE showed in the 34 cases class ≥2 for megrim, hake, sole, cod and anchovy, class 0 for tuna in 26 patients, class 0 for emperor in 18 patients and class 0 to Anisakis simplex in all cases. The IgE binding capacity for proteins of allergenic extracts of tested fish revealed, in immunoblotting, the absence of IgE-mediated recognition abstract dogfish by the "pool" of polysensitised patient sera. Testing in vivo and in vitro demonstrated the low allergenicity of dogfish. Dogfish brings an alternative to eating fish in polysensitised patients. Copyright © 2015 SEICAP. Published by Elsevier Espana. All rights reserved.

  19. Mercury concentrations in lean fish from the Western Mediterranean Sea: Dietary exposure and risk assessment in the population of the Balearic Islands.

    PubMed

    Llull, Rosa Maria; Garí, Mercè; Canals, Miquel; Rey-Maquieira, Teresa; Grimalt, Joan O

    2017-10-01

    The present study reports total mercury (THg) and methylmercury (MeHg) concentrations in 32 different lean fish species from the Western Mediterranean Sea, with a special focus on the Balearic Islands. The concentrations of THg ranged between 0.05mg/kg ww and 3.1mg/kg ww (mean 0.41mg/kg ww). A considerable number of the most frequently fish species consumed by the Spanish population exceed the maximum levels proposed by the European legislation when they originate from the Mediterranean Sea, such as dusky grouper (100% of the examined specimens), common dentex (65%), conger (45%), common sole (38%), hake (26%) and angler (15%), among others. The estimated weekly intakes (EWI) in children (7-12 years of age) and adults from the Spanish population (2.7µg/kg bw and 2.1µg/kg bw, respectively) for population only consuming Mediterranean fish were below the provisional tolerable weekly intake (PTWI) of THg established by EFSA in 2012, 4µg/kg bw. However, the equivalent estimations for methylmercury, involving PTWI of 1.3µg/kg bw, were two times higher in children and above 50% in adults. For hake, sole, angler and dusky grouper, the most frequently consumed fish, the estimated weekly intakes in both children and adults were below the maximum levels accepted. These intakes correspond to maximum potential estimations because fish from non-Mediterranean origin is often consumed by the Spanish population including the one from the Balearic Islands. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Invasive range expansion by the Humboldt squid, Dosidicus gigas, in the eastern North Pacific.

    PubMed

    Zeidberg, Louis D; Robison, Bruce H

    2007-07-31

    A unique 16-year time series of deep video surveys in Monterey Bay reveals that the Humboldt squid, Dosidicus gigas, has substantially expanded its perennial geographic range in the eastern North Pacific by invading the waters off central California. This sustained range expansion coincides with changes in climate-linked oceanographic conditions and a reduction in competing top predators. It is also coincident with a decline in the abundance of Pacific hake, the most important commercial groundfish species off western North America. Recognizing the interactive effects of multiple changes in the environment is an issue of growing concern in ocean conservation and sustainability research.

  1. The nature of the in vivo sodium and chloride uptake mechanisms through the epithelium against sodium and of bicarbonate against chloride.

    PubMed

    García Romeu, F; Salibián, A; Pezzani-Hernádez, S

    1969-06-01

    The Chilean frog, Calyptocephallela gayi, placed in dilute NaCl solutions may pump Na(+) and Cl(-) at very different rates depending on the kind of bath solutions in which it was preadapted. Furthermore, Na(+) and Cl(-) may be absorbed from solutions in which the accompanying coion, such as sulfate and choline, respectively, is impermeant. In all these cases it is obligatory to postulate the existence of two ionic exchange mechanisms, Cl(-) and Na(+), being exchanged against endogenous anions and cations, respectively. It has been determined that Na(+) is exchanged against endogenous H(+) and that Cl(-) is exchanged against HCO(3) (-). In animals pumping Na(+) and Cl(-) from dilute NaCl solutions Na(+) or Cl(-) uptake may be selectively inhibited, while the flux of the accompanying ion remains unchanged. This is considered to be an additional proof that both Na(+) and Cl(-) fluxes are always independent. The role of the ionic exchange mechanisms in the direct regulation of the Na(+) and Cl(-) levels in the internal medium is discussed as well as their relationship in the regulation of the acid-base equilibrium; other physioecological considerations have been treated.

  2. Invasive range expansion by the Humboldt squid, Dosidicus gigas, in the eastern North Pacific

    PubMed Central

    Zeidberg, Louis D.; Robison, Bruce H.

    2007-01-01

    A unique 16-year time series of deep video surveys in Monterey Bay reveals that the Humboldt squid, Dosidicus gigas, has substantially expanded its perennial geographic range in the eastern North Pacific by invading the waters off central California. This sustained range expansion coincides with changes in climate-linked oceanographic conditions and a reduction in competing top predators. It is also coincident with a decline in the abundance of Pacific hake, the most important commercial groundfish species off western North America. Recognizing the interactive effects of multiple changes in the environment is an issue of growing concern in ocean conservation and sustainability research. PMID:17646649

  3. Rate of Learning Models, Mental Models, and Item Response Theory

    NASA Astrophysics Data System (ADS)

    Pritchard, David E.; Lee, Y.; Bao, L.

    2006-12-01

    We present three learning models that make different assumptions about how the rate of a student's learning depends on the amount that they know already. These are motivated by the mental models of Tabula Rasa, Constructivist, and Tutoring theories. These models predict the postscore for a given prescore after a given period of instruction. Constructivist models show a close connection with Item Response Theory. Comparison with data from both Hake and MIT shows that the Tabula Rasa models not only fit incomparably better, but fit the MIT data within error across a wide range of pretest scores. We discuss the implications of this finding.

  4. Overfishing of small pelagic fishes increases trophic overlap between immature and mature striped dolphins in the Mediterranean Sea.

    PubMed

    Gómez-Campos, Encarna; Borrell, Assumpció; Cardona, Luis; Forcada, Jaume; Aguilar, Alex

    2011-01-01

    The interactions among diet, ecology, physiology, and biochemistry affect N and C stable isotope signatures in animal tissues. Here, we examined if ecological segregation among animals in relation to sex and age existed by analyzing the signatures of δ(15)N and δ(13)C in the muscle of Western Mediterranean striped dolphins. Moreover, we used a Bayesian mixing model to study diet composition and investigated potential dietary changes over the last two decades in this population. For this, we compared isotope signatures in samples of stranded dolphins obtained during two epizootic events occurring in 1990 and 2007-2008. Mean δ(13)C values for females and males were not significantly different, but age-related variation indicated δ(13)C enrichment in both sexes, suggesting that females and males most likely fed in the same general areas, increasing their consumption of benthic prey with age. Enrichment of δ(15)N was only observed in females, suggesting a preference for larger or higher trophic level prey than males, which could reflect different nutritional requirements. δ(13)C values showed no temporal variation, although the mean δ(15)N signature decreased from 1990 to 2007-2008, which could indicate a dietary shift in the striped dolphin over the last two decades. The results of SIAR indicated that in 1990, hake and sardine together contributed to 60% on the diet of immature striped dolphins, and close to 90% for mature striped dolphins. Conversely, the diet of both groups in 2007-2008 was more diverse, as hake and sardine contributed to less than 40% of the entire diet. These results suggest a dietary change that was possibly related to changes in food availability, which is consistent with the depletion of sardine stocks by fishing.

  5. Xenopus laevis and Emerging Amphibian Pathogens in Chile.

    PubMed

    Soto-Azat, Claudio; Peñafiel-Ricaurte, Alexandra; Price, Stephen J; Sallaberry-Pincheira, Nicole; García, María Pía; Alvarado-Rybak, Mario; Cunningham, Andrew A

    2016-12-01

    Amphibians face an extinction crisis with no precedence. Two emerging infectious diseases, ranaviral disease caused by viruses within the genus Ranavirus and chytridiomycosis due to Batrachochytrium dendrobatidis (Bd), have been linked with amphibian mass mortalities and population declines in many regions of the globe. The African clawed frog (Xenopus laevis) has been indicated as a vector for the spread of these pathogens. Since the 1970s, this species has been invasive in central Chile. We collected X. laevis and dead native amphibians in Chile between 2011 and 2013. We conducted post-mortem examinations and molecular tests for Ranavirus and Bd. Eight of 187 individuals (4.3 %) tested positive for Ranavirus: seven X. laevis and a giant Chilean frog (Calyptocephallela gayi). All positive cases were from the original area of X. laevis invasion. Bd was found to be more prevalent (14.4 %) and widespread than Ranavirus, and all X. laevis Bd-positive animals presented low to moderate levels of infection. Sequencing of a partial Ranavirus gene revealed 100 % sequence identity with Frog Virus 3. This is the first report of Ranavirus in Chile, and these preliminary results are consistent with a role for X. laevis as an infection reservoir for both Ranavirus and Bd.

  6. Lost and found: the Plecoptera types of Blanchard and Mabille, with further contributions to the stoneflies of Chile.

    PubMed

    Murányi, Dávid; Gamboa, Maribet; Vera, Alejandro

    2016-12-01

    Types of five of the six Plecoptera species described by Émile Blanchard and the holotype of the single stonefly described by Jules François Mabille were discovered in the National Museum Prague, Czech Republic. The identity of P. myrmidon Mabille, 1891 and P. pictetii Blanchard, 1854 are confirmed as Potamoperla myrmidon and Pictetoperla gayi (Pictet, 1841), respectively. Perla virescentipennis Blanchard, 1851 is considered as Diamphipnopsis virescentipennis comb. n., with Diamphipnosis samali Illies, 1960 syn. n. as a junior subjective synonym, and Diamphipnoa chillanae nom. n. is proposed for D. virescentipennis sensu Illies 1960. Lectotypes are designated for three species: Nemoura rufescens Blanchard, 1851 is redescribed as Austronemoura rufescens (Blanchard, 1851) comb. n., with Perla infuscata Blanchard, 1851 syn. n. and Perla blanchardi Jakobson & Bianchi, 1905 syn. n. designated as junior subjective synonyms, whereas Perla stictica Blanchard, 1851 is treated as Neonemura stictica (Blanchard, 1851) comb. n., nomen dubium. Paralectotypes of these three species belong to further four taxa. Due to the missing syntypes, Perla lineatocollis Blanchard, 1851 is treated as a nomen dubium of uncertain suborder assignment. Specimens of the Blanchard collections that cannot regarded as types are enumerated belonging to six species. Recent collections of 15 species from Chile are also reported.

  7. Partial purification and characterization of cysteine proteinase inhibitor from chicken plasma.

    PubMed

    Rawdkuen, Saroat; Benjakul, Soottawat; Visessanguan, Wonnop; Lanier, Tyre C

    2006-08-01

    A high-molecular-weight cysteine proteinase inhibitor (CPI) was purified from chicken (Gallus gallus) plasma using polyethylene glycol (PEG) fractionation and affinity chromatography on carboxymethyl-papain-Sepharose-4B. The CPI was purified 96.8-fold with a yield of 28.9%. Based on inhibitory activity staining for papain, CPI was shown to have an apparent molecular mass of 122 kDa. No inhibitory activity was obtained under reducing condition, indicating that CPI from chicken plasma was stabilized by disulfide bonds. CPI was stable in temperature ranges from 40 to 70 degrees C for 10 min; however, more than 50% of the inhibitory activity towards papain was lost within 30 min of heating at 90 degrees C. CPI was stable in the presence of salt up to 3%. The purified CPI exhibited the inhibitory activity toward autolysis of arrowtooth flounder (Atheresthes stomias) and Pacific whiting (Merluccius productus) natural actomyosin (NAM) in a concentration-dependent manner.

  8. Measuring student learning using initial and final concept test in an STEM course

    NASA Astrophysics Data System (ADS)

    Kaw, Autar; Yalcin, Ali

    2012-06-01

    Effective assessment is a cornerstone in measuring student learning in higher education. For a course in Numerical Methods, a concept test was used as an assessment tool to measure student learning and its improvement during the course. The concept test comprised 16 multiple choice questions and was given in the beginning and end of the class for three semesters. Hake's gain index, a measure of learning gains from pre- to post-tests, of 0.36 to 0.41 were recorded. The validity and reliability of the concept test was checked via standard measures such as Cronbach's alpha, content and criterion-related validity, item characteristic curves and difficulty and discrimination indices. The performance of various subgroups such as pre-requisite grades, transfer students, gender and age were also studied.

  9. The fish and fisheries of Jones Bank and the wider Celtic Sea

    NASA Astrophysics Data System (ADS)

    Martinez, I.; Ellis, J. R.; Scott, B.; Tidd, A.

    2013-10-01

    The Celtic Sea is a diverse fishing ground that supports important commercial fisheries for a range of demersal fish, large and small-bodied pelagic fish and a variety of cephalopods and other shellfish. A regional overview of the main commercial fish stocks of the Celtic Sea and of the fish that occur in the vicinity of Jones Bank are provided through analyses of landings data from English and Welsh vessels, and from scientific trawl surveys. Dedicated smaller scale sampling via trawl surveys combined with baited cameras on and around the Jones Bank were also analysed to investigate the importance of sandbank habitats with attention paid to the differences in the species occurring on the top of the bank in comparison to adjacent off-bank habitats. Official landing statistics for UK (English and Welsh) vessels indicated that the predominant commercial demersal species in ICES Divisions VIIg,h (in terms of quantities landed) were anglerfish, megrim, pollack and skates (Rajidae). There were, however, regional differences in the distribution of fish and fisheries, and the area surrounding Jones Bank (ICES Rectangles 28E1 and 28E2) supports fisheries for megrim, anglerfish, skates, hake, ling and turbot, with otter trawl, gillnet and beam trawl the main gears used. Recent survey data collected with GOV (Grande Ouverture Verticale) trawl from the Celtic Sea (ICES Divisions VIIe-h, 2007-2010) were used to highlight the broad scale distribution of the main fish assemblages in the Celtic Sea. Analyses of the fish and cephalopod catches from these surveys indicated that there were four broad assemblages in the area, including (i) a region around the Cornwall (which will also be partly influenced by the necessity to use rockhopper ground gear on these rough grounds), (ii) the shallower regions of the north-western Celtic Sea (including parts of the Bristol Channel), (iii) the deeper parts of the outer shelf and (iv) the central Celtic Sea. These data also provided

  10. Detection of Different DNA Animal Species in Commercial Candy Products.

    PubMed

    Muñoz-Colmenero, Marta; Martínez, Jose Luis; Roca, Agustín; Garcia-Vazquez, Eva

    2016-03-01

    Candy products are consumed all across the world, but there is not much information about their composition. In this study we have used a DNA-based approach for determining the animal species occurring in 40 commercial candies of different types. We extracted DNA and performed PCR amplification, cloning and sequencing for obtaining species-informative DNA sequences. Eight species were identified including fish (hake and anchovy) in 22% of the products analyzed. Bovine and porcine were the most abundant appearing in 27 samples each one. Most products contained a mixture of species. Marshmallows (7), jelly-types, and gummies (20) contained a significantly higher number of species than hard candies (9). We demonstrated the presence of DNA animal species in candy product which allow consumers to make choices and prevent allergic reaction. © 2016 Institute of Food Technologists®

  11. Multi-criteria dynamic decision under uncertainty: a stochastic viability analysis and an application to sustainable fishery management.

    PubMed

    De Lara, M; Martinet, V

    2009-02-01

    Managing natural resources in a sustainable way is a hard task, due to uncertainties, dynamics and conflicting objectives (ecological, social, and economical). We propose a stochastic viability approach to address such problems. We consider a discrete-time control dynamical model with uncertainties, representing a bioeconomic system. The sustainability of this system is described by a set of constraints, defined in practice by indicators - namely, state, control and uncertainty functions - together with thresholds. This approach aims at identifying decision rules such that a set of constraints, representing various objectives, is respected with maximal probability. Under appropriate monotonicity properties of dynamics and constraints, having economic and biological content, we characterize an optimal feedback. The connection is made between this approach and the so-called Management Strategy Evaluation for fisheries. A numerical application to sustainable management of Bay of Biscay nephrops-hakes mixed fishery is given.

  12. Impacts of curricular change: Implications from 8 years of data in introductory physics

    NASA Astrophysics Data System (ADS)

    Pollock, Steven J.; Finkelstein, Noah

    2013-01-01

    Introductory calculus-based physics classes at the University of Colorado Boulder were significantly transformed beginning in 2004. They now regularly include: interactive engagement using clickers in large lecture settings, Tutorials in Introductory Physics with use of undergraduate Learning Assistants in recitation sections, and a staffed help-room setting where students work on personalized CAPA homework. We compile and summarize conceptual (FMCE and BEMA) pre- and post-data from over 9,000 unique students after 16 semesters of both Physics 1 and 2. Within a single institution with stable pre-test scores, we reproduce results of Hake's 1998 study that demonstrate the positive impacts of interactive engagement on student performance. We link the degree of faculty's use of interactive engagement techniques and their experience levels on student outcomes, and argue for the role of such systematic data collection in sustained course and institutional transformations.

  13. Evaluating learning and teaching using the Force Concept Inventory

    NASA Astrophysics Data System (ADS)

    Zitzewitz, Paul

    1997-04-01

    Teaching methods used in the calculus-based mechanics course for engineers and scientists (P150) at the University of Michigan-Dearborn were markedly changed in September, 1996. Lectures emphasize active learning with Mazur's ConcepTests, Sokoloff's Interactive Demonstrations, and Van Heuvelen's ALPS Kit worksheets. Students solve context-rich problems using Van Heuvelen's multiple representation format in cooperative groups in discussion sections. Labs were changed to use MBL emphasizing concepts and Experiment Problems to learn lab-based problem solving. Pre- and post-testing of 400 students with the Force Concept Inventory has demonstrated considerable success. The average increase in score has been 35-45methods as defined by Hake. The methods and results will be discussed. Detailed analyses of the FCI results will look at success in teaching specific concepts and the effect of student preparation in mathematics and high school physics.

  14. Thermal performance curves under daily thermal fluctuation: A study in helmeted water toad tadpoles.

    PubMed

    Bartheld, José L; Artacho, Paulina; Bacigalupe, Leonardo

    2017-12-01

    Most research in physiological ecology has focused on the effects of mean changes in temperature under the classic "hot vs cold" acclimation treatment; however, current evidence suggests that an increment in both the mean and variance of temperature could act synergistically to amplify the negative effects of global temperature increase and how it would affect fitness and performance-related traits in ectothermic organisms. We assessed the effects of acclimation to daily variance of temperature on thermal performance curves of swimming speed in helmeted water toad tadpoles (Calyptocephalella gayi). Acclimation treatments were 20°C ± 0.1 SD (constant) and 20°C ± 1.5 SD (fluctuating). We draw two key findings: first, tadpoles exposed to daily temperature fluctuation had reduced maximal performance (Z max ), and flattened thermal performance curves, thus supporting the "vertical shift or faster-slower" hypothesis, and suggesting that overall swimming performance would be lower through an examination of temperatures under more realistic and ecologically-relevant fluctuating regimens; second, there was significant interindividual variation in performance traits by means of significant repeatability estimates. Our present results suggest that the widespread use of constant acclimation temperatures in laboratory experiments to estimate thermal performance curves (TPCs) may lead to an overestimation of actual organismal performance. We encourage the use of temperature fluctuation acclimation treatments to better understand the variability of physiological traits, which predict ecological and evolutionary responses to global change. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Human exposure to lead, cadmium and mercury through fish and seafood product consumption in Italy: a pilot evaluation.

    PubMed

    Pastorelli, A A; Baldini, M; Stacchini, P; Baldini, G; Morelli, S; Sagratella, E; Zaza, S; Ciardullo, S

    2012-01-01

    The presence of selected toxic heavy metals, such as cadmium (Cd), lead (Pb) and mercury (Hg), was investigated in fish and seafood products, namely, blue mussel, carpet shell clam, European squid, veined squid, deep-water rose shrimp, red mullet, European seabass, gilthead seabream, Atlantic cod, European hake, Atlantic bluefin tuna and swordfish so as to assess their human exposure through diet. Metals were detected by quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS) and hydride generation atomic absorption spectrometry (Hg-AAS). Measurements of Cd, Pb and Hg were performed by means of analytical methods validated in compliance with UNI CEI EN ISO/IEC 17025 [2005. General requirements for the competence of testing and calibration laboratories. Milano (Italy): UNI Ente Nazionale Italiano di Unificazione]. The exposure assessment was undertaken matching the levels of Cd, Pb and total Hg with consumption data related to fish and seafood products selected for this purpose. In order to establish human health implications, the estimated weekly intakes (EWIs) for Cd, Pb and Hg were compared with the standard tolerable weekly intakes (TWI) for Cd and provisional tolerable weekly intakes (PTWIs) for Pb and Hg stipulated by the European Food Safety Authority (EFSA) and the Food and Agriculture Organization/World Health Organization (FAO/WHO) Joint Expert Committee on Food Additives (JECFA). The found metal concentrations were largely below the maximum levels (MLs) established at the European Union level with the exception of Cd. This metal exceeded the MLs in squid, red mullet, European hake and Atlantic cod. Squid and blue mussel showed the highest Pb concentrations which accounted for 60% and 10% of the MLs, respectively. Highest Hg levels were found in predatory fish. The concentrations of Hg in swordfish, Atlantic bluefin tuna and red mullet accounted for 50%, 30% and 30% of the MLs, respectively. The EWIs for Cd, Pb and Hg related to the consumption

  16. Levels of total mercury in marine organisms from Adriatic Sea, Italy.

    PubMed

    Perugini, Monia; Visciano, Pierina; Manera, Maurizio; Zaccaroni, Annalisa; Olivieri, Vincenzo; Amorena, Michele

    2009-08-01

    The presence of total mercury in fish, crustacean and cephalopod from Adriatic Sea, was investigated. The highest concentrations were observed in decreasing order in: Norway lobster (0.97 +/- 0.24 mg/kg; mean +/- SE), European hake (0.59 +/- 0.14 mg/kg), red mullet (0.48 +/- 0.09 mg/kg), blue whiting (0.38 +/- 0.09 mg/kg), Atlantic mackerel (0.36 +/- 0.08 mg/kg) and European flying squid (0.25 +/- 0.03 mg/kg). A significant difference (p < 0.01) was found between the levels of total mercury in Norway lobster and those detected in all other species. The 25% of all samples exceeded the maximum limit fixed by Commission Regulation (EC) No 1881/2006. The results show that fish and fishery products can exceed the maximum levels and stress the need of more information for consumers in particular for people that eat large amount of fish.

  17. Software Process Modeling and Execution within Virtual Environments

    DTIC Science & Technology

    1997-08-01

    LhFEX@nOHX@nOe+L X@L X[Lhq³AKe.?HWLvJ&%HV,=>brP"sK\\QehJQFK\\QH�X@nOehJQuUJQehJQHWLe.=�RaHnX>V.VhJQHWY�=@seR³ qwe .?H"L.X>PH?³sP[X>ApX>SUHA...HWLhe.HWYðR³ qwe .?H"YKHWL.nOVhJQFehJQ=@Aº=>bX>VoehJcb X@nOeOLiX>RE=>u@H@IÛe.?H?KsP�X>AºX>S@HAKe+LJQAºe.?HFV.=nOHWL.LX>V.HV.HFV.H� LhH...EX@LiLhsReOX@LhGLCr�’?H ÊUÇ�ÅÄWÀEÕUÄ+Õ,Lhe+Xke.HYUJMY A=@e,nO=@V.V.HWLlFE=@AEY�e.=�XkA³ qwe +XULhGÙIX>AEY�Lh=JQe,giX@L’VoHP=>u@HWYC

  18. Measuring Student Effort and Engagement in an Introductory Physics Course

    NASA Astrophysics Data System (ADS)

    Bonham, Scott

    2007-11-01

    Multiple scales reflecting student effort were developed using factor and scale analysis on data from an introductory physics course. This data included interactions with an on-line homework system. One of the scales displays many characteristics of a metric of the individual level of engagement in the course. This scale is shown to be a good predictor of performance on class exams and the Force Concept Inventory (FCI). Furthermore, normalized learning gains on the FCI are well predicted by this scale while pre-instructional FCI scores provide no additional predictive ability, agreeing with observations by Richard Hake. This scale also correlates strongly with epistemological beliefs that learning is related to effort and is the responsibility of the student. The factors that enter into this scale, writing and mastering expert-like problem-solving, are consistent with this being a measure of individual levels of class engagement.

  19. Basing assessment and treatment of problem behavior on behavioral momentum theory: Analyses of behavioral persistence.

    PubMed

    Schieltz, Kelly M; Wacker, David P; Ringdahl, Joel E; Berg, Wendy K

    2017-08-01

    The connection, or bridge, between applied and basic behavior analysis has been long-established (Hake, 1982; Mace & Critchfield, 2010). In this article, we describe how clinical decisions can be based more directly on behavioral processes and how basing clinical procedures on behavioral processes can lead to improved clinical outcomes. As a case in point, we describe how applied behavior analyses of maintenance, and specifically the long-term maintenance of treatment effects related to problem behavior, can be adjusted and potentially enhanced by basing treatment on Behavioral Momentum Theory. We provide a brief review of the literature including descriptions of two translational studies that proposed changes in how differential reinforcement of alternative behavior treatments are conducted based on Behavioral Momentum Theory. We then describe current clinical examples of how these translations are continuing to impact the definitions, designs, analyses, and treatment procedures used in our clinical practice. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. SPME-GC-pyrolysis-AFS determination of methylmercury in marine fish products by alkaline sample preparation and aqueous phase phenylation derivatization.

    PubMed

    Jókai, Zsuzsa; Abrankó, László; Fodor, Péter

    2005-07-13

    Characterization of a cost-efficient analytical method based on alkaline sample digestion with KOH and NaOH, followed by aqueous phase phenylation derivatization with NaBPh4 and solid phase microextraction (SPME) for the determination of methylmercury in typical fish-containing food samples commercially available in Hungary, is reported. The sample preparation procedure along with the applied SPME-GC-pyrolysis-AFS system was validated by measuring certified reference materials (CRM) BCR-464, TORT-2, and a candidate CRM BCR 710. To carry out an estimation of average Hungarian methylmercury exposures via marine fish and/or fish-containing food consumption, 16 commercially available products and 3 pooled representative seafood samples of-according to a previous European survey--the three most consumed fish species in Hungary, herring, sardines, and hake, were analyzed. Methylmercury concentrations of the analyzed samples were in the range 0.016-0.137 microg of MeHg g(-1) dry weight as Hg.

  1. Influence of Electron Molecule Resonant Vibrational Collisions over the Symmetric Mode and Direct Excitation-Dissociation Cross Sections of CO2 on the Electron Energy Distribution Function and Dissociation Mechanisms in Cold Pure CO2 Plasmas.

    PubMed

    Pietanza, L D; Colonna, G; Laporta, V; Celiberto, R; D'Ammando, G; Laricchiuta, A; Capitelli, M

    2016-05-05

    A new set of electron-vibrational (e-V) processes linking the first 10 vibrational levels of the symmetric mode of CO2 is derived by using a decoupled vibrational model and inserted in the Boltzmann equation for the electron energy distribution function (eedf). The new eedf and dissociation rates are in satisfactory agreement with the corresponding ones obtained by using the e-V cross sections reported in the database of Hake and Phelps (H-P). Large differences are, on the contrary, found when the experimental dissociation cross sections of Cosby and Helm are inserted in the Boltzman equation. Comparison of the corresponding rates with those obtained by using the low-energy threshold energy, reported in the H-P database, shows differences up to orders of magnitude, which decrease with the increasing of the reduced electric field. In all cases, we show the importance of superelastic vibrational collisions in affecting eedf and dissociation rates either in the direct electron impact mechanism or in the pure vibrational mechanism.

  2. Seating Arrangement, Group Composition and Competition-driven Interaction: Effects on Students' Performance in Physics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Roxas, R. M.; Monterola, C.; Carreon-Monterola, S. L.

    2010-07-28

    We probe the effect of seating arrangement, group composition and group-based competition on students' performance in Physics using a teaching technique adopted from Mazur's peer instruction method. Ninety eight lectures, involving 2339 students, were conducted across nine learning institutions from February 2006 to June 2009. All the lectures were interspersed with student interaction opportunities (SIO), in which students work in groups to discuss and answer concept tests. Two individual assessments were administered before and after the SIO. The ratio of the post-assessment score to the pre-assessment score and the Hake factor were calculated to establish the improvement in student performance.more » Using actual assessment results and neural network (NN) modeling, an optimal seating arrangement for a class was determined based on student seating location. The NN model also provided a quantifiable method for sectioning students. Lastly, the study revealed that competition-driven interactions increase within-group cooperation and lead to higher improvement on the students' performance.« less

  3. Comparative phylogeography of co-distributed Phrygilus species (Aves, Thraupidae) from the Central Andes.

    PubMed

    Álvarez-Varas, R; González-Acuña, D; Vianna, J A

    2015-09-01

    The Neotropical ecoregion has been an important place of avian diversification where dispersal and allopatric events coupled with periods of active orogeny and climate change (Late Pliocene-Pleistocene) have shaped the biogeography of the region. In the Neotropics, avian population structure has been sculpted not only by geographical barriers, but also by non-allopatric factors such as natural selection and local adaptation. We analyzed the genetic variation of six co-distributed Phrygilus species from the Central Andes, based on mitochondrial and nuclear markers in conjunction with morphological differentiation. We examined if Phrygilus species share patterns of population structure and historical demography, and reviewed the intraspecific taxonomy in part of their geographic range. Our results showed different phylogeographic patterns between species, even among those belonging to the same phylogenetic clade. P. alaudinus, P. atriceps, and P. unicolor showed genetic differentiation mediated by allopatric mechanisms in response to specific geographic barriers; P. gayi showed sympatric lineages in northern Chile, while P. plebejus and P. fruticeti showed a single genetic group. We found no relationship between geographic range size and genetic structure. Additionally, a signature of expansion was found in three species related to the expansion of paleolakes in the Altiplano region and the drying phase of the Atacama Desert. Morphological analysis showed congruence with molecular data and intraspecific taxonomy in most species. While we detected genetic and phenotypic patterns that could be related to natural selection and local adaptation, our results indicate that allopatric events acted as a major factor in the population differentiation of Phrygilus species. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Life cycle assessment of European pilchard (Sardina pilchardus) consumption. A case study for Galicia (NW Spain).

    PubMed

    Vázquez-Rowe, Ian; Villanueva-Rey, Pedro; Hospido, Almudena; Moreira, María Teresa; Feijoo, Gumersindo

    2014-03-15

    European pilchard or sardines (Sardina pilchardus) are an attractive raw material to extract from Iberian waters, since they constitute a cheap source of protein and they are a popular product among consumers. This has led to a wide range of final products available for consumers to purchase based on this single raw material. Therefore, this study presents a cross-product environmental assessment using life cycle assessment of three different final products based on sardine landings: canned sardines, fresh sardines and European hake caught by using sardine as bait. In addition, the products were followed throughout their entire life cycle, considering different cooking methods for each final product. Results showed high variability in environmental impacts, not only between the three final products, but also when one single product was cooked in different ways, highlighting the importance that the consumption phase and other post-landing stages may have on the final environmental profile of seafood. Results are then analysed regarding relevant limitations and uncertainties, as well as in terms of the consumer and policy implications. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Poetry for physicists

    NASA Astrophysics Data System (ADS)

    Tobias, Sheila; Abel, Lynne S.

    1990-09-01

    In an effort to discover what makes the humanities difficult and unpopular with some science and engineering students, 14 Cornell faculty from the disciplines of chemistry, physics, applied mathematics, geology, materials science, and engineering were invited to become ``surrogate learners'' in a junior/senior level poetry seminar designed expressly for them. Their encounter with humanistic pedagogy and scholarship was meant to be an extension of ``Peer Perspectives on Science'' [see S. Tobias and R. R. Hake, ``Professors as physics students: What can they teach us?'' Am. J. Phys. 56, 786 (1988)]. The results challenge certain assumptions about differences between scholarship and pedagogy in the humanities and science (as regards ``certainty'' and models). But the experiment uncovered other problems that affect ``marketing'' the humanities to science and engineering students. Results are some additional insights into what makes science ``hard'' for humanities students and why physical science and engineering students have difficulty with and tend to avoid courses in literature, as well as into what can make humanities courses valuable for science students.

  6. Effect of frying, grilling, and steaming on amino acid composition of marine fishes.

    PubMed

    Erkan, Nuray; Özden, Özkan; Selçuk, Arif

    2010-12-01

    Amino acid and proximate compositions were determined in six raw and cooked marine fish species that are commonly consumed in Turkey. The changes in amino acid and proximate content were found to be significant for all cooking methods in all fish species. Cooking did, in general, significantly increase the contents of essential, semiessential, and other amino acids compared with raw fish species. Grilled Atlantic bonito, anchovy, and bluefish and fried mullet and hake appeared to be more valuable fish dishes for obtaining the officially recommended appropriate daily intake of essential amino acids for humans. Moisture, fat, ash, and carbohydrate contents of raw fish ranged between 48.01% and 83.05%, 0.87% and 30.48%, 1.10% and 1.61%, and 0.09% and 8.70%, respectively. All fresh fish investigated were high in protein: 11.20-17.14 g/100 g. Wide variations in protein content (18.11-25.65 g/100 g) between species and methods of cooking were observed. Fried fish had intermediate fat values, whereas grilled and steamed fishes had a comparatively low value.

  7. 78 FR 26117 - Magnuson-Stevens Fishery Conservation and Management Act Provisions; Fisheries of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-03

    ...Through this interim final rule, NMFS announces that it partially approves Framework Adjustment 48 to the NE Multispecies Fishery Management Plan (FMP) and implements the approved measures in the regulations. Framework 48 is the first of two parallel and related actions developed by the New England Fishery Management Council (Council) to respond to updated stock status information and to adjust other management measures in the NE multispecies (groundfish) fishery beginning in fishing year (FY) 2013. This action implements new status determination criteria for Gulf of Maine (GOM) cod, Georges Bank (GB) cod, Southern New England/Mid-Atlantic (SNE/MA) yellowtail flounder, and white hake based on new benchmark assessments completed for these stocks in 2012 and 2013. NMFS is approving and implementing updated status determination criteria for white hake through this interim final rule and accepting further comment on this measure since it was not available for comment in the Framework 48 proposed rule. NMFS will publish a subsequent final rule to respond to any comments received, if necessary. Through this action, NMFS has also approved and is implementing the following Framework 48 measures: Elimination of dockside monitoring requirements for the groundfish fishery; lower minimum fish sizes for several groundfish stocks; clarified goals and performance standard for groundfish monitoring programs; revisions to the allocation of GB yellowtail flounder to the scallop fishery; and establishment of sub-annual catch limits (ACLs) of GB yellowtail flounder and SNE/MA windowpane flounder for the scallop and other non- groundfish fisheries. NMFS also approved revisions to recreational and commercial accountability measures (AMs), including amendments to existing AMs for windowpane flounder, ocean pout, and Atlantic halibut, and new ``reactive'' AMs for Atlantic wolffish and SNE/MA winter flounder, to address a remand by the U.S. District Court of Appeals. NMFS disapproved

  8. Quality changes during storage of minced fish products containing dietary fiber and fortified with ω3 fatty acids.

    PubMed

    Cardoso, C; Mendes, R; Pedro, S; Vaz-Pires, P; Nunes, M L

    2010-02-01

    Two ready-to-eat minced fish products from hake were developed, their proximate composition and fatty acid profiles determined and their quality changes followed during 3.5 months under refrigeration at 2 ± 1 °C and 10 ± 1 °C. These products contain dietary fiber and are innovative and healthy. The formulation was identical, except vegetable oil (VO), 5.6% (w/w) in one group and 2.7% (w/w) plus 2.9% (w/w) cod liver oil (CLO) in the other. CLO products had a higher ω3/ω6 ratio (0.54 ± 0.02 versus 0.08 ± 0.02) and ensured, per 100 g serving, the 500 mg recommended daily intake of eicosapentaenoic and docosahexaenoic acids. CLO products showed lower gel strength (p ≤ 0.05), however, other textural properties were similar to those of the VO group. Thiobarbituric acid reactive substances values were higher in CLO products. All groups presented acceptable sensory scores and no microbiological growth. During storage products became redder and less yellow, while seafood aroma and flavor declined and saltiness perception augmented. Temperature had a negative effect on sensory elasticity and instrumental texture.

  9. Assessing the Impacts of a Hybrid ``Flipped'' Approach to University Physics.

    NASA Astrophysics Data System (ADS)

    Hughes, Chris; Paulson, Scott

    2015-03-01

    Over the course of several years, the physics faculty at James Madison University has been gradually reforming the introductory calculus-based physics sequence to a hybrid model using a ``flipped classroom'' approach. The content traditionally delivered during lecture was divided into approximately 150 short (5-10 minute) videos. For homework, students are assigned 3-5 videos to watch before each class session. These assignments are combined with in-class activities including gouger problem solving and the tutorials developed by the University of Washington group to provide the students with focused guidance on concepts and skills that students traditionally have left our classes not having mastered. For the fall semester course on mechanics, the Force Concept Inventory (FCI) was used to evaluate student outcomes. For the spring semester course on E&M and optics, the Conceptual Survey of Electricity and Magnetism (CSEM) was used. Student reaction to the course structure was generally positive though there were some complaints in the student evaluations at the end of each semester. However, a positive impact on student outcomes was observed based on the Hake gains on the FCI.

  10. Meta-analysis of teaching methods: a 50k+ student study

    NASA Astrophysics Data System (ADS)

    Sayre, Eleanor; Archibeque, Benjamin; Gomez, K. Alison; Heckendorf, Tyrel; Madsen, Adrian M.; McKagan, Sarah B.; Schenk, Edward W.; Shepard, Chase; Sorell, Lane; von Korff, Joshua

    2015-04-01

    The Force Concept Inventory (FCI) and the Force and Motion Conceptual Evaluation (FMCE) are the two most widely-used conceptual tests in introductory mechanics. Because they are so popular, they provide an excellent avenue to compare different teaching methods at different kinds of institutions with varying student populations. We conducted a secondary analysis of all peer-reviewed papers which publish data from US and Canadian colleges and universities. Our data include over fifty thousand students drawn from approximately 100 papers; papers were drawn from Scopus, ERIC, ComPADRE, and journal websites. We augment published data about teaching methods with institutional data such as Carnegie Classification and average SAT scores. We statistically determine the effectiveness of different teaching methods as measured by FCI and FMCE gains and mediated by institutional and course factors. As in the landmark 1998 Hake study, we find that classes using interactive engagement (IE) have significantly larger learning gains than classes using traditional instruction. However, we find a broader distribution of normalized gains occurs in each of traditional and IE classes, and the differences between IE and traditional instruction have changed over time and are more context dependent.

  11. Integrating Anisakis spp. parasites data and host genetic structure in the frame of a holistic approach for stock identification of selected Mediterranean Sea fish species.

    PubMed

    Mattiucci, S; Cimmaruta, R; Cipriani, P; Abaunza, P; Bellisario, B; Nascetti, G

    2015-01-01

    The unique environment of the Mediterranean Sea makes fish stock assessment a major challenge. Stock identification of Mediterranean fisheries has been based mostly from data on biology, morphometrics, artificial tags, otolith shape and fish genetics, with less effort on the use of parasites as biomarkers. Here we use some case studies comparing Mediterranean vs Atlantic fish stocks in a multidisciplinary framework. The generalized Procrustes Rotation (PR) was used to assess the association between host genetics and larval Anisakis spp. datasets on demersal (hake) and pelagic (horse mackerel, swordfish) species. When discordant results emerged, they were due to the different features of the data. While fish population genetics can detect changes over an evolutionary timescale, providing indications on the cohesive action of gene flow, parasites are more suitable biomarkers when considering fish stocks over smaller temporal and spatial scales, hence giving information of fish movements over their lifespan. Future studies on the phylogeographic analysis of parasites suitable as biomarkers, and that of their fish host, performed on the same genes, will represent a further tool to be included in multidisciplinary studies on fish stock structure.

  12. Designing experiments on thermal interactions by secondary-school students in a simulated laboratory environment

    NASA Astrophysics Data System (ADS)

    Lefkos, Ioannis; Psillos, Dimitris; Hatzikraniotis, Euripides

    2011-07-01

    Background and purpose: The aim of this study was to explore the effect of investigative activities with manipulations in a virtual laboratory on students' ability to design experiments. Sample Fourteen students in a lower secondary school in Greece attended a teaching sequence on thermal phenomena based on the use of information and communication technology, and specifically of the simulated virtual laboratory 'ThermoLab'. Design and methods A pre-post comparison was applied. Students' design of experiments was rated in eight dimensions; namely, hypothesis forming and verification, selection of variables, initial conditions, device settings, materials and devices used, process and phenomena description. A three-level ranking scheme was employed for the evaluation of students' answers in each dimension. Results A Wilcoxon signed-rank test revealed a statistically significant difference between the students' pre- and post-test scores. Additional analysis by comparing the pre- and post-test scores using the Hake gain showed high gains in all but one dimension, which suggests that this improvement was almost inclusive. Conclusions We consider that our findings support the statement that there was an improvement in students' ability to design experiments.

  13. Learning to Work with Databases in Astronomy: Quantitative Analysis of Science Educators' and Students' Pre-/Post-Tests

    NASA Astrophysics Data System (ADS)

    Schwortz, Andria C.; Burrows, Andrea C.; Myers, Adam D.

    2015-01-01

    Astronomy is increasingly moving towards working with large databases, from the state-of-the-art Sloan Digital Sky Survey Data Release 10, to the historical Digital Access to a Sky Century at Harvard. Non-astronomy fields as well tend to work with large datasets, be it in the form of warehouse inventory, health trends, or the stock market. However very few fields explicitly teach students the necessary skills to analyze such data. The authors studied a matched set of 37 participants working with 200-entry databases in astronomy using Google Spreadsheets, with limited information about a random set of quasars drawn from SDSS DR5. Here the authors present the quantitative results from an eight question pre-/post-test, with questions designed to span Bloom's taxonomy, on both the topics of the skills of using spreadsheets, and the content of quasars. Participants included both Astro 101 summer students and professionals including in-service K-12 teachers and science communicators. All groups showed statistically significant gains (as per Hake, 1998), with the greatest difference between women's gains of 0.196 and men's of 0.480.

  14. Evolution in the block: common elements of 5S rDNA organization and evolutionary patterns in distant fish genera.

    PubMed

    Campo, Daniel; García-Vázquez, Eva

    2012-01-01

    The 5S rDNA is organized in the genome as tandemly repeated copies of a structural unit composed of a coding sequence plus a nontranscribed spacer (NTS). The coding region is highly conserved in the evolution, whereas the NTS vary in both length and sequence. It has been proposed that 5S rRNA genes are members of a gene family that have arisen through concerted evolution. In this study, we describe the molecular organization and evolution of the 5S rDNA in the genera Lepidorhombus and Scophthalmus (Scophthalmidae) and compared it with already known 5S rDNA of the very different genera Merluccius (Merluccidae) and Salmo (Salmoninae), to identify common structural elements or patterns for understanding 5S rDNA evolution in fish. High intra- and interspecific diversity within the 5S rDNA family in all the genera can be explained by a combination of duplications, deletions, and transposition events. Sequence blocks with high similarity in all the 5S rDNA members across species were identified for the four studied genera, with evidences of intense gene conversion within noncoding regions. We propose a model to explain the evolution of the 5S rDNA, in which the evolutionary units are blocks of nucleotides rather than the entire sequences or single nucleotides. This model implies a "two-speed" evolution: slow within blocks (homogenized by recombination) and fast within the gene family (diversified by duplications and deletions).

  15. Individual determinants of fish choosing in open-air street markets from Santo André, SP/Brazil.

    PubMed

    Vasconcellos, Juliana Parreira; Vasconcellos, Silvio Arruda; Pinheiro, Sonia Regina; de Oliveira, Thaís Helena Nishikata; Ribeiro, Naassom Almeida Souza; Martins, Cassia Neves; Porfírio, Bruno Augusti; Sanches, Sandra Abelardo; de Souza, Orlando Bispo; Telles, Evelise Oliveira; Balian, Simone de Carvalho

    2013-09-01

    The objective of this study was to identify the determinants of fish consumption in the population that attends open-air street markets in the city of Santo André, SP, Brazil.We performed a survey, covering approximately 482 people in 49 street markets.It consisted of free-answer questions, half open choice and half multiple-choice options, for the identification and evaluation of socioeconomic factors that facilitate and hinder fish consumption.A descriptive analysis of the data and further tests were used to determine the association between variables and linearity with consumption, with a significance level of 5%. The most commonly cited types of fish consumed were hake, sardine and dogfish. The factors that facilitate the purchase and consumption of fish are listed as follows: a preference for purchasing fish at street markets, appearance, firmness, fresh presentation, frozen presentation, as well as the respondent's education and individual monthly income. Limiting factors were identified as the price and the presence of spines. Perishability, odour, ethnicity, proximity to points of sale of residence and work, gender, age, number of people in the household, presence of children and acquisition supermarket were not characteristics that influenced decisions about fish consumption. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. A reconnaissance study of oxygen, hydrogen and strontium isotopes in geochemically diverse lakes, Western Nebraska, USA

    USGS Publications Warehouse

    Gosselin, D.C.; Nabelek, P.E.; Peterman, Z.E.; Sibray, S.

    1997-01-01

    Reconnaissance ??18O,, ??D, and ??87Sr data for fifteen lakes in the Western Lakes Region of the Sand Hills of Nebraska indicate dynamic hydrologic systems. The rather narrow range of ??87Sr from lake water (1.1 to 2.1) and groundwater (0.9 to 1.7) indicates that the groundwater is generally unradiogenic. Groundwater residence times and relatively unradiogenic volcanic ash within the dune sediments control the ??87Sr values. Based on the mutual variations of ??18O and ??D, the lakes can be divided into three groups. In Group 1, both ??18O and ??D values increase from spring to fall. The ??18O and ??D values in Group 2 decreased from spring to fall. Group 3 are ephemeral lakes that went dry some time during 1992. The data and isotopic modeling show that variations in the ratio of evaporation relative to groundwater inflow, local humidity conditions, and the ??(a) has substantial influence on the isotopic composition. In addition, isotopic behavior in ephemeral hakes can be rather unusual because of the changing activities of water and mineral precipitation and redissolution. The annual and interannual isotopic variability of these lakes which is reflected in the paleonvironmental indicators may be the rule rather than the exception in these types of systems.

  17. Viability and Management Targets of Mediterranean Demersal Fisheries: The Case of the Aegean Sea.

    PubMed

    Tserpes, George; Nikolioudakis, Nikolaos; Maravelias, Christos; Carvalho, Natacha; Merino, Gorka

    2016-01-01

    Management of the Mediterranean demersal stocks has proven challenging mainly due to the multi-species character of the fisheries. In the present work, we focus on the multi-species demersal fisheries of the Aegean Sea (eastern Mediterranean) aiming to study the effects of different management measures on the main commercial stocks, as well as to explore the economic viability of the fisheries depending upon these resources, by means of simulated projections. Utilizing the limited available data, our results demonstrated that, under the current exploitation pattern, the economic viability of the fleets is threatened, particularly if fuel prices increase. Additionally, the biological targets set for the most exploited species, such as hake, will not be met under the current management regime. The projections also showed that the only management scenario under which both resource sustainability and economic viability of the fisheries are ensured is the decrease of fleet capacity in terms of vessel numbers. In this case, however, measures to support the fisheries-dependent communities need to be implemented to prevent the collapse of local economies due to employment decrease. Scenarios assuming selectivity improvements would be also beneficial for the stocks but they showed low economic performance and their application would threaten the viability of the fleets, particularly that of the trawlers.

  18. The role of Argopecten purpuratus shells structuring the soft bottom community in shallow waters of southern Peru

    NASA Astrophysics Data System (ADS)

    Lomovasky, Betina J.; Gamero, Patricia A.; Romero, Leonardo; Firstater, Fausto N.; Gamarra Salazar, Alex; Hidalgo, Fernando; Tarazona, Juan; Iribarne, Oscar O.

    2015-12-01

    Accumulation of Argopecten purpuratus shells often occurs after El Niño events in shallow waters of Independencia Bay (14°17‧S-76°10‧W; Pisco, Peru). Here we experimentally investigate the effects of their shell accumulation on macrobenthos assemblages in soft bottom, shallow areas of the bay. A field experiment (from May 2006 to May 2007), including four treatments with different coverage levels of empty shells of A. purpuratus, were randomly arranged in: (1) areas devoid of shells ("Empty" treatment: experimental control), (2) 50% of the plot area covered with shells haphazardly distributed over the bottom ("medium" treatment), (3) 100% of the plot area covered with shells, forming a 10 cm valve layer ("full" treatment) and (4) "natural control". We found a total of 124 taxa throughout the experiment. Polychaetes, crustaceans and mollusks were the most abundant groups in "natural controls", dominated by the gastropod Nassarius gayi and the polychaetes Prionospio peruana, Platynereis bicanaliculata and Mediomastus branchiferus. The abundance of individuals (N) and the species richness (S) were higher in the "medium" treatment, but only in one month under positive sea bottom thermal anomalies. Similarity analysis (Bray-Curtis) showed that "natural control", "empty" and "full" treatments were more similar among them than the "medium" treatment. Multidimensional analysis showed no clear species association among treatments and a higher grouping among the samplings of Jun-06, Aug-06 and Nov-06. Our results also showed that the commercial crab Romaleon polyodon and the polyplacophora Tonicia elegans were positively affected by shell accumulations ("medium" treatment), while the limpet Fissurella crassa was negatively affected. Our study shows that directly by changing habitat structure or indirectly by changing sediment characteristics, the addition of scallop shells to the soft bottom can modify the macrobenthic assemblage; however, the seasonal oceanographic

  19. Annotated type catalogue of the Chrysididae (Insecta, Hymenoptera) deposited in the collection of Maximilian Spinola (1780–1857), Turin

    PubMed Central

    Rosa, Paolo; Xu, Zai-fu

    2015-01-01

    Abstract A critical and annotated catalogue of the ninety-six type specimens of Chrysididae (Hymenoptera), belonging to sixty-seven species, housed in the insect collection of Maximilian Spinola is given. The neotypes of six species are designated: Chrysis bicolor Lepeletier, 1806; Chrysis comparata Lepeletier, 1806; Chrysis dives Dahlbom, 1854; Chrysis pumila Klug, 1845; Chrysis succincta Linnaeus, 1767; Hedychrum bidentulum Lepeletier, 1806. The lectotypes of twenty-four species are designated: Chrysis aequinoctialis Dahlbom, 1854; Chrysis analis Spinola, 1808; Chrysis assimilis Dahlbom, 1854; Chrysis bihamata Spinola, 1838; Chrysis chilensis Spinola, 1851; Chrysis dichroa Dahlbom, 1854; Chrysis distinguenda Dahlbom, 1854; Chrysis episcopalis Spinola, 1838; Chrysis grohmanni Dahlbom, 1854; Chrysis incrassata Spinola, 1838; Chrysis pallidicornis Spinola, 1838; Chrysis pulchella Spinola, 1808; Chrysis ramburi Dahlbom, 1854; Chrysis refulgens Spinola, 1806; Chrysis splendens Dahlbom, 1854; Chrysis succinctula Dahlbom, 1854; Chrysis versicolor Spinola, 1808; Elampus gayi Spinola, 1851; Hedychrum caerulescens Lepeletier, 1806; Hedychrum chloroideum Dahlbom, 1854; Hedychrum difficile Spinola, 1851; Hedychrum virens Dahlbom, 1854; Holopyga janthina Dahlbom, 1854; Holopyga luzulina Dahlbom, 1854. Previous lectotype designations of five species are set aside: Chrysis bicolor Lepeletier, 1806 (designated by Morgan 1984); Chrysis calimorpha Mocsáry, 1882 (designated by Móczár 1965); Chrysis elegans Lepeletier, 1806 (designated by Bohart (in Kimsey and Bohart 1991)); Hedychrum chloroideum Dahlbom, 1854 (designated by Kimsey 1986); Hedychrum rutilans Dahlbom, 1854 (designated by Morgan 1984). Three new synonymies are proposed: Hedychrum intermedium Dahlbom, 1845, syn. n. of Holopyga fervida (Fabricius, 1781); Chrysis sicula Dahlbom, 1854, syn. n. of Chrysis elegans Lepeletier, 1806; Chrysis succinctula Dahlbom, 1854, syn. n. of Chrysis germari Wesmael, 1839. Chrysis

  20. The role of internal waves in larval fish interactions with potential predators and prey

    NASA Astrophysics Data System (ADS)

    Greer, Adam T.; Cowen, Robert K.; Guigand, Cedric M.; Hare, Jonathan A.; Tang, Dorothy

    2014-09-01

    Tidally driven internal wave packets in coastal environments have the potential to influence patchiness of larval fishes, prey, and gelatinous predators. We used the In Situ Ichthyoplankton Imaging System (ISIIS) to synoptically sample larval fishes, copepods, and planktonic predators (ctenophores, hydromedusae, chaetognaths, and polychaetes) across these predictable features in the summer near Stellwagen Bank, Massachusetts, USA. Full water column profiles and fixed depth transects (∼10 m depth) were used to quantify vertical and horizontal components of the fish and invertebrate distributions during stable and vertically mixed conditions associated with tidally generated internal waves. Larval fishes, consisting mostly of Urophycis spp., Merluccius bilinearis, and Labridae, were concentrated near the surface, with larger sizes generally occupying greater depths. During stable water column conditions, copepods formed a near surface thin layer several meters above the chlorophyll-a maximum that was absent when internal waves were propagating. In contrast, ctenophores and other predators were much more abundant at depth, but concentrations near 10 m increased immediately after the internal hydraulic jump mixed the water column. During the propagation of internal waves, the fine-scale abundance of larval fishes was more correlated with the abundance of gelatinous predators and less correlated with copepods compared to the stable conditions. Vertical oscillations caused by the internal hydraulic jump can disperse patches of zooplankton and force surface dwelling larval fishes into deeper water where probability of predator contact is increased, creating conditions potentially less favorable for larval fish growth and survival on short time scales.

  1. Implementation of an active instructional design for teaching the concepts of current, voltage and resistance

    NASA Astrophysics Data System (ADS)

    Orlaineta-Agüero, S.; Del Sol-Fernández, S.; Sánchez-Guzmán, D.; García-Salcedo, R.

    2017-01-01

    In the present work we show the implementation of a learning sequence based on an active learning methodology for teaching Physics, this proposal tends to promote a better learning in high school students with the use of a comic book and it combines the use of different low-cost experimental activities for teaching the electrical concepts of Current, Resistance and Voltage. We consider that this kind of strategy can be easily extrapolated to higher-education levels like Engineering-college/university level and other disciplines of Science. To evaluate this proposal, we used some conceptual questions from the Electric Circuits Concept Evaluation survey developed by Sokoloff and the results from this survey was analysed with the Normalized Conceptual Gain proposed by Hake and the Concentration Factor that was proposed by Bao and Redish, to identify the effectiveness of the methodology and the models that the students presented after and before the instruction, respectively. We found that this methodology was more effective than only the implementation of traditional lectures, we consider that these results cannot be generalized but gave us the opportunity to view many important approaches in Physics Education; finally, we will continue to apply the same experiment with more students, in the same and upper levels of education, to confirm and validate the effectiveness of this methodology proposal.

  2. Human exposure to brominated flame retardants through the consumption of fish and shellfish in Tarragona County (Catalonia, Spain).

    PubMed

    Trabalón, Laura; Vilavert, Lolita; Domingo, José L; Pocurull, Eva; Borrull, Francesc; Nadal, Martí

    2017-06-01

    The concentrations of 19 brominated flame retardants (BFRs) (8 polybrominated diphenyl ethers (PBDEs), 8 methoxylated PBDEs (MeO-PBDEs) and 3 emerging flame retardants) were determined in 10 species of fish and shellfish widely consumed in Tarragona County (Catalonia, Spain), by pressurized liquid extraction followed by gas chromatography coupled to tandem mass spectrometry. A higher occurrence of PBDEs was found in all the analyzed samples, while MeO-PBDEs were only detected in a few ones and the levels of emerging pollutants were relatively low. In contrast, hexabromobenzene was found in almost all samples at concentrations ranging between non detected and 0.2 ng g -1 wet weight (w.w.). Salmon, sole, hake, cod and tuna showed the highest concentrations of ΣPBDEs (>0.8 ng g -1  w.w.), while mussel was the species with the highest level of MeO-PBDEs (1.5 ng g -1  w.w.). The dietary exposure of BFRs through consumption of these 10 species of fish and shellfish by the population of Tarragona County was estimated for different subpopulations, classified according to age and gender. Furthermore, calculations were performed in upper-, middle- and lower-bound risk scenarios. According to our data, the current concentrations of BFRs in fish and shellfish suggest no significant health risks for the consumers. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Extending Vulnerability Assessment to Include Life Stages Considerations

    PubMed Central

    Hodgson, Emma E.; Essington, Timothy E.; Kaplan, Isaac C.

    2016-01-01

    Species are experiencing a suite of novel stressors from anthropogenic activities that have impacts at multiple scales. Vulnerability assessment is one tool to evaluate the likely impacts that these stressors pose to species so that high-vulnerability cases can be identified and prioritized for monitoring, protection, or mitigation. Commonly used semi-quantitative methods lack a framework to explicitly account for differences in exposure to stressors and organism responses across life stages. Here we propose a modification to commonly used spatial vulnerability assessment methods that includes such an approach, using ocean acidification in the California Current as an illustrative case study. Life stage considerations were included by assessing vulnerability of each life stage to ocean acidification and were used to estimate population vulnerability in two ways. We set population vulnerability equal to: (1) the maximum stage vulnerability and (2) a weighted mean across all stages, with weights calculated using Lefkovitch matrix models. Vulnerability was found to vary across life stages for the six species explored in this case study: two krill–Euphausia pacifica and Thysanoessa spinifera, pteropod–Limacina helicina, pink shrimp–Pandalus jordani, Dungeness crab–Metacarcinus magister and Pacific hake–Merluccius productus. The maximum vulnerability estimates ranged from larval to subadult and adult stages with no consistent stage having maximum vulnerability across species. Similarly, integrated vulnerability metrics varied greatly across species. A comparison showed that some species had vulnerabilities that were similar between the two metrics, while other species’ vulnerabilities varied substantially between the two metrics. These differences primarily resulted from cases where the most vulnerable stage had a low relative weight. We compare these methods and explore circumstances where each method may be appropriate. PMID:27416031

  4. Parasites as biological tags for stock discrimination in marine fish from South American Atlantic waters.

    PubMed

    Timi, Juan T

    2007-06-01

    The use of parasites as biological tags in population studies of marine fish in the south-western Atlantic has proved to be a successful tool for discriminating stocks for all species to which it has been applied, namely: Scomber japonicus, Engraulis anchoita, Merluccius hubbsi and Cynoscion guatucupa, the latter studied on a broader geographic scale, including samples from Uruguayan and Brazilian waters. The distribution patterns of marine parasites are determined mainly by temperature-salinity profiles and by their association with specific masses of water. Analyses of distribution patterns of some parasite species in relation to gradients in environmental (oceanographic) conditions showed that latitudinal gradients in parasite distribution are common in the study area, and are probably directly related to water temperature. Indeed, temperature, which is a good predictor of latitudinal gradients of richness and diversity of species, shows a latitudinal pattern in south-western Atlantic coasts, decreasing southwards, due to the influence of subtropical and subantarctic marine currents flowing along the edge of the continental slope. This pattern also determines the distribution of zooplankton, with a characteristic specific composition in different water masses. The gradient in the distribution of parasites determines differential compositions of their communities at different latitudes, which makes possible the identification of different stocks of their fish hosts. Other features of the host-parasite systems contributing to the success of the parasitological method are: (1) parasites identified as good biological tags (i.e. anisakids) are widely distributed in the local fauna; (2) many of these species show low specificity and use paratenic hosts; and (3) the structure of parasite communities are, to a certain degree, predictable in time and space.

  5. Probabilistic risk analysis of mercury intake via food consumption in Spain.

    PubMed

    Moreno-Ortega, Alicia; Moreno-Rojas, Rafael; Martínez-Álvarez, Jesús Román; González Estecha, Montserrat; Castro González, Numa Pompilio; Amaro López, Manuel Ángel

    2017-09-01

    In Spain, recently, the public institutions have given information to the population in relation to fish consumption and the risk that it poses to health from the ingestion of mercury supposedly contained in the fish. At the same time, several scientific societies have published various works in this direction. All this without there being, up to now, any study on the evaluation of a probabilistic risk from mercury due to fish and seafood intake in Spain, which is the objective of this present work. For that purpose, we took individual data from a survey of the total diet of 3000 people, whose consumption of the principal fish and seafood species (49) was estimated. We compiled individualized data (2000) on the total mercury content of those species, which were completed and validated with bibliographic statistical data. After estimating the distributions of each fish and seafood species, both of their consumption and their mercury content, a simulation was made of the distribution of mercury ingestion from fish and seafood offered by 2.6% of the Spanish population at risk of exceeding total mercury recommendations, and between 12.2% and 21.2% of those exceeding methylmercury ones. The main species responsible were tuna fish, swordfish and hake, and significant differences were identified in fish consumption between sexes and ages, although, in the risk percentage, what stands out is an increase in the latter with an increase in age. Copyright © 2017 Elsevier GmbH. All rights reserved.

  6. Fish debris in sediments of the upwelling zone off central Peru: a late Quaternary record

    NASA Astrophysics Data System (ADS)

    De Vries, Thomas J.; Pearcy, William G.

    1982-01-01

    Scales of the anchoveta were abundantly represented among fish remains preserved in partly laminated marine sediments on the upper continental slope of Peru. Hake scales were less common. Sardine scales occurred only sporadically. Recent accumulation rates of scales indicate that prior to exploitation the anchoveta standing stock off Peru was about five times that of northern anchovy off California. During glacial time, however, clupeoids were less abundant off Peru and were more evenly distributed among sardines and anchoveta. Evidence from fish scales and phytoplankton assemblages suggests that the coastal waters off Peru did not respond to continental glacial and neoglacial advances simply by cooling. High accumulation rates of scales from warm-water fishes and tests of cool-water phytoplankton preceded and succeeded an interval containing low numbers of dominantly warm-water taxa. This interval coincided with the second neoglacial advance (2000 to 2700 y B.P.). Similar but less well-defined warm-water and cool-water assemblages coincided with the third neoglacial advance (200 to 400 y B.P.) and the last glacial retreat. Upwelling intensity probably fluctuated more widely during early and late phases of glacial and neoglacial cooling episodes, accounting for the mix of distinctly warm-water and cool-water assemblages and perhaps for an enhanced productivity. A weakened Intertropical Convergence Zone or strengthened coastal countercurrent may explain the warm-water marine faunas and floras and wet climates on the mainland of Peru inferred by others for neoglacial or glacial time.

  7. Comparison of solid phase extraction, saponification and gel permeation chromatography for the clean-up of microwave-assisted biological extracts in the analysis of polycyclic aromatic hydrocarbons.

    PubMed

    Navarro, P; Cortazar, E; Bartolomé, L; Deusto, M; Raposo, J C; Zuloaga, O; Arana, G; Etxebarria, N

    2006-09-22

    The feasibility of different clean-up procedures was studied for the determination of polycyclic aromatic hydrocarbons (PAHs) in biota samples such as oysters, mussels and fish liver. In this sense, once the samples were extracted--essentially with acetone and in a microwave system--and before they could be analysed by gas chromatography-mass spectrometry (GC-MS), three different approaches were studied for the clean-up step: solid phase extraction (SPE), microwave-assisted saponification (MAS) and gel permeation chromatography (GPC). The main aim of this work was to maximise the recoveries of PAHs and to minimise the presence of interfering compounds in the last extract. In the case of SPE, Florisil cartridges of 1, 2 and 5 g, and silica cartridges of 5 g were studied. In that case, and with oysters and mussels, microwave-assisted extraction and 5 g Florisil cartridges provided good results. In addition, the concentrations obtained for Standard Reference Material (SRM) NIST 2977 (mussel tissue) were in good agreement with the certified values. In the case of microwave-assisted saponification, the extracts were not as clean as those obtained with 5 g Florisil and this fact lead to overestimate the concentration of the heaviest PAHs. Finally, the cleanest extracts were obtained by GPC. The method was successfully applied to mussels, oysters and hake liver, and the results obtained for NIST 2977 (mussel tissue) were within the confidence interval of the certified reference material for most of the certified analytes.

  8. Trophic structure in the Gulf of Lions marine ecosystem (north-western Mediterranean Sea) and fishing impacts

    NASA Astrophysics Data System (ADS)

    Bănaru, D.; Mellon-Duval, C.; Roos, D.; Bigot, J.-L.; Souplet, A.; Jadaud, A.; Beaubrun, P.; Fromentin, J.-M.

    2013-02-01

    The Gulf of Lions ecosystem was described using the Ecopath mass-balance model to characterise its structure and functioning and to examine the effects of the multispecific fisheries operating in this area. The model is composed of 40 compartments, including 1 group of seabirds, 2 groups of cetaceans, 18 groups of fish, 12 groups of invertebrates, 5 groups of primary producers, detritus and discards. Input data were based on several recurrent scientific surveys, two alternative datasets for fishing data, stock assessment outputs, stomach content analyses and published information. Results showed that the functional groups were organised into five trophic levels with the highest one represented by dolphins, anglerfish, Atlantic bluefin tuna, European hake and European conger. European pilchard and European anchovy dominated in terms of fish biomass and catch. Other fish with high biomass such as Atlantic mackerel and blue whiting were highly important in the food web. Seabirds, dolphins and cuttlefish-squids represented keystone species. Important coupled pelagic-demersal-benthic interactions were described. The 7 different fisheries analysed were operating at mean trophic levels situated between 2.6 for small artisanal boats, and 4.1 for purse seines (> 24 m) targeting large pelagic fish, indicating an intensively exploited ecosystem. Large trawlers (24-40 m) had the highest impact on most of the groups considered; while purse seines (12-24 m) targeting small pelagic fish had the lowest impact. Preliminary results highlighted the importance of data sources for further ecosystem and fisheries analyses and management scenarios.

  9. Using video games for volcanic hazard education and communication: an assessment of the method and preliminary results

    NASA Astrophysics Data System (ADS)

    Mani, Lara; Cole, Paul D.; Stewart, Iain

    2016-07-01

    This paper presents the findings from a study aimed at understanding whether video games (or serious games) can be effective in enhancing volcanic hazard education and communication. Using the eastern Caribbean island of St. Vincent, we have developed a video game - St. Vincent's Volcano - for use in existing volcano education and outreach sessions. Its twin aims are to improve residents' knowledge of potential future eruptive hazards (ash fall, pyroclastic flows and lahars) and to integrate traditional methods of education in a more interactive manner. Here, we discuss the process of game development including concept design through to the final implementation on St. Vincent. Preliminary results obtained from the final implementation (through pre- and post-test knowledge quizzes) for both student and adult participants provide indications that a video game of this style may be effective in improving a learner's knowledge. Both groups of participants demonstrated a post-test increase in their knowledge quiz score of 9.3 % for adults and 8.3 % for students and, when plotted as learning gains (Hake, 1998), show similar overall improvements (0.11 for adults and 0.09 for students). These preliminary findings may provide a sound foundation for the increased integration of emerging technologies within traditional education sessions. This paper also shares some of the challenges and lessons learnt throughout the development and testing processes and provides recommendations for researchers looking to pursue a similar study.

  10. The role of economics and weekend meals in impacted fish bone occurrence in central Israel.

    PubMed

    Dagan, Elad; Yakirevich, Arkadi; Migirov, Lela; Wolf, Michael

    2011-01-01

    The fish-eating habits of Israelis who present with impacted fish bones in the aerodigestive tract are unknown. To retrospectively investigate the relation between an impacted fish bone in the aerodigestive tract, the species of fish, and the place of occurrence in an Israeli population. The current prospective observational study included all patients with aerodigestive impacted fish bones who were treated in our emergency department from 1 September 2008 to 30 September 2009. The data retrieved from their medical records included age, gender, place of event (at home or elsewhere), species of fish, and method of removing the bone. A total of 108 patients--aged 1.5-87 years (median 48 years), 52.8% female--met the study criteria. Most (87%) of the events occurred at home, and 50.9% occurred during the weekend (Friday-Saturday). The bones were from low-priced fish (e.g., carp, hake) in 62% of the cases, high-priced fish (e.g., salmon, red snapper) in 30.5%, and of unknown species in 10.2%. The proportion of cases in which the fish bone was from a high-priced fish eaten out of the home was significantly higher than the cases in which a low-priced fish was eaten at home (64.3% vs. 22.3%, P = 0.04). One hundred bones were removed during direct oral inspection and 8 bones were removed under general anesthesia by endoscopy. Most fish bone impactions in the aerodigestive tract in central Israel involve low-priced fish and take place at home over the weekend.

  11. Initial Development and Pilot Study Design of Interactive Lecture Demonstrations for ASTRO 101

    NASA Astrophysics Data System (ADS)

    Schwortz, Andria C.; French, D. A; Gutierrez, Joseph V; Sanchez, Richard L; Slater, Timothy F.; Tatge, Coty

    2014-06-01

    Interactive lecture demonstrations (ILDs) have repeatedly shown to be effective tools for improving student achievement in the context of learning physics. As a first step toward systematic development of interactive lecture demonstrations in ASTRO 101, the introductory astronomy survey course, a systematic review of education research, describing educational computer simulations (ECSs) reveals that initial development requires a targeted study of how ASTRO 101 students respond to ECSs in the non-science majoring undergraduate lecture setting. In this project we have adopted the process by which ILDs were designed, pilot-tested, and successfully implemented in the context of physics teaching (Sokoloff & Thornton, 1997; Sokoloff & Thornton, 2004). We have designed the initial pilot-test set of ASTRO 101 ILD instructional materials relying heavily on ECSs. Both an instructor’s manual and a preliminary classroom-ready student workbook have been developed, and we are implementing a pilot study to explore their effectiveness in communicating scientific content, and the extent to which they might enhance students’ knowledge of and perception about astronomy and science in general. The study design uses a pre-/post-test quasi-experimental study design measuring students’ normalized gain scores, calculated as per Hake (1998) and Prather (2009), using a slightly modified version of S. Slater’s (2011) Test Of Astronomy STandards TOAST combined with other instruments. The results of this initial study will guide the iterative development of ASTRO 101 ILDs that are intended to both be effective at enhancing student achievement and easy for instructors to successfully implement.

  12. Effects of various cooking processes on the concentrations of arsenic, cadmium, mercury, and lead in foods.

    PubMed

    Perelló, Gemma; Martí-Cid, Roser; Llobet, Juan M; Domingo, José L

    2008-12-10

    The effects of cooking processes commonly used by the population of Catalonia (Spain) on total arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb) concentrations in various foodstuffs were investigated. All food samples were randomly acquired in local markets, big supermarkets, and grocery stores of Reus (Catalonia). Foods included fish (sardine, hake, and tuna), meat (veal steak, loin of pork, breast and thigh of chicken, and steak and rib of lamb), string bean, potato, rice, and olive oil. For each food item, two composite samples were prepared for metal analyses, whose levels in raw and cooked (fried, grilled, roasted, and boiled) samples were determined by inductively coupled plasma-mass spectrometry (ICP-MS). The highest concentrations of As, Hg, and Pb (raw and cooked samples) were mainly found in fish, with a clear tendency, in general, to increase metal concentrations after cooking. However, in these samples, Cd levels were very close to their detection limit. In turn, the concentrations of metals in raw and cooked meat samples were detected in all samples (As) or only in a very few samples (Cd, Hg, and Pb). A similar finding corresponded to string beans, rice, and olive oil, while in potatoes, Hg could not be detected and Pb only was detected in the raw samples. In summary, the results of the present study show that, in general terms, the cooking process is only of a very limited value as a means of reducing metal concentrations. This hypothetical reduction depends upon cooking conditions (time, temperature, and medium of cooking).

  13. Sustainable use of flatfish resources: Addressing the credibility crisis in mixed fisheries management

    NASA Astrophysics Data System (ADS)

    Rijnsdorp, A. D.; Daan, N.; Dekker, W.; Poos, J. J.; Van Densen, W. L. T.

    2007-02-01

    Many flatfish species are caught in mixed demersal trawl fisheries and managed by Total Allowable Catch (TAC). Despite decades of fisheries management, several major stocks are severely depleted. Using the Common Fisheries Policy (CFP) as an example, the failure of mixed-fisheries management is analysed by focussing on: the management system; the role of science; the role of managers and politicians; the response of fisheries to management. Failure of the CFP management could be ascribed to: incorrect management advice owing to bias in stock assessments; the tendency of politicians to set the TAC well above the recommended level; and non-compliance of the fisheries with the management regulations. We conclude that TAC management, although apparently successful in some single-species fisheries, inevitably leads to unsustainable exploitation of stocks caught in mixed demersal fisheries as it promotes discarding of over-quota catch and misreporting of catches, thereby corrupting the basis of the scientific advice and increasing the risk of stock collapse. This failure in mixed demersal fisheries has resulted in the loss of credibility of both scientists and managers, and has undermined the support of fishermen for management regulations. An approach is developed to convert the TAC system into a system that controls the total allowable effort (TAE). The approach takes account of the differences in catch efficiency between fleets as well as seasonal changes in the distribution of the target species and can also be applied in the recovery plans for rebuilding specific components of the demersal fish community, such as plaice, cod and hake.

  14. Identification of fish species after cooking by SDS-PAGE and urea IEF: a collaborative study.

    PubMed

    Etienne, M; Jérôme, M; Fleurence, J; Rehbein, H; Kündiger, R; Mendes, R; Costa, H; Pérez-Martín, R; Piñeiro-González, C; Craig, A; Mackie, I; Malmheden Yman, I; Ferm, M; Martínez, I; Jessen, F; Smelt, A; Luten, J

    2000-07-01

    A collaborative study, to validate the use of SDS-PAGE and urea IEF, for the identification of fish species after cooking has been performed by nine laboratories. By following optimized standard operation procedures, 10 commercially important species (Atlantic salmon, sea trout, rainbow trout, turbot, Alaska pollock, pollack, pink salmon, Arctic char, chum salmon, and New Zealand hake) had to be identified by comparison with 22 reference samples. Some differences in the recoveries of proteins from cooked fish flesh were noted between the urea and the SDS extraction procedures used. Generally, the urea extraction procedure appears to be less efficient than the SDS extraction for protein solubilization. Except for some species belonging to the Salmonidae family (Salmo, Oncorhynchus), both of the analytical techniques tested (urea IEF, SDS-PAGE) enabled identification of the species of the samples to be established. With urea IEF, two laboratories could not differentiate Salmo salar from Salmo trutta. The same difficulties were noted for differentiation between Oncorhynchus gorbuscha and Oncorhynchus keta samples. With SDS-PAGE, three laboratories had some difficulties in identifying the S. trutta samples. However, in the contrast with the previous technique, SDS-PAGE allows the characterization of most of the Oncorhynchus species tested. Only Oncorhynchus mykiss was not clearly recognized by one laboratory. Therefore, SDS-PAGE (Excel gel homogeneous 15%) appears to be better for the identification, after cooking, of fish such as the tuna and salmon species which are characterized by neutral and basic protein bands, and urea IEF (CleanGel) is better for the gadoid species, which are characterized by acid protein bands (parvalbumins). Nevertheless, in contentious cases it is preferable to use both analytical methods.

  15. Effect of annatto seed and coriander leaves as natural antioxidants in fish meatballs during frozen storage.

    PubMed

    Sancho, Renata Aparecida Soriano; de Lima, Fabíola Aliaga; Costa, Gabriel Guerra; Mariutti, Lilian Regina Barros; Bragagnolo, Neura

    2011-08-01

    The effects of annatto (0.1 g/100g) and coriander (0.5 g/100g) were assessed against lipid oxidation in white hake meatballs cooked in boiling water (95 ± 1 °C) for 30 min and stored at -18 °C for 120 d. The fatty acids (FA) and the nutritional quality, cholesterol, cholesterol oxides, thiobarbituric acid reactive substances (TBARS) values, and conjugated dienes were analyzed to follow the course of oxidation. Annatto and coriander were efficient in the control of lipid oxidation, also preserving the essential FA. At 120 d of storage, the eicosapentaenoic acid (EPA) concentration decreased respectively by 43%, 32%, 12%, and 9% in the control, coriander, annatto, and annatto + coriander patties. For docosahexaenoic acid (DHA), these concentrations decreased, respectively, 44%, 30%, 11%, and 7%, revealing a probable synergistic effect among the antioxidant compounds present in both spices. On the other hand, annatto and coriander were not able to act protecting the meatballs against lipid oxidation when they were cooked, also not exerted any effect in the cholesterol oxidation. Spices, especially coriander and annatto, can be an alternative to substitute synthetic additives with antioxidants to prevent loss of important unsaturated fatty acids (UFA) in fish meatballs during frozen storage for 120 d. The maximum effect was observed when 0.5% coriander and 0.1% annatto were used in combination. Cooking did not induce the formation of cholesterol oxides, compounds that can cause more health damages than cholesterol itself; however, during storage the cholesterol oxides levels presented a little increase regardless of spice addition. © 2011 Institute of Food Technologists®

  16. Estimation of the carbon footprint of the Galician fishing activity (NW Spain).

    PubMed

    Iribarren, Diego; Vázquez-Rowe, Ian; Hospido, Almudena; Moreira, María Teresa; Feijoo, Gumersindo

    2010-10-15

    The food production system as a whole is recognized as one of the major contributors to environmental impacts. Accordingly, food production, processing, transport and consumption account for a relevant portion of the greenhouse gas (GHG) emissions associated with any country. In this context, there is an increasing market demand for climate-relevant information regarding the global warming impact of consumer food products throughout the supply chains. This article deals with the assessment of the carbon footprint of seafood products as a key subgroup in the food sector. Galicia (NW Spain) was selected as a case study. The analysis is based on a representative set of species within the Galician fishing sector, including species obtained from coastal fishing (e.g. horse mackerel, Atlantic mackerel, European pilchard and blue whiting), offshore fishing (e.g. European hake, megrim and anglerfish), deep-sea fishing (skipjack and yellowfin tuna), extensive aquaculture (mussels) and intensive aquaculture (turbot). The carbon footprints associated with the production-related activities of each selected species were quantified following a business-to-business approach on the basis of 1year of fishing activity. These individual carbon footprints were used to calculate the carbon footprint for each of the different Galician fisheries and culture activities. Finally, the lump sum of the carbon footprints for coastal, offshore and deep-sea fishing and extensive and intensive aquaculture brought about the carbon footprint of the Galician fishing activity (i.e., capture and culture). A benchmark for quantifying and communicating emission reductions was then provided, and opportunities to reduce the GHG emissions associated with the Galician fishing activity could be prioritized. Copyright © 2010 Elsevier B.V. All rights reserved.

  17. Genomic and Phylogenetic Characterization of Luminous Bacteria Symbiotic with the Deep-Sea Fish Chlorophthalmus albatrossis (Aulopiformes: Chlorophthalmidae)

    PubMed Central

    Dunlap, Paul V.; Ast, Jennifer C.

    2005-01-01

    Bacteria forming light-organ symbiosis with deep-sea chlorophthalmid fishes (Aulopiformes: Chlorophthalmidae) are considered to belong to the species Photobacterium phosphoreum. The identification of these bacteria as P. phosphoreum, however, was based exclusively on phenotypic traits, which may not discriminate between phenetically similar but evolutionarily distinct luminous bacteria. Therefore, to test the species identification of chlorophthalmid symbionts, we carried out a genomotypic (repetitive element palindromic PCR genomic profiling) and phylogenetic analysis on strains isolated from the perirectal light organ of Chlorophthalmus albatrossis. Sequence analysis of the 16S rRNA gene of 10 strains from 5 fish specimens placed these bacteria in a cluster related to but phylogenetically distinct from the type strain of P. phosphoreum, ATCC 11040T, and the type strain of Photobacterium iliopiscarium, ATCC 51760T. Analysis of gyrB resolved the C. albatrossis strains as a strongly supported clade distinct from P. phosphoreum and P. iliopiscarium. Genomic profiling of 109 strains from the 5 C. albatrossis specimens revealed a high level of similarity among strains but allowed identification of genomotypically different types from each fish. Representatives of each type were then analyzed phylogenetically, using sequence of the luxABFE genes. As with gyrB, analysis of luxABFE resolved the C. albatrossis strains as a robustly supported clade distinct from P. phosphoreum. Furthermore, other strains of luminous bacteria reported as P. phosphoreum, i.e., NCIMB 844, from the skin of Merluccius capensis (Merlucciidae), NZ-11D, from the light organ of Nezumia aequalis (Macrouridae), and pjapo.1.1, from the light organ of Physiculus japonicus (Moridae), grouped phylogenetically by gyrB and luxABFE with the C. albatrossis strains, not with ATCC 11040T. These results demonstrate that luminous bacteria symbiotic with C. albatrossis, together with certain other strains of

  18. Genomic and phylogenetic characterization of luminous bacteria symbiotic with the deep-sea fish Chlorophthalmus albatrossis (Aulopiformes: Chlorophthalmidae).

    PubMed

    Dunlap, Paul V; Ast, Jennifer C

    2005-02-01

    Bacteria forming light-organ symbiosis with deep-sea chlorophthalmid fishes (Aulopiformes: Chlorophthalmidae) are considered to belong to the species Photobacterium phosphoreum. The identification of these bacteria as P. phosphoreum, however, was based exclusively on phenotypic traits, which may not discriminate between phenetically similar but evolutionarily distinct luminous bacteria. Therefore, to test the species identification of chlorophthalmid symbionts, we carried out a genomotypic (repetitive element palindromic PCR genomic profiling) and phylogenetic analysis on strains isolated from the perirectal light organ of Chlorophthalmus albatrossis. Sequence analysis of the 16S rRNA gene of 10 strains from 5 fish specimens placed these bacteria in a cluster related to but phylogenetically distinct from the type strain of P. phosphoreum, ATCC 11040(T), and the type strain of Photobacterium iliopiscarium, ATCC 51760(T). Analysis of gyrB resolved the C. albatrossis strains as a strongly supported clade distinct from P. phosphoreum and P. iliopiscarium. Genomic profiling of 109 strains from the 5 C. albatrossis specimens revealed a high level of similarity among strains but allowed identification of genomotypically different types from each fish. Representatives of each type were then analyzed phylogenetically, using sequence of the luxABFE genes. As with gyrB, analysis of luxABFE resolved the C. albatrossis strains as a robustly supported clade distinct from P. phosphoreum. Furthermore, other strains of luminous bacteria reported as P. phosphoreum, i.e., NCIMB 844, from the skin of Merluccius capensis (Merlucciidae), NZ-11D, from the light organ of Nezumia aequalis (Macrouridae), and pjapo.1.1, from the light organ of Physiculus japonicus (Moridae), grouped phylogenetically by gyrB and luxABFE with the C. albatrossis strains, not with ATCC 11040(T). These results demonstrate that luminous bacteria symbiotic with C. albatrossis, together with certain other strains of

  19. First Step Towards a Coastal Modelling System for South Africa: a St. Helena Bay Case Study

    NASA Astrophysics Data System (ADS)

    Collins, C.; Lamont, T.; Loveday, B. R.; Hermes, J. C.; Veitch, J.; Backeberg, B.

    2016-02-01

    St. Helena Bay, forming part of the southern Benguela ecosystem, is the largest bay on the west coast of South Africa and is a biologically important region for pelagic fish, hake, and rock lobster. To date, only a few infrequent studies have focussed on variations in the bay scale circulation. A monthly ship-based monitoring line, the St. Helena Bay Monitoring Line (SHBML), was initiated in 2000 to determine the seasonal changes in cross-shelf hydrography and biology. Even though there has been an increase in ocean modelling in and around South Africa in recent years, coastal modelling is still in its infancy. The 12-year observational data set in the St. Helena Bay region, the only long-term, cross-shelf, full water column data-set for South Africa, makes this area the perfect natural laboratory for the development of a coastal modelling system. In this study, the climatological mean temperature and salinity from three different ROMS simulations and a HYCOM simulation are evaluated against the in situ observations from the SHBML with the aim of determining the influence of different forcing products, horizontal and vertical resolution as well as vertical coordinate schemes on the vertical structure of the ocean. The model simulations tend to overestimate the temperature and salinity across the shelf, and particularly within St. Helena Bay. Furthermore, the models misrepresent the vertical salinity and temperature structures. Interestingly, below 800m, there is a better agreement between temperature in the models and the in-situ observations. This is the first detailed comparison of modelled and in-situ data for the greater St. Helena Bay area at this scale and the next phase will examine whether the model that is most congruent with the observations resolves the same interannual signals as observed in the in-situ data.

  20. Foraging ecology and movement patterns of jumbo squid (Dosidicus gigas) in the California Current System

    NASA Astrophysics Data System (ADS)

    Field, John C.; Elliger, Carl; Baltz, Ken; Gillespie, Graham E.; Gilly, William F.; Ruiz-Cooley, R. I.; Pearse, Devon; Stewart, Julia S.; Matsubu, William; Walker, William A.

    2013-10-01

    From 2002 to 2010, the jumbo squid (Dosidicus gigas) has been regularly encountered in large numbers throughout the California Current System (CCS). This species, usually found in subtropical waters, could affect coastal pelagic ecosystems and fisheries as both predator and prey. Neither the abundance of jumbo squid nor the optimal ocean conditions in which they flourish are well known. To understand better the potential impacts of this species on both commercial fisheries and on food-web structure we collected nearly 900 specimens from waters of the CCS, covering over 20° of latitude, over a range of depths and seasons. We used demographic information (size, sex, and maturity state) and analyzed stomach contents using morphological and molecular methods to best understand the foraging ecology of this species in different habitats of the CCS. Squid were found to consume a broad array of prey. Prey in offshore waters generally reflected the forage base reported in previous studies (mainly mesopelagic fishes and squids), whereas in more coastal waters (shelf, shelf break and slope habitats) squid foraged on a much broader mix that included substantial numbers of coastal pelagic fishes (Pacific herring and northern anchovy, as well as osmerids and salmonids in northern waters) and groundfish (Pacific hake, several species of rockfish and flatfish). We propose a seasonal movement pattern, based on size and maturity distributions along with qualitative patterns of presence or absence, and discuss the relevance of both the movement and distribution of jumbo squid over space and time. We find that jumbo squid are a generalist predator, which feeds primarily on small, pelagic or mesopelagic micronekton but also on larger fishes when they are available. We also conclude that interactions with and potential impacts on ecosystems likely vary over space and time, in response to both seasonal movement patterns and highly variable year-to-year abundance of the squid themselves.

  1. Implementation literacy strategies on health technology theme Learning to enhance Indonesian Junior High School Student's Physics Literacy

    NASA Astrophysics Data System (ADS)

    Feranie, Selly; Efendi, Ridwan; Karim, Saeful; Sasmita, Dedi

    2016-08-01

    according to Hake's classification.

  2. An Applied Framework for Incorporating Multiple Sources of Uncertainty in Fisheries Stock Assessments.

    PubMed

    Scott, Finlay; Jardim, Ernesto; Millar, Colin P; Cerviño, Santiago

    2016-01-01

    Estimating fish stock status is very challenging given the many sources and high levels of uncertainty surrounding the biological processes (e.g. natural variability in the demographic rates), model selection (e.g. choosing growth or stock assessment models) and parameter estimation. Incorporating multiple sources of uncertainty in a stock assessment allows advice to better account for the risks associated with proposed management options, promoting decisions that are more robust to such uncertainty. However, a typical assessment only reports the model fit and variance of estimated parameters, thereby underreporting the overall uncertainty. Additionally, although multiple candidate models may be considered, only one is selected as the 'best' result, effectively rejecting the plausible assumptions behind the other models. We present an applied framework to integrate multiple sources of uncertainty in the stock assessment process. The first step is the generation and conditioning of a suite of stock assessment models that contain different assumptions about the stock and the fishery. The second step is the estimation of parameters, including fitting of the stock assessment models. The final step integrates across all of the results to reconcile the multi-model outcome. The framework is flexible enough to be tailored to particular stocks and fisheries and can draw on information from multiple sources to implement a broad variety of assumptions, making it applicable to stocks with varying levels of data availability The Iberian hake stock in International Council for the Exploration of the Sea (ICES) Divisions VIIIc and IXa is used to demonstrate the framework, starting from length-based stock and indices data. Process and model uncertainty are considered through the growth, natural mortality, fishing mortality, survey catchability and stock-recruitment relationship. Estimation uncertainty is included as part of the fitting process. Simple model averaging is used to

  3. Thinking Like a Scientist: The RITES Path for K-12 Students to Learn the Scientific Method

    NASA Astrophysics Data System (ADS)

    Murray, D. P.; Dooley, H., Jr.; Cardace, D.

    2015-12-01

    Bringing Research on Learning to the Geosciences (Manduca et al, 2002) stated that "An overaching goal for geoscience education is to help every student to 'think like a scientist'", and that continues to challenge geoscience education. The Rhode Island Technology Enhanced Science (RITES) project addresses that goal, and this presentation chronicles that successful effort. RITES strives to improve science education by providing professional development (PD) to the majority of science teachers at the 5th through 12th grade levels throughout Rhode Island. The PD is presented through ~forty 2.5 day workshops that emphasize the innovative use of technology and best teaching practices, consistent with the recommendations detailed in Manduca et al (2002). The presentation will focus on two of these workshops that provide middle and high school teachers with strategies and techniques for guiding student-run explorations of earthquakes as a result of tectonic plate movements. Teachers address these topics much as a scientist would by carrying out the following activities: 1) Identifying the relationships between faults, EQs and plate boundaries; 2) Using GPS data to quantify interseismic deformation; 3) Constructing an Earthquake machine; and 4) Scaling their observations from desktop to crustal scale, and (5) Using the results to forecast earthquakes along the SAF and to estimate the magnitude of earthquakes on ancient faults. As it is unrealistic to expect teachers to be able to incorporate all of this material into their syllabi, we have introduced the concept of Subtle Shifts (Exploratorium, 2006) as a means by which they can easily blend workshop material into their existing courses. Teacher surveys reflect a high level of satisfaction (81-100%), and pre- and post-evaluations show significant normalized gains (Hake, 1998), in about 90% of the courses. Moreover, students of RITES teachers demonstrate statistically significant gains in inquiry skills and content

  4. Analysis of different thermal processing methods of foodstuffs to optimize protein, calcium, and phosphorus content for dialysis patients.

    PubMed

    Vrdoljak, Ivica; Panjkota Krbavčić, Ines; Bituh, Martina; Vrdoljak, Tea; Dujmić, Zoran

    2015-05-01

    To analyze how different thermal processing methods affect the protein, calcium, and phosphorus content of hospital food served to dialysis patients and to generate recommendations for preparing menus that optimize nutritional content while minimizing the risk of hyperphosphatemia. Standard Official Methods of Analysis (AOAC) methods were used to determine dry matter, protein, calcium, and phosphorus content in potatoes, fresh and frozen carrots, frozen green beans, chicken, beef and pork, frozen hake, pasta, and rice. These levels were determined both before and after boiling in water, steaming, stewing in oil or water, or roasting. Most of the thermal processing methods did not significantly reduce protein content. Boiling increased calcium content in all foodstuffs because of calcium absorption from the hard water. In contrast, stewing in oil containing a small amount of water decreased the calcium content of vegetables by 8% to 35% and of chicken meat by 12% to 40% on a dry weight basis. Some types of thermal processing significantly reduced the phosphorus content of the various foodstuffs, with levels decreasing by 27% to 43% for fresh and frozen vegetables, 10% to 49% for meat, 7% for pasta, and 22.8% for rice on a dry weight basis. On the basis of these results, we modified the thermal processing methods used to prepare a standard hospital menu for dialysis patients. Foodstuffs prepared according to the optimized menu were similar in protein content, higher in calcium, and significantly lower in phosphorus than foodstuffs prepared according to the standard menu. Boiling in water and stewing in oil containing some water significantly reduced phosphorus content without affecting protein content. Soaking meat in cold water for 1 h before thermal processing reduced phosphorus content even more. These results may help optimize the design of menus for dialysis patients. Copyright © 2015 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights

  5. Evaluation of marine subareas of Europe using life history parameters and trophic levels of selected fish populations.

    PubMed

    Jayasinghe, R P Prabath K; Amarasinghe, Upali S; Newton, Alice

    2015-12-01

    European marine waters include four regional seas that provide valuable ecosystem services to humans, including fish and other seafood. However, these marine environments are threatened by pressures from multiple anthropogenic activities and climate change. The European Marine Strategy Framework Directive (MSFD) was adopted in 2008 to achieve good environmental status (GEnS) in European Seas by year 2020, using an Ecosystem Approach. GEnS is to be assessed using 11 descriptors and up to 56 indicators. In the present analysis two descriptors namely "commercially exploited fish and shellfish populations" and "food webs" were used to evaluate the status of subareas of FAO 27 area. Data on life history parameters, trophic levels and fisheries related data of cod, haddock, saithe, herring, plaice, whiting, hake and sprat were obtained from the FishBase online database and advisory reports of International Council for the Exploration of the Sea (ICES). Subareas inhabited by r and K strategists were identified using interrelationships of life history parameters of commercially important fish stocks. Mean trophic level (MTL) of fish community each subarea was calculated and subareas with species of high and low trophic level were identified. The Fish in Balance (FiB) index was computed for each subarea and recent trends of FiB indices were analysed. The overall environmental status of each subarea was evaluated considering life history trends, MTL and FiB Index. The analysis showed that subareas I, II, V, VIII and IX were assessed as "good" whereas subareas III, IV, VI and VII were assessed as "poor". The subareas assessed as "good" were subject to lower environmental pressures, (less fishing pressure, less eutrophication and more water circulation), while the areas with "poor" environment experienced excessive fishing pressure, eutrophication and disturbed seabed. The evaluation was based on two qualitative descriptors ("commercially exploited fish and shellfish

  6. Fine-scale spatial patterns in the demersal fish and invertebrate community in a northwest Atlantic ecosystem

    NASA Astrophysics Data System (ADS)

    Malek, Anna J.; Collie, Jeremy S.; Gartland, James

    2014-06-01

    The abundance, biomass, diversity, and species composition of the demersal fish and invertebrate community in Rhode Island Sound and Block Island Sound, an area identified for offshore renewable energy development, were evaluated for spatial and seasonal structure. We conducted 58 otter trawls and 51 beam trawls in the spring, summer and fall of 2009-2012, and incorporated additional data from 88 otter trawls conducted by the Northeast Area Monitoring and Assessment Program. We used regionally-grouped abundance, biomass, diversity, and size spectra to assess spatial patterns in the aggregate fish community, and hierarchical cluster analysis to evaluate trends in species assemblages. Our analyses revealed coherent gradients in fish community biomass, diversity and species composition extending from inshore to offshore waters, as well as patterns related to the differing bathymetry of Rhode Island and Block Island Sounds. The fish communities around Block Island and Cox's Ledge are particularly diverse, suggesting that the proximity of hard bottom habitat may be important in structuring fish communities in this area. Species assemblages in Rhode Island and Block Island Sounds are characterized by a combination of piscivores (silver hake, summer flounder, spiny dogfish), benthivores (American lobster, black sea bass, Leucoraja spp. skates, scup) and planktivores (sea scallop), and exhibit geographic patterns that are persistent from year to year, yet variable by season. Such distributions reflect the cross-shelf migration of fish and invertebrate species in the spring and fall, highlighting the importance of considering seasonal fish behavior when planning construction schedules for offshore development projects. The fine spatial scale (10 s of kms) of this research makes it especially valuable for local marine spatial planning efforts by identifying local-scale patterns in fish community structure that will enable future assessment of the ecological impacts of

  7. Epipelagic and mesopelagic fishes in the southern California Current System: Ecological interactions and oceanographic influences on their abundance

    NASA Astrophysics Data System (ADS)

    Koslow, J. Anthony; Davison, Peter; Lara-Lopez, Ana; Ohman, Mark D.

    2014-10-01

    We use zooplankton and ichthyoplankton data from the ~ 60-year CalCOFI time series to examine relationships of mesopelagic (i.e. midwater) fishes in the California Current System with midwater predators, potential competitors (epipelagic planktivorous fishes) and zooplankton prey, within the context of local and basin-scale oceanography. Equilibrium-based near-steady state models and the “wasp-waist” paradigm for eastern boundary currents predict tightly-coupled trophic interactions, with negative correlations between the abundance of planktivorous competitors and between dominant planktivores and their prey. Testing these hypotheses with the CalCOFI time series, we found them to be generally invalid. Potential competitors within the mesopelagic community (planktivorous vertical migrators (VMs) and non-migrators (NMs)) were highly positively correlated, as were these groups with the mesopelagic piscivores (e.g. dragonfishes) that prey on them. In addition, the abundance of VMs was mostly positively correlated with that of epipelagic planktivores, such as anchovy, mackerels and hake. The VMs and epipelagic planktivores were negatively correlated with key potential planktonic prey groups, indicating a lack of bottom-up forcing. However, neither do these negative correlations appear to signify top-down forcing, since they seem to be mediated through correlations with key environmental drivers, such as the Pacific Decadal Oscillation (PDO), sea surface temperature, and the relative strength of the California Current. We suggest that the web of correlations linking key meso- and epipelagic planktivores, their predators and prey is mediated through common links with basin-scale oceanographic drivers, such as the PDO and ENSO cycles. Thus, the abundance of mesopelagic fishes in the California Current is closely tied to variation in the oxygen minimum zone, whose dynamics have been linked to the PDO. The PDO and other drivers are also linked to the transport of the

  8. Does Structured Quizzing with Process Specific Feedback Lead to Learning Gains in an Active Learning Geoscience Classroom?

    NASA Astrophysics Data System (ADS)

    Palsole, S.; Serpa, L. F.

    2013-12-01

    There is a great realization that efficient teaching in the geosciences has the potential to have far reaching effects in outreach to decision and policy makers (Herbert, 2006; Manduca & Mogk, 2006). This research in turn informs educators that the geosciences by the virtue of their highly integrative nature play an important role in serving as an entry point into STEM disciplines and helping developing a new cadre of geoscientists, scientists and a general population with an understanding of science. Keeping these goals in mind we set to design introductory geoscience courses for non-majors and majors that move away from the traditional lecture models which don't necessarily contribute well to knowledge building and retention ((Handelsman et al., 2007; Hake, 1997) to a blended active learning classroom where basic concepts and didactic information is acquired online via webquests, lecturettes and virtual field trips and the face to face portions of the class are focused on problem solving exercises. The traditional way to ensure that students are prepared for the in-class activity is to have the students take a quiz online to demonstrate basic competency. In the process of redesign, we decided to leverage the technology to build quizzes that are highly structured and map to a process (formation of divergent boundaries for example) or sets of earth processes that we needed the students to know before in-class activities. The quizzes can be taken multiple times and provide process specific feedback, thus serving as a heuristic to the students to ensure they have acquired the necessary competency. The heuristic quizzes were developed and deployed over a year with the student data driving the redesign process to ensure synchronicity. Preliminary data analysis indicates a positive correlation between higher student scores on in-class application exercises and time spent on the process quizzes. An assessment of learning gains also indicate a higher degree of self

  9. Trophic flows, ecosystem structure and fishing impacts in the South Catalan Sea, Northwestern Mediterranean

    NASA Astrophysics Data System (ADS)

    Coll, Marta; Palomera, Isabel; Tudela, Sergi; Sardà, Francesc

    2006-01-01

    An exploited ecosystem from the continental shelf and upper slope of the Northwestern Mediterranean Sea was described by means of an Ecopath mass-balance model with the aim of characterising its functioning and structure and describing the ecosystem impacts of fishing. This application included some complexities added to the general modelling methodology due to the high biodiversity of the Mediterranean Sea and the multispecific nature of the fishery, and to the difficulties of working with fishing data which are usually irregularly or imprecisely collected. The model comprised 40 functional groups including primary producers, the main species of benthic, demersal and pelagic invertebrates, fishes and non-fish vertebrates and three detritus groups. In addition, trawling, purse seine, longline and troll bait fishing fleets were included. Results showed that the functional groups were organized into four trophic levels with the highest levels corresponding to anglerfish, dolphins, large pelagic fishes and adult hake. The system was dominated by the pelagic fraction, where sardine and anchovy prevailed in terms of fish biomasses and catches. Detritus and detritivorous groups also played key roles in the ecosystem and important coupled pelagic-demersal interactions were described. Considering Odum's theory of ecosystem development, the ecosystem was placed on an intermediate-low developmental stage due, at least partially, to the impact of fishing activity. This highlighted the high intensity of fishing in the ecosystem, in accordance with the general assessment of western Mediterranean marine resources, and fishing fleets were ranked as top predators of the system. The low trophic level of the catch was in line with the long history of exploitation in the area. However, the steady decline of pelagic landings between 1994 and 2003, coupled with a decrease of the pelagic biomass within the system, underlined the low resistance of the system in front of perturbations

  10. The north polar lakes of Titan as observed by Cassini Radar

    NASA Astrophysics Data System (ADS)

    Mitchell, K. L.; Paillou, P.; Kirk, R. L.; Lunine, J. I.; Stofan, E. R.; Radebaugh, J.; Wall, S. D.; Hayes, A. G.; Lopes, R. M.; Stiles, B. W.; Ostro, S. J.; Lorenz, R. D.; Wood, C. A.; Cassini RADAR Team

    2007-12-01

    Over the course of a year, Cassini RADAR obtained Synthetic Aperture Radar images covering 69 percent of Titan's polar region north of 65 degrees; the region being 1.4E6 km3 in extent, greater than double the land area of the USA. We observe several hundred lakes with a range of morphological expression, including areally massive and morphologically distinctive "seas", covering ~15% of the polar region. Lakes are extremely radar dark, consistent with a lossy liquid hydrocarbon. Preliminary laboratory estimates suggest that loss tangents in the range 10E4 to 2x10E3 are reasonable, which implies that one can see through at least a few to many tens of m of liquids before the noise floor is reached, consistent with observed brightening towards many lake shores. North polar lake volumes are most likely in the 8E3 - 1.4E6 km3 range. Uncertainties will be reduced as more data, both image-based and experimental, are obtained but we can conclude with a high degree of confidence that hydrocarbon lakes on Titan are more voluminous than known terrestrial oil reserves; current estimates range from 2248 - 3896 billion barrels of oil (J. Hakes, 2000, Long Term World Oil Supply, Meeting of the Am. Ass. Pet. Geol., 18th April 2000, New Orleans, LA, http://www.eia.doe.gov/pub/oil_gas/petroleum/presentations/2000/long_term_supply.), hence 357 - 619 km3 . Small lakes often occupy steep-sided depressions, and although thermal and cryovolcanic origins cannot be completely ruled out, we are seeing growing geomorphologic evidence for dissolution chemistry, indicative of karst-like geology. The dichotomy between small lakes over slightly more than one half of the region, and seas on the other half, may be best explained by a topographic anomaly causing sub-surface flow of materials from the lakes to the seas. This may also explain observations by the Cassini ISS team (E. Turtle et al., in prep.) of a putative massive sea extending considerably further south than other observed north polar

  11. Some taxonomic and nomenclatural changes in American Mantodea (Insecta, Dictyoptera)--Part I.

    PubMed

    Agudelo, Antonio A; Rivera, Julio

    2015-03-20

    Multiple nomenclatural problems persist in mantodean taxonomy. This constitutes an important challenge for praying mantis systematics, its forthcoming development and future consolidation. In this first contribution, we attempt solving a number of issues involving mostly Neotropical praying mantis species described by Brazilian entomologists Paulo S. Terra, Cândido F. de Mello-Leitão, Salvador de Toledo Piza Junior and Lauro J. Jantsch. We provide evidence to justify the following nomenclatural changes. In Acanthopidae, Acontiothespis travassosi Jantsch, 1986 is a new synonym of Raptrix perspicua (F. 1787). Changes in Thespidae are: Emboicy Terra, 1982 is a new synonym of Chloromiopteryx Giglio-Tos, 1915, E. mirim Terra, 1982 is transferred to Chloromiopteryx as C. mirim (Terra, 1982) (new combination); Musoniola plurilobata Mello-Leitão, 1937 is transferred to Chloromiopteryx as C. plurilobata (Mello-Leitão, 1937) (new combination); Metathespis modesta Piza, 1968 is removed from synonymy with Chloromiopteryx thalassina (Burmeister, 1838) and considered valid as C. modesta (Piza, 1968) (new combination and status revalidated); Metathespis precaria Piza, 1968 is removed from synonymy with Chloromiopteryx thalassina (Burmeister, 1838) and considered a new synonym of Miobantia rustica (Fabricius, 1781); Eumiopteryx magna Jantsch, 1991 is transferred to Anamiopteryx as A. magna (Jantsch, 1991) (new combination). For Mantidae/Amelinae, Tithrone corseuli Jantsch, 1986 and T. clauseni Jantsch, 1995 are new synonyms of Litaneutria minor (Scudder, 1872); in Mantidae/Photininae Coptopteryx gigliotosi Piza, 1960 (non Werner, 1925), its replacement name Coptopteryx ermannoi Jantsch & Corseuil, 1988 and Paraphotina precaria Piza, 1966 (the latter currently placed within Coptopteryx) are all new synonyms of Coptopteryx argentina (Burmeister, 1838), whereas Brachypteromantis bonariensis Piza 1960 (currently placed among Coptopteryx) is a new synonym of Coptopteryx gayi

  12. The Principles of Buoyancy in Marine Fish Eggs and Their Vertical Distributions across the World Oceans

    PubMed Central

    Sundby, Svein; Kristiansen, Trond

    2015-01-01

    for recruitment to the population. An example of adaptation to such conditions is Cape hake spawning above the critical layer in the Northern Benguela upwelling ecosystem. The eggs rise slowly in the onshore subsurface current below the Ekman layer, hence being advected inshore where the hatched larvae concentrate with optimal feeding conditions. PMID:26465149

  13. The Principles of Buoyancy in Marine Fish Eggs and Their Vertical Distributions across the World Oceans.

    PubMed

    Sundby, Svein; Kristiansen, Trond

    2015-01-01

    recruitment to the population. An example of adaptation to such conditions is Cape hake spawning above the critical layer in the Northern Benguela upwelling ecosystem. The eggs rise slowly in the onshore subsurface current below the Ekman layer, hence being advected inshore where the hatched larvae concentrate with optimal feeding conditions.

  14. An in vitro study of urea, water, ion and CO2/HCO3- transport in the gastrointestinal tract of the dogfish shark (Squalus acanthias): the influence of feeding.

    PubMed

    Liew, Hon Jung; De Boeck, Gudrun; Wood, Chris M

    2013-06-01

    In vitro gut sac preparations made from the cardiac stomach (stomach 1), pyloric stomach (stomach 2), intestine (spiral valve) and colon were used to examine the impact of feeding on transport processes in the gastrointestinal tract of the dogfish shark. Preparations were made from animals that were euthanized after 1-2 weeks of fasting, or at 24-48 h after voluntary feeding on a 3% ration of teleost fish (hake). Sacs were incubated under initially symmetrical conditions with dogfish saline on both surfaces. In comparison to an earlier in vivo study, the results confirmed that feeding caused increases in H(+) secretion in both stomach sections, but an increase in Cl(-) secretion only in stomach 2. Na(+) absorption, rather than Na(+) secretion, occurred in both stomach sections after feeding. All sections of the tract absorbed water and the intestine strongly absorbed Na(+) and Cl(-), regardless of feeding condition. The results also confirmed that feeding increased water absorption in the intestine (but not in the colon), and had little influence on the handling of Ca(2+) and Mg(2+), which exhibited negligible absorption across the tract. However, K(+) was secreted in the intestine in both fasted and fed preparations. Increased intestinal water absorption occurred despite net osmolyte secretion into the mucosal saline. The largest changes occurred in urea and CO2/HCO3(-) fluxes. In fasted preparations, urea was absorbed at a low rate in all sections except the intestine, where it was secreted. Instead of an increase in intestinal urea secretion predicted from in vivo data, feeding caused a marked switch to net urea absorption. This intestinal urea transport occurred at a rate comparable to urea reabsorption rates reported at gills and kidney, and was apparently active, establishing a large serosal-to-mucosal concentration gradient. Feeding also greatly increased intestinal CO2/HCO3(-) secretion; if interpreted as HCO3(-) transport, the rates were in the upper range

  15. Osmoregulation, ionoregulation and acid-base regulation by the gastrointestinal tract after feeding in the elasmobranch (Squalus acanthias).

    PubMed

    Wood, Chris M; Kajimura, Makiko; Bucking, Carol; Walsh, Patrick J

    2007-04-01

    In order to study the physiological consequences of voluntary feeding in the gastrointestinal tract of a ureotelic marine elasmobranch, dogfish (fasted for 96 h) were sampled at various times up to 360 h after consuming a 5-6% ration of teleost fish (hake) under natural feeding conditions. Digestion and absorption were completed between 120 and 360 h post-feeding. The tissue masses of different segments of the gastrointestinal tract increased and decreased markedly as the chyme moved through, mainly because of fluid engorgement rather than hyperplasia. In fasted dogfish, the cardiac and pyloric stomachs contained only small volumes of highly acidic fluid (pH 1.77+/-1.12, 2.05+/-0.08) similar in composition to seawater. Feeding resulted in gastric pHs of 3.20+/-0.31 and 3.95+/-0.40 at 6 h, followed by slow declines through 60 h. An alkaline tide in the blood also occurred at 6 h. In the face of large changing masses of highly acidic chyme in the stomachs, the pH (6.50+/-0.10), ionic composition and volume of chyme in the intestine (spiral valve) were precisely regulated from 6 to 60 h post-feeding at very different values from those in the stomachs, and intestinal HCO3(-) remained low (5.12+/-0.83 mmol l(-1)). The colon was usually empty and its pH constant at 7.20+/-0.16 at all times. Despite the ingestion of strongly hypo-osmotic teleost tissue, the osmolality of the chyme remained in equilibrium with that of the blood plasma in all segments at all times after feeding. Much of the osmotic equilibration was because of the secretion of urea into the chyme, particularly in the intestine. After feeding, gastric fluid concentrations of Na(+) and Mg(2+) declined, K(+) and Ca(2+) increased, whereas Cl(-) exhibited little change, indicating that additional drinking of seawater was minimal. Na(+), K(+), water and especially Cl(-) were absorbed in the intestine, whereas Mg(2+) and Ca(2+) were largely excluded. Our results illustrate the complex integration of digestive and

  16. Ambilpolar Electric Field and Diffusive Cooling of Electrons in Meteor Trails

    NASA Astrophysics Data System (ADS)

    Pasko, V. P.; Kelley, M. C.

    2017-12-01

    electric field and lose thermal energy. Under considered conditions electron heating in super elastic collisions with rotationally excited ambient molecules becomes important and we will illustrate related time scales by Monte Carlo simulations based on modeling framework of [Frost and Phelps, Phys. Rev., 127, 1621, 1962; Hake and Phelps, Phys. Rev., 158, 70, 1967].

  17. The genomics of wild yeast populations sheds light on the domestication of man's best (micro) friend.

    PubMed

    Eberlein, Chris; Leducq, Jean-Baptiste; Landry, Christian R

    2015-11-01

    The domestication of plants, animals and microbes by humans are the longest artificial evolution experiments ever performed. The study of these long-term experiments can teach us about the genomics of adaptation through the identification of the genetic bases underlying the traits favoured by humans. In laboratory evolution, the characterization of the molecular changes that evolved specifically in some lineages is straightforward because the ancestors are readily available, for instance in the freezer. However, in the case of domesticated species, the ancestor is often missing, which leads to the necessity of going back to nature in order to infer the most likely ancestral state. Significant and relatively recent examples of this approach include wolves as the closest wild relative to domestic dogs (Axelsson et al. 2013) and teosinte as the closest relative to maize (reviewed in Hake & Ross-Ibarra 2015). In both cases, the joint analysis of domesticated lineages and their wild cousins has been key in reconstructing the molecular history of their domestication. While the identification of closest wild relatives has been done for many plants and animals, these comparisons represent challenges for micro-organisms. This has been the case for the budding yeast Saccharomyces cerevisiae, whose natural ecological niche is particularly challenging to define. For centuries, this unicellular fungus has been the cellular factory for wine, beer and bread crafting, and currently for bioethanol and drug production. While the recent development of genomics has lead to the identification of many genetic elements associated with important wine characteristics, the historical origin of some of the domesticated wine strains has remained elusive due to the lack of knowledge of their close wild relatives. In this issue of Molecular Ecology, Almeida et al. (2015) identified what is to date the closest known wild population of the wine yeast. This population is found associated with

  18. Marine Biodiversity in South Africa: An Evaluation of Current States of Knowledge

    PubMed Central

    Griffiths, Charles L.; Robinson, Tamara B.; Lange, Louise; Mead, Angela

    2010-01-01

    Continental South Africa has a coastline of some 3,650 km and an Exclusive Economic Zone (EEZ) of just over 1 million km2. Waters in the EEZ extend to a depth of 5,700 m, with more than 65% deeper than 2,000 m. Despite its status as a developing nation, South Africa has a relatively strong history of marine taxonomic research and maintains comprehensive and well-curated museum collections totaling over 291,000 records. Over 3 million locality records from more than 23,000 species have been lodged in the regional AfrOBIS (African Ocean Biogeographic Information System) data center (which stores data from a wider African region). A large number of regional guides to the marine fauna and flora are also available and are listed. The currently recorded marine biota of South Africa numbers at least 12,914 species, although many taxa, particularly those of small body size, remain poorly documented. The coastal zone is relatively well sampled with some 2,500 samples of benthic invertebrate communities have been taken by grab, dredge, or trawl. Almost none of these samples, however, were collected after 1980, and over 99% of existing samples are from depths shallower than 1,000 m—indeed 83% are from less than 100 m. The abyssal zone thus remains almost completely unexplored. South Africa has a fairly large industrial fishing industry, of which the largest fisheries are the pelagic (pilchard and anchovy) and demersal (hake) sectors, both focused on the west and south coasts. The east coast has fewer, smaller commercial fisheries, but a high coastal population density, resulting in intense exploitation of inshore resources by recreational and subsistence fishers, and this has resulted in the overexploitation of many coastal fish and invertebrate stocks. South Africa has a small aquaculture industry rearing mussels, oysters, prawns, and abalone—the latter two in land-based facilities. Compared with many other developing countries, South Africa has a well

  19. The mass balance of production and consumption: Supporting policy-makers for aquatic food security

    NASA Astrophysics Data System (ADS)

    Lopes, A. S.; Ferreira, J. G.; Vale, C.; Johansen, J.

    2017-03-01

    This work addresses divergences between data on consumption and availability for wild-caught and farmed fish, and normalisation of reported production data, to support integrated fisheries and aquaculture management. The methodologies developed, centred on improved parameterisation and on mass balance closure, were tested in two case studies: (i) the cod fishery in Europe, with particular emphasis on Iceland and the United Kingdom; and (ii) the overall balance of aquatic products for Portugal, the ICES member with the most diverse range of landed marine species. Data for consumption, Illegal, Unreported, or Unregulated (IUU) catch, and official availability statistics were used to identify discrepancies between consumption and official availability data. The identification of discrepancies between supply and demand, when coupled with source-discriminated data, showed a pattern where products with no unmet demand tend to display a considerable IUU percentage-above 9% in three cases (hake, sardine, and horse mackerel). By contrast with fished products with an over-met demand such as cod (144%) and sardine (124%), farmed species display low Optimal Consumption Level (OCL) satisfaction. Atlantic salmon, gilthead seabream, and European seabass register 45%, 58% and 44% respectively; this suggests a considerable unmet demand for these products and/or a high volume of undeclared fish reaching consumers, which may be due to the lack of landings control that exists for wild-caught fish. Improvements to production estimates using live-weight coefficients illustrate the impacts of seafood processing. Different processing methods can generate variations in live-weight estimates, leading to errors in officially reported data, and expose the limitations of the current statistical methods. As an example, the corrected per capita consumption for Portugal for 2014 (the latest FAO data) increases from 57 to 66 kg ind-1 y-1, which places the country as the second-greatest consumer in

  20. Trophic modeling of the Northern Humboldt Current Ecosystem, Part I: Comparing trophic linkages under La Niña and El Niño conditions

    NASA Astrophysics Data System (ADS)

    Tam, Jorge; Taylor, Marc H.; Blaskovic, Verónica; Espinoza, Pepe; Michael Ballón, R.; Díaz, Erich; Wosnitza-Mendo, Claudia; Argüelles, Juan; Purca, Sara; Ayón, Patricia; Quipuzcoa, Luis; Gutiérrez, Dimitri; Goya, Elisa; Ochoa, Noemí; Wolff, Matthias

    2008-10-01

    The El Niño of 1997-98 was one of the strongest warming events of the past century; among many other effects, it impacted phytoplankton along the Peruvian coast by changing species composition and reducing biomass. While responses of the main fish resources to this natural perturbation are relatively well known, understanding the ecosystem response as a whole requires an ecotrophic multispecies approach. In this work, we construct trophic models of the Northern Humboldt Current Ecosystem (NHCE) and compare the La Niña (LN) years in 1995-96 with the El Niño (EN) years in 1997-98. The model area extends from 4°S-16°S and to 60 nm from the coast. The model consists of 32 functional groups of organisms and differs from previous trophic models of the Peruvian system through: (i) division of plankton into size classes to account for EN-associated changes and feeding preferences of small pelagic fish, (ii) increased division of demersal groups and separation of life history stages of hake, (iii) inclusion of mesopelagic fish, and (iv) incorporation of the jumbo squid ( Dosidicus gigas), which became abundant following EN. Results show that EN reduced the size and organization of energy flows of the NHCE, but the overall functioning (proportion of energy flows used for respiration, consumption by predators, detritus and export) of the ecosystem was maintained. The reduction of diatom biomass during EN forced omnivorous planktivorous fish to switch to a more zooplankton-dominated diet, raising their trophic level. Consequently, in the EN model the trophic level increased for several predatory groups (mackerel, other large pelagics, sea birds, pinnipeds) and for fishery catch. A high modeled biomass of macrozooplankton was needed to balance the consumption by planktivores, especially during EN condition when observed diatoms biomass diminished dramatically. Despite overall lower planktivorous fish catches, the higher primary production required-to-catch ratio implied a

  1. Changes in food web structure under scenarios of overfishing in the southern Benguela: Comparison of the Ecosim and OSMOSE modelling approaches

    NASA Astrophysics Data System (ADS)

    Travers, M.; Watermeyer, K.; Shannon, L. J.; Shin, Y.-J.

    2010-01-01

    Ecosystem models provide a platform allowing exploration into the possible responses of marine food webs to fishing pressure and various potential management decisions. In this study we investigate the particular effects of overfishing on the structure and function of the southern Benguela food web, using two models with different underlying assumptions: the spatialized, size-based individual-based model, OSMOSE, and the trophic mass-balance model, Ecopath with Ecosim (EwE). Starting from the same reference state of the southern Benguela upwelling ecosystem during the 1990s, we compare the response of the food web to scenarios of overfishing using these two modelling approaches. A scenario of increased fishing mortality is applied to two distinct functional groups: i) two species of Cape hake, representing important target predatory fish, and ii) the forage species anchovy, sardine and redeye. In these simulations, fishing mortality on the selected functional groups is doubled for 10 years, followed by 10 years at the initial fishing mortality. We compare the food web states before the increase of fishing mortality, after 10 years of overfishing and after a further 10 years during which fishing was returned to initial levels. In order to compare the simulated food web structures with the reference state, and between the two modelling approaches, we use a set of trophic indicators: the mean trophic level of the community and in catches, the trophic pyramid (biomass per discrete trophic level), and the predatory/forage fish biomass ratio. OSMOSE and EwE present globally similar results for the trophic functioning of the ecosystem under fishing pressure: the biomass of targeted species decreases whereas that of their potential competitors increases. The reaction of distant species is more diverse, depending on the feeding links between the compartments. The mean trophic level of the community does not vary enough to be used for assessing ecosystem impacts of fishing

  2. Demersal fish distribution and habitat use within and near Baltimore and Norfolk Canyons, U.S. Middle Atlantic Slope

    USGS Publications Warehouse

    Ross, Steve W.; Rhode, Mike; Quattrini, Andrea M.

    2015-01-01

    brosme, and Helicolenus dactylopterus, exhibited a variety of habitat use patterns. In general, fish assemblages in the soft substrata areas (dominated by P. chesteri, N. bairdii, Glyptocephalus cynoglossus, Lophius americanus, Merluccius albidus) were different from those in more complex habitats (dominated by Laemonema spp., Hoplostethus spp., B. brosme,Benthocometes robustus, L. americanus, Dysommina rugosa). Although, when present, the dense coral and sponge cover did not statistically affect general fish assemblage patterns in hard bottom habitats, these sessile organisms markedly increased habitat complexity, and some fish species exhibited close association with them. Fish species compositions in the two canyons were not substantially different from the surrounding slopes. However, the diversity of habitats within both the canyons and seeps exerted an important influence on assemblage structure. At least for some species (e.g., B. brosme) canyon and seep environments may be a refuge from intensive bottom fishing activities. We frequently observed evidence of commercial and recreational fishing activity (lost gear on bottom and fishing boats in the area) throughout the canyons and some resulting habitat damage. Conservation measures for the unique and more vulnerable areas (seep and coral habitats) have recently been approved.

  3. Annotated type catalogue of the Bulimulidae (Mollusca, Gastropoda, Orthalicoidea) in the Natural History Museum, London

    PubMed Central

    Breure, Abraham S.H.; Ablett, Jonathan D.

    2014-01-01

    ); Kuschelenia (Kuschelenia) culmineus edwardsi (Morelet, 1863); Kuschelenia (K.) gayi (Pfeiffer, 1857); Kuschelenia (Kuschelenia) tupacii (d’Orbigny, 1835); Kuschelenia (Vermiculatus) anthisanensis (Pfeiffer, 1853); Kuschelenia (Vermiculatus) aquilus (Reeve, 1848); Kuschelenia (Vermiculatus) bicolor (Sowerby I, 1835); Kuschelenia (Vermiculatus) caliginosus (Reeve, 1849); Kuschelenia (Vermiculatus) cotopaxiensis (Pfeiffer, 1853); Kuschelenia (Vermiculatus) filaris (Pfeiffer, 1853); Kuschelenia (Vermiculatus) ochracea (Morelet, 1863); Kuschelenia (Vermiculatus) petiti (Pfeiffer, 1846); Kuschelenia (Vermiculatus) purpuratus (Reeve, 1849); Kuschelenia (Vermiculatus) quechuarum (Crawford, 1939); Naesiotus cinereus (Reeve, 1849); Naesiotus dentritis (Morelet, 1863); Naesiotus fontainii (d’Orbigny, 1838); Naesiotus orbignyi (Pfeiffer, 1846); Protoglyptus pilosus (Guppy, 1871); Protoglyptus sanctaeluciae (E.A. Smith, 1889). Type material of the following taxa is figured herein for the first time: Bulimus cinereus Reeve, 1849; Bulimus coriaceus Pfeiffer, 1857; Bulimulus laxostylus Rolle, 1904; Bulimus pliculatus Pfeiffer, 1857; Bulimus simpliculus Pfeiffer, 1855. PMID:24715782

  4. L'impact d'une simulation sur des dispositifs mobiles et en situation de collaboration sur la comprehension de l'effet photoelectrique au niveau collegial

    NASA Astrophysics Data System (ADS)

    Droui, Mohamed

    noted an average gain of learning qualified at a moderate level according to Hake (1998). Interview results were used to identify some conceptual difficulties of student learning. Analysis of collected data from video sequences, questionnaires and recovered tracks allowed us to better understand the process of collaborative learning and has revealed that the number and the time of interactions between students are strongly correlated with the gain of learning. At first, this research project is a success in the designing of a learning scenario of a phenomenon as complex as the photoelectric effect and respects many criteria (collaboration, simulation, mobile devices, etc.) that it seemed for us extremely utopian to combine them in an effective learning situation in the classroom. For instance, this scenario could be adapted to the learning of other concepts in physics. It could also be considered for the design of collaborative environments for innovative mobile learning focused on the needs of learners that integrate the technologies at the right time and for the right activity. Keywords : collaborative learning, simulation, mobile learning, conceptual change, photoelectric effect.

  5. Feminist Physics Education: Deconstructed Physics and Students' Multiple Subjectivities

    NASA Astrophysics Data System (ADS)

    Jammula, Diane Crenshaw

    Physics is one of the least diverse sciences; in the U.S. in 2010, only 21% of bachelors degrees in physics were awarded to women, 2.5% to African Americans, and 4% to Hispanic Americans (AIP, 2012). Though physics education reform efforts supporting interactive engagement have doubled students' learning gains (Hake, 1998), gender and race gaps persist (Brewe et al., 2010; Kost, Pollock, & Finkelstein, 2009). When students' subjectivities align with presentations of physics, they are more likely to develop positive physics identities (Hughes, 2001). However, both traditional and reformed physics classrooms may present physics singularly as abstract, elite, and rational (Carlone, 2004). Drawing from feminist science, I argue that binaries including abstract / concrete, elite / accessible, and rational / emotional are hierarchal and gendered, raced and classed. The words on the left define conventional physics and are associated with middle class white masculinity, while the words on the right are associated with femininity or other, and are often missing or delegitimized in physics education, as are females and minorities. To conceptualize a feminist physics education, I deconstructed these binaries by including the words on the right as part of doing physics. I do not imply that women and men think differently, but that broadening notions of physics may allow a wider range of students to connect with the discipline. I used this conceptual framework to modify a popular reformed physics curriculum called Modeling Instruction (Hestenes, 1987). I taught this curriculum at an urban public college in an introductory physics course for non-science majors. Twenty-three students of diverse gender, race, ethnic, immigrant and class backgrounds enrolled. I conducted an ethnography of the classroom to learn how students negotiate their subjectivities to affiliate with or alienate from their perceptions of physics, and to understand how classroom experiences exacerbate or

  6. Tidal deformation of Enceladus' ice shell with variable thickness and Maxwell rheology

    NASA Astrophysics Data System (ADS)

    Soucek, Ondrej; Behounkova, Marie; Cadek, Ondrej; Tobie, Gabriel; Choblet, Gael

    2017-04-01

    anomalies of the surface heat flux and, together with other effects (e.g. Souček et al., 2016), may thus contribute to the hemispheric dichotomy observed on Enceladus. Alnaes, M. S., Blechta, J., Hake, J., Johansson, J., Kehlet, B., Logg, A., Richardson, C., Ring, J., Rognes, M. E.,Wells, G. N., 2015. The FEniCS Project Version 1.5. Archive of Numerical Software 3 (100), 9-23. Cadek, O., Tobie, G., van Hoolst, T., Masse, M., Choblet, G., Lefevre, A., Mitri, G., Baland, R.-M., Behounkova, M., Bourgeois, O., Trinh, A., 2016. Enceladus's internal ocean and ice shell constrained from Cassini gravity, shape, and libration data. Geophys. Res. Let. 46, 5653-5660. Iess, L., Stevenson, D. J., Parisi, M., Hemingway, D., Jacobson, R. A., Lunine, J. I., Nimmo, F., Armstrong, J. W., Asmar, S. W., Ducci, M., Tortora, P., Apr. 2014. The Gravity Field and Interior Structure of Enceladus. Science 344, 78-80. McKinnon, W. B., Apr. 2015. Effect of Enceladus's rapid synchronous spin on interpretation of Cassini gravity. Geophys. Res. Let. 42, 2137-2143. Nimmo, F., Bills, B. G., Thomas, P. C., 2011. Geophysical implications of the long-wavelength topography of the Saturnian satellites. J. Geophys. Res. 116 (E15), E11001. Soucek, O., Hron, J., Behounkova, M., Cadek, O., 2016. Effect of the tiger stripes on the deformation of Saturn's moon Enceladus. Geophys. Res. Let. 43, 7417-7423.

  7. Regular structural and compositional characteristics of Mercury predicted by the wave planetology

    NASA Astrophysics Data System (ADS)

    Kochemasov, G. G.

    2012-09-01

    across was predicted and now observed by the MESSENGER measurements: magnetic field variations, gravity anomalies, topographic uplifts [2- 4, 8]. As was shown earlier [9], there is a direct correlation between tectonic granule radii and relief ranges of terrestrial planets. The small relief range of Mercury (a few kms) corresponds with its fine tectonic granulation. Using petrography terms one may say that Mercury is "fine gra ined", Venus "mediu m grained", Ea rth "coars e grained", and Mars "pegmatoid". Thes e tectonic s tructures of rotating terrestrial planets force them to build subsided blocks of denser material than uplifted ones to keep more or less equilibrated their angular momenta. Higher relief range more significant must be density difference between risen and fallen tectonic blocks. In the row of terrestrial planets their s ubs ided "oceanic" areas become more Fe - rich (thus, denser) in direction from Mercury to Mars; their uplifted "highland" areas become mo re Si and alka lis -rich (thus, less dense) [10]. Mercury having the smallest tectonic granules and relief range has the smallest density diffe rence between "up" and "down" blocks and Mg -rich magmat ic lithologies in both [10, Fig. 3]. That is why Mercury has so dull appearance contrary to Mars with very high albedo difference between fallen north and risen south. In full agreement with the above regularity is an important conclusion of [11] about a regular rising K/Th in crusts from Mercury to Mars. To this one could add our earlier observation on decreasing atmospheric masses in the s ame direction due to diminis hing "wave s haking" - "sweeping out" volatiles fro m the solid bodies (the warping waves become larger and less frequent). Ratio of radiogenic to primordial argon in atmospheres regularly increases outwards: Venus 1, Earth 300, Mars 3000 [12]. Mercury shows very pronounced traces of very intensive degassing (numerous pits [13], contracting features). Surprising high sulfur content in X