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Sample records for atlantic cod populations

  1. Ocean Acidification Effects on Atlantic Cod Larval Survival and Recruitment to the Fished Population.

    PubMed

    Stiasny, Martina H; Mittermayer, Felix H; Sswat, Michael; Voss, Rüdiger; Jutfelt, Fredrik; Chierici, Melissa; Puvanendran, Velmurugu; Mortensen, Atle; Reusch, Thorsten B H; Clemmesen, Catriona

    2016-01-01

    How fisheries will be impacted by climate change is far from understood. While some fish populations may be able to escape global warming via range shifts, they cannot escape ocean acidification (OA), an inevitable consequence of the dissolution of anthropogenic carbon dioxide (CO2) emissions in marine waters. How ocean acidification affects population dynamics of commercially important fish species is critical for adapting management practices of exploited fish populations. Ocean acidification has been shown to impair fish larvae's sensory abilities, affect the morphology of otoliths, cause tissue damage and cause behavioural changes. Here, we obtain first experimental mortality estimates for Atlantic cod larvae under OA and incorporate these effects into recruitment models. End-of-century levels of ocean acidification (~1100 μatm according to the IPCC RCP 8.5) resulted in a doubling of daily mortality rates compared to present-day CO2 concentrations during the first 25 days post hatching (dph), a critical phase for population recruitment. These results were consistent under different feeding regimes, stocking densities and in two cod populations (Western Baltic and Barents Sea stock). When mortality data were included into Ricker-type stock-recruitment models, recruitment was reduced to an average of 8 and 24% of current recruitment for the two populations, respectively. Our results highlight the importance of including vulnerable early life stages when addressing effects of climate change on fish stocks.

  2. Ocean Acidification Effects on Atlantic Cod Larval Survival and Recruitment to the Fished Population

    PubMed Central

    Stiasny, Martina H.; Mittermayer, Felix H.; Sswat, Michael; Voss, Rüdiger; Jutfelt, Fredrik; Chierici, Melissa; Puvanendran, Velmurugu; Mortensen, Atle; Reusch, Thorsten B. H.; Clemmesen, Catriona

    2016-01-01

    How fisheries will be impacted by climate change is far from understood. While some fish populations may be able to escape global warming via range shifts, they cannot escape ocean acidification (OA), an inevitable consequence of the dissolution of anthropogenic carbon dioxide (CO2) emissions in marine waters. How ocean acidification affects population dynamics of commercially important fish species is critical for adapting management practices of exploited fish populations. Ocean acidification has been shown to impair fish larvae’s sensory abilities, affect the morphology of otoliths, cause tissue damage and cause behavioural changes. Here, we obtain first experimental mortality estimates for Atlantic cod larvae under OA and incorporate these effects into recruitment models. End-of-century levels of ocean acidification (~1100 μatm according to the IPCC RCP 8.5) resulted in a doubling of daily mortality rates compared to present-day CO2 concentrations during the first 25 days post hatching (dph), a critical phase for population recruitment. These results were consistent under different feeding regimes, stocking densities and in two cod populations (Western Baltic and Barents Sea stock). When mortality data were included into Ricker-type stock-recruitment models, recruitment was reduced to an average of 8 and 24% of current recruitment for the two populations, respectively. Our results highlight the importance of including vulnerable early life stages when addressing effects of climate change on fish stocks. PMID:27551924

  3. Evolutionary history and adaptive significance of the polymorphic Pan I in migratory and stationary populations of Atlantic cod (Gadus morhua).

    PubMed

    Andersen, Øivind; Johnsen, Hanne; De Rosa, Maria Cristina; Præbel, Kim; Stjelja, Suzana; Kirubakaran, Tina Graceline; Pirolli, Davide; Jentoft, Sissel; Fevolden, Svein-Erik

    2015-08-01

    The synaptophysin (SYP) family comprises integral membrane proteins involved in vesicle-trafficking events, but the physiological function of several members has been enigmatic for decades. The presynaptic SYP protein controls neurotransmitter release, while SYP-like 2 (SYPL2) contributes to maintain normal Ca(2+)-signaling in the skeletal muscles. The polymorphic pantophysin (Pan I) of Atlantic cod shows strong genetic divergence between stationary and migratory populations, which seem to be adapted to local environmental conditions. We have investigated the functional involvement of Pan I in the different ecotypes by analyzing the 1) phylogeny, 2) spatio-temporal gene expression, 3) structure-function relationship of the Pan I(A) and I(B) protein variants, and 4) linkage to rhodopsin (rho) recently proposed to be associated with different light sensitivities in Icelandic populations of Atlantic cod. We searched for SYP family genes in phylogenetic key species and identified a single syp-related gene in three invertebrate chordates, while four members, Syp, Sypl1, Sypl2 and synaptoporin (Synpr), were found in tetrapods, Comoran coelacanth and spotted gar. Teleost fish were shown to possess duplicated syp, sypl2 and synpr genes of which the sypl2b paralog is identical to Pan I. The ubiquitously expressed cod Pan I codes for a tetra-spanning membrane protein possessing five amino acid substitutions in the first intravesicular loop, but only minor structural differences were shown between the allelic variants. Despite sizable genomic distance (>2.5 Mb) between Pan I and rho, highly significant linkage disequilibrium was found by genotyping shallow and deep water juvenile settlers predominated by the Pan I(A)-rho(A) and Pan I(B)-rho(B) haplotypes, respectively. However, the predicted rhodopsin protein showed no amino acid changes, while multiple polymorphic sites in the upstream region might affect the gene expression and pigment levels in stationary and migratory cod

  4. Evidence of microsatellite hitch-hiking selection in Atlantic cod (Gadus morhua L.): implications for inferring population structure in nonmodel organisms.

    PubMed

    Nielsen, Einar E; Hansen, Michael M; Meldrup, Dorte

    2006-10-01

    Microsatellites have gained wide application for elucidating population structure in nonmodel organisms. Since they are generally noncoding, neutrality is assumed but rarely tested. In Atlantic cod (Gadus morhua L.), microsatellite studies have revealed highly heterogeneous estimates of genetic differentiation among loci. In particular one locus, Gmo 132, has demonstrated elevated genetic differentiation. We investigated possible hitch-hiking selection at this and other microsatellite loci in Atlantic cod. We employed 11 loci for analysing samples from the Baltic Sea, North Sea, Barents Sea and Newfoundland covering a large part of the species' distributional range. The 'classical' Lewontin-Krakauer test for selection based on variance in estimates of F(ST) and (standardized genetic differentiation) revealed only one significant pairwise test (North Sea-Barents Sea), and the source of the elevated variance could not be ascribed exclusively to Gmo 132. In contrast, different variants of the recently developed ln Rtheta test for selective sweeps at microsatellite loci revealed a high number of significant outcomes of pair-wise tests for Gmo 132. Further, the presence of selection was indicated in at least one other locus. The results suggest that many previous estimates of genetic differentiation in cod based on microsatellites are inflated, and in some cases relationships among populations are obscured by one or more loci being the subject to hitch-hiking selection. Likewise, temporal estimates of effective population sizes in Atlantic cod may be flawed. We recommend, generally, to use a higher number of microsatellite loci to elucidate population structure in marine fishes and other nonmodel species to allow for identification of outlier loci that are subject to selection.

  5. Behavioral responses of Atlantic cod to sea temperature changes.

    PubMed

    Freitas, Carla; Olsen, Esben Moland; Moland, Even; Ciannelli, Lorenzo; Knutsen, Halvor

    2015-05-01

    Understanding responses of marine species to temperature variability is essential to predict impacts of future climate change in the oceans. Most ectotherms are expected to adjust their behavior to avoid extreme temperatures and minimize acute changes in body temperature. However, measuring such behavioral plasticity in the wild is challenging. Combining 4 years of telemetry-derived behavioral data on juvenile and adult (30-80 cm) Atlantic cod (Gadus morhua), and in situ ocean temperature measurements, we found a significant effect of sea temperature on cod depth use and activity level in coastal Skagerrak. During summer, cod were found in deeper waters when sea surface temperature increased. Further, this effect of temperature was stronger on larger cod. Diel vertical migration, which consists in a nighttime rise to shallow feeding habitats, was stronger among smaller cod. As surface temperature increased beyond ∼15°C, their vertical migration was limited to deeper waters. In addition to larger diel vertical migrations, smaller cod were more active and travelled larger distances compared to larger specimens. Cold temperatures during winter tended, however, to reduce the magnitude of diel vertical migrations, as well as the activity level and distance moved by those smaller individuals. Our findings suggest that future and ongoing rises in sea surface temperature may increasingly deprive cod in this region from shallow feeding areas during summer, which may be detrimental for local populations of the species.

  6. Transcriptome analysis of gill tissue of Atlantic cod Gadus morhua L. from the Baltic Sea.

    PubMed

    Małachowicz, Magdalena; Kijewska, Agnieszka; Wenne, Roman

    2015-10-01

    The Atlantic cod (Gadus morhua L.) is one of the most ecologically and economically important marine fish species in the North Atlantic Ocean. Using Roche GS-FLX 454 pyrosequencing technique 962,516 reads, representing 379Mbp of the Baltic cod transcriptome, were obtained. Data was assembled into 14,029 contigs of which 100% displayed homology to the Atlantic cod transcriptome. Despite a high similarity between transcripts, evidence for significant differences between Baltic and Atlantic cod was found.

  7. Yersiniosis in Atlantic cod, Gadus morhua (L.), characterization of the infective strain and host reactions.

    PubMed

    Gudmundsdottir, B K; Gudmundsdottir, S; Gudmundsdottir, S; Magnadottir, B

    2014-06-01

    A disease outbreak in farmed Atlantic cod caused by Yersinia ruckeri is reported. Mortality started following vaccination of cod reared in two tanks (A and B). The accumulated mortality reached 1.9% in A and 4.8% in B in the following 30 days when treatment with oxytetracycline was applied. Biochemical and molecular analysis of Y. ruckeri isolates from the cod and other fish species from fresh and marine waters in Iceland revealed a high salinity-tolerant subgroup of Y. ruckeri serotype O1. Infected fish showed clinical signs comparable with those of Y. ruckeri -infected salmonids, with the exception of granuloma formations in infected cod tissues, which is a known response of cod to bacterial infections. Immunohistological examination showed Y. ruckeri antigens in the core of granulomas and the involvement of immune parameters that indicates a strong association between complement and lysozyme killing of bacteria. Experimental infection of cod with a cod isolate induced disease, and the calculated LD50 was 1.7 × 10(4) CFU per fish. The results suggest that yersiniosis can be spread between populations of freshwater and marine fish. Treatment of infected cod with antibiotic did not eliminate the infection, which can be explained by the immune response of cod producing prolonged granulomatous infection.

  8. Adaptation to Low Salinity Promotes Genomic Divergence in Atlantic Cod (Gadus morhua L.).

    PubMed

    Berg, Paul R; Jentoft, Sissel; Star, Bastiaan; Ring, Kristoffer H; Knutsen, Halvor; Lien, Sigbjørn; Jakobsen, Kjetill S; André, Carl

    2015-05-20

    How genomic selection enables species to adapt to divergent environments is a fundamental question in ecology and evolution. We investigated the genomic signatures of local adaptation in Atlantic cod (Gadus morhua L.) along a natural salinity gradient, ranging from 35‰ in the North Sea to 7‰ within the Baltic Sea. By utilizing a 12 K SNPchip, we simultaneously assessed neutral and adaptive genetic divergence across the Atlantic cod genome. Combining outlier analyses with a landscape genomic approach, we identified a set of directionally selected loci that are strongly correlated with habitat differences in salinity, oxygen, and temperature. Our results show that discrete regions within the Atlantic cod genome are subject to directional selection and associated with adaptation to the local environmental conditions in the Baltic- and the North Sea, indicating divergence hitchhiking and the presence of genomic islands of divergence. We report a suite of outlier single nucleotide polymorphisms within or closely located to genes associated with osmoregulation, as well as genes known to play important roles in the hydration and development of oocytes. These genes are likely to have key functions within a general osmoregulatory framework and are important for the survival of eggs and larvae, contributing to the buildup of reproductive isolation between the low-salinity adapted Baltic cod and the adjacent cod populations. Hence, our data suggest that adaptive responses to the environmental conditions in the Baltic Sea may contribute to a strong and effective reproductive barrier, and that Baltic cod can be viewed as an example of ongoing speciation.

  9. Potential Use of Atlantic Cod Trypsin in Biomedicine

    PubMed Central

    Gudmundsdóttir, Ágústa; Hilmarsson, Hilmar; Stefansson, Bjarki

    2013-01-01

    Surface proteins of viruses and bacteria used for cell attachment and invasion are candidates for degradation by proteases. Trypsin from Atlantic cod (Gadus morhua) was previously demonstrated to have efficacy against influenza viruses in vitro and on skin. In this paper, cod trypsin is shown to be 3–12 times more effective in degrading large native proteins than its mesophilic analogue, bovine trypsin. This is in agreement with previous findings where cod trypsin was found to be the most active among twelve different proteases in cleaving various cytokines and pathological proteins. Furthermore, our results show that cod trypsin has high efficacy against herpes simplex virus type 1 (HSV-1) and the respiratory syncytial virus (RSV) in vitro. The results on the antipathogenic properties of cod trypsin are important because rhinovirus, RSV, and influenza are the most predominant pathogenic viruses in upper respiratory tract infections. Results from a clinical study presented in this paper show that a specific formulation containing cod trypsin was preferred for wound healing over other methods used in the study. Apparently, the high digestive ability of the cold-adapted cod trypsin towards large native proteins plays a role in its efficacy against pathogens and its positive effects on wounds. PMID:23555095

  10. Three chromosomal rearrangements promote genomic divergence between migratory and stationary ecotypes of Atlantic cod

    PubMed Central

    Berg, Paul R.; Star, Bastiaan; Pampoulie, Christophe; Sodeland, Marte; Barth, Julia M. I.; Knutsen, Halvor; Jakobsen, Kjetill S.; Jentoft, Sissel

    2016-01-01

    Identification of genome-wide patterns of divergence provides insight on how genomes are influenced by selection and can reveal the potential for local adaptation in spatially structured populations. In Atlantic cod – historically a major marine resource – Northeast-Arctic- and Norwegian coastal cod are recognized by fundamental differences in migratory and non-migratory behavior, respectively. However, the genomic architecture underlying such behavioral ecotypes is unclear. Here, we have analyzed more than 8.000 polymorphic SNPs distributed throughout all 23 linkage groups and show that loci putatively under selection are localized within three distinct genomic regions, each of several megabases long, covering approximately 4% of the Atlantic cod genome. These regions likely represent genomic inversions. The frequency of these distinct regions differ markedly between the ecotypes, spawning in the vicinity of each other, which contrasts with the low level of divergence in the rest of the genome. The observed patterns strongly suggest that these chromosomal rearrangements are instrumental in local adaptation and separation of Atlantic cod populations, leaving footprints of large genomic regions under selection. Our findings demonstrate the power of using genomic information in further understanding the population dynamics and defining management units in one of the world’s most economically important marine resources. PMID:26983361

  11. Three chromosomal rearrangements promote genomic divergence between migratory and stationary ecotypes of Atlantic cod.

    PubMed

    Berg, Paul R; Star, Bastiaan; Pampoulie, Christophe; Sodeland, Marte; Barth, Julia M I; Knutsen, Halvor; Jakobsen, Kjetill S; Jentoft, Sissel

    2016-03-17

    Identification of genome-wide patterns of divergence provides insight on how genomes are influenced by selection and can reveal the potential for local adaptation in spatially structured populations. In Atlantic cod - historically a major marine resource - Northeast-Arctic- and Norwegian coastal cod are recognized by fundamental differences in migratory and non-migratory behavior, respectively. However, the genomic architecture underlying such behavioral ecotypes is unclear. Here, we have analyzed more than 8.000 polymorphic SNPs distributed throughout all 23 linkage groups and show that loci putatively under selection are localized within three distinct genomic regions, each of several megabases long, covering approximately 4% of the Atlantic cod genome. These regions likely represent genomic inversions. The frequency of these distinct regions differ markedly between the ecotypes, spawning in the vicinity of each other, which contrasts with the low level of divergence in the rest of the genome. The observed patterns strongly suggest that these chromosomal rearrangements are instrumental in local adaptation and separation of Atlantic cod populations, leaving footprints of large genomic regions under selection. Our findings demonstrate the power of using genomic information in further understanding the population dynamics and defining management units in one of the world's most economically important marine resources.

  12. Genomic characterization of the Atlantic cod sex-locus

    PubMed Central

    Star, Bastiaan; Tørresen, Ole K.; Nederbragt, Alexander J.; Jakobsen, Kjetill S.; Pampoulie, Christophe; Jentoft, Sissel

    2016-01-01

    A variety of sex determination mechanisms can be observed in evolutionary divergent teleosts. Sex determination is genetic in Atlantic cod (Gadus morhua), however the genomic location or size of its sex-locus is unknown. Here, we characterize the sex-locus of Atlantic cod using whole genome sequence (WGS) data of 227 wild-caught specimens. Analyzing more than 55 million polymorphic loci, we identify 166 loci that are associated with sex. These loci are located in six distinct regions on five different linkage groups (LG) in the genome. The largest of these regions, an approximately 55 Kb region on LG11, contains the majority of genotypes that segregate closely according to a XX-XY system. Genotypes in this region can be used genetically determine sex, whereas those in the other regions are inconsistently sex-linked. The identified region on LG11 and its surrounding genes have no clear sequence homology with genes or regulatory elements associated with sex-determination or differentiation in other species. The functionality of this sex-locus therefore remains unknown. The WGS strategy used here proved adequate for detecting the small regions associated with sex in this species. Our results highlight the evolutionary flexibility in genomic architecture underlying teleost sex-determination and allow practical applications to genetically sex Atlantic cod. PMID:27499266

  13. Chapter 3. Effects of climate change and commercial fishing on Atlantic cod Gadus morhua.

    PubMed

    Mieszkowska, Nova; Genner, Martin J; Hawkins, Stephen J; Sims, David W

    2009-01-01

    During the course of the last century, populations of Atlantic cod Gadus morhua L. have undergone dramatic declines in abundance across their biogeographic range, leading to debate about the relative roles of climatic warming and overfishing in driving these changes. In this chapter, we describe the geographic distributions of this important predator of North Atlantic ecosystems and document extensive evidence for limitations of spatial movement and local adaptation from population genetic markers and electronic tagging. Taken together, this evidence demonstrates that knowledge of spatial population ecology is critical for evaluating the effects of climate change and commercial harvesting. To explore the possible effects of climate change on cod, we first describe thermal influences on individual physiology, growth, activity and maturation. We then evaluate evidence that temperature has influenced population-level processes including direct effects on recruitment through enhanced growth and activity, and indirect effects through changes to larval food resources. Although thermal regimes clearly define the biogeographic range of the species, and strongly influence many aspects of cod biology, the evidence that population declines across the North Atlantic are strongly linked to fishing activity is now overwhelming. Although there is considerable concern about low spawning stock biomasses, high levels of fishing activity continues in many areas. Even with reduced fishing effort, the potential for recovery from low abundance may be compromised by unfavourable climate and Allee effects. Current stock assessment and management approaches are reviewed, alongside newly advocated methods for monitoring stock status and recovery. However, it remains uncertain whether the rebuilding of cod to historic population sizes and demographic structures will be possible in a warmer North Atlantic.

  14. Iodine nutrition and toxicity in Atlantic cod (Gadus morhua) larvae.

    PubMed

    Penglase, S; Harboe, T; Sæle, O; Helland, S; Nordgreen, A; Hamre, K

    2013-01-01

    Copepods as feed promote better growth and development in marine fish larvae than rotifers. However, unlike rotifers, copepods contain several minerals such as iodine (I), at potentially toxic levels. Iodine is an essential trace element and both under and over supply of I can inhibit the production of the I containing thyroid hormones. It is unknown whether marine fish larvae require copepod levels of I or if mechanisms are present that prevent I toxicity. In this study, larval Atlantic cod (Gadus morhua) were fed rotifers enriched to intermediate (26 mg I kg(-1) dry weight; MI group) or copepod (129 mg I kg(-1) DW; HI group) I levels and compared to cod larvae fed control rotifers (0.6 mg I kg(-1) DW). Larval I concentrations were increased by 3 (MI) and 7 (HI) fold compared to controls during the rotifer feeding period. No differences in growth were observed, but the HI diet increased thyroid follicle colloid to epithelium ratios, and affected the essential element concentrations of larvae compared to the other groups. The thyroid follicle morphology in the HI larvae is typical of colloid goitre, a condition resulting from excessive I intake, even though whole body I levels were below those found previously in copepod fed cod larvae. This is the first observation of dietary induced I toxicity in fish, and suggests I toxicity may be determined to a greater extent by bioavailability and nutrient interactions than by total body I concentrations in fish larvae. Rotifers with 0.6 mg I kg(-1) DW appeared sufficient to prevent gross signs of I deficiency in cod larvae reared with continuous water exchange, while modelling of cod larvae versus rotifer I levels suggests that optimum I levels in rotifers for cod larvae is 3.5 mg I kg(-1) DW.

  15. Iodine nutrition and toxicity in Atlantic cod (Gadus morhua) larvae

    PubMed Central

    Penglase, S; Harboe, T; Sæle, Ø; Helland, S; Nordgreen, A

    2013-01-01

    Copepods as feed promote better growth and development in marine fish larvae than rotifers. However, unlike rotifers, copepods contain several minerals such as iodine (I), at potentially toxic levels. Iodine is an essential trace element and both under and over supply of I can inhibit the production of the I containing thyroid hormones. It is unknown whether marine fish larvae require copepod levels of I or if mechanisms are present that prevent I toxicity. In this study, larval Atlantic cod (Gadus morhua) were fed rotifers enriched to intermediate (26 mg I kg-1 dry weight; MI group) or copepod (129 mg I kg-1 DW; HI group) I levels and compared to cod larvae fed control rotifers (0.6 mg I kg-1 DW). Larval I concentrations were increased by 3 (MI) and 7 (HI) fold compared to controls during the rotifer feeding period. No differences in growth were observed, but the HI diet increased thyroid follicle colloid to epithelium ratios, and affected the essential element concentrations of larvae compared to the other groups. The thyroid follicle morphology in the HI larvae is typical of colloid goitre, a condition resulting from excessive I intake, even though whole body I levels were below those found previously in copepod fed cod larvae. This is the first observation of dietary induced I toxicity in fish, and suggests I toxicity may be determined to a greater extent by bioavailability and nutrient interactions than by total body I concentrations in fish larvae. Rotifers with 0.6 mg I kg-1 DW appeared sufficient to prevent gross signs of I deficiency in cod larvae reared with continuous water exchange, while modelling of cod larvae versus rotifer I levels suggests that optimum I levels in rotifers for cod larvae is 3.5 mg I kg-1 DW. PMID:23638355

  16. Adaptation to Low Salinity Promotes Genomic Divergence in Atlantic Cod (Gadus morhua L.)

    PubMed Central

    Berg, Paul R.; Jentoft, Sissel; Star, Bastiaan; Ring, Kristoffer H.; Knutsen, Halvor; Lien, Sigbjørn; Jakobsen, Kjetill S.; André, Carl

    2015-01-01

    How genomic selection enables species to adapt to divergent environments is a fundamental question in ecology and evolution. We investigated the genomic signatures of local adaptation in Atlantic cod (Gadus morhua L.) along a natural salinity gradient, ranging from 35‰ in the North Sea to 7‰ within the Baltic Sea. By utilizing a 12 K SNPchip, we simultaneously assessed neutral and adaptive genetic divergence across the Atlantic cod genome. Combining outlier analyses with a landscape genomic approach, we identified a set of directionally selected loci that are strongly correlated with habitat differences in salinity, oxygen, and temperature. Our results show that discrete regions within the Atlantic cod genome are subject to directional selection and associated with adaptation to the local environmental conditions in the Baltic- and the North Sea, indicating divergence hitchhiking and the presence of genomic islands of divergence. We report a suite of outlier single nucleotide polymorphisms within or closely located to genes associated with osmoregulation, as well as genes known to play important roles in the hydration and development of oocytes. These genes are likely to have key functions within a general osmoregulatory framework and are important for the survival of eggs and larvae, contributing to the buildup of reproductive isolation between the low-salinity adapted Baltic cod and the adjacent cod populations. Hence, our data suggest that adaptive responses to the environmental conditions in the Baltic Sea may contribute to a strong and effective reproductive barrier, and that Baltic cod can be viewed as an example of ongoing speciation. PMID:25994933

  17. Rhodopsin gene polymorphism associated with divergent light environments in Atlantic cod.

    PubMed

    Pampoulie, Christophe; Skirnisdottir, Sigurlaug; Star, Bastiaan; Jentoft, Sissel; Jónsdóttir, Ingibjörg G; Hjörleifsson, Einar; Thorsteinsson, Vilhjálmur; Pálsson, Ólafur K; Berg, Paul R; Andersen, Øivind; Magnusdottir, Steinunn; Helyar, Sarah J; Daníelsdóttir, Anna K

    2015-03-01

    The spectral sensitivity of visual pigments in vertebrate eyes is optimized for specific light conditions. One of such pigments, rhodopsin (RH1), mediates dim-light vision. Amino acid replacements at tuning sites may alter spectral sensitivity, providing a mechanism to adapt to ambient light conditions and depth of habitat in fish. Here we present a first investigation of RH1 gene polymorphism among two ecotypes of Atlantic cod in Icelandic waters, which experience divergent light environments throughout the year due to alternative foraging behaviour. We identified one synonymous single nucleotide polymorphism (SNP) in the RH1 protein coding region and one in the 3' untranslated region (3'-UTR) that are strongly divergent between these two ecotypes. Moreover, these polymorphisms coincided with the well-known panthophysin (Pan I) polymorphism that differentiates coastal and frontal (migratory) populations of Atlantic cod. While the RH1 SNPs do not provide direct inference for a specific molecular mechanism, their association with this dim-sensitive pigment indicates the involvement of the visual system in local adaptation of Atlantic cod.

  18. Trans-species polymorphism at antimicrobial innate immunity cathelicidin genes of Atlantic cod and related species.

    PubMed

    Halldórsdóttir, Katrín; Árnason, Einar

    2015-01-01

    Natural selection, the most important force in evolution, comes in three forms. Negative purifying selection removes deleterious variation and maintains adaptations. Positive directional selection fixes beneficial variants, producing new adaptations. Balancing selection maintains variation in a population. Important mechanisms of balancing selection include heterozygote advantage, frequency-dependent advantage of rarity, and local and fluctuating episodic selection. A rare pathogen gains an advantage because host defenses are predominantly effective against prevalent types. Similarly, a rare immune variant gives its host an advantage because the prevalent pathogens cannot escape the host's apostatic defense. Due to the stochastic nature of evolution, neutral variation may accumulate on genealogical branches, but trans-species polymorphisms are rare under neutrality and are strong evidence for balancing selection. Balanced polymorphism maintains diversity at the major histocompatibility complex (MHC) in vertebrates. The Atlantic cod is missing genes for both MHC-II and CD4, vital parts of the adaptive immune system. Nevertheless, cod are healthy in their ecological niche, maintaining large populations that support major commercial fisheries. Innate immunity is of interest from an evolutionary perspective, particularly in taxa lacking adaptive immunity. Here, we analyze extensive amino acid and nucleotide polymorphisms of the cathelicidin gene family in Atlantic cod and closely related taxa. There are three major clusters, Cath1, Cath2, and Cath3, that we consider to be paralogous genes. There is extensive nucleotide and amino acid allelic variation between and within clusters. The major feature of the results is that the variation clusters by alleles and not by species in phylogenetic trees and discriminant analysis of principal components. Variation within the three groups shows trans-species polymorphism that is older than speciation and that is suggestive of

  19. Constant proportion harvest policies: dynamic implications in the Pacific halibut and Atlantic cod fisheries.

    PubMed

    Yakubu, Abdul-Aziz; Li, Nianpeng; Conrad, Jon M; Zeeman, Mary-Lou

    2011-07-01

    Overfishing, pollution and other environmental factors have greatly reduced commercially valuable stocks of fish. In a 2006 Science article, a group of ecologists and economists warned that the world may run out of seafood from natural stocks if overfishing continues at current rates. In this paper, we explore the interaction between a constant proportion harvest policy and recruitment dynamics. We examine the discrete-time constant proportion harvest policy discussed in Ang et al. (2009) and then expand the framework to include stock-recruitment functions that are compensatory and overcompensatory, both with and without the Allee effect. We focus on constant proportion policies (CPPs). CPPs have the potential to stabilize complex overcompensatory stock dynamics, with or without the Allee effect, provided the rates of harvest stay below a threshold. If that threshold is exceeded, CPPs are known to result in the sudden collapse of a fish stock when stock recruitment exhibits the Allee effect. In case studies, we analyze CPPs as they might be applied to Gulf of Alaska Pacific halibut fishery and the Georges Bank Atlantic cod fishery based on harvest rates from 1975 to 2007. The best fit models suggest that, under high fishing mortalities, the halibut fishery is vulnerable to sudden population collapse while the cod fishery is vulnerable to steady decline to zero. The models also suggest that CPP with mean harvesting levels from the last 30 years can be effective at preventing collapse in the halibut fishery, but these same policies would lead to steady decline to zero in the Atlantic cod fishery. We observe that the likelihood of collapse in both fisheries increases with increased stochasticity (for example, weather variability) as predicted by models of global climate change.

  20. The genome sequence of Atlantic cod reveals a unique immune system.

    PubMed

    Star, Bastiaan; Nederbragt, Alexander J; Jentoft, Sissel; Grimholt, Unni; Malmstrøm, Martin; Gregers, Tone F; Rounge, Trine B; Paulsen, Jonas; Solbakken, Monica H; Sharma, Animesh; Wetten, Ola F; Lanzén, Anders; Winer, Roger; Knight, James; Vogel, Jan-Hinnerk; Aken, Bronwen; Andersen, Oivind; Lagesen, Karin; Tooming-Klunderud, Ave; Edvardsen, Rolf B; Tina, Kirubakaran G; Espelund, Mari; Nepal, Chirag; Previti, Christopher; Karlsen, Bård Ove; Moum, Truls; Skage, Morten; Berg, Paul R; Gjøen, Tor; Kuhl, Heiner; Thorsen, Jim; Malde, Ketil; Reinhardt, Richard; Du, Lei; Johansen, Steinar D; Searle, Steve; Lien, Sigbjørn; Nilsen, Frank; Jonassen, Inge; Omholt, Stig W; Stenseth, Nils Chr; Jakobsen, Kjetill S

    2011-08-10

    Atlantic cod (Gadus morhua) is a large, cold-adapted teleost that sustains long-standing commercial fisheries and incipient aquaculture. Here we present the genome sequence of Atlantic cod, showing evidence for complex thermal adaptations in its haemoglobin gene cluster and an unusual immune architecture compared to other sequenced vertebrates. The genome assembly was obtained exclusively by 454 sequencing of shotgun and paired-end libraries, and automated annotation identified 22,154 genes. The major histocompatibility complex (MHC) II is a conserved feature of the adaptive immune system of jawed vertebrates, but we show that Atlantic cod has lost the genes for MHC II, CD4 and invariant chain (Ii) that are essential for the function of this pathway. Nevertheless, Atlantic cod is not exceptionally susceptible to disease under natural conditions. We find a highly expanded number of MHC I genes and a unique composition of its Toll-like receptor (TLR) families. This indicates how the Atlantic cod immune system has evolved compensatory mechanisms in both adaptive and innate immunity in the absence of MHC II. These observations affect fundamental assumptions about the evolution of the adaptive immune system and its components in vertebrates.

  1. Historical DNA reveals the demographic history of Atlantic cod (Gadus morhua) in medieval and early modern Iceland.

    PubMed

    Ólafsdóttir, Guðbjörg Ásta; Westfall, Kristen M; Edvardsson, Ragnar; Pálsson, Snæbjörn

    2014-02-22

    Atlantic cod (Gadus morhua) vertebrae from archaeological sites were used to study the history of the Icelandic Atlantic cod population in the time period of 1500-1990. Specifically, we used coalescence modelling to estimate population size and fluctuations from the sequence diversity at the cytochrome b (cytb) and Pantophysin I (PanI) loci. The models are consistent with an expanding population during the warm medieval period, large historical effective population size (NE), a marked bottleneck event at 1400-1500 and a decrease in NE in early modern times. The model results are corroborated by the reduction of haplotype and nucleotide variation over time and pairwise population distance as a significant portion of nucleotide variation partitioned across the 1550 time mark. The mean age of the historical fished stock is high in medieval times with a truncation in age in early modern times. The population size crash coincides with a period of known cooling in the North Atlantic, and we conclude that the collapse may be related to climate or climate-induced ecosystem change.

  2. Climate warming causes life-history evolution in a model for Atlantic cod (Gadus morhua)

    PubMed Central

    Holt, Rebecca E.; Jørgensen, Christian

    2014-01-01

    Climate change influences the marine environment, with ocean warming being the foremost driving factor governing changes in the physiology and ecology of fish. At the individual level, increasing temperature influences bioenergetics and numerous physiological and life-history processes, which have consequences for the population level and beyond. We provide a state-dependent energy allocation model that predicts temperature-induced adaptations for life histories and behaviour for the North-East Arctic stock (NEA) of Atlantic cod (Gadus morhua) in response to climate warming. The key constraint is temperature-dependent respiratory physiology, and the model includes a number of trade-offs that reflect key physiological and ecological processes. Dynamic programming is used to find an evolutionarily optimal strategy of foraging and energy allocation that maximizes expected lifetime reproductive output given constraints from physiology and ecology. The optimal strategy is then simulated in a population, where survival, foraging behaviour, growth, maturation and reproduction emerge. Using current forcing, the model reproduces patterns of growth, size-at-age, maturation, gonad production and natural mortality for NEA cod. The predicted climate responses are positive for this stock; under a 2°C warming, the model predicted increased growth rates and a larger asymptotic size. Maturation age was unaffected, but gonad weight was predicted to more than double. Predictions for a wider range of temperatures, from 2 to 7°C, show that temperature responses were gradual; fish were predicted to grow faster and increase reproductive investment at higher temperatures. An emergent pattern of higher risk acceptance and increased foraging behaviour was also predicted. Our results provide important insight into the effects of climate warming on NEA cod by revealing the underlying mechanisms and drivers of change. We show how temperature-induced adaptations of behaviour and several life

  3. Elucidation of different cold-adapted Atlantic cod (Gadus morhua) trypsin X isoenzymes.

    PubMed

    Stefansson, Bjarki; Sandholt, Gunnar B; Gudmundsdottir, Ágústa

    2017-01-01

    Trypsins from Atlantic cod (Gadus morhua), consisting of several isoenzymes, are highly active cold-adapted serine proteases. These trypsins are isolated for biomedical use in an eco-friendly manner from underutilized seafood by-products. Our group has explored the biochemical properties of trypsins and their high potential in biomedicine. For broader utilization of cod trypsins, further characterization of biochemical properties of the individual cod trypsin isoenzymes is of importance. For that purpose, a benzamidine purified trypsin isolate from Atlantic cod was analyzed. Anion exchange chromatography revealed eight peaks containing proteins around 24kDa with tryptic activity. Based on mass spectrometric analysis, one isoenzyme gave the best match to cod trypsin I and six isoenzymes gave the best match to cod trypsin X. Amino terminal sequencing of two of these six trypsin isoenzymes showed identity to cod trypsin X. Three sequence variants of trypsin X were identified by cDNA analysis demonstrating that various forms of this enzyme exist. One trypsin X isoenzyme was selected for further characterization based on abundance and stability. Stepwise increase in catalytic efficiency (kcat/Km) of this trypsin X isoenzyme was obtained with substrates containing one to three amino acid residues. The study demonstrates that the catalytic efficiency of this trypsin X isoenzyme is comparable to that of cod trypsin I, the most abundant and highly active isoenzyme in the benzamidine cod trypsin isolate. Differences in pH stability and sensitivity to inhibitors of the trypsin X isoenzyme compared to cod trypsin I were detected that may be important for practical use.

  4. Harvest selection on Atlantic cod behavioral traits: implications for spatial management

    PubMed Central

    Olsen, Esben Moland; Heupel, Michelle R; Simpfendorfer, Colin A; Moland, Even

    2012-01-01

    Harvesting wild populations may contrast or reinforce natural agents of selection and potentially cause evolutionary changes in life-history traits such as growth and maturation. Harvest selection may also act on behavioral traits, although this field of research has so far received less attention. We used acoustic tags and a network of receivers to monitor the behavior and fate of individual Atlantic cod (Gadus morhua, N = 60) in their natural habitat on the Norwegian Skagerrak coast. Fish with a strong diel vertical migration, alternating between shallow- and deep-water habitats, had a higher risk of being captured in the fishery (traps, gillnet, hand line) as compared to fish that stayed in deeper water. There was also a significant negative correlation between fish size (30–66 cm) and the magnitude of diel vertical migration. Natural selection on behavior was less clear, but tended to favor fish with a large activity space. On a monthly time scale we found significant repeatabilities for cod behavior, meaning that individual characteristics tended to persist and therefore may be termed personality traits. We argue that an evolutionary approach to fisheries management should consider fish behavior. This would be of particular relevance for spatial management actions such as marine reserve design. PMID:22957161

  5. Expression of vasa and nanos3 during primordial germ cell formation and migration in Atlantic cod (Gadus morhua L.).

    PubMed

    Presslauer, C; Nagasawa, K; Fernandes, J M O; Babiak, I

    2012-10-01

    Primordial germ cells (PGCs), progenitors of gametes, are specified very early in embryonic development and undergo an active migration to the site where the future gonads will form. While the developmental pattern of PGCs during embryogenesis has been documented in few model teleost fishes, there is currently no information available for any representative of Superorder Paracanthopterygii. This includes Atlantic cod (Gadus morhua), which is a historically important food fish in both fisheries and aquaculture industries. In the present study, we cloned and characterized vasa and nanos3 and used them as germ cell markers in Atlantic cod. Sequencing results showed prospective vasa and nanos3 mRNA contained the domains used to describe their respective protein family. Furthermore, phylogenetic analysis using the amino acid sequence placed Atlantic cod Vasa distinct from representatives of three other taxonomic Superorders. Atlantic cod Nanos3 was placed with other homologues from the Nanos3 subfamily. Expression of both genes was detected from the first cleavage division; both were specifically expressed in Atlantic cod PGCs from the 32-cell stage. While nanos3 expression ceased during early somitogenesis, vasa was strongly expressed throughout embryonic development. Using vasa as a marker, we described the Atlantic cod PGC migration pattern. We demonstrated that Atlantic cod PGCs migrate ventral to the trunk mesoderm. With the exception of Pacific herring (Clupea pallasii), PGCs in other described teleost fishes migrate lateral to the trunk. The results from this study are the first step toward understanding germ line formation in Atlantic cod.

  6. Flow cytometry assays of respiratory burst in Atlantic salmon (Salmo salar L.) and in Atlantic cod (Gadus morhua L.) leucocytes.

    PubMed

    Kalgraff, Cathrine A K; Wergeland, Heidrun I; Pettersen, Eirin Fausa

    2011-09-01

    The oxidation of dihydrorhodamine 123 (DHR) to the fluorescent rhodamine 123 (RHO) was detected using flow cytometry. This assay for detection of respiratory burst activity was established in peripheral blood leucocytes (PBL) and head kidney leucocytes (HKL) of Atlantic salmon and Atlantic cod. The leucocytes were stimulated by phorbol 12-myristate 13-acetate (PMA). For cod cells 10 times lower concentration of PMA had to be used compared to salmon cells, as higher concentrations were toxic and resulted in considerable cell death. The cells found to be RHO-positive were monocytes/macrophages and neutrophils based on the scatter dot plots, but for salmon also some small cells were found to have high fluorescence intensity both in the flow cytometry analyses and by fluorescence microscopy of cytospin preparations. The nature of these cells is not known. For cod leucocytes, such cells were not obvious. The instrument settings are a bit more demanding for cod, as cod cells die more easily compared to salmon cells. In both assays the limit between negative and positive cells has to be carefully considered. The presented flow cytometry protocols for measurements of respiratory burst in salmon and cod leucocytes can be applied in various studies where respiratory burst functions are involved, such as to verify if it is activated or suppressed in connection with infections and immunostimulation.

  7. Trans-species polymorphism at antimicrobial innate immunity cathelicidin genes of Atlantic cod and related species

    PubMed Central

    Árnason, Einar

    2015-01-01

    Natural selection, the most important force in evolution, comes in three forms. Negative purifying selection removes deleterious variation and maintains adaptations. Positive directional selection fixes beneficial variants, producing new adaptations. Balancing selection maintains variation in a population. Important mechanisms of balancing selection include heterozygote advantage, frequency-dependent advantage of rarity, and local and fluctuating episodic selection. A rare pathogen gains an advantage because host defenses are predominantly effective against prevalent types. Similarly, a rare immune variant gives its host an advantage because the prevalent pathogens cannot escape the host’s apostatic defense. Due to the stochastic nature of evolution, neutral variation may accumulate on genealogical branches, but trans-species polymorphisms are rare under neutrality and are strong evidence for balancing selection. Balanced polymorphism maintains diversity at the major histocompatibility complex (MHC) in vertebrates. The Atlantic cod is missing genes for both MHC-II and CD4, vital parts of the adaptive immune system. Nevertheless, cod are healthy in their ecological niche, maintaining large populations that support major commercial fisheries. Innate immunity is of interest from an evolutionary perspective, particularly in taxa lacking adaptive immunity. Here, we analyze extensive amino acid and nucleotide polymorphisms of the cathelicidin gene family in Atlantic cod and closely related taxa. There are three major clusters, Cath1, Cath2, and Cath3, that we consider to be paralogous genes. There is extensive nucleotide and amino acid allelic variation between and within clusters. The major feature of the results is that the variation clusters by alleles and not by species in phylogenetic trees and discriminant analysis of principal components. Variation within the three groups shows trans-species polymorphism that is older than speciation and that is suggestive of

  8. Effects of perimortem stress on farmed Atlantic cod product quality: a baseline study.

    PubMed

    Erikson, Ulf; Digre, Hanne; Misimi, Ekrem

    2011-05-01

    The potential effects of handling stress on the product quality of farmed Atlantic cod were studied in a controlled experiment (fish anesthetized with metomidate or isoeugenol, or subjected to stress by chasing for 30 min). For comparison, stress and fillet quality was also studied for commercially slaughtered farmed cod (fish sampled from waiting cage, after pumping and stunning with carbon dioxide, and after bleeding and chilling). Baseline values for stress-related parameters (blood chemistry, muscle high-energy phosphates and inosine monophospate, initial pH, muscle twitches, and rigor mortis) of rested Atlantic cod have been established. Since our stress bout showed that this species was not easily excitable, we were less convinced that we actually did study the other extreme, namely, exhausted fish. Nevertheless, the present data from the commercial slaughter of cod suggested that our stress bout was of adequate magnitude to represent potential poor handling routines. Our results consistently showed largely no differences between treatments, and that perimortem handling stress did not cause inferior flesh quality. This suggested that farmed cod can be processed with little risk of reducing product quality (quality index, fillet water content, water-holding capacity, ultimate pH, adenosine triphosphate-related degradation products and K-value, skin and fillet color, water and salt-soluble proteins, hardness, and gaping). For better maintenance of skin appearance after storage, the importance of storing the gutted cod on the belly, avoiding direct contact between skin and crushed ice, is demonstrated.

  9. “Islands of Divergence” in the Atlantic Cod Genome Represent Polymorphic Chromosomal Rearrangements

    PubMed Central

    Sodeland, Marte; Jorde, Per Erik; Lien, Sigbjørn; Jentoft, Sissel; Berg, Paul R.; Grove, Harald; Kent, Matthew P.; Arnyasi, Mariann; Olsen, Esben Moland; Knutsen, Halvor

    2016-01-01

    In several species genetic differentiation across environmental gradients or between geographically separate populations has been reported to center at “genomic islands of divergence,” resulting in heterogeneous differentiation patterns across genomes. Here, genomic regions of elevated divergence were observed on three chromosomes of the highly mobile fish Atlantic cod (Gadus morhua) within geographically fine-scaled coastal areas. The “genomic islands” extended at least 5, 9.5, and 13 megabases on linkage groups 2, 7, and 12, respectively, and coincided with large blocks of linkage disequilibrium. For each of these three chromosomes, pairs of segregating, highly divergent alleles were identified, with little or no gene exchange between them. These patterns of recombination and divergence mirror genomic signatures previously described for large polymorphic inversions, which have been shown to repress recombination across extensive chromosomal segments. The lack of genetic exchange permits divergence between noninverted and inverted chromosomes in spite of gene flow. For the rearrangements on linkage groups 2 and 12, allelic frequency shifts between coastal and oceanic environments suggest a role in ecological adaptation, in agreement with recently reported associations between molecular variation within these genomic regions and temperature, oxygen, and salinity levels. Elevated genetic differentiation in these genomic regions has previously been described on both sides of the Atlantic Ocean, and we therefore suggest that these polymorphisms are involved in adaptive divergence across the species distributional range. PMID:26983822

  10. Genomic Sequencing of Ranaviruses Isolated from Turbot (Scophthalmus maximus) and Atlantic Cod (Gadus morhua)

    PubMed Central

    Steckler, Natalie K.; Olesen, Niels J.; Waltzek, Thomas B.

    2016-01-01

    Ranaviruses have been isolated from Atlantic cod (Gadus morhua) and turbot (Scophthalmus maximus) in Denmark. Phylogenomic analyses revealed that these two ranaviruses are nearly identical and form a distinct clade at the base of the ranavirus tree branching off near other fish ranaviruses. PMID:27979944

  11. Why does the immune system of Atlantic cod lack MHC II?

    PubMed

    Star, Bastiaan; Jentoft, Sissel

    2012-08-01

    MHC II, a major feature of the adaptive immune system, is lacking in Atlantic cod, and there are different scenarios (metabolic cost hypothesis or functional shift hypothesis) that might explain this loss. The lack of MHC II coincides with an increased number of genes for MHC I and Toll-like receptors (TLRs).

  12. Genomic analysis of the host response to nervous necrosis virus in Atlantic cod (Gadus morhua) brain.

    PubMed

    Krasnov, Aleksei; Kileng, Øyvind; Skugor, Stanko; Jørgensen, Sven Martin; Afanasyev, Sergey; Timmerhaus, Gerrit; Sommer, Ann-Inger; Jensen, Ingvill

    2013-07-01

    Genome sequencing combined with transcriptome profiling promotes exploration of defence against pathogens and discovery of immune genes. Based on sequences from the recently released genome of Atlantic cod, a genome-wide oligonucleotide microarray (ACIQ-1) was designed and used for analyses of gene expression in the brain during infection with nervous necrosis virus (NNV). A challenge experiment with NNV was performed with Atlantic cod juveniles and brain samples from virus infected and uninfected fish were used for microarray analysis. Expression of virus induced genes increased at 5 days post challenge and persisted at stable level to the last sampling at 25 days post challenge. A large fraction of the up-regulated genes (546 features) were known or expected to have immune functions and most of these have not previously been characterized in Atlantic cod. Transcriptomic changes induced by the virus involved strong activation of genes associated with interferon and tumour necrosis factor related responses and acute inflammation. Up-regulation of genes involved in adaptive immunity suggested a rapid recruitment of B and T lymphocytes to the NNV infected brain. QPCR analyses of 15 candidate genes of innate immunity showed rapid induction by poly(I:C) in Atlantic cod larvae cells suggesting an antiviral role. Earliest and greatest expression changes after poly I:C stimulation was observed for interferon regulatory factors IRF4 and IRF7. Comparative studies between teleost species provided new knowledge about the evolution of innate antiviral immunity in fish. A number of genes is present or responds to viruses only in fish. Innate immunity of Atlantic cod is characterized by selective expansion of several medium-sized multigene families with ribose binding domains. An interesting finding was the high representation of three large gene families among the early antiviral genes, including tripartite motif proteins (TRIM) and proteins with PRY-SPRY and NACHT domains. The

  13. Influence of photoperiod on expression of DNA (cytosine-5) methyltransferases in Atlantic cod.

    PubMed

    Giannetto, Alessia; Nagasawa, Kazue; Fasulo, Salvatore; Fernandes, Jorge M O

    2013-05-01

    Photoperiod manipulation during early juvenile stages can influence growth in Atlantic cod. In the present study, one group of cod juveniles were reared under natural photoperiod conditions for Bodø (67° N, 14° E), whereas their counterparts were kept under continuous illumination. The mean weight of juvenile cod reared under continuous illumination was found to be 13% greater than those kept under natural photoperiod after 120days of light treatment. The molecular basis of this phenotypic plasticity is currently unknown but it is likely that DNA (cytosine-5)-methyltransferases (dnmts) are involved, since these genes play a crucial role in epigenetic regulation of gene expression. Phylogenetic analysis of Atlantic cod dnmt1, dnmt2 and dnmt3a revealed that within each group, the phylogeny follows the taxonomic relationship between the various species and comparative mapping of dnmt paralogues showed that these genes lie within regions of conserved synteny amongst teleosts. Of the three dnmt paralogues, dnmt3a had the highest expression in fast muscle of adult cod. In addition, dnmt1 and dnmt2 were differentially expressed between tissues but with prominent expression in gonads. Dnmt1 and dnmt3a transcript levels showed a significant increase in fast muscle of juvenile cod from the continuous light group at several time points. Remarkably, dnmt1 and dnmt3a transcript levels were 2-fold higher at 120days, by which point photoperiod conditions between the two light groups had become identical. Our data revealed that photoperiod can have an extended effect on expression of dnmt genes, which may be involved in the epigenetic regulation of muscle growth by photoperiod in Atlantic cod.

  14. Characterization of Atlantic cod spawning habitat and behavior in Icelandic coastal waters

    USGS Publications Warehouse

    Grabowski, Timothy B.; Boswell, Kevin M.; McAdam, Bruce J.; Wells, R. J. David; Marteinsdóttir, Gudrún

    2012-01-01

    The physical habitat used during spawning may potentially be an important factor affecting reproductive output of broadcast spawning marine fishes, particularly for species with complex, substrate-oriented mating systems and behaviors, such as Atlantic cod Gadus morhua. We characterized the habitat use and behavior of spawning Atlantic cod at two locations off the coast of southwestern Iceland during a 2-d research cruise (15–16 April 2009). We simultaneously operated two different active hydroacoustic gear types, a split beam echosounder and a dual frequency imaging sonar (DIDSON), as well as a remotely operated underwater vehicle (ROV). A total of five fish species were identified through ROV surveys: including cusk Brosme brosme, Atlantic cod, haddock Melanogrammus aeglefinus, lemon sole Microstomus kitt, and Atlantic redfish Sebastes spp. Of the three habitats identified in the acoustic surveys, the transitional habitat between boulder/lava field and sand habitats was characterized by greater fish density and acoustic target strength compared to that of sand or boulder/lava field habitats independently. Atlantic cod were observed behaving in a manner consistent with published descriptions of spawning. Individuals were observed ascending 1–5 m into the water column from the bottom at an average vertical swimming speed of 0.20–0.25 m s−1 and maintained an average spacing of 1.0–1.4 m between individuals. Our results suggest that cod do not choose spawning locations indiscriminately despite the fact that it is a broadcast spawning fish with planktonic eggs that are released well above the seafloor.

  15. Characterization of Atlantic cod spawning habitat and behavior in Icelandic coastal waters.

    PubMed

    Grabowski, Timothy B; Boswell, Kevin M; McAdam, Bruce J; Wells, R J David; Marteinsdóttir, Guđrún

    2012-01-01

    The physical habitat used during spawning may potentially be an important factor affecting reproductive output of broadcast spawning marine fishes, particularly for species with complex, substrate-oriented mating systems and behaviors, such as Atlantic cod Gadus morhua. We characterized the habitat use and behavior of spawning Atlantic cod at two locations off the coast of southwestern Iceland during a 2-d research cruise (15-16 April 2009). We simultaneously operated two different active hydroacoustic gear types, a split beam echosounder and a dual frequency imaging sonar (DIDSON), as well as a remotely operated underwater vehicle (ROV). A total of five fish species were identified through ROV surveys: including cusk Brosme brosme, Atlantic cod, haddock Melanogrammus aeglefinus, lemon sole Microstomus kitt, and Atlantic redfish Sebastes spp. Of the three habitats identified in the acoustic surveys, the transitional habitat between boulder/lava field and sand habitats was characterized by greater fish density and acoustic target strength compared to that of sand or boulder/lava field habitats independently. Atlantic cod were observed behaving in a manner consistent with published descriptions of spawning. Individuals were observed ascending 1-5 m into the water column from the bottom at an average vertical swimming speed of 0.20-0.25 m s(-1) and maintained an average spacing of 1.0-1.4 m between individuals. Our results suggest that cod do not choose spawning locations indiscriminately despite the fact that it is a broadcast spawning fish with planktonic eggs that are released well above the seafloor.

  16. Characterization of Atlantic Cod Spawning Habitat and Behavior in Icelandic Coastal Waters

    PubMed Central

    Grabowski, Timothy B.; Boswell, Kevin M.; McAdam, Bruce J.; Wells, R. J. David; Marteinsdóttir, Guđrún

    2012-01-01

    The physical habitat used during spawning may potentially be an important factor affecting reproductive output of broadcast spawning marine fishes, particularly for species with complex, substrate-oriented mating systems and behaviors, such as Atlantic cod Gadus morhua. We characterized the habitat use and behavior of spawning Atlantic cod at two locations off the coast of southwestern Iceland during a 2-d research cruise (15–16 April 2009). We simultaneously operated two different active hydroacoustic gear types, a split beam echosounder and a dual frequency imaging sonar (DIDSON), as well as a remotely operated underwater vehicle (ROV). A total of five fish species were identified through ROV surveys: including cusk Brosme brosme, Atlantic cod, haddock Melanogrammus aeglefinus, lemon sole Microstomus kitt, and Atlantic redfish Sebastes spp. Of the three habitats identified in the acoustic surveys, the transitional habitat between boulder/lava field and sand habitats was characterized by greater fish density and acoustic target strength compared to that of sand or boulder/lava field habitats independently. Atlantic cod were observed behaving in a manner consistent with published descriptions of spawning. Individuals were observed ascending 1–5 m into the water column from the bottom at an average vertical swimming speed of 0.20–0.25 m s−1 and maintained an average spacing of 1.0–1.4 m between individuals. Our results suggest that cod do not choose spawning locations indiscriminately despite the fact that it is a broadcast spawning fish with planktonic eggs that are released well above the seafloor. PMID:23236471

  17. Daily Rhythmicity of Clock Gene Transcripts in Atlantic Cod Fast Skeletal Muscle

    PubMed Central

    Lazado, Carlo C.; Kumaratunga, Hiruni P. S.; Nagasawa, Kazue; Babiak, Igor; Giannetto, Alessia; Fernandes, Jorge M. O.

    2014-01-01

    The classical notion of a centralized clock that governs circadian rhythmicity has been challenged with the discovery of peripheral oscillators that enable organisms to cope with daily changes in their environment. The present study aimed to identify the molecular clock components in Atlantic cod (Gadus morhua) and to investigate their daily gene expression in fast skeletal muscle. Atlantic cod clock genes were closely related to their orthologs in teleosts and tetrapods. Synteny was conserved to varying degrees in the majority of the 18 clock genes examined. In particular, aryl hydrocarbon receptor nuclear translocator-like 2 (arntl2), RAR-related orphan receptor A (rora) and timeless (tim) displayed high degrees of conservation. Expression profiling during the early ontogenesis revealed that some transcripts were maternally transferred, namely arntl2, cryptochrome 1b and 2 (cry1b and cry2), and period 2a and 2b (per2a and per2b). Most clock genes were ubiquitously expressed in various tissues, suggesting the possible existence of multiple peripheral clock systems in Atlantic cod. In particular, they were all detected in fast skeletal muscle, with the exception of neuronal PAS (Per-Arnt-Single-minded) domain-containing protein (npas1) and rora. Rhythmicity analysis revealed 8 clock genes with daily rhythmic expression, namely arntl2, circadian locomotor output cycles kaput (clock), npas2, cry2, cry3 per2a, nuclear receptor subfamily 1, group D, member 1 (nr1d1), and nr1d2a. Transcript levels of the myogenic genes myogenic factor 5 (myf5) and muscleblind-like 1 (mbnl1) strongly correlated with clock gene expression. This is the first study to unravel the molecular components of peripheral clocks in Atlantic cod. Taken together, our data suggest that the putative clock system in fast skeletal muscle of Atlantic cod has regulatory implications on muscle physiology, particularly in the expression of genes related to myogenesis. PMID:24921252

  18. Ontogeny of redox regulation in Atlantic cod (Gadus morhua) larvae.

    PubMed

    Hamre, Kristin; Penglase, Samuel J; Rasinger, Josef D; Skjærven, Kaja H; Olsvik, Pål A

    2014-08-01

    The reduction potential of a cell is related to its fate. Proliferating cells are more reduced than those that are differentiating, whereas apoptotic cells are generally the most oxidized. Glutathione is considered the most important cellular redox buffer and the average reduction potential (Eh) of a cell or organism can be calculated from the concentrations of glutathione (GSH) and glutathione disulfide (GSSG). In this study, triplicate groups of cod larvae at various stages of development (3 to 63 days post-hatch; dph) were sampled for analyses of GSSG/2GSH concentrations, together with activities of antioxidant enzymes and expression of genes encoding proteins involved in redox metabolism. The concentration of total GSH (GSH+GSSG) increased from 610 ± 100 to 1260 ± 150 μmol/kg between 7 and 14 dph and was then constant until 49 dph, after which it decreased to 810 ± 100 μmol/kg by 63 dph. The 14- to 49-dph period, when total GSH concentrations were stable, coincides with the proposed period of metamorphosis in cod larvae. The concentration of GSSG comprised approximately 1% of the total GSH concentration and was stable throughout the sampling series. This resulted in a decreasing Eh from -239 ± 1 to -262 ± 7 mV between 7 and 14 dph, after which it remained constant until 63 dph. The changes in GSH and Eh were accompanied by changes in the expression of several genes involved in redox balance and signaling, as well as changes in activities of antioxidant enzymes, with the most dynamic responses occurring in the early phase of cod larval development. It is hypothesized that metamorphosis in cod larvae starts with the onset of mosaic hyperplasia in the skeletal muscle at approximately 20 dph (6.8mm standard length (SL)) and ends with differentiation of the stomach and disappearance of the larval finfold at 40 to 50 dph (10-15 mm SL). Thus, metamorphosis in cod larvae seems to coincide with high and stable total concentrations of GSH.

  19. Low plastic ingestion rate in Atlantic cod (Gadus morhua) from Newfoundland destined for human consumption collected through citizen science methods.

    PubMed

    Liboiron, Max; Liboiron, France; Wells, Emily; Richárd, Natalie; Zahara, Alexander; Mather, Charles; Bradshaw, Hillary; Murichi, Judyannet

    2016-12-15

    Marine microplastics are a contaminant of concern because their small size allows ingestion by a wide range of marine life. Using citizen science during the Newfoundland recreational cod fishery, we sampled 205 Atlantic cod (Gadus morhua) destined for human consumption and found that 5 had eaten plastic, an ingestion prevalence rate of 2.4%. This ingestion rate for Atlantic cod is the second lowest recorded rate in the reviewed published literature (the lowest is 1.4%), and the lowest for any fish in the North Atlantic. This is the first report for plastic ingestion in fish in Newfoundland, Canada, a province dependent on fish for sustenance and livelihoods.

  20. Thermal habitat constraints on zooplankton species associated with Atlantic cod (Gadus morhua) on the US Northeast Continental Shelf

    NASA Astrophysics Data System (ADS)

    Friedland, Kevin D.; Kane, Joe; Hare, Jonathan A.; Lough, R. Gregory; Fratantoni, Paula S.; Fogarty, Michael J.; Nye, Janet A.

    2013-09-01

    The US Northeast Continental Shelf is experiencing a period of increasing temperature levels and range, which impacts the quantity of thermal habitats within the ecosystem. With increasing temperatures, the amount of warmer, surface water thermal habitats (16-27 °C) has increased while there has been a reciprocal decline in cooler water habitats (5-15 °C). These cooler water habitats are the most abundant and comprise the core habitats of the ecosystem. The coldest thermal habitats (1-4 °C), however, have increased slightly in amount or have remained constant, reflecting a discontinuity in the progression of warming along a latitudinal gradient. This discontinuity may be the result of recent changes in the circulation of water masses in the northern Gulf of Maine, potentially associated with the Labrador Current. The contraction of core thermal habitats appears to have had biological consequences on multiple trophic levels. In particular, two zooplankton species associated with the larval feeding of Atlantic cod, Gadus morhua, have declined in abundance in the same areas where cod populations have exhibited continually poor recruitment. The zooplankton species group Pseudocalanus spp., which is associated with winter-spawning cod, has declined on Georges Bank and in the Eastern Gulf of Maine. The zooplankton Centropages typicus has declined in the Gulf of Maine during late summer into fall, potentially affecting spring-spawning cod in that area. These observations are consistent with the hypothesis that portions of the population complex of cod have lower reproductive output due to changes in zooplankton abundance, which we associate with the distribution of temperatures within the ecosystem.

  1. Effect of petroleum aromatic hydrocarbons on monogeneids parasitizing Atlantic cod, Gadus morhua L

    SciTech Connect

    Khan, R.A.; Kiceniuk, J.W.

    1988-07-01

    Fish gills appear to be more susceptible than other tissues to toxicants. The latter include petroleum aromatic hydrocarbons, which can induce lesions characterized by excessive mucus secretion, hyperplasia, fusion of secondary gill lamellae and capillary dilation. Fish are also natural hosts to several species of ectoparasites, especially monogeneans which live among the gill filaments. A previous study on the interrelation of water quality, gill parasites and gill pathology provided evidence that fish living in habitats degraded by pollutants such as Biscayne Bay, Florida, were heavily infested with monogeneids especially when gill lesions were severe. Atlantic cod, Gadus morhua, are hosts to monogeneans. The authors reported previously that crude oil fractions induced gill lesions in cod and also affected some gastrointestinal parasites. In the light of these reports, a study was undertaken to ascertain whether any relationship existed between gill lesions and gill parasites in cod following chronic exposure to petroleum hydrocarbons.

  2. Photoperiod influences growth and mll (mixed-lineage leukaemia) expression in Atlantic cod.

    PubMed

    Nagasawa, Kazue; Giannetto, Alessia; Fernandes, Jorge M O

    2012-01-01

    Photoperiod is associated to phenotypic plasticity of somatic growth in several teleost species. However, the molecular mechanisms underlying this phenomenon are currently unknown but it is likely that epigenetic regulation by methyltransferases is involved. The MLL (mixed-lineage leukaemia) family comprises histone methyltransferases that play a critical role in regulating gene expression during early development in mammals. So far, these genes have received scant attention in teleost fish. In the present study, the mean weight of Atlantic cod juveniles reared under continuous illumination was found to be 13% greater than those kept under natural photoperiod conditions for 120 days. We newly determined cDNA sequences of five mll (mll1, mll2, mll3a, mll4b and mll5) and two setd1 (setd1a and setd1ba) paralogues from Atlantic cod. Phylogenetic analysis revealed that the cod genes clustered within the appropriate mll clade and comparative mapping of mll paralogues showed that these genes lie within a region of conserved synteny among teleosts. All mll and setd1 genes were highly expressed in gonads and fast muscle of adult cod, albeit at different levels, and they were differentially regulated with photoperiod in muscle of juvenile fish. Following only one day of exposure to constant light, mll1, mll4b and setd1a were up to 57% lower in these fish compared to the natural photoperiod group. In addition, mRNA expression of myogenic regulatory factors (myog and myf-5) and pax7 in fast muscle was also affected by different photoperiod conditions. Notably, myog was significantly elevated in the continuous illumination group throughout the time course of the experiment. The absence of a day/night cycle is associated with a generalised decrease in mll expression concomitant with an increase in myog transcript levels in fast muscle of Atlantic cod, which may be involved in the observed epigenetic regulation of growth by photoperiod in this species.

  3. Identification of the Atlantic cod L-amino acid oxidase and its alterations following bacterial exposure.

    PubMed

    Kitani, Yoichiro; Fernandes, Jorge M O; Kiron, Viswanath

    2015-06-01

    Antibacterial factors that are present in epidermal mucus of fish have a potential role in the first line of host defence to bacterial pathogens. This study reports the identification of L-amino acid oxidase (LAO) in Atlantic cod (GmLao) and the changes in the molecule following bacterial exposure. The gmlao transcripts and LAO activity were present on both the body surface and in the internal organs of the fish. Relative mRNA level of gmlao increased significantly in the gills, the spleen and the head kidney (up to 8-fold) of fish that were challenged with the pathogen Vibrio anguillarum. The gmlao expression in skin was 4-fold higher in challenged fish. Our data indicate that LAO may be an important effector of antibacterial defence in Atlantic cod.

  4. Irreversible binding of o,p'-DDD in interrenal cells of Atlantic cod (Gadus morhua).

    PubMed

    Lindhe, Orjan; Brandt, Ingvar; Christiansen, Jørgen Schou; Ingebrigtsen, Kristian

    2003-03-01

    Precision-cut tissue slices of the anterior kidney from Atlantic cod (Gadus morhua) were prepared with a Krumdieck tissue slicer and exposed to 2-(2-chlorophenyl)-2-(4-chloro-(14C)phenyl)-1,1-dichlorethane (o,p(')-[14C]DDD) in vitro. Microautoradiography revealed irreversible o,p(')-DDD-derived binding confined to the glucocorticoid producing interrenal cells (adrenocortical analogues). This cell-selective binding was confirmed by means of autoradiography at different levels of resolution on Atlantic cod administered o,p(')-[14C]DDD intragastrically. The results provide evidence for a site-specific metabolic activation and irreversible binding of o,p(')-DDD in the interrenal cells, which, in turn, may modify glucocorticoid homeostasis.

  5. Severe tissue damage in Atlantic cod larvae under increasing ocean acidification

    NASA Astrophysics Data System (ADS)

    Frommel, Andrea Y.; Maneja, Rommel; Lowe, David; Malzahn, Arne M.; Geffen, Audrey J.; Folkvord, Arild; Piatkowski, Uwe; Reusch, Thorsten B. H.; Clemmesen, Catriona

    2012-01-01

    Ocean acidification, caused by increasing atmospheric concentrations of CO2 (refs , , ), is one of the most critical anthropogenicthreats to marine life. Changes in seawater carbonate chemistry have the potential to disturb calcification, acid-base regulation, blood circulation and respiration, as well as the nervous system of marine organisms, leading to long-term effects such as reduced growth rates and reproduction. In teleost fishes, early life-history stages are particularly vulnerable as they lack specialized internal pH regulatory mechanisms. So far, impacts of relevant CO2 concentrations on larval fish have been found in behaviour and otolith size, mainly in tropical, non-commercial species. Here we show detrimental effects of ocean acidification on the development of a mass-spawning fish species of high commercial importance. We reared Atlantic cod larvae at three levels of CO2, (1) present day, (2) end of next century and (3) an extreme, coastal upwelling scenario, in a long-term ( months) mesocosm experiment. Exposure to CO2 resulted in severe to lethal tissue damage in many internal organs, with the degree of damage increasing with CO2 concentration. As larval survival is the bottleneck to recruitment, ocean acidification has the potential to act as an additional source of natural mortality, affecting populations of already exploited fish stocks.

  6. Evolutionary redesign of the Atlantic cod (Gadus morhua L.) Toll-like receptor repertoire by gene losses and expansions.

    PubMed

    Solbakken, Monica H; Tørresen, Ole K; Nederbragt, Alexander J; Seppola, Marit; Gregers, Tone F; Jakobsen, Kjetill S; Jentoft, Sissel

    2016-04-29

    Genome sequencing of the teleost Atlantic cod demonstrated loss of the Major Histocompatibility Complex (MHC) class II, an extreme gene expansion of MHC class I and gene expansions and losses in the innate pattern recognition receptor (PRR) family of Toll-like receptors (TLR). In a comparative genomic setting, using an improved version of the genome, we characterize PRRs in Atlantic cod with emphasis on TLRs demonstrating the loss of TLR1/6, TLR2 and TLR5 and expansion of TLR7, TLR8, TLR9, TLR22 and TLR25. We find that Atlantic cod TLR expansions are strongly influenced by diversifying selection likely to increase the detectable ligand repertoire through neo- and subfunctionalization. Using RNAseq we find that Atlantic cod TLRs display likely tissue or developmental stage-specific expression patterns. In a broader perspective, a comprehensive vertebrate TLR phylogeny reveals that the Atlantic cod TLR repertoire is extreme with regards to losses and expansions compared to other teleosts. In addition we identify a substantial shift in TLR repertoires following the evolutionary transition from an aquatic vertebrate (fish) to a terrestrial (tetrapod) life style. Collectively, our findings provide new insight into the function and evolution of TLRs in Atlantic cod as well as the evolutionary history of vertebrate innate immunity.

  7. Evolutionary redesign of the Atlantic cod (Gadus morhua L.) Toll-like receptor repertoire by gene losses and expansions

    PubMed Central

    Solbakken, Monica H.; Tørresen, Ole K.; Nederbragt, Alexander J.; Seppola, Marit; Gregers, Tone F.; Jakobsen, Kjetill S.; Jentoft, Sissel

    2016-01-01

    Genome sequencing of the teleost Atlantic cod demonstrated loss of the Major Histocompatibility Complex (MHC) class II, an extreme gene expansion of MHC class I and gene expansions and losses in the innate pattern recognition receptor (PRR) family of Toll-like receptors (TLR). In a comparative genomic setting, using an improved version of the genome, we characterize PRRs in Atlantic cod with emphasis on TLRs demonstrating the loss of TLR1/6, TLR2 and TLR5 and expansion of TLR7, TLR8, TLR9, TLR22 and TLR25. We find that Atlantic cod TLR expansions are strongly influenced by diversifying selection likely to increase the detectable ligand repertoire through neo- and subfunctionalization. Using RNAseq we find that Atlantic cod TLRs display likely tissue or developmental stage-specific expression patterns. In a broader perspective, a comprehensive vertebrate TLR phylogeny reveals that the Atlantic cod TLR repertoire is extreme with regards to losses and expansions compared to other teleosts. In addition we identify a substantial shift in TLR repertoires following the evolutionary transition from an aquatic vertebrate (fish) to a terrestrial (tetrapod) life style. Collectively, our findings provide new insight into the function and evolution of TLRs in Atlantic cod as well as the evolutionary history of vertebrate innate immunity. PMID:27126702

  8. An investigation of appetite-related peptide transcript expression in Atlantic cod (Gadus morhua) brain following a Camelina sativa meal-supplemented feeding trial.

    PubMed

    Tuziak, Sarah M; Rise, Matthew L; Volkoff, Hélène

    2014-10-25

    Camelina sativa is a hardy oilseed crop with seeds that contain high levels of ω3 polyunsaturated fatty acids and protein, which are critical components of fish feed. Camelina might thus be used as a cheaper and more sustainable supplement to fish-based products in aquaculture. Atlantic cod, Gadus morhua, is a species of interest in the aquaculture industry due to a decrease in wild populations and subsequent collapse of some cod fisheries. As cod are carnivorous fish, it is necessary to determine how this species physiologically tolerates plant-based diets. In this study, juvenile Atlantic cod were subjected to 13 weeks of either 15 or 30% camelina meal (CM)-supplemented diets or a control fish meal feed. Growth and food intake were evaluated and the mRNA expression of appetite-related hormones [pro-melanin-concentrating hormone (pmch), hypocretin (synonym: orexin, hcrt), neuropeptide Y (npy) and cocaine- and amphetamine-regulated transcript (cart)] was assessed using quantitative real-time PCR in brain regions related to food intake regulation (telencephalon/preoptic area, optic tectum/thalamus and hypothalamus). CM inclusion diets caused decreases in both growth and food intake in Atlantic cod. Optic tectum pmch transcript expression was significantly higher in fish fed the 30% CM diet compared to fish fed the 15% CM diet. In the hypothalamus, compared to fish fed the control diet, hcrt expression was significantly higher in fish fed the 30% CM diet, while npy transcript expression was significantly higher in fish fed the 15% CM diet. cart mRNA expression was not affected by diet in any brain region. Further studies are needed to determine which factors (e.g. anti-nutritional factors, palatability and nutritional deficits) contribute to reduced feed intake and growth, as well as the maximum CM inclusion level that does not negatively influence feed intake, growth rate and the transcript expression of appetite-related factors in Atlantic cod.

  9. Spawning behavior in Atlantic cod: analysis by use of data storage tags

    USGS Publications Warehouse

    Grabowski, Timothy B.; Thorsteinsson, Vilhjalmur; Marteinsdóttir, Gudrún

    2014-01-01

     Electronic data storage tags (DSTs) were implanted into Atlantic cod captured in Icelandic waters from 2002 to 2007 and the depth profiles recovered from these tags (females: n = 31, males: n = 27) were used to identify patterns consistent with published descriptions of cod courtship and spawning behavior. The individual periods of time that males spent exhibiting behavior consistent with being present in a spawning aggregation—i.e. periods consisting of a clear tidal signature in the DST depth profile associated with an individual remaining on or near the substrate—were longer than those of females. Over the course of a spawning season, male cod spent approximately twice the amount of time in spawning aggregations than females, but female cod visited more aggregations per unit time. On average, males participated in approximately 57% more putative spawning events, i.e. vertical ascents potentially corresponding to gamete release, than did females. However, males <85 cm total length participated in the same number of putative spawning events as females of comparable size. In both sexes, larger individuals and/or individuals that spent a longer period of time within an aggregation participated in a larger number of putative spawning events. Although further validation and refinement is necessary, particularly in the identification of spawning events, the ability offered by DSTs to quantify cod spawning behavior may aid in the development of management and conservation plans.

  10. Gene regulation of lipid and phospholipid metabolism in Atlantic cod (Gadus morhua) larvae.

    PubMed

    Li, Keshuai; Østensen, Mari-Ann; Attramadal, Kari; Winge, Per; Sparstad, Torfinn; Bones, Atle M; Vadstein, Olav; Kjørsvik, Elin; Olsen, Yngvar

    2015-12-01

    The mechanism of essentiality of dietary phospholipid (PL) for larval fish is not clear. The main objective of the present study was to determine if the PL requirement of Atlantic cod larvae was due to any genetic impairment caused by functional immaturity. Cod larvae were sampled at 1, 3, 8, 13, 17, 18, 30, 42 and 60 days post hatch (dph) for transcriptome analysis using a recently developed microarray. The fatty acid profile and gene expression levels of cod larvae at 17 dph were compared after feeding differently enriched rotifers, which contained different DHA levels in PL. No significant differences (p<0.05) were found for the two rotifer diets in the overall gene expression level of cod larvae, their growth and survival, and their DHA levels in total lipid and PL fraction. The fatty acid data suggested that dietary EPA was elongated to DPA by cod larvae, and a threshold DHA level in PL to maintain membrane fluidity and other functions may exist. There appeared to be no major effect of development on the expression of key genes of PL biosynthesis suggesting no genetic constrain in early developmental stages. Our overall data suggested that besides the possible limited de novo PC synthesis ability in the intestine, other metabolic constraints should also be considered, especially the possible low input of bile PC as a result of immature liver. Further studies are needed to elucidate the gene expression level and enzyme activity in the PL biosynthesis pathways for specific tissue or cells.

  11. Nucleotide variation and balancing selection at the Ckma gene in Atlantic cod: analysis with multiple merger coalescent models.

    PubMed

    Árnason, Einar; Halldórsdóttir, Katrín

    2015-01-01

    High-fecundity organisms, such as Atlantic cod, can withstand substantial natural selection and the entailing genetic load of replacing alleles at a number of loci due to their excess reproductive capacity. High-fecundity organisms may reproduce by sweepstakes leading to highly skewed heavy-tailed offspring distribution. Under such reproduction the Kingman coalescent of binary mergers breaks down and models of multiple merger coalescent are more appropriate. Here we study nucleotide variation at the Ckma (Creatine Kinase Muscle type A) gene in Atlantic cod. The gene shows extreme differentiation between the North (Canada, Greenland, Iceland, Norway, Barents Sea) and the South (Faroe Islands, North-, Baltic-, Celtic-, and Irish Seas) with FST > 0.8 between regions whereas neutral loci show no differentiation. This is evidence of natural selection. The protein sequence is conserved by purifying selection whereas silent and non-coding sites show extreme differentiation. The unfolded site-frequency spectrum has three modes, a mode at singleton sites and two high frequency modes at opposite frequencies representing divergent branches of the gene genealogy that is evidence for balancing selection. Analysis with multiple-merger coalescent models can account for the high frequency of singleton sites and indicate reproductive sweepstakes. Coalescent time scales vary with population size and with the inverse of variance in offspring number. Parameter estimates using multiple-merger coalescent models show that times scales are faster than under the Kingman coalescent.

  12. Nucleotide variation and balancing selection at the Ckma gene in Atlantic cod: analysis with multiple merger coalescent models

    PubMed Central

    Halldórsdóttir, Katrín

    2015-01-01

    High-fecundity organisms, such as Atlantic cod, can withstand substantial natural selection and the entailing genetic load of replacing alleles at a number of loci due to their excess reproductive capacity. High-fecundity organisms may reproduce by sweepstakes leading to highly skewed heavy-tailed offspring distribution. Under such reproduction the Kingman coalescent of binary mergers breaks down and models of multiple merger coalescent are more appropriate. Here we study nucleotide variation at the Ckma (Creatine Kinase Muscle type A) gene in Atlantic cod. The gene shows extreme differentiation between the North (Canada, Greenland, Iceland, Norway, Barents Sea) and the South (Faroe Islands, North-, Baltic-, Celtic-, and Irish Seas) with FST > 0.8 between regions whereas neutral loci show no differentiation. This is evidence of natural selection. The protein sequence is conserved by purifying selection whereas silent and non-coding sites show extreme differentiation. The unfolded site-frequency spectrum has three modes, a mode at singleton sites and two high frequency modes at opposite frequencies representing divergent branches of the gene genealogy that is evidence for balancing selection. Analysis with multiple-merger coalescent models can account for the high frequency of singleton sites and indicate reproductive sweepstakes. Coalescent time scales vary with population size and with the inverse of variance in offspring number. Parameter estimates using multiple-merger coalescent models show that times scales are faster than under the Kingman coalescent. PMID:25755922

  13. Genetic and morphological variation in Echinorhynchus gadi Zoega in Müller, 1776 (Acanthocephala: Echinorhynchidae) from Atlantic cod Gadus morhua L.

    PubMed

    Sobecka, E; Szostakowska, B; MacKenzie, K; Hemmingsen, W; Prajsnar, S; Eydal, M

    2012-03-01

    Previous studies have shown considerable variability in morphological features and the existence of genetically distinct sibling species in the acanthocephalan Echinorhynchus gadi Zoega in Müller, 1776. The aim of the present study was to follow up and extend those earlier studies by using a combination of DNA analysis and morphometrics to investigate differences between samples of E. gadi from Atlantic cod Gadus morhua L. caught at five fishing grounds in the Baltic Sea and three in different parts of the North Atlantic. Twelve morphological features were measured in 431 specimens of E. gadi, 99 individuals were studied by polymerase chain reaction-restriction fragment length polymorphosm (PCR-RFLP), and selected PCR products were sequenced. The molecular analyses showed the nucleotide sequences of E. gadi rDNA from cod caught at all the sampling sites to be identical. The comparative morphological study, in contrast, revealed significant differences between samples of E. gadi from different sampling sites and showed the separation of E. gadi into two groups corresponding approximately to the systematic classification of cod into the two subspecies, Atlantic G. morhua morhua and Baltic G. morhua callarias. The E. gadi infrapopulation size had a significant effect on some of the morphological features. The results are discussed in relation to cod population biology, the hydrography of the study area and the history of the Baltic Sea formation.

  14. Effects of ocean acidification on the calcification of otoliths of larval Atlantic cod, Gadus morhua L.

    NASA Astrophysics Data System (ADS)

    Maneja, R. H.; Frommel, A. Y.; Geffen, A. J.; Folkvord, A.; Piatkowski, U.; Chang, M. Y.; Clemmesen, C.

    2012-04-01

    The aragonitic calcium carbonate composition of the otoliths of teleost fishes could bring the organism in direct risk to ocean acidification. The potential effects of increase in atmospheric CO2 on the calcification of the otoliths were investigated by rearing Atlantic cod larvae (Gadus morhua L.) in three pCO2 concentrations, control-370, medium-1800, and high-4200 ppm from March to May 2010. Hypercalcification of otoliths were observed from 7 to 46-dph cod larvae cultured at elevated pCO2 concentrations. The sagittae and lapilli were largest at the high pCO2 treatment followed by medium and control with the biggest difference (83.8%) in mean otolith (sagitta) surface area at 32-dph between the high and control groups. The shift in the growth rates of the sagittae and lapilli also occurred much earlier in the high treatment with the growth of the sagitta surpassing that of the lapillus already at 32-dph. On the other hand, Atlantic cod larvae showed no trends in fluctuating asymmetry of the otoliths vis-a-vis the increase in otolith growth from elevated pCO2.

  15. Cape Cod

    Atmospheric Science Data Center

    2014-05-15

    article title:  Winter in Cape Cod     View Larger Image Cape Cod extends over 50 miles into the Atlantic Ocean. Its rugged coastline, ... February 18, 2001 - Snow and thin clouds over Cape Cod. project:  MISR category:  gallery ...

  16. Factors regulating early life history dispersal of Atlantic cod (Gadus morhua) from coastal Newfoundland.

    PubMed

    Stanley, Ryan R E; deYoung, Brad; Snelgrove, Paul V R; Gregory, Robert S

    2013-01-01

    To understand coastal dispersal dynamics of Atlantic cod (Gadus morhua), we examined spatiotemporal egg and larval abundance patterns in coastal Newfoundland. In recent decades, Smith Sound, Trinity Bay has supported the largest known overwintering spawning aggregation of Atlantic cod in the region. We estimated spawning and dispersal characteristics for the Smith Sound-Trinity Bay system by fitting ichthyoplankton abundance data to environmentally-driven, simplified box models. Results show protracted spawning, with sharply increased egg production in early July, and limited dispersal from the Sound. The model for the entire spawning season indicates egg export from Smith Sound is 13%•day(-1) with a net mortality of 27%•day(-1). Eggs and larvae are consistently found in western Trinity Bay with little advection from the system. These patterns mirror particle tracking models that suggest residence times of 10-20 days, and circulation models indicating local gyres in Trinity Bay that act in concert with upwelling dynamics to retain eggs and larvae. Our results are among the first quantitative dispersal estimates from Smith Sound, linking this spawning stock to the adjacent coastal waters. These results illustrate the biophysical interplay regulating dispersal and connectivity originating from inshore spawning of coastal northwest Atlantic.

  17. Plastic ingestion by Atlantic cod (Gadus morhua) from the Norwegian coast.

    PubMed

    Bråte, Inger Lise N; Eidsvoll, David P; Steindal, Calin Constantin; Thomas, Kevin V

    2016-11-15

    This study documents the occurrence of microplastic (<5mm), mesoplastics (5-20mm) and macroplastic (>20mm) in Atlantic cod (Gadus morhua), a common and economically important species of marine fish in Norway. Fish stomachs (n=302) were examined from six different locations along the coast of Norway. Three percent of the individual stomachs contained items identified by Fourier transform infrared spectroscopy (FTIR) as synthetic polymers. Bergen City Harbour was a hotspot with 27% of the cod examined found to contain plastic. Polyester was the most frequently detected polymer. All bar one of the stomachs that contained plastic were full of organic stomach content, suggesting a plastic gut clearance rate similar to the ingested food. It is proposed that stomach fullness is an important metric in order to avoid underestimations when assessing the levels of microplastic ingested by fish.

  18. Transcriptome profiling of the antiviral immune response in Atlantic cod macrophages.

    PubMed

    Eslamloo, Khalil; Xue, Xi; Booman, Marije; Smith, Nicole C; Rise, Matthew L

    2016-10-01

    A study was conducted to determine the transcriptome response of Atlantic cod (Gadus morhua) macrophages to the viral mimic, polyriboinosinic polyribocytidylic acid (pIC), using a 20K Atlantic cod microarray platform and qPCR. We identified 285 significantly up-regulated and 161 significantly down-regulated probes in cod macrophages 24 h after pIC stimulation. A subset of 26 microarray-identified transcripts was subjected to qPCR validation using samples treated with pIC or phosphate-buffered saline (control) over time (3, 6, 12, 24, 48 h), and 77% of them showed a significant response to pIC. The microarray and qPCR analyses in this study showed that pIC induced the expression of cod macrophage transcripts involved in RLR- and TLR-dependent pathogen recognition (e.g. tlr3, tlr7, mda5 and lgp2), as well as signal transducers (e.g. stat1 and nfkbia) and transcription activators (e.g. irf7 and irf10) in the MyD88-independent and dependent signalling pathways. Several immune effectors (e.g. isg15s, viperin, herc4, mip2 and ccl13) were significantly up-regulated in pIC-stimulated cod macrophages. The expression of some transcripts (e.g. irf7, irf10, viperin) was significantly up-regulated by pIC as early as 12 h. All pIC-induced transcripts had peak expression at either 24 h (e.g. tlr7, irf7, mip2) or 48 h (e.g. tlr3, lgp2, stat1). This study suggests possible roles of both vertebrate-conserved (e.g. tlr3 as an up-regulated gene) and fish-specific (tlr22g as a down-regulated gene) receptors in dsRNA recognition, and the importance of conserved and potentially fish-specific interferon stimulated genes in cod macrophages.

  19. Recombinant cold-adapted trypsin I from Atlantic cod-expression, purification, and identification.

    PubMed

    Jónsdóttir, Gudrún; Bjarnason, Jón Bragi; Gudmundsdóttir, Agústa

    2004-01-01

    Atlantic cod trypsin I is a cold-adapted proteolytic enzyme exhibiting approximately 20 times higher catalytic efficiency (kcat/KM) than its mesophilic bovine counterpart for the simple amide substrate BAPNA. In general, cold-adapted proteolytic enzymes are sensitive to autolytic degradation, thermal inactivation as well as molecular aggregation, even at temperatures as low as 18-25 degrees C which may explain the problems observed with their expression, activation, and purification. Prior to the data presented here, there have been no reports in the literature on the expression of psychrophilic or cold-adapted proteolytic enzymes from fish. Nevertheless, numerous cold-adapted proteolytic microbial enzymes have been successfully expressed in bacteria and yeast. This report describes successful expression, activation, and purification of the recombinant cod trypsin I in the His-Patch ThioFusion Escherichia coli expression system. The E. coli pThioHis expression vector used in the study enabled the formation of a fusion protein between a highly soluble fraction of HP-thioredoxin contained in the vector and the N-terminal end of the precursor form of cod trypsin I. The HP-thioredoxin part of the fusion protein binds to a metal-chelating ProBond column, which facilitated its purification. The cod trypsin I part of the purified fusion protein was released by proteolytic cleavage, resulting in concomitant activation of the recombinant enzyme. The recombinant cod trypsin I was purified to homogeneity on a trypsin-specific benzamidine affinity column. The identity of the recombinant enzyme was demonstrated by electrophoresis and chromatography.

  20. Isolation and biochemical characterisation of lipid rafts from Atlantic cod (Gadus morhua) intestinal enterocytes.

    PubMed

    Gylfason, Gudjón Andri; Knútsdóttir, Erna; Asgeirsson, Bjarni

    2010-01-01

    Lipid rafts are glycosphingolipid/cholesterol-enriched membrane microdomains that have been extensively studied during the past two decades. Our aim was to isolate and perform biochemical characterization of lipid rafts from the intestinal brush border membrane (BBM) of Atlantic cod (Gadus morhua) to confirm their existence in a cold-water species and compare their characteristics with lipid rafts from other species in terms of lipid and protein content. To validate the isolation process, we assayed marker enzymes for subcellular organelles, including alkaline phosphatase (AP) and leucine aminopeptidase (LAP), both well-known marker enzymes for BBM and lipid rafts. All biochemical methods showed enrichment of AP in both the BBM and lipid raft fractions. Proteomic studies were performed by MALDI-TOF mass spectrometry using trypsin digested SDS-PAGE samples. Various proteins were associated with the cod intestinal lipid raft preparation such as aminopeptidase-N, prohibitin, and beta-actin. Lipid analysis with (31)P NMR and thin layer chromatography on BBMs and lipid rafts samples gave higher content of sphingomyelin than previously reported in the BBM and lower content of phosphatidylcholine. Furthermore, sphingomyelin was highly dominant in the lipid rafts together with cholesterol. The existence of lipid rafts containing previously reported lipid raft characteristics from the cod intestine has, therefore, been confirmed in a ray-finned fish for the first time to the best of our knowledge.

  1. Diet affects the redox system in developing Atlantic cod (Gadus morhua) larvae

    PubMed Central

    Penglase, Samuel; Edvardsen, Rolf B.; Furmanek, Tomasz; Rønnestad, Ivar; Karlsen, Ørjan; van der Meeren, Terje; Hamre, Kristin

    2015-01-01

    The growth and development of marine fish larvae fed copepods is superior to those fed rotifers, but the underlying molecular reasons for this are unclear. In the following study we compared the effects of such diets on redox regulation pathways during development of Atlantic cod (Gadus morhua) larvae. Cod larvae were fed a control diet of copepods or the typical rotifer/Artemia diet commonly used in commercial marine fish hatcheries, from first feeding until after metamorphosis. The oxidised and reduced glutathione levels, the redox potential, and the mRNA expression of 100 genes in redox system pathways were then compared between treatments during larval development. We found that rotifer/Artemia-fed cod larvae had lower levels of oxidised glutathione, a more reduced redox potential, and altered expression of approximately half of the redox system genes when compared to copepod-fed larvae. This rotifer/Artemia diet-induced differential regulation of the redox system was greatest during periods of suboptimal growth. Upregulation of the oxidative stress response transcription factor, nrf2, and NRF2 target genes in rotifer/Artemia fed larvae suggest this diet induced an NRF2-mediated oxidative stress response. Overall, the data demonstrate that nutritional intake plays a role in regulating the redox system in developing fish larvae. This may be a factor in dietary-induced differences observed in larval growth. PMID:26099546

  2. Organization of a β and α globin gene set in the teleost Atlantic cod, Gadus morhua.

    PubMed

    Halldórsdóttir, Katrín; Árnason, Einar

    2009-12-01

    Developmental globin gene expression and gene switching in vertebrates have been extensively studied. Globin gene regions have been characterized in some fish species and show linked α and β loci. Understanding coordinated expression between α and β globin genes in fish is of importance for further insights into globin gene regulation in teleosts and higher vertebrates. We characterize linked β and α globin genes in Atlantic cod, pulled from the Atlantic cod genome with a PCR research strategy, by screening a genomic λ library and primer walking. The genes are oriented tail-to-head (5'-3'), differing from the head-to-head orientation in transcriptional polarity characteristic of teleostean globin genes. Four tandem repeats are found in an intergenic region of 1500 base pairs. One microsatellite, which consists primarily of atg tandem repeats, has an open reading frame. The globin genes and open reading frame have a CCAAT promoter element and TATA boxes. The promoters of the open reading frame and the β gene share an 89-bp block (with 100% identity) that probably regulates transcription.

  3. Substantial Downregulation of Myogenic Transcripts in Skeletal Muscle of Atlantic Cod during the Spawning Period

    PubMed Central

    Edvardsen, Vigdis

    2016-01-01

    Gonadal maturation is an extremely energy consuming process for batch spawners and it is associated with a significant decrease in growth and seasonal deterioration in flesh quality. Our knowledge about the molecular mechanisms linking sexual maturation and muscle growth is still limited. In the present study, we performed RNA-Seq using 454 GS-FLX pyrosequencing in fast skeletal muscle sampled from two-year-old Atlantic cod (Gadus morhua) at representative time points throughout the reproductive cycle (August, March and May). In total, 126,937 good quality reads were obtained, with 546 nucleotide length and 52% GC content on average. RNA-Seq analysis using the CLC Genomics Workbench with the Atlantic cod reference UniGene cDNA data revealed 59,581 (46.9%) uniquely annotated reads. Pairwise comparison for expression levels identified 153 differentially expressed UniGenes between time points. Notably, we found a significant suppression of myh13 and myofibrillar gene isoforms in fast skeletal muscle during the spawning season. This study uncovered a large number of differentially expressed genes that may be influenced by gonadal maturation, thus representing a significant contribution to our limited understanding of the molecular mechanisms regulating muscle wasting and regeneration in batch spawners during their reproductive cycle. PMID:26844771

  4. Antibiotic uptake by cultured Atlantic cod leucocytes and effect on intracellular Francisella noatunensis subsp. noatunensis replication.

    PubMed

    Kaldestad, Marte; Haugland, Gyri T; Rønneseth, Anita; Wergeland, Heidrun I; Samuelsen, Ole Bent

    2014-02-04

    The granuloma disease caused by Francisella noatunensis subsp. noatunensis in farmed Atlantic cod has not been successfully treated by use of antibacterials, even when antibacterial resistance testing indicates a sufficient effect. The reason for this treatment failure may be the intracellular existence of the bacteria within immune cells, mainly macrophages. To investigate the effect of antibacterials on intracellular Francisella replication, we established a protocol for the detection of drugs within Atlantic cod immune cells using high-performance liquid chromatography (HPLC). When the uptake and intracellular concentrations of oxolinic acid and flumequine were analysed in isolated adherent head kidney leucocytes (HKLs) by HPLC, we found that uptake was rapid and the intracellular concentrations reflected the extracellular exposure concentrations. To investigate the effect of the antibacterial compounds on intracellular bacterial replication, adherent HKLs experimentally infected with the bacteria were analysed using flow cytometry and intracellular labelling of bacteria by specific antibodies. We found that flumequine did not inhibit intracellular bacterial replication. Unexpectedly, the results indicated that the intracellularly effiacy of the drug was reduced. The HPLC method used proved to be highly applicable for accurate determination of intracellular drug concentrations. When combined with sensitive and specific flow cytometry analyses for identification and measurement of intracellular bacterial replication, we suggest that this approach can be very valuable for the design of antibacterial treatments of intracellular pathogens.

  5. The immune response of juvenile Atlantic cod (Gadus morhua L.) to chronic exposure to produced water.

    PubMed

    Pérez-Casanova, Juan C; Hamoutene, Dounia; Samuelson, Stephanie; Burt, Kimberly; King, Thomas L; Lee, Kenneth

    2010-07-01

    Produced water (PW) is the main discharge from the offshore oil industry and contains oil-derived compounds such as poly-aromatic hydrocarbons, phenols, alkylphenols, and heavy metals. Studies suggest that PW discharges may affect the biota over larger areas from the oil drilling sites at sea than originally predicted. We investigated the effects of chronic exposure to PW on some aspects of juvenile Atlantic cod immunity, stress response and growth by intermittently exposing fish to 0, 100 or 200 ppm of PW for 22 weeks. No significant effects of PW were observed on growth, hepatosomatic index, condition factor or plasma cortisol. The respiratory burst (RB) of circulating leukocytes was significantly elevated in the 100 ppm group only, while the RB of head-kidney leukocytes was significantly decreased in both the 100 and 200 ppm groups. Significant up-regulation of the mRNA expression of beta-2-microglobulin, immunoglobulin-M light chain and interleukins-1beta and -8 was observed in the 200 ppm group, while the down-regulation of interferon stimulated gene 15 was obvious for both the 100 and 200 ppm groups. The results suggest that chronic exposure to environmentally relevant concentrations of PW causes modulations of the immune system of juvenile Atlantic cod with most immune parameters being stimulated, potentially resulting in an energetic cost that may be detrimental to the fish.

  6. Synergies between climate and management for Atlantic cod fisheries at high latitudes.

    PubMed

    Kjesbu, Olav Sigurd; Bogstad, Bjarte; Devine, Jennifer A; Gjøsæter, Harald; Howell, Daniel; Ingvaldsen, Randi B; Nash, Richard D M; Skjæraasen, Jon Egil

    2014-03-04

    The widespread depletion of commercially exploited marine living resources is often seen as a general failure of management and results in criticism of contemporary management procedures. When populations show dramatic and positive changes in population size, this invariably leads to questions about whether favorable climatic conditions or good management (or both) were responsible. The Barents Sea cod (Gadus morhua) stock has recently increased markedly and the spawning stock biomass is now at an unprecedented high. We identify the crucial social and environmental factors that made this unique growth possible. The relationship between vital rates of Barents Sea cod stock productivity (recruitment, growth, and mortality) and environment is investigated, followed by simulations of population size under different management scenarios. We show that the recent sustained reduction in fishing mortality, facilitated by the implementation of a "harvest control rule," was essential to the increase in population size. Simulations show that a drastic reduction in fishing mortality has resulted in a doubling of the total population biomass compared with that expected under the former management regime. However, management alone was not solely responsible. We document that prevailing climate, operating through several mechanistic links, positively reinforced management actions. Heightened temperature resulted in an increase in the extent of the suitable feeding area for Barents Sea cod, likely offering a release from density-dependent effects (for example, food competition and cannibalism) through prolonged overlap with prey and improved adult stock productivity. Management and climate may thus interact to give a positive outlook for exploited high-latitude marine resources.

  7. Effects of North Sea oil and alkylphenols on biomarker responses in juvenile Atlantic cod (Gadus morhua).

    PubMed

    Sturve, Joachim; Hasselberg, Linda; Fälth, Herman; Celander, Malin; Förlin, Lars

    2006-06-01

    A consequence of oil drilling at sea is the release of produced water contaminated with e.g. polycyclic aromatic hydrocarbons (PAH) and alkylphenols. In the present study, juvenile Atlantic cod were exposed to North Sea oil, nonylphenol and a combination of the North Sea oil and an alkylphenol mixture in a flow-through system. A suite of hepatic biomarkers were analysed. Exposure to North Sea oil resulted in strong induction of CYP1A protein levels and EROD activities. Exposure to nonylphenol, on the other hand, resulted in decreased CYP1A levels and EROD activities. Thus, nonylphenol appears to down-regulate CYP1A expression in Atlantic cod. Combined exposure to North Sea oil with an alkylphenol mixture resulted in lower EROD induction, compared to that in fish exposed to North Sea oil alone. This difference was not statistically significant, but still we believe that the alkylphenols have inhibited CYP1A activities in the fish which may have compromised CYP1A mediated metabolism of other xenobiotics, including PAH. CYP3A protein levels were lower, compared to controls, in fish exposed to nonylphenol and the combination of North Sea oil and alkylphenol mixture. In contrast, the oil alone had no effect on CYP3A protein content. North Sea oil exposure, alone or in combination with alkylphenols, caused oxidative stress observed as elevated levels of GSSG content and GR and CAT activities. Interestingly, exposure to nonylphenol resulted in a marked depletion of total glutathione levels. This apparent depletion may be a consequence of increased conjugation of glutathione to nonylphenol followed by excretion. An increase in conjugation enzyme GST activity was observed in the nonylphenol exposed group, although the difference was not significant. No sign of oxidative damage, measured as lipid peroxidation, was observed in any of the exposures experiments. This study suggests that North Sea oil may lead to oxidative stress and altered CYP1A and CYP3A expression

  8. Residency, site fidelity and habitat use of Atlantic cod (Gadus morhua) at an offshore wind farm using acoustic telemetry.

    PubMed

    Reubens, Jan T; Pasotti, Francesca; Degraer, Steven; Vincx, Magda

    2013-09-01

    Because offshore wind energy development is fast growing in Europe it is important to investigate the changes in the marine environment and how these may influence local biodiversity and ecosystem functioning. One of the species affected by these ecosystem changes is Atlantic cod (Gadus morhua), a heavily exploited, commercially important fish species. In this research we investigated the residency, site fidelity and habitat use of Atlantic cod on a temporal scale at windmill artificial reefs in the Belgian part of the North Sea. Acoustic telemetry was used and the Vemco VR2W position system was deployed to quantify the movement behaviour. In total, 22 Atlantic cod were tagged and monitored for up to one year. Many fish were present near the artificial reefs during summer and autumn, and demonstrated strong residency and high individual detection rates. When present within the study area, Atlantic cod also showed distinct habitat selectivity. We identified aggregation near the artificial hard substrates of the wind turbines. In addition, a clear seasonal pattern in presence was observed. The high number of fish present in summer and autumn alternated with a period of very low densities during the winter period.

  9. First feed affects the expressions of microRNA and their targets in Atlantic cod.

    PubMed

    Bizuayehu, Teshome Tilahun; Furmanek, Tomasz; Karlsen, Ørjan; van der Meeren, Terje; Edvardsen, Rolf Brudvik; Rønnestad, Ivar; Hamre, Kristin; Johansen, Steinar D; Babiak, Igor

    2016-04-14

    To our knowledge, there is no report on microRNA (miRNA) expression and their target analysis in relation to the type of the first feed and its effect on the further growth of fish. Atlantic cod (Gadus morhua) larvae have better growth and development performance when fed natural zooplankton as a start-feed, as compared with those fed typical aquaculture start-feeds. In our experiment, two groups of Atlantic cod larvae were fed reference feed (zooplankton, mostly copepods, filtered from a seawater pond) v. aquaculture feeds: enriched rotifers (Brachionus sp.) and later brine shrimp (Artemia salina). We examined the miRNA expressions of six defined developmental stages as determined and standardised by body length from first feeding for both diet groups. We found eight miRNA (miR-9, miR-19a, miR-130b, miR-146, miR-181a, miR-192, miR-206 and miR-11240) differentially expressed between the two feeding groups in at least one developmental stage. We verified the next-generation sequencing data using real-time RT-PCR. We found 397 putative targets (mRNA) to the differentially expressed miRNA; eighteen of these mRNA showed differential expression in at least one stage. The patterns of differentially expressed miRNA and their putative target mRNA were mostly inverse, but sometimes also concurrent. The predicted miRNA targets were involved in different pathways, including metabolic, phototransduction and signalling pathways. The results of this study provide new nutrigenomic information on the potential role of miRNA in mediating nutritional effects on growth during the start-feeding period in fish larvae.

  10. Multiple specialised goose-type lysozymes potentially compensate for an exceptional lack of chicken-type lysozymes in Atlantic cod.

    PubMed

    Seppola, Marit; Bakkemo, Kathrine Ryvold; Mikkelsen, Helene; Myrnes, Bjørnar; Helland, Ronny; Irwin, David M; Nilsen, Inge W

    2016-06-21

    Previous analyses of the Atlantic cod genome showed unique combinations of lacking and expanded number of genes for the immune system. The present study examined lysozyme activity, lysozyme gene distribution and expression in cod. Enzymatic assays employing specific bacterial lysozyme inhibitors provided evidence for presence of g-type, but unexpectedly not for c-type lysozyme activity. Database homology searches failed to identify any c-type lysozyme gene in the cod genome or in expressed sequence tags from cod. In contrast, we identified four g-type lysozyme genes (LygF1a-d) constitutively expressed, although differentially, in all cod organs examined. The active site glutamate residue is replaced by alanine in LygF1a, thus making it enzymatic inactive, while LygF1d was found in two active site variants carrying alanine or glutamate, respectively. In vitro and in vivo infection by the intracellular bacterium Francisella noatunensis gave a significantly reduced LygF1a and b expression but increased expression of the LygF1c and d genes as did also the interferon gamma (IFNγ) cytokine. These results demonstrate a lack of c-type lysozyme that is unprecedented among vertebrates. Our results further indicate that serial gene duplications have produced multiple differentially regulated cod g-type lysozymes with specialised functions potentially compensating for the lack of c-type lysozymes.

  11. Influence of environmental changes in the north-western Atlantic Ocean on a parasite, Echinorhynchus gadi (Acanthocephala) of Atlantic cod ( Gadus morhua) occurring off coastal Labrador, Canada.

    PubMed

    Khan, R A

    2008-09-01

    A study was conducted to determine the influence of environmental change on an endoparasite, Echinorhynchus gadi (Acanthocephala) of Atlantic cod (Gadus morhua) over a 30-year period off the coast of Labrador in the north-western Atlantic, North Atlantic Fisheries Organization subareas 2J-3K. Cod, once an abundant fish species that had been commercially exploited for many decades, declined precipitously during the mid-1980s onwards. This decline was attributed to climatic changes that affected the entire food chain from zooplankton to fish, sea birds and marine mammals. A monitoring programme was introduced, sampling cod by otter trawling using research vessels. The fish, after capture, were frozen at - 20 degrees C, subsequently thawed and the digestive tract removed and examined for the parasite in 2006. Data from samples taken in 1976, 1980-81, 1986, 1990, 2000 and 2003 were compared statistically with those collected in 2006. The results indicate a decline in the prevalence and mean abundance of E. gadi in 1986 with a minimum in 2000 but increasing gradually in 2003 and 2006. These changes were coincident initially with a decline of oceanic temperature and the entire food web, including capelin (Mallotus villosus), a preferred prey of cod and primary source of E. gadi. The increase in prevalence and mean abundance of the parasite in 2006 were associated with an increase of oceanic temperature and the return of small schools of capelin to offshore areas. Cod older than 4 years harboured a greater abundance of E. gadi than younger fish, while no difference was observed between the sexes. The results suggest that the abundance of E. gadi can be useful as a bioindicator of environmental changes in the north-western Atlantic.

  12. Effects of ocean acidification increase embryonic sensitivity to thermal extremes in Atlantic cod, Gadus morhua.

    PubMed

    Dahlke, Flemming T; Leo, Elettra; Mark, Felix C; Pörtner, Hans-Otto; Bickmeyer, Ulf; Frickenhaus, Stephan; Storch, Daniela

    2017-04-01

    Thermal tolerance windows serve as a powerful tool for estimating the vulnerability of marine species and their life stages to increasing temperature means and extremes. However, it remains uncertain to which extent additional drivers, such as ocean acidification, modify organismal responses to temperature. This study investigated the effects of CO2 -driven ocean acidification on embryonic thermal sensitivity and performance in Atlantic cod, Gadus morhua, from the Kattegat. Fertilized eggs were exposed to factorial combinations of two PCO2 conditions (400 μatm vs. 1100 μatm) and five temperature treatments (0, 3, 6, 9 and 12 °C), which allow identifying both lower and upper thermal tolerance thresholds. We quantified hatching success, oxygen consumption (MO2 ) and mitochondrial functioning of embryos as well as larval morphometrics at hatch and the abundance of acid-base-relevant ionocytes on the yolk sac epithelium of newly hatched larvae. Hatching success was high under ambient spawning conditions (3-6 °C), but decreased towards both cold and warm temperature extremes. Elevated PCO2 caused a significant decrease in hatching success, particularly at cold (3 and 0 °C) and warm (12 °C) temperatures. Warming imposed limitations to MO2 and mitochondrial capacities. Elevated PCO2 stimulated MO2 at cold and intermediate temperatures, but exacerbated warming-induced constraints on MO2 , indicating a synergistic interaction with temperature. Mitochondrial functioning was not affected by PCO2 . Increased MO2 in response to elevated PCO2 was paralleled by reduced larval size at hatch. Finally, ionocyte abundance decreased with increasing temperature, but did not differ between PCO2 treatments. Our results demonstrate increased thermal sensitivity of cod embryos under future PCO2 conditions and suggest that acclimation to elevated PCO2 requires reallocation of limited resources at the expense of embryonic growth. We conclude that ocean acidification constrains

  13. Rested and stressed farmed Atlantic cod (Gadus morhua) chilled in ice or slurry and effects on quality.

    PubMed

    Digre, Hanne; Erikson, Ulf; Aursand, Ida G; Gallart-Jornet, Lorena; Misimi, Ekrem; Rustad, Turid

    2011-01-01

    The main objectives of this study were to investigate (1) whether rested harvest of farmed cod was better maintained by chilling with slurry rather than by traditional ice storage, (2) whether chilling with slurry would be a feasible chilling method to assure low core temperatures (≤0 °C) at packing of gutted fish, and (3) the effects of superchilling compared with traditional ice on selected quality parameters of cod during storage. In the experiment, seawater slurry at -2.0 ± 0.3 °C was used. Anesthetized (AQUI-S™), percussion stunned, and stressed cod chilled in slurry were compared. Cod stored on ice were used as reference group. The fish were evaluated at the day of slaughter, and after 7 and 14 d of storage according to handling stress (initial muscle pH, muscle twitches, rigor mortis), core temperatures, quality index method, microbial counts, weight changes, salt and water content, water distribution, pH, adenosine triphosphate-degradation products, K-value, water-holding capacity, fillet color, and texture. Chilling cod in slurry was more rapid than chilling in ice. Prechilling (1 d) of cod in slurry before subsequent ice storage resulted in lower quality 7 d postmortem compared with both ice and continuous slurry storage. The potential advantages of superchilling became more prominent after 14 d with lower microbiological activity, better maintenance of freshness (lower total quality index scores and lower K-values) compared with fish stored on ice. A drawback with slurry-stored fish was that cloudy eyes developed earlier, in addition to weight gain and salt uptake compared to ice-stored fish. Practical Application: Chilling is an essential operation in any fish-processing plant. This manuscript addresses different applications of slurry ice in the processing and storage of Atlantic cod. Cod quality was assessed after 7 and 14 d of iced and superchilled storage.

  14. Direct and social genetic parameters for growth and fin damage traits in Atlantic cod (Gadus morhua)

    PubMed Central

    2014-01-01

    Background The aim of the study was to estimate genetic parameters for direct and social genetic effects (SGE) for growth and welfare traits in farmed Atlantic cod (Gadus morhua). A SGE refers to the effect of an individual’s genes on trait performance of its social partners. In total, 2100 individually tagged juveniles from 100 families at an average age of 222 days post-hatching were used. Each family was separated into three groups of seven fish, and were randomly assigned to 100 experimental tanks, together with fish from two other families. Body weight and length of the first, second and third dorsal fin and the caudal fin measured by digital image analysis were measured at the start of the experiment, after two weeks, and after six weeks. Fin erosion was scored subjectively after six weeks. Variance components estimated using a conventional animal model were compared to those of an animal model including a SGE. Results Heritabilities from the conventional animal model ranged from 0.24 to 0.34 for body weight and 0.05 to 0.80 for fin length. Heritabilities for fin erosion were highest for the first dorsal fin (0.83 ± 0.08, mean ± standard error) and lowest for the third dorsal fin (0.01 ± 0.04). No significant SGE were found for body weight, whereas SGE for fin lengths were significant after two and six weeks. Contributions to the total heritable variance were equal to 21.5% (6.1 ± 2.1) for the direct effect, 33.1% (9.4 ± 3.2) for the direct-social covariance, and 45.4% (12.9 ± 4.1) for the social variance for length of the first dorsal fin. For fin erosion, SGE were only significant for the second and third dorsal fin. Conclusions Including SGE for fin length and fin erosion in the animal model increased the estimated heritable variation. However, estimates of total heritable variances were inaccurate and a larger experiment is needed to accurately quantify total heritable variance. Despite this, our results demonstrate that

  15. Variation in embryonic mortality and maternal transcript expression among Atlantic cod (Gadus morhua) broodstock: a functional genomics study.

    PubMed

    Rise, Matthew L; Nash, Gordon W; Hall, Jennifer R; Booman, Marije; Hori, Tiago S; Trippel, Edward A; Gamperl, A Kurt

    2014-12-01

    Early life stage mortality is an important issue for Atlantic cod aquaculture, yet the impact of the cod maternal (egg) transcriptome on egg quality and mortality during embryonic development is poorly understood. In the present work, we studied embryonic mortality and maternal transcript expression using eggs from 15 females. Total mortality at 7days post-fertilization (7 dpf, segmentation stage) was used as an indice of egg quality. A 20,000 probe (20K) microarray experiment compared the 7hours post-fertilization (7 hpf, ~2-cell stage) egg transcriptome of the two lowest quality females (>90% mortality at 7 dpf) to that of the highest quality female (~16% mortality at 7 dpf). Forty-three microarray probes were consistently differentially expressed in both low versus high quality egg comparisons (25 higher expressed in low quality eggs, and 18 higher expressed in high quality eggs). The microarray experiment also identified many immune-relevant genes [e.g. interferon (IFN) pathway genes ifngr1 and ifrd1)] that were highly expressed in eggs of all 3 females regardless of quality. Twelve of the 43 candidate egg quality-associated genes, and ifngr1, ifrd1 and irf7, were included in a qPCR study with 7 hpf eggs from all 15 females. Then, the genes that were confirmed by qPCR to be greater than 2-fold differentially expressed between 7 hpf eggs from the lowest and highest quality females (dcbld1, ddc, and acy3 more highly expressed in the 2 lowest quality females; kpna7 and hacd1 more highly expressed in the highest quality female), and the 3 IFN pathway genes, were included in a second qPCR study with unfertilized eggs. While some maternal transcripts included in these qPCR studies were associated with extremes in egg quality, there was little correlation between egg quality and gene expression when all females were considered. Both dcbld1 and ddc showed greater than 100-fold differences in transcript expression between females and were potentially influenced by

  16. Detection of Francisella piscicida in Atlantic cod (Gadus morhua L) by the loop-mediated isothermal amplification (LAMP) reaction.

    PubMed

    Caipang, Christopher M A; Kulkarni, Amod; Brinchmann, Monica F; Korsnes, Kjetil; Kiron, Viswanath

    2010-06-01

    The loop-mediated isothermal amplification (LAMP) reaction was evaluated for its speed and sensitivity in detecting the presence of Francisella piscicida, the causative agent of francisellosis in Atlantic cod (Gadus morhua). Four primer sets, consisting of two outer and two inner, were designed from the groEL gene of the pathogen. The LAMP reaction was optimised at 63 degrees C for 1h using bacterial genomic DNA as the template and the products were visualised under ultra-violet light and analysed by agarose gel electrophoresis. A ladder-like pattern of bands, specific for F. piscicida, was amplified from positive samples. The method was highly specific for the detection of F. piscicida and was 100 times more sensitive than conventional PCR. In addition, the LAMP assay was able to detect the pathogen in kidney and splenic samples of naturally-infected Atlantic cod.

  17. Experimental Challenge of Atlantic Cod (Gadus morhua) with a Brucella pinnipedialis Strain from Hooded Seal (Cystophora cristata)

    PubMed Central

    Nymo, Ingebjørg Helena; Seppola, Marit; Al Dahouk, Sascha; Bakkemo, Kathrine Ryvold; Jiménez de Bagüés, María Pilar; Godfroid, Jacques; Larsen, Anett Kristin

    2016-01-01

    Pathology has not been observed in true seals infected with Brucella pinnipedialis. A lack of intracellular survival and multiplication of B. pinnipedialis in hooded seal (Cystophora cristata) macrophages in vitro indicates a lack of chronic infection in hooded seals. Both epidemiology and bacteriological patterns in the hooded seal point to a transient infection of environmental origin, possibly through the food chain. To analyse the potential role of fish in the transmission of B. pinnipedialis, Atlantic cod (Gadus morhua) were injected intraperitoneally with 7.5 x 107 bacteria of a hooded seal field isolate. Samples of blood, liver, spleen, muscle, heart, head kidney, female gonads and feces were collected on days 1, 7, 14 and 28 post infection to assess the bacterial load, and to determine the expression of immune genes and the specific antibody response. Challenged fish showed an extended period of bacteremia through day 14 and viable bacteria were observed in all organs sampled, except muscle, until day 28. Neither gross lesions nor mortality were recorded. Anti-Brucella antibodies were detected from day 14 onwards and the expression of hepcidin, cathelicidin, interleukin (IL)-1β, IL-10, and interferon (IFN)-γ genes were significantly increased in spleen at day 1 and 28. Primary mononuclear cells isolated from head kidneys of Atlantic cod were exposed to B. pinnipedialis reference (NCTC 12890) and hooded seal (17a-1) strain. Both bacterial strains invaded mononuclear cells and survived intracellularly without any major reduction in bacterial counts for at least 48 hours. Our study shows that the B. pinnipedialis strain isolated from hooded seal survives in Atlantic cod, and suggests that Atlantic cod could play a role in the transmission of B. pinnipedialis to hooded seals in the wild. PMID:27415626

  18. Integrative Approach for the Reliable Detection and Specific Identification of the Microsporidium Loma morhua in Atlantic Cod (Gadus morhua).

    PubMed

    Frenette, Aaron P; Eydal, Matthías; Hansen, Haakon; Burt, Michael D B; Duffy, Michael S

    2017-01-01

    Microsporidia are fungal parasites that infect diverse invertebrate and vertebrate hosts. Finfish aquaculture supports epizootics due to high host density and the high biotic potential of these parasites. Reliable methods for parasite detection and identification are a necessary precursor to empirical assessment of strategies to mitigate the effects of these pathogens during aquaculture. We developed an integrative approach to detect and identify Loma morhua infecting Atlantic cod. We show that the spleen is more reliable than the commonly presumed gills as best organ for parasite detection in spite of substantial morphological plasticity in xenoma complexes. We developed rDNA primers with 100% sensitivity in detecting L. morhua and with utility in distinguishing some congeneric Loma species. ITS sequencing is necessary to distinguish L. morhua from other congeneric microsporidia due to intraspecific nucleotide variation. 64% of L. morhua ITS variants from Atlantic cod have a 9-nucleotide motif that distinguishes it from Loma spp. infecting non-Gadus hosts. The remaining 36% of ITS variants from Atlantic cod are distinguished from currently represented Loma spp., particularly those infecting Gadus hosts, based on a 14-nucleotide motif. This research approach is amenable to developing templates in support of reliable detection and identification of other microsporidian parasites in fishes.

  19. Unraveling the evolution of the Atlantic cod's (Gadus morhua L.) alternative immune strategy.

    PubMed

    Malmstrøm, Martin; Jentoft, Sissel; Gregers, Tone F; Jakobsen, Kjetill S

    2013-01-01

    Genes encoding the major histocompatibility complex (MHC) have been thought to play a vital role in the adaptive immune system in all vertebrates. The discovery that Atlantic cod (Gadus morhua) has lost important components of the MHC II pathway, accompanied by an unusually high number of MHC I genes, shed new light on the evolution and plasticity of the immune system of teleosts as well as in higher vertebrates. The overall aim of this study was to further investigate the highly expanded repertoire of MHC I genes using a cDNA approach to obtain sequence information of both the binding domains and the sorting signaling potential in the cytoplasmic tail. Here we report a novel combination of two endosomal sorting motifs, one tyrosine-based associated with exogenous peptide presentation by cross-presenting MHCI molecules, and one dileucine-based associated with normal MHC II functionality. The two signal motifs were identified in the cytoplasmic tail in a subset of the genes. This indicates that these genes have evolved MHC II-like functionality, allowing a more versatile use of MHC I through cross-presentation. Such an alternative immune strategy may have arisen through adaptive radiation and acquisition of new gene function as a response to changes in the habitat of its ancestral lineage.

  20. Maternal transfer and transcriptional onset of immune genes during ontogenesis in Atlantic cod.

    PubMed

    Seppola, Marit; Johnsen, Hanne; Mennen, Saskia; Myrnes, Bjørnar; Tveiten, Helge

    2009-11-01

    The immune system in teleosts is not completely developed during embryonic and larval stages and immune competence is assumed to be restricted. This study is the first to address whether immune transcripts are maternally transferred to offspring and when immune genes are transcriptionally active in Atlantic cod (Gadus morhua). In unfertilised eggs, transcripts encoding lysozyme and cathelicidin were found indicating maternal transfer of antibacterial transcripts. Lysozyme activity was also present at this stage suggesting the presence of a functional protein. Transcripts of two other putative antibacterial genes (hepcidin and pentraxin) and antiviral genes (ISG15 and LGP2) were absent in unfertilised eggs. The transcriptional onset of these genes occurred during the gastrula period. Transcripts of the heavy chain constant regions of the immunoglobulin (Ig) D, membrane-associated and secreted form of IgM were absent in unfertilised eggs. Transcription of the heavy chain locus commenced at low levels during the segmentation period indicating the onset of B-cell development. Most innate immune genes showed an increase in transcription around hatch and first feeding, indicating a preparation for increased pathogen exposure at this time. Prior to and during metamorphosis all genes showed a pronounced elevation in transcript levels indicating a further maturation of the immune system during this period.

  1. Environmental toxicology: population modeling of cod larvae shows high sensitivity to loss of zooplankton prey.

    PubMed

    Stige, Leif Christian; Ottersen, Geir; Hjermann, Dag Ø; Dalpadado, Padmini; Jensen, Louise K; Stenseth, Nils Chr

    2011-02-01

    Two factors determine whether pollution is likely to affect a population indirectly through loss of prey: firstly, the sensitivity of the prey to the pollutants, and secondly, the sensitivity of the predator population to loss of prey at the given life stage. We here apply a statistical recruitment model for Northeast Arctic cod to evaluate the sensitivity of cod cohorts to loss of zooplankton prey, for example following an oil spill. The calculations show that cod cohorts are highly sensitive to possible zooplankton biomass reductions in the distribution area of the cod larvae, and point to a need for more knowledge about oil-effects on zooplankton. Our study illustrates how knowledge about population dynamics may guide which indirect effects to consider in environmental impact studies.

  2. Changes in natural mortality of Atlantic cod ( Gadus morhua) on Eastern Georges Bank

    NASA Astrophysics Data System (ADS)

    Wang, Yanjun

    2016-10-01

    The assessment of Eastern Georges Bank cod with the assumption of a constant natural mortality of 0.2 has over-estimated stock productivity, resulting in a severe retrospective pattern since the late 2000s. Comparing relative exploitation rate (ratio of fishery catch at age to survey abundance indices at age) with total mortality calculated from the age distribution in surveys indicated a conflict when constant natural mortality was assumed. This inconsistency implies an increase in natural mortality since the mid-1990s. In this paper, natural mortality estimated by Virtual Population Analysis (VPA) indicated that natural mortality for this stock has increased to 0.8 since the mid-1990s for ages 6+. Potential factors contributing to this elevated natural mortality, including poor fish conditions and increased losses due to seal predation were discussed.

  3. Nucleotide enrichment of live feed: a promising protocol for rearing of Atlantic cod Gadus morhua larvae.

    PubMed

    Lanes, Carlos Frederico Ceccon; Bolla, Sylvie; Fernandes, Jorge M O; Nicolaisen, Ove; Kiron, Viswanath; Babiak, Igor

    2012-10-01

    We investigated the effect of two commercial nucleotide products (NT1 and NT2), administered through live feed, on growth and stress tolerance of Atlantic cod larvae. Expression of genes related to muscle growth (igf-1, igf1r, igf-2, fst, fgf6, myod, and myhc) and nucleotide metabolism (uox, hprt, ndk, and uck) was evaluated during larval development. In addition, the expression of genes related to stress (hif-1α, hif-2α, hif-3α, and mb) was studied after an air exposure stress test. The enrichment of rotifers with nucleotides did not reveal any difference in nucleotide profiles, the exception being the RNA level of the NT1-enriched group that was significantly higher than the unenriched rotifer. Unenriched Artemia showed poor nucleotide profiles compared to enriched Artemia since 5' UMP, 5' GMP, and 5' AMP were observed only in the nucleotide groups. At 38 days post-hatch (dph), NT1 group had significantly higher dry weight (3.1 ± 0.1 mg) than the control (CON; 2.3 ± 0.1 mg). The treatments did not produce any significant differences in the expression of the key myogenic genes. Among the genes associated with nucleotide metabolism, ndk was down-regulated in NT1 at 38 dph. In the air exposure test, survival was significantly higher in the CON (77 ± 6 %) than in NT1 (48 ± 3 %) and NT2 (50 ± 3 %). After air exposure, mb was expressed at lower levels in NT2 group, hif-2α was induced in NT1 group, and hif-3α was upregulated in all groups. Our findings indicate that the improvement in the nucleotide profile of Artemia upon nucleotide enrichment could eventuate in the rapid growth of larvae.

  4. Temperature Modulates the Effects of Ocean Acidification on Intestinal Ion Transport in Atlantic Cod, Gadus morhua

    PubMed Central

    Hu, Marian Y.; Michael, Katharina; Kreiss, Cornelia M.; Stumpp, Meike; Dupont, Sam; Tseng, Yung-Che; Lucassen, Magnus

    2016-01-01

    CO2-driven seawater acidification has been demonstrated to enhance intestinal bicarbonate secretion rates in teleosts, leading to an increased release of CaCO3 under simulated ocean acidification scenarios. In this study, we investigated if increasing CO2 levels stimulate the intestinal acid–base regulatory machinery of Atlantic cod (Gadus morhua) and whether temperatures at the upper limit of thermal tolerance stimulate or counteract ion regulatory capacities. Juvenile G. morhua were acclimated for 4 weeks to three CO2 levels (550, 1200, and 2200 μatm) covering present and near-future natural variability, at optimum (10°C) and summer maximum temperature (18°C), respectively. Immunohistochemical analyses revealed the subcellular localization of ion transporters, including Na+/K+-ATPase (NKA), Na+/H+-exchanger 3 (NHE3), Na+/HCO3− cotransporter (NBC1), pendrin-like Cl−/HCO3− exchanger (SLC26a6), V-type H+-ATPase subunit a (VHA), and Cl− channel 3 (CLC3) in epithelial cells of the anterior intestine. At 10°C, proteins and mRNA were generally up-regulated for most transporters in the intestinal epithelium after acclimation to higher CO2 levels. This supports recent findings demonstrating increased intestinal HCO3− secretion rates in response to CO2 induced seawater acidification. At 18°C, mRNA expression and protein concentrations of most ion transporters remained unchanged or were even decreased, suggesting thermal compensation. This response may be energetically favorable to retain blood HCO3− levels to stabilize pHe, but may negatively affect intestinal salt and water resorption of marine teleosts in future oceans. PMID:27313538

  5. Temperature Modulates the Effects of Ocean Acidification on Intestinal Ion Transport in Atlantic Cod, Gadus morhua.

    PubMed

    Hu, Marian Y; Michael, Katharina; Kreiss, Cornelia M; Stumpp, Meike; Dupont, Sam; Tseng, Yung-Che; Lucassen, Magnus

    2016-01-01

    CO2-driven seawater acidification has been demonstrated to enhance intestinal bicarbonate secretion rates in teleosts, leading to an increased release of CaCO3 under simulated ocean acidification scenarios. In this study, we investigated if increasing CO2 levels stimulate the intestinal acid-base regulatory machinery of Atlantic cod (Gadus morhua) and whether temperatures at the upper limit of thermal tolerance stimulate or counteract ion regulatory capacities. Juvenile G. morhua were acclimated for 4 weeks to three CO2 levels (550, 1200, and 2200 μatm) covering present and near-future natural variability, at optimum (10°C) and summer maximum temperature (18°C), respectively. Immunohistochemical analyses revealed the subcellular localization of ion transporters, including Na(+)/K(+)-ATPase (NKA), Na(+)/H(+)-exchanger 3 (NHE3), Na(+)/[Formula: see text] cotransporter (NBC1), pendrin-like Cl(-)/[Formula: see text] exchanger (SLC26a6), V-type H(+)-ATPase subunit a (VHA), and Cl(-) channel 3 (CLC3) in epithelial cells of the anterior intestine. At 10°C, proteins and mRNA were generally up-regulated for most transporters in the intestinal epithelium after acclimation to higher CO2 levels. This supports recent findings demonstrating increased intestinal [Formula: see text] secretion rates in response to CO2 induced seawater acidification. At 18°C, mRNA expression and protein concentrations of most ion transporters remained unchanged or were even decreased, suggesting thermal compensation. This response may be energetically favorable to retain blood [Formula: see text] levels to stabilize pHe, but may negatively affect intestinal salt and water resorption of marine teleosts in future oceans.

  6. Diversification of the expanded teleost-specific toll-like receptor family in Atlantic cod, Gadus morhua

    PubMed Central

    2012-01-01

    Background Toll-like receptors (Tlrs) are major molecular pattern recognition receptors of the innate immune system. Atlantic cod (Gadus morhua) is the first vertebrate known to have lost most of the mammalian Tlr orthologues, particularly all bacterial recognising and other cell surface Tlrs. On the other hand, its genome encodes a unique repertoire of teleost-specific Tlrs. The aim of this study was to investigate if these duplicate Tlrs have been retained through adaptive evolution to compensate for the lack of other cell surface Tlrs in the cod genome. Results In this study, one tlr21, 12 tlr22 and two tlr23 genes representing the teleost-specific Tlr family have been cloned and characterised in cod. Phylogenetic analysis grouped all tlr22 genes under a single clade, indicating that the multiple cod paralogues have arisen through lineage-specific duplications. All tlrs examined were transcribed in immune-related tissues as well as in stomach, gut and gonads of adult cod and were differentially expressed during early development. These tlrs were also differentially regulated following immune challenge by immersion with Vibrio anguillarum, indicating their role in the immune response. An increase in water temperature from 4 to 12°C was associated with a 5.5-fold down-regulation of tlr22d transcript levels in spleen. Maximum likelihood analysis with different evolution models revealed that tlr22 genes are under positive selection. A total of 24 codons were found to be positively selected, of which 19 are in the ligand binding region of ectodomain. Conclusion Positive selection pressure coupled with experimental evidence of differential expression strongly support the hypothesis that teleost-specific tlr paralogues in cod are undergoing neofunctionalisation and can recognise bacterial pathogen-associated molecular patterns to compensate for the lack of other cell surface Tlrs. PMID:23273344

  7. The effect of temperature and body size on metabolic scope of activity in juvenile Atlantic cod Gadus morhua L.

    PubMed

    Tirsgaard, Bjørn; Behrens, Jane W; Steffensen, John F

    2015-01-01

    Changes in ambient temperature affect the physiology and metabolism and thus the distribution of fish. In this study we used intermittent flow respirometry to determine the effect of temperature (2, 5, 10, 15 and 20°C) and wet body mass (BM) (~30-460g) on standard metabolic rate (SMR, mgO2h(-1)), maximum metabolic rate (MMR, mgO2h(-1)) and metabolic scope (MS, mgO2h(-1)) of juvenile Atlantic cod. SMR increased with BM irrespectively of temperature, resulting in an average scaling exponent of 0.87 (0.82-0.92). Q10 values were 1.8-2.1 at temperatures between 5 and 15°C but higher (2.6-4.3) between 2 and 5°C and lower (1.6-1.4) between 15 and 20°C in 200 and 450g cod. MMR increased with temperature in the smallest cod (50g) but in the larger cod MMR plateaued between 10, 15 and 20°C. This resulted in a negative correlation between the optimal temperature for MS (Topt) and BM, Topt being respectively 14.5, 11.8 and 10.9°C in a 50, 200 and 450g cod. Irrespective of BM cold water temperatures resulted in a reduction (30-35%) of MS whereas the reduction of MS at warm temperatures was only evident for larger fish (200 and 450g), caused by plateauing of MMR at 10°C and above. Warm temperatures thus seem favourable for smaller (50g) juvenile cod, but not for larger conspecifics (200 and 450g).

  8. Global transcriptome analysis identifies regulated transcripts and pathways activated during oogenesis and early embryogenesis in Atlantic cod.

    PubMed

    Kleppe, Lene; Edvardsen, Rolf Brudvik; Furmanek, Tomasz; Taranger, Geir Lasse; Wargelius, Anna

    2014-07-01

    The molecular mechanisms underlying oogenesis and maternally controlled embryogenesis in fish are not fully understood, especially in marine species. Our aim was to study the egg and embryo transcriptome during oogenesis and early embryogenesis in Atlantic cod. Follicles from oogenesis stages (pre-, early-, and late-vitellogenic), ovulated eggs, and two embryonic stages (blastula, gastrula) were collected from broodstock fish and fertilized eggs. Gene expression profiles were measured in a 44 K oligo microarray consisting of 23,000 cod genes. Hundreds of differentially expressed genes (DEGs) were identified in the follicle stages investigated, implicating a continuous accumulation and degradation of polyadenylated transcripts throughout oogenesis. Very few DEGs were identified from ovulated egg to blastula, showing a more stable maternal RNA pool in early embryonic stages. The highest induction of expression was observed between blastula and gastrula, signifying the onset of zygotic transcription. During early vitellogenesis, several of the most upregulated genes are linked to nervous system signaling, suggesting increasing requirements for ovarian synaptic signaling to stimulate the rapid growth of oocytes. Highly upregulated genes during late vitellogenesis are linked to protein processing, fat metabolism, osmoregulation, and arrested meiosis. One of the genes with the highest upregulation in the ovulated egg is involved in oxidative phosphorylation, reflecting increased energy requirements during fertilization and the first rapid cell divisions of early embryogenesis. In conclusion, this study provides a large-scale presentation of the Atlantic cod's maternally controlled transcriptome in ovarian follicles through oogenesis, ovulated eggs, and early embryos.

  9. Low impact of exposure to environmentally relevant doses of 226Ra in Atlantic cod (Gadus morhua) embryonic cells.

    PubMed

    Olsvik, Pål A; Berntssen, Marc H G; Hylland, Ketil; Eriksen, Dag Ø; Holen, Elisabeth

    2012-07-01

    The aim of this study was to investigate whether (226)Ra, a radionuclide present in produced water from oil platforms in the North Sea and other offshore drilling areas, could affect vulnerable early life stages of Atlantic cod (Gadus morhua). Blastula-stage embryonic cells (EC) from fertilized eggs of Atlantic cod were isolated and exposed to environmental relevant concentrations of (226)Ra and transcription of selected genes quantified. The results showed a weak, but significant up-regulation of GPx3 and HSP70 transcripts after 48 h of exposure to 2.11 Bq/L. In EC exposed to three (226)Ra concentrations (2.11, 23 and 117 Bq/L) for 12 h, metallothionein, HSP90AA, thioredoxin and caspase 8 were significantly up-regulated in cells exposed to 117 Bq/L, whereas thioredoxin was also significantly up-regulated in EC exposed to 23 Bq/L. When EC were exposed to the same (226)Ra concentrations for 48 h, only heme oxygenase was significantly up-regulated in the 23 Bq/L exposure group. The results suggest that environmentally relevant activities of (226)Ra may induce oxidative stress and apoptosis in fish ECs. Exposure of Atlantic cod EC to Cd, selected as a model toxicant, supported the ability of EC around blastula stage to respond to toxicants by altered transcription. Due to dilution, environmentally relevant concentrations of radionuclides present in produced water would be expected to pose a minor threat to early life stages of fish.

  10. Skeletal muscle growth dynamics and the influence of first-feeding diet in Atlantic cod larvae (Gadus morhua L.).

    PubMed

    Vo, Tu A; Galloway, Trina F; Bardal, Tora; Halseth, Christine K; Øie, Gunvor; Kjørsvik, Elin

    2016-11-15

    Dynamics between hypertrophy (increase in cell size) and hyperplasia (increase in cell numbers) of white and red muscle in relation to body size [standard length (SL)], and the influence of the first-feeding diets on muscle growth were investigated in Atlantic cod larvae (Gadus morhua). Cod larvae were fed copepod nauplii or rotifers of different nutritional qualities from 4 to 29 days post hatching (dph), Artemia nauplii from 20 to 40 dph and a formulated diet from 36 to 60 dph. The short period of feeding with cultivated copepod nauplii had a positive effect on both muscle hyperplasia and hypertrophy after the copepod/rotifer phase (19 dph), and a positive long term effect on muscle hypertrophy (60 dph). The different nutritional qualities of rotifers did not significantly affect muscle growth. We suggest here a model of the dynamics between hyperplasia and hypertrophy of red and white muscle fibre cells in relation to cod SL (4 to 30 mm), where the different red and white muscle growth phases clearly coincided with different metamorphosis stages in cod larvae. These shifts could be included as biomarkers for the different stages of development during metamorphosis. The main dietary muscle effect was that hypertrophic growth of red muscle fibres was stronger in cod larvae that were fed copepods than in larvae that were fed rotifers, both in relation to larval age and size. Red muscle fibres are directly involved in larval locomotory performance, but may also play an important role in the larval myogenesis. This can have a long term effect on growth potential and fish performance.

  11. Skeletal muscle growth dynamics and the influence of first-feeding diet in Atlantic cod larvae (Gadus morhua L.)

    PubMed Central

    Vo, Tu A.; Galloway, Trina F.; Bardal, Tora; Halseth, Christine K.; Øie, Gunvor

    2016-01-01

    ABSTRACT Dynamics between hypertrophy (increase in cell size) and hyperplasia (increase in cell numbers) of white and red muscle in relation to body size [standard length (SL)], and the influence of the first-feeding diets on muscle growth were investigated in Atlantic cod larvae (Gadus morhua). Cod larvae were fed copepod nauplii or rotifers of different nutritional qualities from 4 to 29 days post hatching (dph), Artemia nauplii from 20 to 40 dph and a formulated diet from 36 to 60 dph. The short period of feeding with cultivated copepod nauplii had a positive effect on both muscle hyperplasia and hypertrophy after the copepod/rotifer phase (19 dph), and a positive long term effect on muscle hypertrophy (60 dph). The different nutritional qualities of rotifers did not significantly affect muscle growth. We suggest here a model of the dynamics between hyperplasia and hypertrophy of red and white muscle fibre cells in relation to cod SL (4 to 30 mm), where the different red and white muscle growth phases clearly coincided with different metamorphosis stages in cod larvae. These shifts could be included as biomarkers for the different stages of development during metamorphosis. The main dietary muscle effect was that hypertrophic growth of red muscle fibres was stronger in cod larvae that were fed copepods than in larvae that were fed rotifers, both in relation to larval age and size. Red muscle fibres are directly involved in larval locomotory performance, but may also play an important role in the larval myogenesis. This can have a long term effect on growth potential and fish performance. PMID:27612513

  12. Multiple linked β and α globin genes in Atlantic cod: A PCR based strategy of genomic exploration.

    PubMed

    Halldórsdóttir, Katrín; Arnason, Einar

    2009-01-01

    Allozyme variation in Atlantic cod hemoglobins shows various signs of natural selection. We report a genomic exploration of globin genes in this non-model organism. Applying a PCR based strategy with a strict criterion of phylogenetically informative sites we estimate the number of linked β and α globin genes. We estimate PCR error rate by PCR of cloned DNA and recloning and by analysis of singleton variable sites among clones. Based on the error rate we exclude variable sites so that the remaining variation meets successively stricter criteria of doubleton and triplet variable site. Applying these criteria we find ten clusters of linked β/α globin genes in the genome of Atlantic cod. Six variable amino acid changes in both genes were found in linkage disequilibrium with silent nucleotide substitutions. A phylogenetic tree, based on our strictly phylogenetically informative sites among 57 clones from 19 individuals, is split into two major branches by an amino acid change in a β gene. This change is supported by extensive linkage disequilibrium between the amino acid change and numerous other phylogenetically informative silent nucleotide sites. The different gene sets in the genome may represent different loci encoding different globins and/or allelic variation at some loci.

  13. Global transcriptome analysis identifies regulated transcripts and pathways activated during oogenesis and early embryogenesis in atlantic cod

    PubMed Central

    Kleppe, Lene; Edvardsen, Rolf Brudvik; Furmanek, Tomasz; Taranger, Geir Lasse; Wargelius, Anna

    2014-01-01

    The molecular mechanisms underlying oogenesis and maternally controlled embryogenesis in fish are not fully understood, especially in marine species. Our aim was to study the egg and embryo transcriptome during oogenesis and early embryogenesis in Atlantic cod. Follicles from oogenesis stages (pre-, early-, and late-vitellogenic), ovulated eggs, and two embryonic stages (blastula, gastrula) were collected from broodstock fish and fertilized eggs. Gene expression profiles were measured in a 44 K oligo microarray consisting of 23,000 cod genes. Hundreds of differentially expressed genes (DEGs) were identified in the follicle stages investigated, implicating a continuous accumulation and degradation of polyadenylated transcripts throughout oogenesis. Very few DEGs were identified from ovulated egg to blastula, showing a more stable maternal RNA pool in early embryonic stages. The highest induction of expression was observed between blastula and gastrula, signifying the onset of zygotic transcription. During early vitellogenesis, several of the most upregulated genes are linked to nervous system signaling, suggesting increasing requirements for ovarian synaptic signaling to stimulate the rapid growth of oocytes. Highly upregulated genes during late vitellogenesis are linked to protein processing, fat metabolism, osmoregulation, and arrested meiosis. One of the genes with the highest upregulation in the ovulated egg is involved in oxidative phosphorylation, reflecting increased energy requirements during fertilization and the first rapid cell divisions of early embryogenesis. In conclusion, this study provides a large-scale presentation of the Atlantic cod's maternally controlled transcriptome in ovarian follicles through oogenesis, ovulated eggs, and early embryos. Mol. Reprod. Dev. 81: 619–635, 2014. © 2014 Wiley Periodicals, Inc. PMID:24687555

  14. Transcriptional effects on glutathione S-transferases in first feeding Atlantic cod (Gadus morhua) larvae exposed to crude oil.

    PubMed

    Olsvik, P A; Nordtug, T; Altin, D; Lie, K K; Overrein, I; Hansen, B H

    2010-05-01

    Polycyclic aromatic hydrocarbons (PAHs) and other oil compounds are known to induce stress and impact health of marine organisms. Water-soluble fractions of oil contain components known to induce glutathione S-transferases (GSTs), one of the major classes of phase II detoxifying enzymes present in essentially all eukaryotic organisms. In this study, the transcriptional responses of six GSTs (GST pi, GST mu, GST omega, GST theta, GSY zeta and GST kappa) were examined in early larvae of Atlantic cod Gadus morhua exposed to five concentrations of dispersed oil (containing oil droplets and water-soluble fraction) and water-soluble fractions (WSF) of oil. When Atlantic cod larvae were exposed to WSF (containing 1.31+/-0.31microg summation PAH/L for 4 days), expression of GSTM3 and GSTO1 was significantly increased, whereas no differences in GST expression were observed in larvae exposed to a corresponding 50% lower amount of dispersed oil (containing 0.36+/-0.10 microg summation PAH/L for 4 days). The study suggest that although the oil clearly had severe negative effects on the larvae (i.e. concentration-dependent lethality and growth reduction), only minor effects on GST transcription could be observed using RNA obtained from pooled whole-larvae homogenates. This result indicates that the expression of these important detoxification enzymes is only moderately inducible at such an early developmental stage either reflecting low tolerance of cod larvae to dispersed oil or alternatively that using whole-larvae homogenates may have masked tissue-specific mRNA induction.

  15. Pre-digestion of dietary lipids has only minor effects on absorption, retention and metabolism in larval stages of Atlantic cod (Gadus morhua).

    PubMed

    Hamre, K; Lukram, I M; Rønnestad, I; Nordgreen, A; Saele, O

    2011-03-01

    The hypothesis of the present study was that cod larvae have a limitation in lipid digestion, and that absorption of lipids would increase by pre-hydrolysation. The diets used were designed to contain 15% lipid, of which 40% was phosphatidylcholine (PC) and 60 % was TAG. Cod larvae (40d post hatch (dph)) were fed a single meal where either PC or TAG was radioactively labelled, and the labelled PC or TAG was either intact or hydrolysed (pre-digested). The larvae were then incubated individually in chambers with collection of CO2 for 10 h. The following fractions were analysed for radioactivity: the incubation water (evacuated feed); the intestine; the body; the CO2 trap. The larvae ate a 16-29 μg diet, equivalent to 3·4-5·2 % of dry body weight. In the whole population, 0-16% of the lipid was evacuated. The larvae that had eaten less than 1·9-2·7 μg lipid absorbed close to 100% of the lipid, absorption being defined conservatively as the amount contained in the carcass and CO2, excluding the intestinal tissue. In these larvae, approximately 100 % of the absorbed lipid was also catabolised. In the larvae that ingested more than 1·9-2·7 μg lipid, there was a linear reduction in lipid absorption to a minimum of 55% at the highest lipid intakes parallel to an increasing retention of lipids in the carcass. There were only minor differences in digestion, absorption, retention and metabolism of lipids between the larvae fed the different diets, and the larvae tended to retain lipid classes as they were present in the feed. The study shows that 40-dph Atlantic cod larvae have an efficient utilisation of dietary lipids supplied as intact PC and TAG.

  16. Population Structure of Atlantic Mackerel (Scomber scombrus)

    PubMed Central

    Jansen, Teunis; Gislason, Henrik

    2013-01-01

    Atlantic mackerel (Scomber scombrus) occurs on both sides of the north Atlantic and has traditionally been grouped into 5 spawning components, some of which were thought to be isolated natal homing stocks. Previous studies have provided no evidence for cross Atlantic migration and no or weak support for isolated spawning components within either side of the North Atlantic. We question the de-facto accepted hypothesis of isolation between spawning components on the basis of spawning and age distribution data. The spawning intensities, proxied by larval abundances, are negatively correlated between the North Sea and Celtic Sea, which indicates that the two spawning components may be connected by straying individuals. This finding is based on unique larvae samples collected before the collapse of North Sea component, thus showing that the exchange is not a recent phenomenon due to the collapse. The analyses of old as well as more recent age distributions show that strong year classes spread into other areas where they spawn as adults (“twinning”). Our findings are in accordance with the lack of solid evidence for stock separation from previous analyses of tagging data, genetics, ectoparasite infections, otolith shapes, and blood phenotypes. Because no method has been able to identify the origin of spawning mackerel unequivocally from any of the traditional spawning components, and in the light of our results, we conclude that straying outweighs spatial segregation. We propose a new model where the population structure of mackerel is described as a dynamic cline, rather than as connected contingents. Temporal changes in hydrography and mackerel behavior may affect the steepness of the cline at various locations. The new interpretation of the population structure of Atlantic mackerel has important implications for research, assessment and management. PMID:23741381

  17. Population structure of Atlantic mackerel (Scomber scombrus).

    PubMed

    Jansen, Teunis; Gislason, Henrik

    2013-01-01

    Atlantic mackerel (Scomber scombrus) occurs on both sides of the north Atlantic and has traditionally been grouped into 5 spawning components, some of which were thought to be isolated natal homing stocks. Previous studies have provided no evidence for cross Atlantic migration and no or weak support for isolated spawning components within either side of the North Atlantic. We question the de-facto accepted hypothesis of isolation between spawning components on the basis of spawning and age distribution data. The spawning intensities, proxied by larval abundances, are negatively correlated between the North Sea and Celtic Sea, which indicates that the two spawning components may be connected by straying individuals. This finding is based on unique larvae samples collected before the collapse of North Sea component, thus showing that the exchange is not a recent phenomenon due to the collapse. The analyses of old as well as more recent age distributions show that strong year classes spread into other areas where they spawn as adults ("twinning"). Our findings are in accordance with the lack of solid evidence for stock separation from previous analyses of tagging data, genetics, ectoparasite infections, otolith shapes, and blood phenotypes. Because no method has been able to identify the origin of spawning mackerel unequivocally from any of the traditional spawning components, and in the light of our results, we conclude that straying outweighs spatial segregation. We propose a new model where the population structure of mackerel is described as a dynamic cline, rather than as connected contingents. Temporal changes in hydrography and mackerel behavior may affect the steepness of the cline at various locations. The new interpretation of the population structure of Atlantic mackerel has important implications for research, assessment and management.

  18. Will you swim into my parlour? In situ observations of Atlantic cod (Gadus morhua) interactions with baited pots, with implications for gear design

    PubMed Central

    Walsh, Philip; Favaro, Brett

    2017-01-01

    Pots (also known as traps) are baited fishing gears widely used in commercial fisheries, and are being considered as a tool for harvesting Atlantic cod (Gadus morhua) in Newfoundland and Labrador, Canada. Pots produce lower environmental impacts than many other fishing gears, but they will only be a viable fishing strategy if they are efficient and selective at catching their target species. To study the behaviour of cod in and around pots, and how those behaviours affect pot efficiency, we used long-duration underwater video cameras to assess two models of cod pot deployed in the nearshore waters of Fogo Island, NL. We examined the number of cod that approached the pot, the number and proportion that successfully completed entries into the pot openings, and the number that exited, and related these factors to the direction of water movement. We observed very few entry attempts relative to the number of approaches by cod, and only 22% of all entry attempts were successful. We observed that 50% of approaches, 70% of entry attempts, and 73% of successful entrances occurred against the current, and 25% of cod were able to exit the pot following capture. Based on our observations, we suggest that future cod pots should have a greater number of entrances, or a mechanism to ensure that entrances rotate in line with the current, in order to maximize their catch efficiency for cod. PMID:28194312

  19. Will you swim into my parlour? In situ observations of Atlantic cod (Gadus morhua) interactions with baited pots, with implications for gear design.

    PubMed

    Meintzer, Phillip; Walsh, Philip; Favaro, Brett

    2017-01-01

    Pots (also known as traps) are baited fishing gears widely used in commercial fisheries, and are being considered as a tool for harvesting Atlantic cod (Gadus morhua) in Newfoundland and Labrador, Canada. Pots produce lower environmental impacts than many other fishing gears, but they will only be a viable fishing strategy if they are efficient and selective at catching their target species. To study the behaviour of cod in and around pots, and how those behaviours affect pot efficiency, we used long-duration underwater video cameras to assess two models of cod pot deployed in the nearshore waters of Fogo Island, NL. We examined the number of cod that approached the pot, the number and proportion that successfully completed entries into the pot openings, and the number that exited, and related these factors to the direction of water movement. We observed very few entry attempts relative to the number of approaches by cod, and only 22% of all entry attempts were successful. We observed that 50% of approaches, 70% of entry attempts, and 73% of successful entrances occurred against the current, and 25% of cod were able to exit the pot following capture. Based on our observations, we suggest that future cod pots should have a greater number of entrances, or a mechanism to ensure that entrances rotate in line with the current, in order to maximize their catch efficiency for cod.

  20. Molecular Evidence that Only Two Opsin Subfamilies, the Blue Light- (SWS2) and Green Light-Sensitive (RH2), Drive Color Vision in Atlantic Cod (Gadus morhua)

    PubMed Central

    Søviknes, Anne Mette; Drivenes, Øyvind; Helvik, Jon Vidar

    2014-01-01

    Teleosts show a great variety in visual opsin complement, due to both gene duplication and gene loss. The repertoire ranges from one subfamily of visual opsins (scotopic vision) including rod opsin only retinas seen in many deep-sea species to multiple subfamilies of visual opsins in some pelagic species. We have investigated the opsin repertoire of Atlantic cod (Gadus morhua) using information in the recently sequenced cod genome and found that despite cod not being a deep sea species it lacks visual subfamilies sensitive towards the most extreme parts of the light spectra representing UV and red light. Furthermore, we find that Atlantic cod has duplicated paralogs of both blue-sensitive SWS2 and green-sensitive RH2 subfamilies, with members belonging to each subfamily linked in tandem within the genome (two SWS2-, and three RH2A genes, respectively). The presence of multiple cone opsin genes indicates that there have been duplication events in the cod ancestor SWS2 and RH2 opsins producing paralogs that have been retained in Atlantic. Our results are supported by expressional analysis of cone opsins, which further revealed an ontogenetic change in the array of cone opsins expressed. These findings suggest life stage specific programs for opsin regulation which could be linked to habitat changes and available light as the larvae is transformed into an early juvenile. Altogether we provide the first molecular evidence for color vision driven by only two families of cone opsins due to gene loss in a teleost. PMID:25551396

  1. Functional genomic analysis of the response of Atlantic cod (Gadus morhua) spleen to the viral mimic polyriboinosinic polyribocytidylic acid (pIC).

    PubMed

    Rise, Matthew L; Hall, Jennifer; Rise, Marlies; Hori, Tiago; Gamperl, A Kurt; Kimball, Jennifer; Hubert, Sophie; Bowman, Sharen; Johnson, Stewart C

    2008-01-01

    In order to improve our understanding of how Atlantic cod (Gadus morhua) respond to viruses, we characterized immune-related gene expression in spleen tissues following stimulation with a synthetic double-stranded RNA polyriboinosinic polyribocytidylic acid (pIC). We used reciprocal suppression subtractive hybridization (SSH) cDNA libraries and quantitative RTPCR (QPCR) to identify and quantify pIC-responsive transcripts. A total of 3874 expressed sequence tags (ESTs) were generated from SSH libraries enriched for genes responsive to pIC. Thirteen immune-relevant genes from the libraries were subjected to QPCR. Genes confirmed as up-regulated by pIC included interferon stimulated gene 15, a small inducible cytokine, interferon regulatory factors (1, 7, and 10), MHC class I, viperin, and ATP-dependent helicase LGP2. Alpha-1-microglobulin (bikunin) was down-regulated, suggesting that pIC may suppress the acute phase response. Since the SSH libraries built for this study identified genes involved in the antiviral response, they are important resources for studying the responses of Atlantic cod to viruses. Evidence is provided for the existence of a RIG-I-like RNA helicase viral recognition pathway in Atlantic cod. Taken together, our data show that Atlantic cod can recognize double-stranded RNA and mount a rapid and potent interferon pathway response that is similar to that observed in other fish species and higher vertebrates.

  2. Evidence from data storage tags for the presence of lunar and semilunar behavioral cycles in spawning Atlantic cod

    USGS Publications Warehouse

    Grabowski, Timothy B.; McAdam, Bruce J.; Thorsteinsson, Vilhjalmur; Marteinsdóttir, Gudrún

    2015-01-01

    Understanding the environmental processes determining the timing and success of reproduction is of critical importance to developing effective management strategies of marine fishes. Unfortunately it has proven difficult to comprehensively study the reproductive behavior of broadcast-spawning fishes. The use of electronic data storage tags (DSTs) has the potential to provide insights into the behavior of fishes. These tags allow for data collection over relatively large spatial and temporal scales that can be correlated to predicted environmental conditions and ultimately be used to refine predictions of year class strength. In this paper we present data retrieved from DSTs demonstrating that events putatively identified as Atlantic cod spawning behavior is tied to a lunar cycle with a pronounced semi-lunar cycle within it. Peak activity occurs around the full and new moon with no evidence of relationship with day/night cycles.

  3. Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L.) larvae - can we identify the underlying factors?

    PubMed

    Karlsen, Ørjan; van der Meeren, Terje; Rønnestad, Ivar; Mangor-Jensen, Anders; Galloway, Trina F; Kjørsvik, Elin; Hamre, Kristin

    2015-01-01

    The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1), groups of cod larvae were fed either (a) natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b) enriched rotifers followed by Artemia (the intensive group). In the second experiment (Exp-2), two groups of larvae were fed as in Exp-1, while a third group was fed copepod nauplii (approximately the size of rotifers) throughout the larval stage. In both experiments, growth was not significantly different between the groups during the first three weeks after hatching, but from the last part of the rotifer feeding period and onwards, the growth of the larvae fed copepods was higher than that of the intensive group. In Exp-2, the growth was similar between the two copepod groups during the expeimental period, indicating that nutrient composition, not prey size caused the better growth on copepods. Analyses of the prey showed that total fatty acid composition and the ratio of phospholipids to total lipids was slightly different in the prey organisms, and that protein, taurine, astaxanthin and zinc were lower on a dry weight basis in rotifers than in copepods. Other measured nutrients as DHA, all analysed vitamins, manganese, copper and selenium were similar or higher in the rotifers. When compared to the present knowledge on nutrient requirements, protein and taurine appeared to be the most likely limiting nutrients for growth in cod larvae fed rotifers and Artemia. Larvae fed rotifers/Artemia had a higher whole body lipid content than larvae fed copepods at the end of the experiment (stage 5) after the fish had been fed the same formulated diet for approximately 2 weeks.

  4. Spatio-temporal dynamics of a fish predator: Density-dependent and hydrographic effects on Baltic Sea cod population.

    PubMed

    Bartolino, Valerio; Tian, Huidong; Bergström, Ulf; Jounela, Pekka; Aro, Eero; Dieterich, Christian; Meier, H E Markus; Cardinale, Massimiliano; Bland, Barbara; Casini, Michele

    2017-01-01

    Understanding the mechanisms of spatial population dynamics is crucial for the successful management of exploited species and ecosystems. However, the underlying mechanisms of spatial distribution are generally complex due to the concurrent forcing of both density-dependent species interactions and density-independent environmental factors. Despite the high economic value and central ecological importance of cod in the Baltic Sea, the drivers of its spatio-temporal population dynamics have not been analytically investigated so far. In this paper, we used an extensive trawl survey dataset in combination with environmental data to investigate the spatial dynamics of the distribution of the Eastern Baltic cod during the past three decades using Generalized Additive Models. The results showed that adult cod distribution was mainly affected by cod population size, and to a minor degree by small-scale hydrological factors and the extent of suitable reproductive areas. As population size decreases, the cod population concentrates to the southern part of the Baltic Sea, where the preferred more marine environment conditions are encountered. Using the fitted models, we predicted the Baltic cod distribution back to the 1970s and a temporal index of cod spatial occupation was developed. Our study will contribute to the management and conservation of this important resource and of the ecosystem where it occurs, by showing the forces shaping its spatial distribution and therefore the potential response of the population to future exploitation and environmental changes.

  5. Spatio-temporal dynamics of a fish predator: Density-dependent and hydrographic effects on Baltic Sea cod population

    PubMed Central

    Bartolino, Valerio; Tian, Huidong; Bergström, Ulf; Jounela, Pekka; Aro, Eero; Dieterich, Christian; Meier, H. E. Markus; Cardinale, Massimiliano; Bland, Barbara

    2017-01-01

    Understanding the mechanisms of spatial population dynamics is crucial for the successful management of exploited species and ecosystems. However, the underlying mechanisms of spatial distribution are generally complex due to the concurrent forcing of both density-dependent species interactions and density-independent environmental factors. Despite the high economic value and central ecological importance of cod in the Baltic Sea, the drivers of its spatio-temporal population dynamics have not been analytically investigated so far. In this paper, we used an extensive trawl survey dataset in combination with environmental data to investigate the spatial dynamics of the distribution of the Eastern Baltic cod during the past three decades using Generalized Additive Models. The results showed that adult cod distribution was mainly affected by cod population size, and to a minor degree by small-scale hydrological factors and the extent of suitable reproductive areas. As population size decreases, the cod population concentrates to the southern part of the Baltic Sea, where the preferred more marine environment conditions are encountered. Using the fitted models, we predicted the Baltic cod distribution back to the 1970s and a temporal index of cod spatial occupation was developed. Our study will contribute to the management and conservation of this important resource and of the ecosystem where it occurs, by showing the forces shaping its spatial distribution and therefore the potential response of the population to future exploitation and environmental changes. PMID:28207804

  6. Melanin-concentrating hormone (MCH) and gonadotropin-releasing hormones (GnRH) in Atlantic cod, Gadus morhua: tissue distributions, early ontogeny and effects of fasting.

    PubMed

    Tuziak, Sarah M; Volkoff, Hélène

    2013-12-01

    Melanin-concentrating hormone (MCH) is classically known for its role in regulating teleost fish skin color change for environmental adaptation. Recent evidence suggests that MCH also has appetite-stimulating properties. The gonadotropin-releasing hormone (GnRH) peptide family has dual roles in endocrine control of reproduction and energy status in fish. Atlantic cod (Gadus morhua) are a commercially important aquaculture species inhabiting the shores of Atlantic Canada. In this study, we examine MCH and GnRH transcript expression profiles during early development as well as in central and peripheral tissues and quantify juvenile Atlantic cod MCH and GnRH hypothalamic mRNA expressions following food deprivation. MCH and GnRH3 cDNAs are maternally deposited into cod eggs, while MCH has variable expression throughout early development. GnRH2 and GnRH3 mRNAs "turn-on" during mid-segmentation once the brain is fully developed. For both MCH and GnRH, highest expression appears during the exogenous feeding stages, perhaps supporting their functions as appetite regulators during early development. MCH and GnRH transcripts are found in brain regions related to appetite regulation (telencephalon/preoptic area, optic tectum/thalamus, hypothalamus), as well as the pituitary gland and the stomach, suggesting a peripheral function in food intake regulation. Atlantic cod MCH mRNA is upregulated during fasting, while GnRH2 and GnRH3 transcripts do not appear to be influenced by food deprivation. In conclusion, MCH might be involved in stimulating food intake in juvenile Atlantic cod, while GnRHs may play a more significant role in appetite regulation during early development.

  7. Optimal control of Atlantic population Canada geese

    USGS Publications Warehouse

    Hauser, C.E.; Runge, M.C.; Cooch, E.G.; Johnson, F.A.; Harvey, W.F.

    2007-01-01

    Management of Canada geese (Branta canadensis) can be a balance between providing sustained harvest opportunity while not allowing populations to become overabundant and cause damage. In this paper, we focus on the Atlantic population of Canada geese and use stochastic dynamic programming to determine the optimal harvest strategy over a range of plausible models for population dynamics. There is evidence to suggest that the population exhibits significant age structure, and it is possible to reconstruct age structure from surveys. Consequently the harvest strategy is a function of the age composition, as well as the abundance, of the population. The objective is to maximize harvest while maintaining the number of breeding adults in the population between specified upper and lower limits. In addition, the total harvest capacity is limited and there is uncertainty about the strength of density-dependence. We find that under a density-independent model, harvest is maximized by maintaining the breeding population at the highest acceptable abundance. However if harvest capacity is limited, then the optimal long-term breeding population size is lower than the highest acceptable level, to reduce the risk of the population growing to an unacceptably large size. Under the proposed density-dependent model, harvest is maximized by maintaining the breeding population at an intermediate level between the bounds on acceptable population size; limits to harvest capacity have little effect on the optimal long-term population size. It is clear that the strength of density-dependence and constraints on harvest significantly affect the optimal harvest strategy for this population. Model discrimination might be achieved in the long term, while continuing to meet management goals, by adopting an adaptive management strategy.

  8. Precision-cut liver slices of Atlantic cod (Gadus morhua): an in vitro system for studying the effects of environmental contaminants.

    PubMed

    Eide, M; Karlsen, O A; Kryvi, H; Olsvik, P A; Goksøyr, A

    2014-08-01

    The Atlantic cod (Gadus morhua) is an economically important species commonly consumed by humans. The widespread distribution of cod in the North Atlantic Ocean makes it vulnerable to effluents from human activities, such as coastal industries and offshore petroleum exploration. It has been demonstrated that many effluents have adverse effects on cod reproduction and health, e.g. by disrupting endocrine signaling pathways. The liver, expressing important components of the biotransformation and the endocrine system, is one of the main target organs. Thus, reliable and reproducible in vitro systems of the liver are important for studying effects of environmental contaminants. The aim of this study was to investigate precision-cut liver slices (PCLS) as an alternative in vitro system for toxicological studies of the Atlantic cod liver. Slices of 8 mm in diameter and 250 μm thickness were prepared and cultivated from immature cod. Several analyses to measure the liver slice viability were performed: enzyme assays, histology, and morphometric analysis, all confirming cell viability for up to 72 h in culture. The liver slices were also exposed to two well-known model environmental contaminants, β-naphthoflavone (BNF) and 17α-ethynylestradiol (EE2), representing established agonists for the aryl hydrocarbon receptor (AHR) and the estrogen receptor (ER), respectively. The results showed increased transcription of the target genes cytochrome P450 1A (CYP1A) and vitellogenin (VTG), both well-established biomarkers for exposure of fish to the selected compounds. In conclusion, PCLS is a promising in vitro system for toxicological studies of cod liver cells. The liver slices are viable in culture for several days and respond to environmental contaminants in a dose- and time-specific manner.

  9. Correlation between microbiota and growth in Mangrove Killifish (Kryptolebias marmoratus) and Atlantic cod (Gadus morhua).

    PubMed

    Forberg, Torunn; Sjulstad, Eli Bjørnø; Bakke, Ingrid; Olsen, Yngvar; Hagiwara, Atsushi; Sakakura, Yoshitaka; Vadstein, Olav

    2016-02-15

    The vertebrate gut is host to large communities of bacteria, and one of the beneficial contributions of this commensal gut microbiota is the increased nutritional gain from feed components that the host cannot degrade on its own. Fish larvae of similar age and under the same rearing conditions often diverge with regards to growth. The underlying reasons for this could be differences in genetic background, feeding behavior or digestive capacity. Both feeding behavior and digestion can be influenced by differences in the microbiota. To investigate possible correlations between the size of fish larvae and their gut microbiota, we analyzed the microbiota small and large genetically homogenous killifish and genetically heterogeneous cod larvae by Bray-Curtis Similarity measures of 16S DNA DGGE patterns. A significant difference in richness (p = 0.037) was observed in the gut microbiota of small and large killifish, but the overall gut microbiota was not found to be significantly different (p = 0.13), indicating strong genetic host selection on microbiota composition at the time of sampling. The microbiota of small and large cod larvae was significantly different with regards to evenness and diversity (p = 0.0001), and a strong correlation between microbiota and growth was observed.

  10. Correlation between microbiota and growth in Mangrove Killifish (Kryptolebias marmoratus) and Atlantic cod (Gadus morhua)

    PubMed Central

    Forberg, Torunn; Sjulstad, Eli Bjørnø; Bakke, Ingrid; Olsen, Yngvar; Hagiwara, Atsushi; Sakakura, Yoshitaka; Vadstein, Olav

    2016-01-01

    The vertebrate gut is host to large communities of bacteria, and one of the beneficial contributions of this commensal gut microbiota is the increased nutritional gain from feed components that the host cannot degrade on its own. Fish larvae of similar age and under the same rearing conditions often diverge with regards to growth. The underlying reasons for this could be differences in genetic background, feeding behavior or digestive capacity. Both feeding behavior and digestion can be influenced by differences in the microbiota. To investigate possible correlations between the size of fish larvae and their gut microbiota, we analyzed the microbiota small and large genetically homogenous killifish and genetically heterogeneous cod larvae by Bray-Curtis Similarity measures of 16S DNA DGGE patterns. A significant difference in richness (p = 0.037) was observed in the gut microbiota of small and large killifish, but the overall gut microbiota was not found to be significantly different (p = 0.13), indicating strong genetic host selection on microbiota composition at the time of sampling. The microbiota of small and large cod larvae was significantly different with regards to evenness and diversity (p = 0.0001), and a strong correlation between microbiota and growth was observed. PMID:26875510

  11. Large scale distribution of dioxins, PCBs, heavy metals, PAH-metabolites and radionuclides in cod (Gadus morhua) from the North Atlantic and its adjacent seas.

    PubMed

    Karl, Horst; Kammann, Ulrike; Aust, Marc-Oliver; Manthey-Karl, Monika; Lüth, Anja; Kanisch, Günter

    2016-04-01

    Regarding cod as sea food for human consumption and as bio indicator of the marine eco system, this study is the first approach to combine the analysis of organic and inorganic contaminants and radionuclides in cod muscle as well as PCDD/Fs and dl-PCBs in its livers from the same fishing areas. Concentrations of 1-hydroxypyrene, PCDD/Fs, PCBs, cesium-137 (Cs-137), cadmium and lead were determined in individual or pooled samples over a wide geographic area, including Greenland Seas, Barents Sea, North and Baltic Sea. Highest concentrations were found in samples from the Baltic Sea, lowest in the pristine areas of the Barents Sea and Greenland. Levels of contaminants in cod muscle were found to be far below the established EU maximum levels (ML), regardless of which fishing grounds. In contrast to this, most cod liver samples from the North and Baltic Sea showed PCDD/F and PCB contents exceeding the ML. In addition, new background assessment criteria (BAC) for 1-hydroxypyrene in cod of 4.6 ng mL(-1) bile and for Cs-137 a BAC of 0.16 Bq kg(-1) wet weight are proposed to be included in the European Marine Strategy Framework Directive for cod from the Northeast Atlantic.

  12. Characterisation and expression of secretory phospholipase A2 group IB during ontogeny of Atlantic cod ( Gadus morhua).

    PubMed

    Sæle, Øystein; Nordgreen, Andreas; Olsvik, Pål A; Hamre, Kristin

    2011-01-01

    The pancreatic enzyme secretory phospholipase A2 group IB (sPLA2 IB) hydrolyses phospholipids at the sn-2 position, resulting in a NEFA and a lyso-phospholipid, which are then absorbed by the enterocytes. The sPLA2 IB is a member of a family of nineteen enzymes sharing the same catalytic ability, of which nine are cytosolic and ten are secretory. Presently, there are no pharmacological tools to separate between the different secretory enzymes when measuring the enzymatic activity. Thus, it is important to support activity data with more precise techniques when isolation of intestinal content is not possible for analysis, as in the case of small teleost larvae, where the whole animal is sometimes analysed. In the present study, we characterise the sPLA2 IB gene in Atlantic cod (Gadus morhua) and describe its ontogeny at the genetic and protein level and compare this to the total sPLA2 activity level. A positive correlation was found between the expression of sPLA2 IB mRNA and protein. Both remained stable and low during the larval stage followed by an increase from day 62 posthatch, coinciding with the development of the pyloric ceaca. Meanwhile, total sPLA2 enzyme activity in cod was stable and relatively high during the early stages when larvae were fed live prey, followed by a decrease in activity when the fish were weaned to a formulated diet. Thus, the expression of sPLA2 IB mRNA and protein did not correlate with total sPLA2 activity.

  13. Ocean warming and acidification modulate energy budget and gill ion regulatory mechanisms in Atlantic cod (Gadus morhua).

    PubMed

    Kreiss, C M; Michael, K; Lucassen, M; Jutfelt, F; Motyka, R; Dupont, S; Pörtner, H-O

    2015-10-01

    Ocean warming and acidification are threatening marine ecosystems. In marine animals, acidification is thought to enhance ion regulatory costs and thereby baseline energy demand, while elevated temperature also increases baseline metabolic rate. Here we investigated standard metabolic rates (SMR) and plasma parameters of Atlantic cod (Gadus morhua) after 3-4 weeks of exposure to ambient and future PCO2 levels (550, 1200 and 2200 µatm) and at two temperatures (10, 18 °C). In vivo branchial ion regulatory costs were studied in isolated, perfused gill preparations. Animals reared at 18 °C responded to increasing CO2 by elevating SMR, in contrast to specimens at 10 °C. Isolated gills at 10 °C and elevated PCO2 (≥1200 µatm) displayed increased soft tissue mass, in parallel to increased gill oxygen demand, indicating an increased fraction of gill in whole animal energy budget. Altered gill size was not found at 18 °C, where a shift in the use of ion regulation mechanisms occurred towards enhanced Na(+)/H(+)-exchange and HCO3 (-) transport at high PCO2 (2200 µatm), paralleled by higher Na(+)/K(+)-ATPase activities. This shift did not affect total gill energy consumption leaving whole animal energy budget unaffected. Higher Na(+)/K(+)-ATPase activities in the warmth might have compensated for enhanced branchial permeability and led to reduced plasma Na(+) and/or Cl(-) concentrations and slightly lowered osmolalities seen at 18 °C and 550 or 2200 µatm PCO2 in vivo. Overall, the gill as a key ion regulation organ seems to be highly effective in supporting the resilience of cod to effects of ocean warming and acidification.

  14. Multi-decadal responses of a cod (Gadus morhua) population to human-induced trophic changes, fishing, and climate.

    PubMed

    Eero, Margit; MacKenzie, Brian R; Köster, Friedrich W; Gislason, Henrik

    2011-01-01

    Understanding how human impacts have interacted with natural variability to affect populations and ecosystems is required for sustainable management and conservation. The Baltic Sea is one of the few large marine ecosystems worldwide where the relative contribution of several key forcings to changes in fish populations can be analyzed with empirical data. In this study we investigate how climate variability and multiple human impacts (fishing, marine mammal hunting, eutrophication) have affected multi-decadal scale dynamics of cod in the Baltic Sea during the 20th century. We document significant climate-driven variations in cod recruitment production at multi-annual timescales, which had major impacts on population dynamics and the yields to commercial fisheries. We also quantify the roles of marine mammal predation, eutrophication, and exploitation on the development of the cod population using simulation analyses, and show how the intensity of these forcings differed over time. In the early decades of the 20th century, marine mammal predation and nutrient availability were the main limiting factors; exploitation of cod was still relatively low. During the 1940s and subsequent decades, exploitation increased and became a dominant forcing on the population. Eutrophication had a relatively minor positive influence on cod biomass until the 1980s. The largest increase in cod biomass occurred during the late 1970s, following a long period of hydrographically related above-average cod productivity coupled to a temporary reduction in fishing pressure. The Baltic cod example demonstrates how combinations of different forcings can have synergistic effects and consequently dramatic impacts on population dynamics. Our results highlight the potential and limitations of human manipulations to influence predator species and show that sustainable management can only be achieved by considering both anthropogenic and naturally varying processes in a common framework.

  15. Life on the edge: O2 binding in Atlantic cod red blood cells near their southern distribution limit is not sensitive to temperature or haemoglobin genotype.

    PubMed

    Barlow, Samantha L; Metcalfe, Julian; Righton, David A; Berenbrink, Michael

    2017-02-01

    Atlantic cod are a commercially important species believed to be threatened by warming seas near their southern, equatorward upper thermal edge of distribution. Limitations to circulatory O2 transport, in particular cardiac output, and the geographic distribution of functionally different haemoglobin (Hb) genotypes have separately been suggested to play a role in setting thermal tolerance in this species. The present study assessed the thermal sensitivity of O2 binding in Atlantic cod red blood cells with different Hb genotypes near their upper thermal distribution limit and modelled its consequences for the arterio-venous O2 saturation difference, Sa-vO2 , another major determinant of circulatory O2 supply rate. The results showed statistically indistinguishable red blood cell O2 binding between the three HbI genotypes in wild-caught Atlantic cod from the Irish Sea (53° N). Red blood cells had an unusually low O2 affinity, with reduced or even reversed thermal sensitivity between pH 7.4 and 7.9, and 5.0 and 20.0°C. This was paired with strongly pH-dependent affinity and cooperativity of red blood cell O2 binding (Bohr and Root effects). Modelling of Sa-vO2  at physiological pH, temperature and O2 partial pressures revealed a substantial capacity for increases in Sa-vO2  to meet rising tissue O2 demands at 5.0 and 12.5°C, but not at 20°C. Furthermore, there was no evidence for an increase of maximal Sa-vO2  with temperature. It is suggested that Atlantic cod at such high temperatures may solely depend on increases in cardiac output and blood O2 capacity, or thermal acclimatisation of metabolic rate, for matching circulatory O2 supply to tissue demand.

  16. Life on the edge: O2 binding in Atlantic cod red blood cells near their southern distribution limit is not sensitive to temperature or haemoglobin genotype

    PubMed Central

    Barlow, Samantha L.; Metcalfe, Julian; Righton, David A.

    2017-01-01

    ABSTRACT Atlantic cod are a commercially important species believed to be threatened by warming seas near their southern, equatorward upper thermal edge of distribution. Limitations to circulatory O2 transport, in particular cardiac output, and the geographic distribution of functionally different haemoglobin (Hb) genotypes have separately been suggested to play a role in setting thermal tolerance in this species. The present study assessed the thermal sensitivity of O2 binding in Atlantic cod red blood cells with different Hb genotypes near their upper thermal distribution limit and modelled its consequences for the arterio-venous O2 saturation difference, Sa–vO2, another major determinant of circulatory O2 supply rate. The results showed statistically indistinguishable red blood cell O2 binding between the three HbI genotypes in wild-caught Atlantic cod from the Irish Sea (53° N). Red blood cells had an unusually low O2 affinity, with reduced or even reversed thermal sensitivity between pH 7.4 and 7.9, and 5.0 and 20.0°C. This was paired with strongly pH-dependent affinity and cooperativity of red blood cell O2 binding (Bohr and Root effects). Modelling of Sa–vO2 at physiological pH, temperature and O2 partial pressures revealed a substantial capacity for increases in Sa–vO2 to meet rising tissue O2 demands at 5.0 and 12.5°C, but not at 20°C. Furthermore, there was no evidence for an increase of maximal Sa–vO2 with temperature. It is suggested that Atlantic cod at such high temperatures may solely depend on increases in cardiac output and blood O2 capacity, or thermal acclimatisation of metabolic rate, for matching circulatory O2 supply to tissue demand. PMID:28148818

  17. Characterization of Francisella sp., GM2212, the first Francisella isolate from marine fish, Atlantic cod (Gadus morhua).

    PubMed

    Ottem, Karl F; Nylund, Are; Karlsbakk, Egil; Friis-Møller, Alice; Krossøy, Bjørn

    2007-05-01

    A Francisella sp., isolate GM2212(T), previously isolated from diseased farmed Atlantic cod Gadus morhua in Norway is characterized. The complete 16S rDNA, 16S-23S intergenic spacer, 23S rDNA, 23S-5S intergenic spacer, 5S rDNA, FopA, lipoprotein TUL4 (LpnA), malate dehydrogenase and a hypothetical lipoprotein (LpnB) is sequenced and compared with Francisella tularensis and Francisella philomiragia. All these sequences support a close relationship between GM2212(T) and F. philomiragia. The bacterium grows at 10-25 degrees C with an optimum at about 20 degrees C, a temperature range clearly different from F. tularensis and F. philomiragia. GM2212(T) is catalase-positive, indole positive, oxidase-negative, do not produce H(2)S in Triple Sugar Iron agar, and does not hydrolyze gelatin, is resistant to erythromycin and susceptible to ceftazidime, the latter five characteristics separating it from F. philomiragia. Cysteine enhances growth. Acid is produced from D: -glucose, maltose, sucrose (weak) but not from lactose or glycerol. GM2212(T) grows on both MacConkey agar and in nutrient broth (6% NaCl). The bacterium is resistant to trimethoprim-sulfamethoxazole, penicillines, cefuroxime and erythromycin; but is susceptible to ceftazidime, tetracycline, gentamicin, ciprofloxacin. Based on the molecular and phenotypical characteristics, we suggest that this GM2212 isolate, may represent a new species of Francisella. Isolate GM2212(T) (=CNCM I-3481(T) = CNCM I-3511(T) = DSM 18777(T)).

  18. Impacts of regular and random noise on the behaviour, growth and development of larval Atlantic cod (Gadus morhua).

    PubMed

    Nedelec, Sophie L; Simpson, Stephen D; Morley, Erica L; Nedelec, Brendan; Radford, Andrew N

    2015-10-22

    Anthropogenic noise impacts behaviour and physiology in many species, but responses could change with repeat exposures. As repeat exposures can vary in regularity, identifying regimes with less impact is important for regulation. We use a 16-day split-brood experiment to compare effects of regular and random acoustic noise (playbacks of recordings of ships), relative to ambient-noise controls, on behaviour, growth and development of larval Atlantic cod (Gadus morhua). Short-term noise caused startle responses in newly hatched fish, irrespective of rearing noise. Two days of both regular and random noise regimes reduced growth, while regular noise led to faster yolk sac use. After 16 days, growth in all three sound treatments converged, although fish exposed to regular noise had lower body width-length ratios. Larvae with lower body width-length ratios were easier to catch in a predator-avoidance experiment. Our results demonstrate that the timing of acoustic disturbances can impact survival-related measures during development. Much current work focuses on sound levels, but future studies should consider the role of noise regularity and its importance for noise management and mitigation measures.

  19. Impacts of regular and random noise on the behaviour, growth and development of larval Atlantic cod (Gadus morhua)

    PubMed Central

    Nedelec, Sophie L.; Simpson, Stephen D.; Morley, Erica L.; Nedelec, Brendan; Radford, Andrew N.

    2015-01-01

    Anthropogenic noise impacts behaviour and physiology in many species, but responses could change with repeat exposures. As repeat exposures can vary in regularity, identifying regimes with less impact is important for regulation. We use a 16-day split-brood experiment to compare effects of regular and random acoustic noise (playbacks of recordings of ships), relative to ambient-noise controls, on behaviour, growth and development of larval Atlantic cod (Gadus morhua). Short-term noise caused startle responses in newly hatched fish, irrespective of rearing noise. Two days of both regular and random noise regimes reduced growth, while regular noise led to faster yolk sac use. After 16 days, growth in all three sound treatments converged, although fish exposed to regular noise had lower body width–length ratios. Larvae with lower body width–length ratios were easier to catch in a predator-avoidance experiment. Our results demonstrate that the timing of acoustic disturbances can impact survival-related measures during development. Much current work focuses on sound levels, but future studies should consider the role of noise regularity and its importance for noise management and mitigation measures. PMID:26468248

  20. Statistical analysis of North Atlantic right whale (Eubalaena glacialis) signal trains in Cape Cod Bay, spring 2012.

    PubMed

    Urazghildiiev, Ildar R

    2014-11-01

    Statistical characteristics of signal trains produced by North Atlantic right whales (NARW) during the winter and early spring in Cape Cod Bay, MA are described. Data analysis was based on four days of acoustic recordings that were obtained with synchronized hydrophones. Based on temporal and geographical clustering of detected signals, 7264 NARW sounds were identified and associated with 559 signal trains. The detected signals were assigned to four classes of narrowband tonal calls--upcalls, downcalls, complex, and high frequency, and two classes of wideband sounds--gunshots and complex. Empirical distributions of the number of signals in trains, total duration of trains, the positions of NARW, and signal classes are presented. Results indicate that 68.9% of all signal trains consisted of 10 or fewer signals. Low and high frequency tonals that lacked wideband sounds formed 69.1% of trains; 5.0% of trains lacked tonals. Trains consisting of only upcalls comprised 44.2% of all detected trains. Because 18.3% of trains contained no upcalls, using detectors that identify all signal classes would improve right whale detection.

  1. The mRNA expression of cortisol axis related genes differs in Atlantic cod (Gadus morhua) categorized as high or low responders.

    PubMed

    Hori, Tiago S; Rise, Matthew L; Johnson, Stewart C; Afonso, Luis O B; Gamperl, A Kurt

    2012-01-15

    Cortisol is a major stress hormone in fish and is known, under normal or stressful conditions, to affect several physiological processes including growth and immunity. Thus, efforts have been made for several cultured finfish species, including the Atlantic cod, to determine whether fish with a high or low cortisol response to stress can be identified and selected. However, we have a limited understanding of the mechanisms that determine these two phenotypes. Thus, we measured total and free plasma cortisol levels in high and low responding cod when subjected to a 30 s handling stress, and the mRNA expression of four key genes in the glucocorticoid (i.e. cortisol) stress axis both pre- and post-stress. The cortisol data is consistent with our previous findings for cod, with high responding (HR) fish having ∼3-fold higher total and free plasma cortisol levels when compared to low responding (LR) fish. Three of the transcripts studied encode key proteins involved in steroidogenesis (StAR, P450scc and 3βHSD), and the constitutive mRNA expression of all three genes was significantly higher (∼2-fold) in the head kidney of HR fish when compared to LR cod. The other gene of interest was the glucocorticoid receptor (GR). We partly cloned and characterized a cDNA from Atlantic cod likely to be this fish's ortholog of the teleost GR1, and showed that while there was no difference in hepatic constitutive GR mRNA expression between groups, HR fish had liver GR mRNA levels that were significantly (1.8-fold) higher at 3 h post-stress as compared to LR fish. Our results suggest that the different magnitude of cortisol response between LR and HR fish is at least partially determined by the capacity of the interrenal tissue to produce steroids.

  2. Harvest Pressure on Coastal Atlantic Cod (Gadus morhua) from Recreational Fishing Relative to Commercial Fishing Assessed from Tag-Recovery Data

    PubMed Central

    Kleiven, Alf Ring; Fernandez-Chacon, Albert; Nordahl, Jan-Harald; Moland, Even; Espeland, Sigurd Heiberg; Knutsen, Halvor; Olsen, Esben Moland

    2016-01-01

    Marine recreational fishing is a popular outdoor activity. However, knowledge about the magnitude of recreational catches relative to commercial catches in coastal fisheries is generally sparse. Coastal Atlantic cod (Gadus morhua) is a target species for recreational fishers in the North Atlantic. In Norway, recreational fishers are allowed to use a variety of traps and nets as well as long-line and rod and line when fishing for cod. From 2005 to 2013, 9729 cod (mean size: 40 cm, range: 15–93 cm) were tagged and released in coastal Skagerrak, southeast Norway. Both high-reward (NOK 500) and low-reward tags (NOK 50) were used in this study. Because some harvested fish (even those posting high-reward tags) may go unreported by fishers, reporting rates were estimated from mark-recovery models that incorporate detection parameters in their structure, in addition to survival and mortality estimates. During 2005 to 2013, a total of 1707 tagged cod were recovered and reported by fishers. We estimate the overall annual survival to be 33% (SE 1.5). Recreational rod and line fishing were responsible for 33.7% (SE 2.4) of total mortality, followed by commercial fisheries (15.1% SE 0.8) and recreational fixed gear (6.8% SE 0.4). Natural mortality was 44.4% (SE 2.5) of total mortality. Our findings suggest that recreational fishing—rod and line fishing in particular—is responsible for a substantial part of fishing mortality exerted on coastal cod in southern Norway. PMID:26959371

  3. Mitochondrial Genomics and Northwestern Atlantic Population Genetics of Marine Annelids

    DTIC Science & Technology

    2005-09-01

    of this thesis was to investigate marine benthic invertebrate phylogenetics and population genetics, focused on the phylum Annelida . Recent expansions...molecular evidence and morphological reinvestigations. This re-interpretation, first proposed by others, synonomizes " Annelida " and "Polychaeta", and...21 CHAPTER 3: Assessment of the Cape Cod phylogeographic break using the bamboo worm Clymenella torquata ( Annelida : Maldanidae

  4. Global transcriptome analysis of Atlantic cod (Gadus morhua) liver after in vivo methylmercury exposure suggests effects on energy metabolism pathways.

    PubMed

    Yadetie, Fekadu; Karlsen, Odd Andre; Lanzén, Anders; Berg, Karin; Olsvik, Pål; Hogstrand, Christer; Goksøyr, Anders

    2013-01-15

    Methylmercury (MeHg) is a widely distributed contaminant polluting many aquatic environments, with health risks to humans exposed mainly through consumption of seafood. The mechanisms of toxicity of MeHg are not completely understood. In order to map the range of molecular targets and gain better insights into the mechanisms of toxicity, we prepared Atlantic cod (Gadus morhua) 135k oligonucleotide arrays and performed global analysis of transcriptional changes in the liver of fish treated with MeHg (0.5 and 2 mg/kg of body weight) for 14 days. Inferring from the observed transcriptional changes, the main pathways significantly affected by the treatment were energy metabolism, oxidative stress response, immune response and cytoskeleton remodeling. Consistent with known effects of MeHg, many transcripts for genes in oxidative stress pathways such as glutathione metabolism and Nrf2 regulation of oxidative stress response were differentially regulated. Among the differentially regulated genes, there were disproportionate numbers of genes coding for enzymes involved in metabolism of amino acids, fatty acids and glucose. In particular, many genes coding for enzymes of fatty acid beta-oxidation were up-regulated. The coordinated effects observed on many transcripts coding for enzymes of energy pathways may suggest disruption of nutrient metabolism by MeHg. Many transcripts for genes coding for enzymes in the synthetic pathways of sulphur containing amino acids were also up-regulated, suggesting adaptive responses to MeHg toxicity. By this toxicogenomics approach, we were also able to identify many potential biomarker candidate genes for monitoring environmental MeHg pollution. These results based on changes on transcript levels, however, need to be confirmed by other methods such as proteomics.

  5. Optimization and comparison of miniaturized extraction techniques for PAHs from crude oil exposed Atlantic cod and haddock eggs.

    PubMed

    Sørensen, Lisbet; Silva, Marta S; Booth, Andy M; Meier, Sonnich

    2016-02-01

    Two miniaturized extraction methods for a wide range of 2-6 ring polycyclic aromatic hydrocarbons (PAHs) and their alkylated homologues in small lipid-rich biota samples (≤100 mg) have been developed. Both methods utilize liquid extraction (LE) prior to a clean-up step using either normal phase solid phase extraction (SPE) or mixed-phase dispersive SPE (dSPE). Optimization of the methods was achieved by comparing the type and amount of sorbents, drying agents, and solvents used. In order to improve the limits of detection (LOD) of target PAHs under high sensitivity gas chromatography-tandem mass spectrometry analysis, specific emphasis was given to minimizing lipid co-extraction. The optimized LE-SPE method comprised extraction with dichloromethane/n-hexane (1:1, v/v) and clean-up by silica SPE, whereas the optimized LE-dSPE method comprised extraction with acetonitrile and clean-up with PSA and C18 sorbents. The methods were validated and directly compared through the analysis of Atlantic cod (Gadus morhua) and haddock (Melanogrammus aeglefinus) eggs exposed to oil. The LE-SPE method resulted in lower levels of co-extracted lipids (14.1 ± 1.7 ng/μL) than the LE-dSPE method (60 ± 14 ng/μL). Achieved PAH LODs for the LE-SPE method were typically an order of magnitude lower (<5 ng/g) than for the LE-dSPE method (<125 ng/g). The LE-SPE method offers the possibility for PAH analysis of small samples of fish eggs (~100 mg) exposed to small quantities of crude oil (~1-10 μg/L total PAHs).

  6. Biological effects of polycyclic aromatic hydrocarbons (PAH) and their first metabolic products in in vivo exposed Atlantic cod (Gadus morhua).

    PubMed

    Pampanin, Daniela M; Le Goff, Jeremie; Skogland, Karianne; Marcucci, Cristian R; Øysæd, Kjell Birger; Lorentzen, Marianne; Jørgensen, Kåre B; Sydnes, Magne O

    2016-01-01

    The monitoring of the presence of polycyclic aromatic hydrocarbons (PAH) in the aquatic environment is a worldwide activity since some of these compounds are well-established carcinogens and mutagens. Contaminants in this class are in fact regarded as priority hazardous substances for environmental pollution (Water Framework Directive 2000/60/EC). In this study, Atlantic cod (Gadus morhua) was selected to assess in vivo effects of two PAH and their first metabolic products, namely, the corresponding trans-dihydrodiols, using biological markers. Fish were exposed for 1 wk to a single PAH (naphthalene or chrysene) and its synthetic metabolites ((1R,2R)-1,2-dihydronaphthalene-1,2-diol and (1R,2R)-1,2-dihydrochrysene-1,2-diol) by intraperitoneal injection in a continuous seawater flow system. After exposure, PAH metabolism including PAH metabolites in bile and ethoxyresorufin O-deethylase (EROD) activity, oxidative stress glutathione S-transferases (GST) and catalase (CAT) activities, and genotoxicity such as DNA adducts were evaluated, as well as general health conditions including condition index (CI), hepatosomatic index (HSI), and gonadosomatic index (GSI). PAH metabolite values were low and not significantly different when measured with the fixed-wavelength fluorescence screening method, while the gas chromatography-mass spectroscopy (GC-MS) method showed an apparent dose response in fish exposed to naphthalene. DNA adduct levels ≥0.16 × 10(-8) relative adduct level (RAL) were detected. It should be noted that 0.16 × 10(-8) RAL is considered the maximal acceptable background level for this species. The other biomarkers activities of catalase, GST, and EROD did not display a particular compound- or dose-related response. The GSI values were significantly lower in some chrysene- and in both naphthalene- and naphthalene diol-exposed groups compared to control.

  7. Discrimination between Weaned and Unweaned Atlantic Cod (Gadus morhua) in Capture-Based Aquaculture (CBA) by X-Ray Imaging and Radio-Frequency Metal Detector

    PubMed Central

    Misimi, Ekrem; Martinsen, Svein; Mathiassen, John Reidar; Erikson, Ulf

    2014-01-01

    The aim of this study was to investigate the feasibility of two detection methods for use in discrimination and sorting of adult Atlantic cod (about 2 kg) in the small scale capture-based aquaculture (CBA). Presently, there is no established method for discrimination of weaned and unweaned cod in CBA. Generally, 60–70% of the wild-caught cod in the CBA are weaned into commercial dry feed. To increase profitability for the fish farmers, unweaned cod must be separated from the stock, meaning the fish must be sorted into two groups – unweaned and weaned from moist feed. The challenges with handling of large numbers of fish in cages, defined the limits of the applied technology. As a result, a working model was established, focusing on implementing different marking materials added to the fish feed, and different technology for detecting the feed presence in the fish gut. X-ray imaging in two modes (planar and dual energy band) and sensitive radio-frequency metal detection were the detection methods that were chosen for the investigations. Both methods were tested in laboratory conditions using dead fish with marked feed inserted into the gut cavity. In particular, the sensitive radio-frequency metal detection method with carbonyl powder showed very promising results in detection of marked feed. Results show also that Dual energy band X-ray imaging may have potential for prediction of fat content in the feed. Based on the investigations it can be concluded that both X-ray imaging and sensitive radio-frequency metal detector technology have the potential for detecting cod having consumed marked feed. These are all technologies that may be adapted to large scale handling of fish from fish cages. Thus, it may be possible to discriminate between unweaned and weaned cod in a large scale grading situation. Based on the results of this study, a suggestion for evaluation of concept for in-situ sorting system is presented. PMID:24743448

  8. Discrimination between weaned and unweaned Atlantic cod (Gadus morhua) in capture-based aquaculture (CBA) by X-ray imaging and radio-frequency metal detector.

    PubMed

    Misimi, Ekrem; Martinsen, Svein; Mathiassen, John Reidar; Erikson, Ulf

    2014-01-01

    The aim of this study was to investigate the feasibility of two detection methods for use in discrimination and sorting of adult Atlantic cod (about 2 kg) in the small scale capture-based aquaculture (CBA). Presently, there is no established method for discrimination of weaned and unweaned cod in CBA. Generally, 60-70% of the wild-caught cod in the CBA are weaned into commercial dry feed. To increase profitability for the fish farmers, unweaned cod must be separated from the stock, meaning the fish must be sorted into two groups - unweaned and weaned from moist feed. The challenges with handling of large numbers of fish in cages, defined the limits of the applied technology. As a result, a working model was established, focusing on implementing different marking materials added to the fish feed, and different technology for detecting the feed presence in the fish gut. X-ray imaging in two modes (planar and dual energy band) and sensitive radio-frequency metal detection were the detection methods that were chosen for the investigations. Both methods were tested in laboratory conditions using dead fish with marked feed inserted into the gut cavity. In particular, the sensitive radio-frequency metal detection method with carbonyl powder showed very promising results in detection of marked feed. Results show also that Dual energy band X-ray imaging may have potential for prediction of fat content in the feed. Based on the investigations it can be concluded that both X-ray imaging and sensitive radio-frequency metal detector technology have the potential for detecting cod having consumed marked feed. These are all technologies that may be adapted to large scale handling of fish from fish cages. Thus, it may be possible to discriminate between unweaned and weaned cod in a large scale grading situation. Based on the results of this study, a suggestion for evaluation of concept for in-situ sorting system is presented.

  9. A review of the contributions of fisheries and climate variability to contrasting dynamics in two Arcto-boreal Atlantic cod (Gadus morhua) stocks: Persistent high productivity in the Barents Sea and collapse on the Newfoundland and Labrador Shelf

    NASA Astrophysics Data System (ADS)

    Lilly, George R.; Nakken, Odd; Brattey, John

    2013-07-01

    Stocks of Atlantic cod (Gadus morhua) across the North Atlantic and adjacent seas have been fished intensively for years, and many are now severely depleted. In order to promote recovery and sustainable harvesting, it is essential to understand factors that have contributed to the declines and to variability in rates of recovery. Considerable insight may be gleaned by comparing and contrasting the histories of the Northeast Arctic (NEA) cod in the Barents Sea - Svalbard area of the northeast Atlantic and the “northern cod” on the Newfoundland and Labrador (NL) shelf in the northwest Atlantic. These two stocks, which were among the 3 largest cod stocks during the middle of the 20th century, are Arcto-boreal, and have many species of prey and predators in common. The biomass of NEA cod has varied considerably over time, and in 2009 was a little above 60% of its maximum observed level, which occurred in the late 1940s and early 1950s. In contrast, the biomass of NL cod decreased steadily from the early 1960s to the late 1970s, increased somewhat during the 1980s, and crashed during the early 1990s to an extremely low level, at which it remained for a decade before showing recent indications of improvement. Although both stocks were influenced by similar changes in harvesting strategies and environmental circumstances, both biotic and abiotic, there are two events which stand out as being particularly influential. First, crises developed in the management of both stocks in the late 1980s. For NEA cod, the crisis was environmental, caused by the collapse of capelin (Mallotus villosus), the main food for adult cod, whereas for NL cod the crisis was caused by a sudden large reduction in scientific perception of stock size. The difference in response to these crises strongly influenced subsequent stock dynamics. Catches of NEA cod were reduced considerably, preventing severe overharvesting of the cod that at that time experienced low productivity, whereas catches of NL

  10. Frequent skipped spawning in the world’s largest cod population

    PubMed Central

    Skjæraasen, Jon Egil; Nash, Richard D. M.; Korsbrekke, Knut; Fonn, Merete; Nilsen, Trygve; Kennedy, James; Nedreaas, Kjell H.; Thorsen, Anders; Witthames, Peter R.; Geffen, Audrey J.; Høie, Hans; Kjesbu, Olav Sigurd

    2012-01-01

    Life-history theory suggests that animals may skip reproductive events after initial maturation to maximize lifetime fitness. In iteroparous teleosts, verifying past spawning history is particularly difficult; the degree of skipped spawning at the population level therefore remains unknown. We unequivocally show frequent skipped spawning in Northeast Arctic cod (NEAC) in a massive field and laboratory effort from 2006 to 2008. This was verified by postovulatory follicles in temporarily arrested ovaries close to the putative spawning period. At the population level, “skippers” were estimated to be approximately equally abundant as spawning females in 2008, constituting ∼24% of the females 60–100 cm. These females never truly started vitellogenesis and principally remained on the feeding grounds when spawners migrated southward, avoiding any migration costs. The proximate cause of skipping seems to be insufficient energy to initiate oocyte development, indicating that skipped spawning may partly be a density-dependent response important in population regulation. Our data also indicate more skipping among smaller females and potential tradeoffs between current and future reproductive effort. We propose that skipped spawning is an integral life-history component for NEAC, likely varying annually, and it could therefore be an underlying factor causing some of the currently unexplained large NEAC recruitment variation. The same may hold for other teleosts. PMID:22615381

  11. Low-dose exposure to alkylphenols adversely affects the sexual development of Atlantic cod (Gadus morhua): acceleration of the onset of puberty and delayed seasonal gonad development in mature female cod.

    PubMed

    Meier, Sonnich; Morton, H Craig; Andersson, Eva; Geffen, Audrey J; Taranger, Geir Lasse; Larsen, Marita; Petersen, Marianne; Djurhuus, Rune; Klungsøyr, Jarle; Svardal, Asbjørn

    2011-09-01

    Produced water (PW), a by-product of the oil-production process, contains large amount of alkylphenols (APs) and other harmful oil compounds. In the last 20 years, there have been increasing concerns regarding the environmental impact of large increases in the amounts of PW released into the North Sea. We have previously shown that low levels of APs can induce disruption of the endocrine and reproductive systems of Atlantic cod (Gadus morhua). The aims of this follow-up study were to: (i) identify the lowest observable effect concentration of APs; (ii) study the effects of exposure to real PW, obtained from a North Sea oil-production platform; and (iii) study the biological mechanism of endocrine disruption in female cod. Fish were fed with feed paste containing several concentrations of four different APs (4-tert-butylphenol, 4-n-pentylphenol, 4-n-hexylphenol and 4-n-heptylphenol) or real PW for 20 weeks throughout the normal period of vitellogenesis in Atlantic cod from October to January. Male and female cod, exposed to AP and PW, were compared to unexposed fish and to fish fed paste containing 17β-oestradiol (E(2)). Approximately 60% of the females and 96% of the males in the unexposed groups were mature at the end of the experiment. Our results show that exposure to APs and E(2) have different effects depending on the developmental stage of the fish. We observed that juvenile females are advanced into puberty and maturation, while gonad development was delayed in both maturing females and males. The AP-exposed groups contained increased numbers of mature females, and significant differences between the untreated group and the AP-treated groups were seen down to a dose of 4 μg AP/kg body weight. In the high-dose AP and the E(2) exposed groups, all females matured and no juveniles were seen. These results suggest that AP-exposure can affect the timing of the onset of puberty in fish even at extremely low concentrations. Importantly, similar effects were not

  12. Seasonal variation in biomarkers in blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua): implications for environmental monitoring in the Barents Sea.

    PubMed

    Nahrgang, J; Brooks, S J; Evenset, A; Camus, L; Jonsson, M; Smith, T J; Lukina, J; Frantzen, M; Giarratano, E; Renaud, P E

    2013-02-01

    In the Barents Sea, the limited data on biological relevant indicators and their responses to various anthropogenic stressors have hindered the development of a consistent scientific basis for selecting indicator species and developing practical procedures for environmental monitoring. Accordingly, the main aim of the present study was to develop a common set of baseline values for contaminants and biomarkers in three species, and to identify their strengths and limitations in monitoring of the Barents Sea. Blue mussel (Mytilus edulis), Icelandic scallop (Chlamys islandica) and Atlantic cod (Gadus morhua) were sampled from a north Norwegian fjord in March, June, September and December 2010. Digestive glands from the bivalve species and liver from Atlantic cod were analysed for biomarkers of oxidative stress (catalase [CAT], glutathione peroxidase [GPX], glutathione-S-transferase activities [GST], lipid peroxidation as thiobarbituric reactive substances [TBARS] and total oxyradical scavenging capacity [TOSC]), biotransformation (ethoxyresorufine-O-deethylase activity [EROD]) and general stress (lysosomal membrane stability [LMS]). Concentrations of polycyclic aromatic hydrocarbons (PAHs) and metals in the bivalves and PAH metabolites in fish bile were quantified. Finally, energy reserves (total lipids, proteins and carbohydrates) and electron transport system (ETS) activity in the digestive gland of the bivalves and liver of Atlantic cod provided background information for reproductive cycle and general physiological status of the organisms. Blue mussel and Icelandic scallop showed very similar trends in biological cycle, biomarker expression and seasonality. Biomarker baselines in Atlantic cod showed weaker seasonal variability. However, important biological events may have been undetected due to the large time intervals between sampling occasions. Physiological biomarkers such as energy reserves and ETS activity were recommended as complementary parameters to the

  13. Effect of replacement of fish oil with camelina (Camelina sativa) oil on growth, lipid class and fatty acid composition of farmed juvenile Atlantic cod (Gadus morhua).

    PubMed

    Hixson, Stefanie M; Parrish, Christopher C; Anderson, Derek M

    2013-12-01

    Camelina (Camelina sativa) oil was tested as a replacement for fish oil in diets for farmed Atlantic cod (Gadus morhua). Camelina differs from other plant oilseeds previously used in aquaculture with high lipid (40 %), α-linolenic acid (40 %), antioxidants and low proportions of saturated fats. Dietary treatments were fed to cod (19 g fish⁻¹ initial weight) for 9 weeks and included a fish oil control (FO), 40 % (CO40) and 80 % (CO80) replacement of fish oil with camelina oil. There was no effect of replacing fish oil with camelina oil included at levels up to 80 % on the growth performance. Cod fed CO80 stored more lipid in the liver (p < 0.01), including more neutral lipid (p < 0.05) and triacylglycerol (p < 0.05). Cod fed CO80 decreased in total polyunsaturated fatty acids (PUFAs) in muscle compared to CO40 and FO (p < 0.05), increased in monounsaturated fatty acids (p < 0.01), decreased in total ω3 fatty acids (FO > CO40 > CO80; p < 0.01) and increased in total ω6 fatty acids (FO < CO40 < CO80; p < 0.01). In the liver, long-chain (LC) PUFA such as 20:4ω6, 20:5ω3, 22:5ω3 and 22:6ω3 decreased when fish oil was removed from the diet (p < 0.05), and increased in 18-carbon fatty acids (p < 0.01). Camelina oil can reduce the amount of fish oil needed to meet lipid requirements, although replacing 80 % of fish oil reduced LC PUFAs in both tissues. A comparison of BF₃ and H₂SO₄ as catalysts to transmethylate cod liver and muscle lipids revealed small but significant differences in some fatty acid proportions.

  14. Population Origin of Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus Bycaught in U.S. Atlantic Coast Fisheries

    PubMed Central

    Wirgin, I.; Maceda, L.; Grunwald, C.; King, T.L.

    2015-01-01

    Microsatellite DNA and mitochondrial DNA control region sequence analyses were used to determine the population and Distinct Population Segment (DPS) origin of 173 Atlantic sturgeon Acipenser oxyrinchus oxyrinchus encountered from the Gulf of Maine to Cape Hatteras, North Carolina in NOAA's Northeast Fisheries Observer Program. It was found that the Hudson River was by far the greatest contributor to this coastal bycatch, with 42.2-46.3% of specimens originating there. Generally, specimens respected the geographic province of the river in which they were spawned, but some specimens, particularly those originating in the South Atlantic DPS, moved great distances. Genetic mixed stock analyses provides an accurate approach to determine the DPS and population origin of Atlantic sturgeon bycaught in coastal waters but most informative management requires that these results be partitioned by locale, season, target fishery, and gear type. PMID:25727098

  15. Ontogenetic effects of diet during early development on growth performance, myosin mRNA expression and metabolic enzyme activity in Atlantic cod juveniles reared at different salinities.

    PubMed

    Koedijk, Roland M; Le François, Nathalie R; Blier, Pierre U; Foss, Atle; Folkvord, Arild; Ditlecadet, Delphine; Lamarre, Simon G; Stefansson, Sigurd O; Imsland, Albert K

    2010-05-01

    This study investigates the effect of diet during early development on growth and metabolic capacity in the juvenile stage of Atlantic cod. Growth in three groups of Atlantic cod juveniles (10-70 g) was measured at two salinities (15 per thousand or 32 per thousand) in combination with two temperatures (10 degrees C or 14 degrees C). Groups of cod from a single egg batch differed by having been fed with rotifers (R) or natural zooplankton (Z) during the first 36 days post hatch. A third group was fed zooplankton from 1 to 22 dph, after which diet changed to rotifers from 22 to 36 dph (ZRZ). All fish were weaned at 36 dph. Juveniles from the Z and ZRZ groups performed equally well under all experimental conditions, but fish that had received rotifers as a larval diet showed overall significantly lower growth rates. Growth was significantly enhanced by reduced salinity. Metabolic enzyme activity and relative myosin mRNA expression levels were not affected by larval diet. Muscle AAT and MDH were affected by salinity while these enzymes in liver tissue were affected by the interaction between salinity and temperature. Metabolic enzymes were stronger correlated with fish size than growth rates. Our results indicate that larval diet has a pronounced effect on juvenile growth rates under varying environmental conditions as optimal larval diet (zooplankton) increased juvenile growth rates significantly. Metabolic enzyme activity and relative myosin mRNA expression were not affected by larval history, which suggests that the persisting juvenile growth difference is not a result of differing metabolic capacity.

  16. Effects of oil pollution and persistent organic pollutants (POPs) on glycerophospholipids in liver and brain of male Atlantic cod (Gadus morhua).

    PubMed

    Bratberg, Mari; Olsvik, Pål A; Edvardsen, Rolf B; Brekken, Hans Kristian; Vadla, Reidun; Meier, Sonnich

    2013-02-01

    Fish in the North Sea are exposed to relatively high levels of halogenated compounds in addition to the pollutants released by oil production activities. In this study male Atlantic cod (Gadus morhua) were orally exposed to environmental realistic levels (low and high) of weathered crude oil and/or a mixture of POPs for 4weeks. Lipid composition in brain and in liver extracts were analysed in order to assess the effects of the various pollutants on membrane lipid composition and fatty acid profiles. Transcriptional effects in the liver were studied by microarray and quantitative real-time RT-PCR. Chemical analyses confirmed uptake of polychlorinated biphenyls (PCBs) and chlorinated pesticides, polybrominated diphenyl ethers (PBDEs) and perfluorooctanesulfonate (PFOS) in the liver and excretion of metabolites of polyaromatic hydrocarbons (PAHs) in the bile. Treatment with POPs and/or crude oil did not induce significant changes in lipid composition in cod liver. Only a few minor changes were observed in the fatty acid profile of the brain and the lipid classes in the liver. The hypothesis that pollution from oil or POPs at environmental realistic levels alters the lipid composition in marine fish was therefore not confirmed in this study. However, the transcriptional data suggest that the fish were affected by the treatment at the mRNA level. This study suggests that a combination of oil and POPs induce the CYP1a detoxification system and gives an increase in the metabolism and clearing rate of PAHs and POPs, but with no effects on membrane lipids in male Atlantic cod.

  17. Differential Survival among Batches of Atlantic Cod (Gadus morhua L.) from Fertilisation through to Post-Metamorphosis

    PubMed Central

    Petersen, Petra E.; Penman, David J.; Dahle, Geir; Patursson, Øystein; Taggart, John B.

    2016-01-01

    Aquaculture production of cod has decreased from over 20,000 tonnes in 2009 to less than 2,000 tonnes in 2014 and the industry faces many challenges, one of which is high and unpredictably variable mortality rates in the early life stages. Hence, full-cycle farming with hatchery produced juveniles is still considered unprofitable compared to fisheries and on-growing of wild cod. In the present study, potential batch differences in progeny survival of wild-caught, hatchery-spawned Faroe Bank cod (Gadus morhua L.) were investigated at two defined periods during early life history; i) the embryo stage (60 day degrees post fertilisation) and ii) the fry stage (110 days post hatch), post metamorphosis. The fry stage experiment was conducted in three replicates (N = 300 per replicate), and a panel of three polymorphic microsatellite markers was used for parental analysis. Mean survival rate at the embryo stage was 69% (± 20% SD). Survival was positively associated with egg diameter (P < 0.01), explaining 90% of the variation in egg survival rates. The data were too scarce to conclude either way concerning a possible correlation between survival rates between the two periods (P < 0.10). Offspring from three batches (from a total of eight) dominated in the fry stage, contributing over 90% of the progeny, and results were consistent over all three replicate tanks. The skewed batch representation observed may be of relevance to the effective management of selective breeding programmes for cod. PMID:27362346

  18. Climate induced temperature effects on growth performance, fecundity and recruitment in marine fish: developing a hypothesis for cause and effect relationships in Atlantic cod ( Gadus morhua) and common eelpout ( Zoarces viviparus)

    NASA Astrophysics Data System (ADS)

    Pörtner, H. O.; Berdal, B.; Blust, R.; Brix, O.; Colosimo, A.; De Wachter, B.; Giuliani, A.; Johansen, T.; Fischer, T.; Knust, R.; Lannig, G.; Naevdal, G.; Nedenes, A.; Nyhammer, G.; Sartoris, F. J.; Serendero, I.; Sirabella, P.; Thorkildsen, S.; Zakhartsev, M.

    2001-12-01

    Effects of global warming on animal distribution and performance become visible in many marine ecosystems. The present study was designed to develop a concept for a cause and effect understanding with respect to temperature changes and to explain ecological findings based on physiological processes. The concept is based on a wide comparison of invertebrate and fish species with a special focus on recent data obtained in two model species of fish. These fish species are both characterized by northern and southern distribution limits in the North Atlantic: eelpout ( Zoarces viviparus), as a typical non-migrating inhabitant of the coastal zone and the cod ( Gadus morhua), as a typical inhabitant of the continental shelf with a high importance for fisheries. Mathematical modelling demonstrates a clear significant correlation between climate induced temperature fluctuations and the recruitment of cod stocks. Growth performance in cod is optimal at temperatures close to 10°C, regardless of the population investigated in a latitudinal cline. However, temperature specific growth rates decrease at higher latitudes. Also, fecundity is less in White Sea than in North and Baltic Sea cod or eelpout populations. These findings suggest that a cold-induced shift in energy budget occurs which is unfavorable for growth performance and fecundity. Thermal tolerance limits shift depending on latitude and are characterized by oxygen limitation at both low or high temperatures. Oxygen supply to tissues is optimized at low temperature by a shift in hemoglobin isoforms and oxygen binding properties to lower affinities and higher unloading potential. Protective stimulation of heat shock protein synthesis was not observed. According to a recent model of thermal tolerance the downward shift of tolerance limits during cold adaptation is associated with rising mitochondrial densities and, thus, aerobic capacity and performance in the cold, especially in eurythermal species. At the same time

  19. New England Cod Collapse and the Climate

    PubMed Central

    Meng, Kyle C.; Oremus, Kimberly L.; Gaines, Steven D.

    2016-01-01

    To improve fishery management, there is an increasing need to understand the long-term consequences of natural and anthropogenic climate variability for ecological systems. New England’s iconic cod populations have been in decline for several decades and have recently reached unprecedented lows. We find that 17% of the overall decline in Gulf of Maine cod biomass since 1980 can be attributed to positive phases of the North Atlantic Oscillation (NAO). This is a consequence of three results: i) a 1-unit increase in the NAO winter index is associated with a 17% decrease in the spring biomass of age-1 cod the following year; ii) this NAO-driven decrease persists as the affected cohort matures; iii) fishing practices appear to exacerbate NAO’s direct biological effect such that, since 1913, a 1-unit increase in the NAO index lowers subsequent cod catch for up to 19 years. The Georges Bank cod stock displays similar patterns. Because we statistically detect a delay between the NAO and subsequent declines in adult biomass, our findings imply that observed current NAO conditions can be used in stock forecasts, providing lead time for adaptive policy. More broadly, our approach can inform forecasting efforts for other fish populations strongly affected by natural and anthropogenic climatic variation. PMID:27463967

  20. Genetic differentiation of brackish water populations of cod Gadus morhua in the southern Baltic, inferred from genotyping using SNP-arrays.

    PubMed

    Poćwierz-Kotus, A; Kijewska, A; Petereit, C; Bernaś, R; Więcaszek, B; Arnyasi, M; Lien, S; Kent, M P; Wenne, R

    2015-02-01

    The Baltic is a semi-enclosed sea characterised by decreasing salinity in the eastern and northern direction with only the deeper parts of the southern Baltic suitable as spawning grounds for marine species like cod. Baltic cod exhibits various adaptations to brackish water conditions, yet the inflow of salty North Sea water near the bottom remains an influence on the spawning success of the Baltic cod. The eastern Baltic population has been very weakly studied in comparison with the western population. The aim of this study is to demonstrate for the first time genetic differentiation by the use of a large number of SNPs between eastern and western Baltic populations existing in differentiated salinity conditions. Two cod samples were collected from the Bay of Gdańsk, Poland and one from the Kiel Bight, Germany. Samples were genotyped using a cod derived SNP-array (Illumina) with 10 913 SNPs. A selection of diagnostic SNPs was performed. A set of 7944 validated SNPs were analysed to assess the differentiation of three samples of cod. Results indicated a clear distinctness of the Kiel Bight from the populations of the eastern Baltic. FST comparison between both eastern samples was non-significant. Clustering analysis, principal coordinates analysis and assignment test clearly indicated that the eastern samples should be considered as one subpopulation, well differentiated from the western subpopulation. With the SNP approach, no differentiation between groups containing 'healthy' and 'non-healthy' cod individuals was observed.

  1. Identification of Atlantic cod (Gadus morhua), ling (Molva molva), and Alaska pollock (Gadus chalcogrammus) by PCR-ELISA using duplex PCR.

    PubMed

    Taboada, Ledicia; Sánchez, Ana; Velasco, Amaya; Santaclara, Francisco J; Pérez-Martín, Ricardo I; Sotelo, Carmen G

    2014-06-18

    Species-specific PCR-ELISA assays for the identification of Atlantic cod (Gadus morhua), Alaska pollock (Gadus chalcogrammus), and ling (Molva molva) in food products have been developed. The method, comprising a set of primers common to the first two species, a set of primers for M. molva, and a probe for each species, was designed using ND4 and cytochrome b genes as molecular markers. The sensitivity and selectivity were then determined for each assay. These assays were afterward used to analyze DNA extracted from commercial fish products. The presence of the target species was successfully detected in all analyzed samples, demonstrating the applicability of this method to the analysis of food products.

  2. Environmental harm assessment of a wastewater discharge from Hammerfest LNG: a study with biomarkers in mussels (Mytilus sp.) and Atlantic cod (Gadus morhua).

    PubMed

    Beyer, Jonny; Aarab, Nadia; Tandberg, Anne Helene; Ingvarsdottir, Anna; Bamber, Shaw; Børseth, Jan Fredrik; Camus, Lionel; Velvin, Roger

    2013-04-15

    Biologically treated wastewater (WW) from the Hammerfest LNG (liquefied natural gas) plant is discharged to the sea. A study using biomarkers in mussels and Atlantic cod was performed to examine whether this discharge meets a zero harmful emission requirement. Caging of mussels close to the outfall and exposure of mussels and fish to WW in the laboratory were conducted, and a suite of contaminant responsive markers was assessed in exposed animals. In mussels the markers included chemical contaminant levels, haemocyte lysosomal instability and nucleus integrity, cellular energy allocation, digestive gland and gonad histopathology and shell-opening behaviour. In fish, biliary PAH metabolites and gill histopathology biomarkers were measured. A consistent cause-effect relationship between WW treatments and markers measured in test animals was not found. The results therefore indicate that the WW emission is unlikely to represent a significant stress factor for the local marine environment under the conditions studied.

  3. Molecular cloning and measurement of telomerase reverse transcriptase (TERT) transcription patterns in tissues of European hake (Merluccius merluccius) and Atlantic cod (Gadus morhua) during aging.

    PubMed

    López de Abechuco, E; Bilbao, E; Soto, M; Díez, G

    2014-05-10

    Telomerase is a reverse transcriptase ribonucleoprotein that maintains the ends of linear chromosomes. This enzyme plays a major role in cell processes like proliferation, differentiation and tumorigenesis, being associated with aging and survival of species. In this study, the gene coding for TERT (Telomerase Reverse Transcriptase) of two commercial fish species, European hake (Merluccius merluccius) and Atlantic cod (Gadus morhua), has been partially cloned. A fragment of 1581bp (hake) and 633bp (cod) showed high homology (identity 74%, query cover 99%, E-value=0) with known Perciformes TERT sequences. TERT transcription patterns were assessed by qRT-PCR in different tissues of hake (brain, ovary, testis, muscle, skin, gills, liver and kidney) and cod (brain, muscle and skin) of different sizes/ages in order to understand its role in the physiological aging of teleosts. TERT was found to be ubiquitously transcribed in all tissues and size/age groups studied in both species. Significantly higher relative transcription levels (p<0.05) were found with increasing size/age of M. merluccius in the kidney, muscle, skin and gonad, the latter exhibiting particularly high relative transcription levels. Male hakes showed higher TERT relative transcription levels in the brain, gonad and liver than females, although these differences were not statistically significant (p<0.05). In G. morhua, higher TERT relative transcription levels were recorded in the muscle and brain of fry and juvenile individuals. Therefore, TERT relative transcription pattern exhibited a higher telomerase demand in early developmental stages and also in mature stages, suggesting tissue renewal or regeneration processes as a conserved mechanism for maintaining long-term cell proliferation capacity and preventing senescence. Thus, it can be concluded that TERT relative transcription level was species and tissue specific and changed with the age of fishes.

  4. Copepods enhance nutritional status, growth and development in Atlantic cod (Gadus morhua L.) larvae — can we identify the underlying factors?

    PubMed Central

    van der Meeren, Terje; Rønnestad, Ivar; Mangor-Jensen, Anders; Galloway, Trina F.; Kjørsvik, Elin; Hamre, Kristin

    2015-01-01

    The current commercial production protocols for Atlantic cod depend on enriched rotifers and Artemia during first-feeding, but development and growth remain inferior to fish fed natural zooplankton. Two experiments were conducted in order to identify the underlying factors for this phenomenon. In the first experiment (Exp-1), groups of cod larvae were fed either (a) natural zooplankton, mainly copepods, increasing the size of prey as the larvae grew or (b) enriched rotifers followed by Artemia (the intensive group). In the second experiment (Exp-2), two groups of larvae were fed as in Exp-1, while a third group was fed copepod nauplii (approximately the size of rotifers) throughout the larval stage. In both experiments, growth was not significantly different between the groups during the first three weeks after hatching, but from the last part of the rotifer feeding period and onwards, the growth of the larvae fed copepods was higher than that of the intensive group. In Exp-2, the growth was similar between the two copepod groups during the expeimental period, indicating that nutrient composition, not prey size caused the better growth on copepods. Analyses of the prey showed that total fatty acid composition and the ratio of phospholipids to total lipids was slightly different in the prey organisms, and that protein, taurine, astaxanthin and zinc were lower on a dry weight basis in rotifers than in copepods. Other measured nutrients as DHA, all analysed vitamins, manganese, copper and selenium were similar or higher in the rotifers. When compared to the present knowledge on nutrient requirements, protein and taurine appeared to be the most likely limiting nutrients for growth in cod larvae fed rotifers and Artemia. Larvae fed rotifers/Artemia had a higher whole body lipid content than larvae fed copepods at the end of the experiment (stage 5) after the fish had been fed the same formulated diet for approximately 2 weeks. PMID:26038712

  5. Screening and characterisation of potentially pathogenic bacteria associated with Atlantic cod Gadus morhua larvae: bath challenge trials using a multidish system.

    PubMed

    Sandlund, Nina; Bergh, Øivind

    2008-09-24

    In intensive aquaculture systems, high concentrations of nutrients and high densities of fish larvae provide favorable conditions for opportunistic pathogenic bacteria to flourish. We screened potentially pathogenic bacterial strains isolated from moribund Atlantic cod Gadus morhua larvae, pollack Pollachius pollachius, coalfish Pollachius virens, Atlantic halibut Hippoglossus hippoglossus, rotifers, algae and water samples from different hatcheries. Three identical challenge experiments tested a total of 53 strains. A multidish system was used: cod eggs were placed in single wells, together with 2 ml of sterile seawater, and exposed to the bacterial cultures. Final bacterial concentrations in the wells were 10(6) and 10(4) CFU ml(-1). Eggs and larvae not exposed to bacteria were used as unchallenged controls. Challenged controls were exposed to Vibrio anguillarum strain 610. Eggs were challenged approximately 48 h prior to hatching and mortality was recorded daily throughout the yolk-sac period. In spite of the high challenge dose of 106 CFU ml(-1), only 5 bacterial strains tested caused higher mortality than the unchallenged controls. Four of these strains were identified by 16S rDNA and gyrase B gene (GyrB) sequencing as resembling V. anguillarum and 1 strain resembled Carnobacterium sp. Most of the larvae exposed to these strains died within 10 d of challenge. Serotyping of the strains resembling V. anguillarum gave inconclusive results. This indicates differences in serology compared to the serotypes O1, O2 and O3, associated with disease. Three bacterial strains seemed to have a slower infection rate, indicating a longer incubation period. The remaining 45 strains did not seem to have a negative effect on larval survival, suggesting that these are not primary pathogens.

  6. Francisella noatunensis subsp. noatunensis replicates within Atlantic cod (Gadus morhua L.) leucocytes and inhibits respiratory burst activity.

    PubMed

    Vestvik, Nils; Rønneseth, Anita; Kalgraff, Cathrine A K; Winther-Larsen, Hanne C; Wergeland, Heidrun I; Haugland, Gyri T

    2013-09-01

    Francisella noatunensis subsp. noatunensis, causing granulomatosis in cod, has been shown to reside within cod immune cells, mainly within monocytes and macrophages. In the present study, we analysed the ability of the bacterium to replicate within adherent cells isolated from head kidney by in vitro infection of leucocytes. Two different technical approaches for flow cytometry analyses were performed for detection of intracellular bacteria. The presence of the wild type was assessed after identification by intracellular binding of specific antibodies to the pathogen. The other way was to use green fluorescent protein (GFP) transformed bacterium for infection studies allowing direct measurements of fluorescence from infected cells. By both methods we found an increase in fluorescence in infected cells, verifying bacterial replication, both after 4 and 28 h post infection in leucocytes isolated from head kidney (HKL). The GFP transformed bacterium was similar to the wild type in growth and infectivity pattern, showing that it can be a valuable tool for further studies of infection routes and pathology. Further, F. noatunensis subsp. noatunensis was found to inhibit respiratory burst activity, a potent pathogen killing mechanism, in cod leucocytes, but not in such cells from salmon. Our findings may indicate that inhibition of respiratory burst during Francisella infection is a key to its intracellular existence. This strategy seems to be conserved through evolution as it is also observed during infections in higher vertebrates caused by bacteria within the Francisella genus. The results presented here, showing the intracellular existence of Francisella, its replication within leucocytes and the inhibitory effect on respiratory burst, strongly support that these factors contribute to disease and pathology in infected cod. The intracellular replication shown in the present study might contribute to explain the problems of obtaining protective vaccines against

  7. Trends in the exploitation of South Atlantic shark populations.

    PubMed

    Barreto, Rodrigo; Ferretti, Francesco; Flemming, Joanna M; Amorim, Alberto; Andrade, Humber; Worm, Boris; Lessa, Rosangela

    2016-08-01

    Approximately 25% of globally reported shark catches occur in Atlantic pelagic longline fisheries. Strong declines in shark populations have been detected in the North Atlantic, whereas in the South Atlantic the situation is less clear, although fishing effort has been increasing in this region since the late 1970s. We synthesized information on shark catch rates (based on 871,177 sharks caught on 86,492 longline sets) for the major species caught by multiple fleets in the South Atlantic between 1979 and 2011. We complied records from fishing logbooks of fishing companies, fishers, and onboard observers that were supplied to Brazilian institutions. By using exploratory data analysis and literature sources, we identified 3 phases of exploitation in these data (Supporting Information). From 1979 to 1997 (phase A), 5 fleets (40 vessels) fished mainly for tunas. From 1998 to 2008 (phase B), 20 fleets (100 vessels) fished for tunas, swordfishes, and sharks. From 2008 to 2011 (phase C), 3 fleets (30 vessels) fished for multiple species, but restrictive measures were implemented. We used generalized linear models to standardize catch rates and identify trends in each of these phases. Shark catch rates increased from 1979 to 1997, when fishing effort was low, decreased from 1998 to 2008, when fishing effort increased substantially, and remained stable or increased from 2008 to 2011, when fishing effort was again low. Our results indicate that most shark populations affected by longlines in the South Atlantic are currently depleted, but these populations may recover if fishing effort is reduced accordingly. In this context, it is problematic that comprehensive data collection, monitoring, and management of these fisheries ceased after 2012. Concurrently with the fact that Brazil is newly identified by FAO among the largest (and in fastest expansion) shark sub-products consumer market worldwide.

  8. The Ontogeny and Brain Distribution Dynamics of the Appetite Regulators NPY, CART and pOX in Larval Atlantic Cod (Gadus morhua L.)

    PubMed Central

    Le, Hoang T. M. D.; Angotzi, Anna Rita; Ebbesson, Lars O. E.; Karlsen, Ørjan

    2016-01-01

    Similar to many marine teleost species, Atlantic cod undergo remarkable physiological changes during the early life stages with concurrent and profound changes in feeding biology and ecology. In contrast to the digestive system, very little is known about the ontogeny and the localization of the centers that control appetite and feed ingestion in the developing brain of fish. We examined the expression patterns of three appetite regulating factors (orexigenic: neuropeptide Y, NPY; prepro-orexin, pOX and anorexigenic: cocaine- and amphetamine-regulated transcript, CART) in discrete brain regions of developing Atlantic cod using chromogenic and double fluorescent in situ hybridization. Differential temporal and spatial expression patterns for each appetite regulator were found from first feeding (4 days post hatch; dph) to juvenile stage (76 dph). Neurons expressing NPY mRNA were detected in the telencephalon (highest expression), diencephalon, and optic tectum from 4 dph onward. CART mRNA expression had a wider distribution along the anterior-posterior brain axis, including both telencephalon and diencephalon from 4 dph. From 46 dph, CART transcripts were also detected in the olfactory bulb, region of the nucleus of medial longitudinal fascicle, optic tectum and midbrain tegmentum. At 4 and 20 dph, pOX mRNA expression was exclusively found in the preoptic region, but extended to the hypothalamus at 46 and 76 dph. Co-expression of both CART and pOX genes were also observed in several hypothalamic neurons throughout larval development. Our results show that both orexigenic and anorexigenic factors are present in the telencephalon, diencephalon and mesencephalon in cod larvae. The telencephalon mostly contains key factors of hunger control (NPY), while the diencephalon, and particularly the hypothalamus may have a more complex role in modulating the multifunctional control of appetite in this species. As the larvae develop, the overall progression in temporal and

  9. The Ontogeny and Brain Distribution Dynamics of the Appetite Regulators NPY, CART and pOX in Larval Atlantic Cod (Gadus morhua L.).

    PubMed

    Le, Hoang T M D; Angotzi, Anna Rita; Ebbesson, Lars O E; Karlsen, Ørjan; Rønnestad, Ivar

    2016-01-01

    Similar to many marine teleost species, Atlantic cod undergo remarkable physiological changes during the early life stages with concurrent and profound changes in feeding biology and ecology. In contrast to the digestive system, very little is known about the ontogeny and the localization of the centers that control appetite and feed ingestion in the developing brain of fish. We examined the expression patterns of three appetite regulating factors (orexigenic: neuropeptide Y, NPY; prepro-orexin, pOX and anorexigenic: cocaine- and amphetamine-regulated transcript, CART) in discrete brain regions of developing Atlantic cod using chromogenic and double fluorescent in situ hybridization. Differential temporal and spatial expression patterns for each appetite regulator were found from first feeding (4 days post hatch; dph) to juvenile stage (76 dph). Neurons expressing NPY mRNA were detected in the telencephalon (highest expression), diencephalon, and optic tectum from 4 dph onward. CART mRNA expression had a wider distribution along the anterior-posterior brain axis, including both telencephalon and diencephalon from 4 dph. From 46 dph, CART transcripts were also detected in the olfactory bulb, region of the nucleus of medial longitudinal fascicle, optic tectum and midbrain tegmentum. At 4 and 20 dph, pOX mRNA expression was exclusively found in the preoptic region, but extended to the hypothalamus at 46 and 76 dph. Co-expression of both CART and pOX genes were also observed in several hypothalamic neurons throughout larval development. Our results show that both orexigenic and anorexigenic factors are present in the telencephalon, diencephalon and mesencephalon in cod larvae. The telencephalon mostly contains key factors of hunger control (NPY), while the diencephalon, and particularly the hypothalamus may have a more complex role in modulating the multifunctional control of appetite in this species. As the larvae develop, the overall progression in temporal and

  10. Assessment of Allergy to Milk, Egg, Cod, and Wheat in Swedish Schoolchildren: A Population Based Cohort Study

    PubMed Central

    Winberg, Anna; West, Christina E; Strinnholm, Åsa; Nordström, Lisbeth; Hedman, Linnea; Rönmark, Eva

    2015-01-01

    Objectives Knowledge about the prevalence of allergies to foods in childhood and adolescence is incomplete. The purpose of this study was to investigate the prevalence of allergies to milk, egg, cod, and wheat using reported data, clinical examinations, and double-blind placebo-controlled food challenges, and to describe the phenotypes of reported food hypersensitivity in a cohort of Swedish schoolchildren. Methods In a population-based cohort of 12-year-old children, the parents of 2612 (96% of invited) completed a questionnaire. Specific IgE antibodies to foods were analyzed in a random sample (n=695). Children reporting complete avoidance of milk, egg, cod, or wheat due to perceived hypersensitivity and without physician-diagnosed celiac disease were invited to undergo clinical examination that included specific IgE testing, a celiac screening test, and categorization into phenotypes of food hypersensitivity according to preset criteria. Children with possible food allergy were further evaluated with double-blind challenges. Results In this cohort, the prevalence of reported food allergy to milk, egg, cod, or wheat was 4.8%. Food allergy was diagnosed in 1.4% of the children after clinical evaluation and in 0.6% following double-blind placebo-controlled food challenge. After clinical examination, children who completely avoided one or more essential foods due to perceived food hypersensitivity were categorized with the following phenotypes: allergy (29%), outgrown allergy (19%), lactose intolerance (40%), and unclear (12%). Conclusions There was a high discrepancy in the prevalence of allergy to milk, egg, cod and wheat as assessed by reported data, clinical evaluation, and double-blind food challenges. Food hypersensitivity phenotyping according to preset criteria was helpful for identifying children with food allergy. PMID:26134827

  11. Cape Cod

    Atmospheric Science Data Center

    2014-05-15

    article title:  Cape Cod, Massachusetts     View Larger ... Pilgrims landed, is located on the west side of Cape Cod Bay, shown in this Multi-angle Imaging SpectroRadiometer (MISR) ... Terra orbit 1708. South of the distinctively-shaped Cape Cod are Nantucket Island and Martha's Vineyard. Further west is Block Island, ...

  12. Response of branchial Na(+)/K(+) ATPase to changes in ambient temperature in Atlantic cod (Gadus morhua) and whiting (Merlangius merlangus).

    PubMed

    Michael, Katharina; Koschnick, Nils; Pörtner, Hans-O; Lucassen, Magnus

    2016-05-01

    The maintenance of ion and pH homeostasis despite changes in ambient temperature is crucial for ectothermic organisms. Thermal sensitivity of Na(+)/K(+) ATPase mRNA expression, protein expression and activity was determined in gills of North Sea cod (NC) and Northeastern Arctic cod (NEAC), acclimated for 6 weeks at 4 and 10 °C and compared to field samples of North Sea cod (sNC), acclimatized to early spring (4 °C) and summer (18 °C) conditions. The same analyses were conducted in gills of the confamiliar whiting, acclimated at 4 and 10 °C. Branchial Na(+)/K(+) ATPase capacities remained uncompensated at functional and protein levels in NC and NEAC at both acclimation temperatures. Na(+)/K(+) ATPase mRNA expression in NEAC acclimated at 10 °C was about twofold higher compared to NC, indicating some population-specific differentiation at this level. Lower Na(+)/K(+) ATPase capacities in gills of warm-acclimatized sNC at common assay temperatures indicate thermal compensation between seasonal extremes, and post-translational modifications contributed to this mitigation at high assay temperature. Together, cod compensates Na(+)/K(+) ATPase capacities on the warm edge of the thermal window and below 4 °C, respectively. In contrast, whiting Na(+)/K(+) ATPase capacities were cold compensated at 4 °C, supported by 1.5-fold higher mRNA and protein expression. Besides, capacities were lower in whiting compared to NC and NEAC at optimum temperature, which may be advantageous in terms of reduced maintenance cost, but at temperatures ≤4 °C, compensation may represent an energy trade-off to maintain homeostasis. The species-specific response of gadid Na(+)/K(+) ATPase indicates certain threshold temperatures beyond which compensation of the pump is elicited, possibly related to the different biogeography of these species.

  13. Bioassay-derived dioxin equivalent concentrations in gonads and livers of the Atlantic cod females from the Baltic Sea.

    PubMed

    Dabrowska, Henryka; Murk, Albertinka J; van den Berg, Hans J

    2010-11-01

    The DR-H4IIE.Luc bioassay is based on the ability of dioxin and dioxin-like contaminants to activate the AhR and its signal transduction pathway, a mechanism through which these contaminants elicit their toxic effects. The bioassay was used to examine the total dioxin-equivalent (TEQ) toxicity in gonads and livers of cod females from the southern Baltic Sea. The bioassay-derived TEQ-luc was measured after 24-h and 48-h exposure periods. Mean concentrations in the 24-h bioassay were 95 and 35 pg TEQ-luc g(-1) lipid in gonads and livers, respectively, and 58 and 38 pg TEQ-luc g(-1) lipid in the 48-h bioassay, respectively. The 48-h TEQ-luc levels displayed significant relationships with ΣPCB(7) and selected PCB congeners but not with the TEQ(DLPCB-REP). Levels in gonads approached 10% of the LC50 for developing larvae of other marine fish, yet the impact on survival of the cod during its early life remains to be assessed in a future.

  14. IBSEM: An Individual-Based Atlantic Salmon Population Model.

    PubMed

    Castellani, Marco; Heino, Mikko; Gilbey, John; Araki, Hitoshi; Svåsand, Terje; Glover, Kevin A

    2015-01-01

    Ecology and genetics can influence the fate of individuals and populations in multiple ways. However, to date, few studies consider them when modelling the evolutionary trajectory of populations faced with admixture with non-local populations. For the Atlantic salmon, a model incorporating these elements is urgently needed because many populations are challenged with gene-flow from non-local and domesticated conspecifics. We developed an Individual-Based Salmon Eco-genetic Model (IBSEM) to simulate the demographic and population genetic change of an Atlantic salmon population through its entire life-cycle. Processes such as growth, mortality, and maturation are simulated through stochastic procedures, which take into account environmental variables as well as the genotype of the individuals. IBSEM is based upon detailed empirical data from salmon biology, and parameterized to reproduce the environmental conditions and the characteristics of a wild population inhabiting a Norwegian river. Simulations demonstrated that the model consistently and reliably reproduces the characteristics of the population. Moreover, in absence of farmed escapees, the modelled populations reach an evolutionary equilibrium that is similar to our definition of a 'wild' genotype. We assessed the sensitivity of the model in the face of assumptions made on the fitness differences between farm and wild salmon, and evaluated the role of straying as a buffering mechanism against the intrusion of farm genes into wild populations. These results demonstrate that IBSEM is able to capture the evolutionary forces shaping the life history of wild salmon and is therefore able to model the response of populations under environmental and genetic stressors.

  15. IBSEM: An Individual-Based Atlantic Salmon Population Model

    PubMed Central

    Castellani, Marco; Heino, Mikko; Gilbey, John; Araki, Hitoshi; Svåsand, Terje; Glover, Kevin A.

    2015-01-01

    Ecology and genetics can influence the fate of individuals and populations in multiple ways. However, to date, few studies consider them when modelling the evolutionary trajectory of populations faced with admixture with non-local populations. For the Atlantic salmon, a model incorporating these elements is urgently needed because many populations are challenged with gene-flow from non-local and domesticated conspecifics. We developed an Individual-Based Salmon Eco-genetic Model (IBSEM) to simulate the demographic and population genetic change of an Atlantic salmon population through its entire life-cycle. Processes such as growth, mortality, and maturation are simulated through stochastic procedures, which take into account environmental variables as well as the genotype of the individuals. IBSEM is based upon detailed empirical data from salmon biology, and parameterized to reproduce the environmental conditions and the characteristics of a wild population inhabiting a Norwegian river. Simulations demonstrated that the model consistently and reliably reproduces the characteristics of the population. Moreover, in absence of farmed escapees, the modelled populations reach an evolutionary equilibrium that is similar to our definition of a ‘wild’ genotype. We assessed the sensitivity of the model in the face of assumptions made on the fitness differences between farm and wild salmon, and evaluated the role of straying as a buffering mechanism against the intrusion of farm genes into wild populations. These results demonstrate that IBSEM is able to capture the evolutionary forces shaping the life history of wild salmon and is therefore able to model the response of populations under environmental and genetic stressors. PMID:26383256

  16. Suspended matter in surface waters of the Atlantic continental margin from Cape Cod to the Florida keys

    USGS Publications Warehouse

    Manheim, F. T.; Meade, R.H.; Bond, G.C.

    1970-01-01

    Appreciable amounts of suspended matter (> 1.0 milligram per liter) in surface waters are restricted to within a few kilometers of the Atlantic coast. Particles that escape estuaries or are discharged by rivers into the shelf region tend to travel longshoreward rather than seaward. Suspended matter farther offshore, chiefly amorphous organic particles, totals 0.1 milligram per liter or less. Soot, fly ash, processed cellulose, and other pollutants are widespread.

  17. Genetic differentiation among North Atlantic killer whale populations.

    PubMed

    Foote, Andrew D; Vilstrup, Julia T; De Stephanis, Renaud; Verborgh, Philippe; Abel Nielsen, Sandra C; Deaville, Robert; Kleivane, Lars; Martín, Vidal; Miller, Patrick J O; Oien, Nils; Pérez-Gil, Monica; Rasmussen, Morten; Reid, Robert J; Robertson, Kelly M; Rogan, Emer; Similä, Tiu; Tejedor, Maria L; Vester, Heike; Víkingsson, Gísli A; Willerslev, Eske; Gilbert, M Thomas P; Piertney, Stuart B

    2011-02-01

    Population genetic structure of North Atlantic killer whale samples was resolved from differences in allele frequencies of 17 microsatellite loci, mtDNA control region haplotype frequencies and for a subset of samples, using complete mitogenome sequences. Three significantly differentiated populations were identified. Differentiation based on microsatellite allele frequencies was greater between the two allopatric populations than between the two pairs of partially sympatric populations. Spatial clustering of individuals within each of these populations overlaps with the distribution of particular prey resources: herring, mackerel and tuna, which each population has been seen predating. Phylogenetic analyses using complete mitogenomes suggested two populations could have resulted from single founding events and subsequent matrilineal expansion. The third population, which was sampled at lower latitudes and lower density, consisted of maternal lineages from three highly divergent clades. Pairwise population differentiation was greater for estimates based on mtDNA control region haplotype frequencies than for estimates based on microsatellite allele frequencies, and there were no mitogenome haplotypes shared among populations. This suggests low or no female migration and that gene flow was primarily male mediated when populations spatially and temporally overlap. These results demonstrate that genetic differentiation can arise through resource specialization in the absence of physical barriers to gene flow.

  18. Atlantic cod (Gadus morhua) larvae can biosynthesis phospholipid de novo from 2-oleoyl-glycerol and glycerol precursors.

    PubMed

    Li, Keshuai; Olsen, Rolf Erik; Østensen, Mari-Ann; Altin, Dag; Kjørsvik, Elin; Olsen, Yngvar

    2016-02-01

    The dietary requirement of phospholipid (PL) of fish larvae has been suggested to originate in an inefficient ability for de novo biosynthesis of PL based on dietary triacylglycerol (TAG). The main objective of the present study was to investigate whether cod larvae could synthesis PL from sn-2-monoacylglycerol (2-MAG) and glycerol precursors. A tube feeding method was used to deliver equal molar aliquots of 2-oleoyl-[1,2,3-(3)H]glycerol and [U-(14)C] glycerol together with bovine serum albumin (BSA) bound 16:0 (palmitic acid) and 22:6n-3 (docosahexaenoic acid, DHA), with or without choline chloride to the foregut of anesthetized cod larvae and thereafter monitoring the metabolism of these components in the larvae through 4 h following injection. Our results showed that both 2-MAG and glycerol precursors contributed to the de novo synthesis of phosphatidylcholine (PC) and the 2-MAG pathway predominated over the G-3-P (glycerol-3-phosphate) pathway in the synthesis of TAG and PC. The molecular ratio of PC/TAG obtained from the 2-MAG and the G-3-P pathways was 0.44-0.74 and 1.02-2.06 within the first hour of tube feeding, suggesting they might have comparable biosynthesis ability of PC and TAG under the conditions of the present study. Furthermore, supplementation of choline chloride significantly increased PC/TAG ratio (p < 0.05) for both pathways. However, further studies are needed to quantify the enzyme activity involved in the CDP-choline (cytidine diphosphate choline) pathway, and the function of choline either in simulating PC synthesis or TAG catabolism or both needs further investigation.

  19. Adjustments of molecular key components of branchial ion and pH regulation in Atlantic cod (Gadus morhua) in response to ocean acidification and warming.

    PubMed

    Michael, Katharina; Kreiss, Cornelia M; Hu, Marian Y; Koschnick, Nils; Bickmeyer, Ulf; Dupont, Sam; Pörtner, Hans-O; Lucassen, Magnus

    2016-03-01

    Marine teleost fish sustain compensation of extracellular pH after exposure to hypercapnia by means of efficient ion and acid-base regulation. Elevated rates of ion and acid-base regulation under hypercapnia may be stimulated further by elevated temperature. Here, we characterized the regulation of transepithelial ion transporters (NKCC1, NBC1, SLC26A6, NHE1 and 2) and ATPases (Na(+)/K(+) ATPase and V-type H(+) ATPase) in gills of Atlantic cod (Gadus morhua) after 4 weeks of exposure to ambient and future PCO2 levels (550 μatm, 1200 μatm, 2200 μatm) at optimum (10 °C) and summer maximum temperature (18 °C), respectively. Gene expression of most branchial ion transporters revealed temperature- and dose-dependent responses to elevated PCO2. Transcriptional regulation resulted in stable protein expression at 10 °C, whereas expression of most transport proteins increased at medium PCO2 and 18 °C. mRNA and protein expression of distinct ion transport proteins were closely co-regulated, substantiating cellular functional relationships. Na(+)/K(+) ATPase capacities were PCO2 independent, but increased with acclimation temperature, whereas H(+) ATPase capacities were thermally compensated but decreased at medium PCO2 and 10 °C. When functional capacities of branchial ATPases were compared with mitochondrial F1Fo ATP-synthase strong correlations of F1Fo ATP-synthase and ATPase capacities generally indicate close coordination of branchial aerobic ATP demand and supply. Our data indicate physiological plasticity in the gills of cod to adjust to a warming, acidifying ocean within limits. In light of the interacting and non-linear, dose-dependent effects of both climate factors the role of these mechanisms in shaping resilience under climate change remains to be explored.

  20. Computer vision-based evaluation of pre- and postrigor changes in size and shape of Atlantic cod (Gadus morhua) and Atlantic salmon (Salmo salar) fillets during rigor mortis and ice storage: effects of perimortem handling stress.

    PubMed

    Misimi, E; Erikson, U; Digre, H; Skavhaug, A; Mathiassen, J R

    2008-03-01

    The present study describes the possibilities for using computer vision-based methods for the detection and monitoring of transient 2D and 3D changes in the geometry of a given product. The rigor contractions of unstressed and stressed fillets of Atlantic salmon (Salmo salar) and Atlantic cod (Gadus morhua) were used as a model system. Gradual changes in fillet shape and size (area, length, width, and roundness) were recorded for 7 and 3 d, respectively. Also, changes in fillet area and height (cross-section profiles) were tracked using a laser beam and a 3D digital camera. Another goal was to compare rigor developments of the 2 species of farmed fish, and whether perimortem stress affected the appearance of the fillets. Some significant changes in fillet size and shape were found (length, width, area, roundness, height) between unstressed and stressed fish during the course of rigor mortis as well as after ice storage (postrigor). However, the observed irreversible stress-related changes were small and would hardly mean anything for postrigor fish processors or consumers. The cod were less stressed (as defined by muscle biochemistry) than the salmon after the 2 species had been subjected to similar stress bouts. Consequently, the difference between the rigor courses of unstressed and stressed fish was more extreme in the case of salmon. However, the maximal whole fish rigor strength was judged to be about the same for both species. Moreover, the reductions in fillet area and length, as well as the increases in width, were basically of similar magnitude for both species. In fact, the increases in fillet roundness and cross-section height were larger for the cod. We conclude that the computer vision method can be used effectively for automated monitoring of changes in 2D and 3D shape and size of fish fillets during rigor mortis and ice storage. In addition, it can be used for grading of fillets according to uniformity in size and shape, as well as measurement of

  1. Understanding climate impacts on recruitment and spatial dynamics of Atlantic cod in the Gulf of Maine: Integration of observations and modeling

    NASA Astrophysics Data System (ADS)

    Runge, Jeffrey A.; Kovach, Adrienne I.; Churchill, James H.; Kerr, Lisa A.; Morrison, John R.; Beardsley, Robert C.; Berlinsky, David L.; Chen, Changsheng; Cadrin, Steven X.; Davis, Cabell S.; Ford, Kathryn H.; Grabowski, Jonathan H.; Howell, W. Huntting; Ji, Rubao; Jones, Rebecca J.; Pershing, Andrew J.; Record, Nicholas R.; Thomas, Andrew C.; Sherwood, Graham D.; Tallack, Shelly M. L.; Townsend, David W.

    2010-10-01

    We put forward a combined observing and modeling strategy for evaluating effects of environmental forcing on the dynamics of spatially structured cod populations spawning in the western Gulf of Maine. Recent work indicates at least two genetically differentiated complexes in this region: a late spring spawning, coastal population centered in Ipswich Bay, and a population that spawns in winter inshore and on nearshore banks in the Gulf of Maine and off southern New England. The two populations likely differ in trophic interactions and in physiological and behavioral responses to different winter and spring environments. Coupled physical-biological modeling has advanced to the point where within-decade forecasting of environmental conditions for recruitment to each of the two populations is feasible. However, the modeling needs to be supported by hydrographic, primary production and zooplankton data collected by buoys, and by data from remote sensing and fixed station sampling. Forecasts of environmentally driven dispersal and growth of planktonic early life stages, combined with an understanding of possible population-specific predator fields, usage of coastal habitat by juveniles and adult resident and migratory patterns, can be used to develop scenarios for spatially explicit population responses to multiple forcings, including climate change, anthropogenic impacts on nearshore juvenile habitat, connectivity among populations and management interventions such as regional fisheries closures.

  2. Characterization of the fatty acyl elongase (elovl) gene family, and hepatic elovl and delta-6 fatty acyl desaturase transcript expression and fatty acid responses to diets containing camelina oil in Atlantic cod (Gadus morhua).

    PubMed

    Xue, Xi; Feng, Charles Y; Hixson, Stefanie M; Johnstone, Kim; Anderson, Derek M; Parrish, Christopher C; Rise, Matthew L

    2014-09-01

    For aquaculture to become sustainable, there is a need to substitute fish oil [FO, rich in ω3 long chain polyunsaturated fatty acids (LC-PUFA) such as 20:5ω3 (EPA) and 22:6ω3 (DHA)] in aquafeed with plant oils such as camelina oil [CO, rich in C18 PUFA such as 18:3ω3 (ALA) and 18:2ω6 (LNA)]. The LC-PUFA are essential components in fish diets for maintaining optimal health, physiology and growth. However, most marine fish including Atlantic cod are inefficient at producing LC-PUFA from shorter chain precursors. Since elovl genes encode enzymes that play key roles in fatty acid biosynthesis, we hypothesized that they may be involved in Atlantic cod responses to diets rich in 18:3ω3 and 18:2ω6. Ten members of the cod elovl gene family were characterized at the mRNA level. RT-PCR was used to study constitutive expression of elovl transcripts in fifteen tissues. Some transcripts (e.g. elovl5) were ubiquitously expressed, while others had tissue-specific expression (e.g. elovl4a in brain and eye). Cod fed a CO-containing diet (100% CO replacement of FO and including solvent-extracted fish meal) had significantly lower weight gain, with significant up-regulation of elovl5 and fadsd6 transcripts in the liver as shown by QPCR analysis, compared with cod on a FO control diet after a 13-week trial. Multivariate statistical analyses (SIMPER and PCA) indicated that high 18:3ω3 and/or low ω3 LC-PUFA levels in the liver were associated with the up-regulation of elovl5 and fadsd6, which are involved in LC-PUFA biosynthesis in cod.

  3. Population differences in response to hypoxic stress in Atlantic salmon.

    PubMed

    Côte, J; Roussel, J-M; Le Cam, S; Bal, G; Evanno, G

    2012-12-01

    Understanding whether populations can adapt to new environmental conditions is a major issue in conservation and evolutionary biology. Aquatic organisms are increasingly exposed to environmental changes linked with human activities in river catchments. For instance, the clogging of bottom substratum by fine sediments is observed in many rivers and usually leads to a decrease in dissolved oxygen concentrations in gravel beds. Such hypoxic stress can alter the development and even be lethal for Atlantic salmon (Salmo salar) embryos that spend their early life into gravel beds. In this study, we used a common garden experiment to compare the responses to hypoxic stress of four genetically differentiated and environmentally contrasted populations. We used factorial crossing designs to measure additive genetic variation of early life-history traits in each population. Embryos were reared under normoxic and hypoxic conditions, and we measured their survival, incubation time and length at the end of embryonic development. Under hypoxic conditions, embryos had a lower survival and hatched later than in normoxic conditions. We found different hypoxia reaction norms among populations, but almost no population effect in both treatments. We also detected significant sire × treatment interactions in most populations and a tendency for heritability values to be lower under stressful conditions. Overall, these results reveal a high degree of phenotypic plasticity in salmon populations that nevertheless differ in their adaptive potential to hypoxia given the distinct reaction norms observed between and within populations.

  4. Discovery of miRNAs and Their Corresponding miRNA Genes in Atlantic Cod (Gadus morhua): Use of Stable miRNAs as Reference Genes Reveals Subgroups of miRNAs That Are Highly Expressed in Particular Organs

    PubMed Central

    Andreassen, Rune; Rangnes, Fredrik; Sivertsen, Maria; Chiang, Michelle; Tran, Michelle; Worren, Merete Molton

    2016-01-01

    Background Atlantic cod (Gadus morhua) is among the economically most important species in the northern Atlantic Ocean and a model species for studying development of the immune system in vertebrates. MicroRNAs (miRNAs) are an abundant class of small RNA molecules that regulate fundamental biological processes at the post-transcriptional level. Detailed knowledge about a species miRNA repertoire is necessary to study how the miRNA transcriptome modulate gene expression. We have therefore discovered and characterized mature miRNAs and their corresponding miRNA genes in Atlantic cod. We have also performed a validation study to identify suitable reference genes for RT-qPCR analysis of miRNA expression in Atlantic cod. Finally, we utilized the newly characterized miRNA repertoire and the dedicated RT-qPCR method to reveal miRNAs that are highly expressed in certain organs. Results The discovery analysis revealed 490 mature miRNAs (401 unique sequences) along with precursor sequences and genomic location of the miRNA genes. Twenty six of these were novel miRNA genes. Validation studies ranked gmo-miR-17-1—5p or the two-gene combination gmo-miR25-3p and gmo-miR210-5p as most suitable qPCR reference genes. Analysis by RT-qPCR revealed 45 miRNAs with significantly higher expression in tissues from one or a few organs. Comparisons to other vertebrates indicate that some of these miRNAs may regulate processes like growth, lipid metabolism, immune response to microbial infections and scar damage repair. Three teleost-specific and three novel Atlantic cod miRNAs were among the differentially expressed miRNAs. Conclusions The number of known mature miRNAs was considerably increased by our identification of miRNAs and miRNA genes in Atlantic cod. This will benefit further functional studies of miRNA expression using deep sequencing methods. The validation study showed that stable miRNAs are suitable reference genes for RT-qPCR analysis of miRNA expression. Applying RT-qPCR we

  5. Collapse and conservation of shark populations in the Northwest Atlantic.

    PubMed

    Baum, Julia K; Myers, Ransom A; Kehler, Daniel G; Worm, Boris; Harley, Shelton J; Doherty, Penny A

    2003-01-17

    Overexploitation threatens the future of many large vertebrates. In the ocean, tunas and sea turtles are current conservation concerns because of this intense pressure. The status of most shark species, in contrast, remains uncertain. Using the largest data set in the Northwest Atlantic, we show rapid large declines in large coastal and oceanic shark populations. Scalloped hammerhead, white, and thresher sharks are each estimated to have declined by over 75% in the past 15 years. Closed-area models highlight priority areas for shark conservation, and the need to consider effort reallocation and site selection if marine reserves are to benefit multiple threatened species.

  6. Effects of 17alpha-methyltestosterone exposure on steroidogenesis and cyclin-B mRNA expression in previtellogenic oocytes of Atlantic cod (Gadus morhua).

    PubMed

    Kortner, Trond M; Arukwe, Augustine

    2007-11-01

    Steroid hormone (estrogens and androgens) synthesis and regulation involve a large number of enzymes and potential biochemical pathways. In the context of these biochemical pathways, it is believed that the true rate-limiting step in acute steroid production is the movement of cholesterol across the mitochondrial membrane by the steroidogenic acute regulatory (StAR) protein and the subsequent conversion to pregnenolone by cytochrome P450-mediated side-chain cleavage (P450scc) enzyme. Oocyte development is a complex process that is triggered by the maturation-promoting factor (MPF) involving cyclin-B as a regulatory factor. In the present study, we evaluated the endocrine effects of 17alpha-methyltestosterone (MT) on steroidogenic pathways of Atlantic cod (Gadus morhua), using an in vitro previtellogenic oocyte culture technique that is based on an agarose floating method. Tissue was cultured in a humidified incubator at 10 degrees C for 1, 5, 10 and 20 days with different concentrations of the synthetic androgen MT (0 (control), 1, 10, 100 and 1000 microM) dissolved in ethanol (0.3%). Gene expressions for StAR, P450scc, aromatase-alpha (P450aromA) and cyclin-B were detected using validated real-time PCR with specific primer pairs. Cellular localization of the StAR protein and P450scc were performed using the immunohistochemical technique with antisera prepared against synthetic peptide for both proteins. Steroid hormones (estradiol-17beta: E2 and testosterone: T) levels were estimated using enzyme immunoassay. Our data showed significant concentration-specific increase (at day 1 and 5) and decrease (at day 10 and 20) of the StAR mRNA expression after exposure to MT. P450scc expression showed a MT concentration-specific decrease during the exposure periods and cyclin-B mRNA expression was decreased in MT concentration-dependent manner at days 10 and 20 (reaching almost total inhibition after exposure to 1000 microM MT). MT exposure produced variable effects on the P

  7. Substitution of fish oil with camelina oil and inclusion of camelina meal in diets fed to Atlantic cod (Gadus morhua) and their effects on growth, tissue lipid classes, and fatty acids.

    PubMed

    Hixson, S M; Parrish, C C

    2014-03-01

    Developing a commercially relevant Atlantic cod aquaculture industry will require improvements in feed sustainability. Camelina oil and meal are potential replacements of fish oil and fish meal in aquaculture feeds. Camelina oil is high in 18:3ω3 (30%), with an ω3/ω6 ratio > 1. Camelina meal has a considerable crude protein level (38%), which includes significant amounts of methionine and phenylalanine. Four diets were tested; each diet was fed to triplicate tanks (3 tanks per diet) of Atlantic cod (14.4 g/fish; 70 fish per tank) for 13 wk. The diets included a fish oil/fish meal control (FO) and three diets which replaced 100% of fish oil with camelina oil: one diet contained fish meal (100CO), another solvent extracted fish meal (100COSEFM), and another had fish meal partially reduced by 15% inclusion of camelina meal (100CO15CM). Growth was measured (length and weight) and tissue samples were collected for lipid analysis (muscle, liver, brain, gut, spleen, skin, and carcass) at wk 0 (before feeding the experimental diet) and at wk 13. Cod fed camelina oil had a lower (P < 0.001) final weight than cod fed the FO diet (50.8 ± 10.3 g/fish). Cod fed 100CO15CM had a lower (P < 0.001) final weight (35.0 ± 8.0 g) than those fed 100CO (43.6 ± 8.9 g) and 100COSEFM (46.7 ± 10.7 g). Cod tissues in the 100COSEFM treatment were most impacted by dietary fatty acid profile. Multivariate statistics revealed that FO and 100COSEFM tissue fatty acid profiles were 21 to 31% different, depending on tissue type. The full replacement of fish oil with camelina oil, plus solvent extracted fish meal had an overarching effect on the entire fatty acid profile of the whole animal. Fatty acid mass balance calculations indicated that cod fed 100COSEFM elongated 13% of 18:3ω3 to 20:3ω3 and oxidized the remaining 87%, whereas cod fed fish oil showed a much lower (P < 0.001) elongation of 18:3ω3 of 1.6%. These results suggest that excess 18:3ω3 from camelina oil caused some fatty acid

  8. US Atlantic coast striped bass: Issues with a recovered population

    USGS Publications Warehouse

    Hartman, K.J.; Margraf, F.J.

    2003-01-01

    Striped bass, Morone saxatilis (Walbaum), is an anadromous species naturally occurring along the US Atlantic coast, which historically supported valuable commercial and recreational fisheries. In response to a near order-of-magnitude decline in landings, the Atlantic States Marine Fisheries Commission enacted a management plan in 1981 protecting fish until they could spawn at least once. By 1989, recruitment increased in natal rivers and regulations were relaxed, permitting limited fisheries by 1990. By 1995, the stock was declared fully recovered. Since the recovery, concern has increased over the health of the stocks. In the 1990s, fish in poor physical condition with dermal lesions became common in Chesapeake Bay. Pathogens of most concern in cultures from fish include the genus Mycobacterium. Coincident with declines in fish health were changes in diets, declines of preferred prey, and reduced growth and condition. Theories were suggested linking declines in condition to reductions in forage base or pathogens. Diets have changed since the 1950s and while many Chesapeake fish are infected with mycobacteria, it is still not known how or if these factors are linked. The highest priorities for research were considered to be: linking numerous local and regional studies to provide a coast-wide perspective; continuation of investigations linking population health to the prey-base; determination of the cause-effect of mycobacteria infections; and formulation of management options.

  9. Process control of lightly salted wild and farmed Atlantic cod (Gadus morhua) by brine injection, brining, and freezing--a low field NMR study.

    PubMed

    Gudjonsdottir, Maria; Gunnlaugsson, Valur N; Finnbogadottir, Gudrun A; Sveinsdottir, Kolbrun; Magnusson, Hannes; Arason, Sigurjon; Rustad, Turid

    2010-10-01

    The aim of this study was to use low-field nuclear magnetic resonance (NMR) and traditional chemical methods to investigate the physical and chemical differences in wild and farmed cod processed pre- and postrigor, and how these properties were affected by brine injection, brining, and freezing. In prerigor processed farmed or wild cod, brine injections followed by brining for 2 d, with brine concentrations up to 5.5% and 4%, respectively, were not sufficient to reach a muscle salt concentration of 2% as aimed for, while wild cod processed postrigor had sufficient salt uptake after the same processing. Low-field NMR gave valuable information about the differences in the muscle structure between wild and farmed cod as well as the state of the water in the muscle during brine injection, brining, and during rigor tension. Low-field NMR is, therefore, a valuable tool that can be used to optimize the salting and storing processes of lightly salted cod products from both wild and farmed cod. For farmed cod to be used in the production of lightly salted products further research is needed. Practical Application: Optimal processing of lightly salted cod products is important to the fish industry, due to an increasing market for this product in southern Europe. Farmed cod, which is seen as a potential steady raw material source for this production, differs considerably from its wild counterparts by having other chemical and physical muscle properties, such as lower water content and lower pH. With the processing procedures used today the farmed cod can, therefore, only be used in some of the products, where wild cod is currently used as raw material. It is, therefore, important that the processing of these products is optimized with regard to these differences in the raw material. This study gives a valuable contribution to further studies about optimal combinations of brine injections, brining, and freezing of pre- and postrigor processed farmed compared to wild cod.

  10. Increased Contracaecum osculatum infection in Baltic cod (Gadus morhua) livers (1982-2012) associated with increasing grey seal (Halichoerus gryphus) populations.

    PubMed

    Haarder, Simon; Kania, Per W; Galatius, Anders; Buchmann, Kurt

    2014-07-01

    Grey seals (Halichoerus gryphus), the main final host of the gastric parasitic nematode Contracaecum osculatum in the Baltic, have recently recolonized the southwestern Baltic Sea. This colonization could lead to an increase in prevalence and intensity of third-stage larvae of C. osculatum in livers of Baltic cod (Gadus morhua), which serve as transport host for this helminth. We performed a parasitologic study of cod in spring 2012 and compared the results with previously unpublished data from 1982/1983. Additionally, grey seals were counted annually from 2000 to 2011 at three haul-out sites in the southwestern Baltic. Of 97 cod livers examined in the 1982/1983 survey, 22% harbored C. osculatum larvae, whereas 55.1% of the examined cod livers (n=185) were infected in 2012; the mean intensity and mean abundance increased from 4.3 and 0.9 to 20.2 and 11.1, respectively. Molecular identification (PCR) confirmed the identity of the larvae. The grey seal population increased markedly during the 12-yr period. We suggest that the elevated parasitism of cod livers is associated with the successful re-establishment of grey seals in the southwestern Baltic.

  11. Stable isotopes indicate population structuring in the southwest Atlantic population of right whales (Eubalaena australis).

    PubMed

    Vighi, Morgana; Borrell, Asunción; Crespo, Enrique A; Oliveira, Larissa R; Simões-Lopes, Paulo C; Flores, Paulo A C; García, Néstor A; Aguilar, Alex; Aguilar, Alejandro

    2014-01-01

    From the early 17th century to the 1970s southern right whales, Eubalaena australis, were subject to intense exploitation along the Atlantic coast of South America. Catches along this coast recorded by whalers originally formed a continuum from Brazil to Tierra del Fuego. Nevertheless, the recovery of the population has apparently occurred fragmentarily, and with two main areas of concentration, one off southern Brazil (Santa Catarina) and another off central Argentina (Peninsula Valdés). This pattern suggests some level of heterogeneity amongst the population, which is apparently contradicted by records that traced individuals moving throughout the whole geographical extension covered by the species in the Southwest Atlantic. To test the hypothesis of the potential occurrence of discrete subpopulations exploiting specific habitats, we investigated N, C and O isotopic values in 125 bone samples obtained from whaling factories operating in the early 1970s in southern Brazil (n=72) and from contemporary and more recent strandings occurring in central Argentina (n=53). Results indicated significant differences between the two sampling areas, being δ13C and δ18O values significantly higher in samples from southern Brazil than in those from central Argentina. This variation was consistent with isotopic baselines from the two areas, indicating the occurrence of some level of structure in the Southwest Atlantic right whale population and equally that whales more likely feed in areas commonly thought to exclusively serve as nursing grounds. Results aim at reconsidering of the units currently used in the management of the southern right whale in the Southwest Atlantic Ocean. In the context of the current die-off affecting the species in Peninsula Valdés, these results also highlight the necessity to better understand movements of individuals and precisely identify their feeding areas.

  12. Stable Isotopes Indicate Population Structuring in the Southwest Atlantic Population of Right Whales (Eubalaena australis)

    PubMed Central

    Vighi, Morgana; Borrell, Asunción; Crespo, Enrique A.; Oliveira, Larissa R.; Simões-Lopes, Paulo C.; Flores, Paulo A. C.; García, Néstor A.; Aguilar, Alejandro

    2014-01-01

    From the early 17th century to the 1970s southern right whales, Eubalaena australis, were subject to intense exploitation along the Atlantic coast of South America. Catches along this coast recorded by whalers originally formed a continuum from Brazil to Tierra del Fuego. Nevertheless, the recovery of the population has apparently occurred fragmentarily, and with two main areas of concentration, one off southern Brazil (Santa Catarina) and another off central Argentina (Peninsula Valdés). This pattern suggests some level of heterogeneity amongst the population, which is apparently contradicted by records that traced individuals moving throughout the whole geographical extension covered by the species in the Southwest Atlantic. To test the hypothesis of the potential occurrence of discrete subpopulations exploiting specific habitats, we investigated N, C and O isotopic values in 125 bone samples obtained from whaling factories operating in the early 1970s in southern Brazil (n = 72) and from contemporary and more recent strandings occurring in central Argentina (n = 53). Results indicated significant differences between the two sampling areas, being δ13C and δ18O values significantly higher in samples from southern Brazil than in those from central Argentina. This variation was consistent with isotopic baselines from the two areas, indicating the occurrence of some level of structure in the Southwest Atlantic right whale population and equally that whales more likely feed in areas commonly thought to exclusively serve as nursing grounds. Results aim at reconsidering of the units currently used in the management of the southern right whale in the Southwest Atlantic Ocean. In the context of the current die-off affecting the species in Peninsula Valdés, these results also highlight the necessity to better understand movements of individuals and precisely identify their feeding areas. PMID:24598539

  13. Implications of isolation and low genetic diversity in peripheral populations of an amphi-Atlantic coral.

    PubMed

    Nunes, F; Norris, R D; Knowlton, N

    2009-10-01

    Limited dispersal and connectivity in marine organisms can have negative fitness effects in populations that are small and isolated, but reduced genetic exchange may also promote the potential for local adaptation. Here, we compare the levels of genetic diversity and connectivity in the coral Montastraea cavernosa among both central and peripheral populations throughout its range in the Atlantic. Genetic data from one mitochondrial and two nuclear loci in 191 individuals show that M. cavernosa is subdivided into three genetically distinct regions in the Atlantic: Caribbean-North Atlantic, Western South Atlantic (Brazil) and Eastern Tropical Atlantic (West Africa). Within each region, populations have similar allele frequencies and levels of genetic diversity; indeed, no significant differentiation was found between populations separated by as much as 3000 km, suggesting that this coral species has the ability to disperse over large distances. Gene flow within regions does not, however, translate into connectivity across the entire Atlantic. Instead, substantial differences in allele frequencies across regions suggest that genetic exchange is infrequent between the Caribbean, Brazil and West Africa. Furthermore, markedly lower levels of genetic diversity are observed in the Brazilian and West African populations. Genetic diversity and connectivity may contribute to the resilience of a coral population to disturbance. Isolated peripheral populations may be more vulnerable to human impacts, disease or climate change relative to those in the genetically diverse Caribbean-North Atlantic region.

  14. [Genetic variation at the pantophysin (PanI) locus in North-East Arctic cod Gadus morhua L. (Gadiformes: Gadidae) population in the Barents Sea and adjacent waters].

    PubMed

    Makeenko, G A; Volkov, A A; Mugue, N S; Zelenina, D A

    2014-12-01

    We investigated polymorphisms in the pantophysin gene (Pan I locus) in a population of North-East Arctic cod, Gadus morhua L., throughout its foraging area in the Barents Sea and adjacent waters. Correlations between the frequencies of Pan I alleles and habitat conditions, such as depth and temperature, were explored. This study was based on a large number of specimens (2210 individuals) of different age and wide geographic sampling coverage. The frequency of the Pan I(A) allele, a known genetic marker of coastal cod, varied from zero to 0.47. Allele frequencies correlated with depth at the sampling location but not with bottom water temperatures. We observed variations in Pan I(A) frequencies among different age cohorts from the same area. The most prominent shift in Pan I polymorphism was detected at the early stages of the fish life cycle, between pelagic juveniles and benthic cod. We found that the Pan I(A) allele frequency in pelagic yearling cod was essentially same throughout the studied areas in the Barents Sea. In turn, juveniles settling at the northern and deep water locations showed a significant decrease in the allele frequency. In contrast, the frequency of the Pan I(A) allele remained constant in juveniles settling in shallow waters when compared to the pelagic stage. These results confirm the selective nature of the cod Pan I locus and indicate that selection process acting on individuals with different genotypes at the Pan I locus leads to the formation of a stable spatial distribution of allele frequencies observed in adult cod.

  15. Effects of elevated dissolved carbon dioxide and perfluorooctane sulfonic acid, given singly and in combination, on steroidogenic and biotransformation pathways of Atlantic cod.

    PubMed

    Preus-Olsen, Gunnhild; Olufsen, Marianne O; Pedersen, Sindre Andre; Letcher, Robert J; Arukwe, Augustine

    2014-10-01

    In the aquatic environments, the predicted changes in water temperature, pO2 and pCO2 could result in hypercapnic and hypoxic conditions for aquatic animals. These conditions are thought to affect several basic cellular and physiological mechanisms. Yet, possible adverse effects of elevated CO2 (hypercapnia) on teleost fish, as well as combined effects with emerging and legacy environmental contaminants are poorly investigated. In this study, juvenile Atlantic cod (Gadus morhua) were divided into groups and exposed to three different water bath PFOS exposure regimes (0 (control), 100 and 200 μg L(-1)) for 5 days at 1h/day, followed by three different CO2-levels (normocapnia, moderate (0.3%) and high (0.9%)). The moderate CO2 level is the predicted near future (within year 2300) level, while 0.9% represent severe hypercapnia. Tissue samples were collected at 3, 6 and 9 days after initiated CO2 exposure. Effects on the endocrine and biotransformation systems were examined by analyzing levels of sex steroid hormones (E2, T, 11-KT) and transcript expression of estrogen responsive genes (ERα, Vtg-α, Vtg-β, ZP2 and ZP3). In addition, transcripts for genes encoding xenobiotic metabolizing enzymes (cyp1a and cyp3a) and hypoxia-inducible factor (HIF-1α) were analyzed. Hypercapnia alone produced increased levels of sex steroid hormones (E2, T, 11-KT) with concomitant mRNA level increase of estrogen responsive genes, while PFOS produced weak and time-dependent effects on E2-inducible gene transcription. Combined PFOS and hypercapnia exposure produced increased effects on sex steroid levels as compared to hypercapnia alone, with transcript expression patterns that are indicative of time-dependent interactive effects. Exposure to hypercapnia singly or in combination with PFOS produced modulations of the biotransformation and hypoxic responses that were apparently concentration- and time-dependent. Loading plots of principal component analysis (PCA) produced a significant

  16. Ocelot Population Status in Protected Brazilian Atlantic Forest

    PubMed Central

    Massara, Rodrigo Lima; Paschoal, Ana Maria de Oliveira; Doherty, Paul Francis; Hirsch, André; Chiarello, Adriano Garcia

    2015-01-01

    Forest fragmentation and habitat loss are detrimental to top carnivores, such as jaguars (Panthera onca) and pumas (Puma concolor), but effects on mesocarnivores, such as ocelots (Leopardus pardalis), are less clear. Ocelots need native forests, but also might benefit from the local extirpation of larger cats such as pumas and jaguars through mesopredator release. We used a standardized camera trap protocol to assess ocelot populations in six protected areas of the Atlantic forest in southeastern Brazil where over 80% of forest remnants are < 50 ha. We tested whether variation in ocelot abundance could be explained by reserve size, forest cover, number of free-ranging domestic dogs and presence of top predators. Ocelot abundance was positively correlated with reserve size and the presence of top predators (jaguar and pumas) and negatively correlated with the number of dogs. We also found higher detection probabilities in less forested areas as compared to larger, intact forests. We suspect that smaller home ranges and higher movement rates in smaller, more degraded areas increased detection. Our data do not support the hypothesis of mesopredator release. Rather, our findings indicate that ocelots respond negatively to habitat loss, and thrive in large protected areas inhabited by top predators. PMID:26560347

  17. Climate and ecosystem linkages explain widespread declines in North American Atlantic salmon populations.

    PubMed

    Mills, Katherine E; Pershing, Andrew J; Sheehan, Timothy F; Mountain, David

    2013-10-01

    North American Atlantic salmon (Salmo salar) populations experienced substantial declines in the early 1990s, and many populations have persisted at low abundances in recent years. Abundance and productivity declined in a coherent manner across major regions of North America, and this coherence points toward a potential shift in marine survivorship, rather than local, river-specific factors. The major declines in Atlantic salmon populations occurred against a backdrop of physical and biological shifts in Northwest Atlantic ecosystems. Analyses of changes in climate, physical, and lower trophic level biological factors provide substantial evidence that climate conditions directly and indirectly influence the abundance and productivity of North American Atlantic salmon populations. A major decline in salmon abundance after 1990 was preceded by a series of changes across multiple levels of the ecosystem, and a subsequent population change in 1997, primarily related to salmon productivity, followed an unusually low NAO event. Pairwise correlations further demonstrate that climate and physical conditions are associated with changes in plankton communities and prey availability, which are ultimately linked to Atlantic salmon populations. Results suggest that poor trophic conditions, likely due to climate-driven environmental factors, and warmer ocean temperatures throughout their marine habitat area are constraining the productivity and recovery of North American Atlantic salmon populations.

  18. The Population Consequences of Disturbance Model Application to North Atlantic Right Whales (Eubalaena Glacialis)

    DTIC Science & Technology

    2013-09-30

    in beaked and sperm whales (R. Rolland, PI; ONR # N000141110540), and a study on the detection and use of hormones from right whale respiratory...1 The Population Consequences of Disturbance Model Application to North Atlantic Right Whales (Eubalaena Glacialis) Scott D. Kraus, Amy R...the revised approach is called PCOD (Population Consequences Of Disturbance) . In North Atlantic right whales (Eubalaena glacialis), extensive data on

  19. Evaluation of the impact of camelina oil-containing diets on the expression of genes involved in the innate anti-viral immune response in Atlantic cod (Gadus morhua).

    PubMed

    Booman, Marije; Xu, Qingheng; Rise, Matthew L

    2014-11-01

    To improve sustainability of aquaculture, especially for carnivorous species like Atlantic cod, replacement of fish oil-based diets with vegetable oil-based diets has been studied. The use of vegetable oil in fish feeds can significantly change the fatty acid composition of fish tissues, and given the importance of fatty acids in inflammation and immunity, this change could potentially impact the immune response and health of the fish. The oilseed Camelina sativa is a promising source for this vegetable oil, because of the high oil content of its seeds (40%), a higher n-3 fatty acid content than most other oilseeds, and a high amount of γ-tocopherol. This study aims to investigate the effect of the replacement of dietary fish oil with oil from Camelina sativa on the immune response of Atlantic cod, as measured by the gene expression in spleen. Juvenile cod were fed on a fish oil-based diet (FO) or one of two diets in which camelina oil replaced 40% or 80% of fish oil (40CO and 80CO respectively) for 67 days, after which they were injected with either the viral mimic polyriboinosinic polyribocytidylic acid (pIC), or phosphate-buffered saline (PBS) as a control. Microarray analysis was used to determine the effect of the diet on the basal spleen transcriptome (pre-injection), and on the response to pIC (24 h post-injection). No marked differences in the spleen transcriptome were found between the three diets, either before or after injection with pIC. All fish, regardless of diet, showed a strong anti-viral response 24 h after pIC injection, with more than 500 genes having a significant difference of expression of 2-fold or higher compared to the PBS-injected fish for the FO, 40CO and 80CO diets. Gene Ontology annotation analysis of the three pIC-responsive gene lists indicated they were highly similar, and that the term 'immune system process' was significantly enriched in the pIC-responsive gene lists for all three diets. QPCR analysis for 5 genes with a known

  20. Atlantic Bluefin Tuna: A Novel Multistock Spatial Model for Assessing Population Biomass

    PubMed Central

    Taylor, Nathan G.; McAllister, Murdoch K.; Lawson, Gareth L.; Carruthers, Tom; Block, Barbara A.

    2011-01-01

    Atlantic bluefin tuna (Thunnus thynnus) is considered to be overfished, but the status of its populations has been debated, partly because of uncertainties regarding the effects of mixing on fishing grounds. A better understanding of spatial structure and mixing may help fisheries managers to successfully rebuild populations to sustainable levels while maximizing catches. We formulate a new seasonally and spatially explicit fisheries model that is fitted to conventional and electronic tag data, historic catch-at-age reconstructions, and otolith microchemistry stock-composition data to improve the capacity to assess past, current, and future population sizes of Atlantic bluefin tuna. We apply the model to estimate spatial and temporal mixing of the eastern (Mediterranean) and western (Gulf of Mexico) populations, and to reconstruct abundances from 1950 to 2008. We show that western and eastern populations have been reduced to 17% and 33%, respectively, of 1950 spawning stock biomass levels. Overfishing to below the biomass that produces maximum sustainable yield occurred in the 1960s and the late 1990s for western and eastern populations, respectively. The model predicts that mixing depends on season, ontogeny, and location, and is highest in the western Atlantic. Assuming that future catches are zero, western and eastern populations are predicted to recover to levels at maximum sustainable yield by 2025 and 2015, respectively. However, the western population will not recover with catches of 1750 and 12,900 tonnes (the “rebuilding quotas”) in the western and eastern Atlantic, respectively, with or without closures in the Gulf of Mexico. If future catches are double the rebuilding quotas, then rebuilding of both populations will be compromised. If fishing were to continue in the eastern Atlantic at the unregulated levels of 2007, both stocks would continue to decline. Since populations mix on North Atlantic foraging grounds, successful rebuilding policies will

  1. Atlantic bluefin tuna: a novel multistock spatial model for assessing population biomass.

    PubMed

    Taylor, Nathan G; McAllister, Murdoch K; Lawson, Gareth L; Carruthers, Tom; Block, Barbara A

    2011-01-01

    Atlantic bluefin tuna (Thunnus thynnus) is considered to be overfished, but the status of its populations has been debated, partly because of uncertainties regarding the effects of mixing on fishing grounds. A better understanding of spatial structure and mixing may help fisheries managers to successfully rebuild populations to sustainable levels while maximizing catches. We formulate a new seasonally and spatially explicit fisheries model that is fitted to conventional and electronic tag data, historic catch-at-age reconstructions, and otolith microchemistry stock-composition data to improve the capacity to assess past, current, and future population sizes of Atlantic bluefin tuna. We apply the model to estimate spatial and temporal mixing of the eastern (Mediterranean) and western (Gulf of Mexico) populations, and to reconstruct abundances from 1950 to 2008. We show that western and eastern populations have been reduced to 17% and 33%, respectively, of 1950 spawning stock biomass levels. Overfishing to below the biomass that produces maximum sustainable yield occurred in the 1960s and the late 1990s for western and eastern populations, respectively. The model predicts that mixing depends on season, ontogeny, and location, and is highest in the western Atlantic. Assuming that future catches are zero, western and eastern populations are predicted to recover to levels at maximum sustainable yield by 2025 and 2015, respectively. However, the western population will not recover with catches of 1750 and 12,900 tonnes (the "rebuilding quotas") in the western and eastern Atlantic, respectively, with or without closures in the Gulf of Mexico. If future catches are double the rebuilding quotas, then rebuilding of both populations will be compromised. If fishing were to continue in the eastern Atlantic at the unregulated levels of 2007, both stocks would continue to decline. Since populations mix on North Atlantic foraging grounds, successful rebuilding policies will

  2. β-naphthoflavone interferes with cyp1c1, cox2 and IL-8 gene transcription and leukotriene B4 secretion in Atlantic cod (Gadus morhua) head kidney cells during inflammation.

    PubMed

    Holen, Elisabeth; Olsvik, Pål A

    2016-07-01

    The objective of this study was to evaluate how β-naphthoflavone interacts with lipopolysaccharide (LPS) and polyinosinic acid: polycytidylic acid (poly I: C) induced innate immune parameters as well as phase I and phase II detoxification enzymes in head kidney cells isolated from Atlantic cod. β-naphthoflavone is a pure agonist of aryl hydrocarbon receptor (AhR) while LPS and poly I: C are not. β-naphthoflavone was added to head kidney leukocytes alone or together with LPS or poly I: C and the responses were evaluated in terms of protein and gene expression. The results showed that β-naphthoflavone (25 nM), with and without LPS, significantly induced cytochrome P450 (cyp1c) transcription in cod head kidney cells. β-naphthoflavone (100 nM) in the presence of the virus mimic, poly I: C, also increased cyp1c1transcription. LPS induced cyp1c1, cyclooxygenase 2 (cox2), interleukin 1β (IL-1β), interleukin 6 (IL-6) and interleukin 8 (IL-8) transcription, genes that were not affected by the tested β-naphthoflavone concentrations alone. However, β-naphthoflavone (25 and 50 nM) strengthened LPS induced cox2 and IL-8 transcription. Cod head kidney cells exposed to β-naphthoflavone concentrations ranging from 25 to 100 nM, with and without LPS or poly I: C, expressed AhR protein. LPS or β-naphthoflavone (5-50 nM) significantly induced leukotriene B4 (LTB4) secretion compared to control. In conclusion, this study suggests that β-naphthoflavone could interfere with LPS induced immune cell signaling in cod head kidney cells.

  3. The role of extracellular matrix components in pin bone attachments during storage-a comparison between farmed Atlantic salmon (Salmo salar) and cod (Gadus morhua L.).

    PubMed

    Rønning, Sissel B; Østbye, Tone-Kari; Krasnov, Aleksei; Vuong, Tram T; Veiseth-Kent, Eva; Kolset, Svein O; Pedersen, Mona E

    2017-04-01

    Pin bones represent a major problem for processing and quality of fish products. Development of methods of removal requires better knowledge of the pin bones' attachment to the muscle and structures involved in the breakdown during loosening. In this study, pin bones from cod and salmon were dissected from fish fillets after slaughter or storage on ice for 5 days, and thereafter analysed with molecular methods, which revealed major differences between these species before and after storage. The connective tissue (CT) attaches the pin bone to the muscle in cod, while the pin bones in salmon are embedded in adipose tissue. Collagens, elastin, lectin-binding proteins and glycosaminoglycans (GAGs) are all components of the attachment site, and this differ between salmon and cod, resulting in a CT in cod that is more resistant to enzymatic degradation compared to the CT in salmon. Structural differences are reflected in the composition of transcriptome. Microarray analysis comparing the attachment sites of the pin bones with a reference muscle sample showed limited differences in salmon. In cod, on the other hand, the variances were substantial, and the gene expression profiles suggested difference in myofibre structure, metabolism and cell processes between the pin bone attachment site and the reference muscle. Degradation of the connective tissue occurs closest to the pin bones and not in the neighbouring tissue, which was shown using light microscopy. This study shows that the attachment of the pin bones in cod and salmon is different; therefore, the development of methods for removal should be tailored to each individual species.

  4. Decline in an Atlantic Puffin Population: Evaluation of Magnitude and Mechanisms

    PubMed Central

    Miles, Will T. S.; Mavor, Roddy; Riddiford, Nick J.; Harvey, Paul V.; Riddington, Roger; Shaw, Deryk N.; Parnaby, David; Reid, Jane M.

    2015-01-01

    Determining which demographic and ecological parameters contribute to variation in population growth rate is crucial to understanding the dynamics of declining populations. This study aimed to evaluate the magnitude and mechanisms of an apparent major decline in an Atlantic Puffin Fratercula arctica population. This was achieved using a 27-year dataset to estimate changes in population size and in two key demographic rates: adult survival and breeding success. Estimated demographic variation was then related to two ecological factors hypothesised to be key drivers of demographic change, namely the abundance of the main predator at the study site, the Great Skua Stercorarius skua, and Atlantic Puffin chick food supply, over the same 27-year period. Using a population model, we assessed whether estimated variation in adult survival and reproductive success was sufficient to explain the population change observed. Estimates of Atlantic Puffin population size decreased considerably during the study period, approximately halving, whereas Great Skua population estimates increased, approximately trebling. Estimated adult Atlantic Puffin survival remained high across all years and did not vary with Great Skua abundance; however, Atlantic Puffin breeding success and quantities of fish prey brought ashore by adults both decreased substantially through the period. A population model combining best possible demographic parameter estimates predicted rapid population growth, at odds with the long-term decrease observed. To simulate the observed decrease, population models had to incorporate low immature survival, high immature emigration, or increasingly high adult non-breeding rates. We concluded that reduced recruitment of immatures into the breeding population was the most likely cause of population decrease. This study showed that increase in the size of a predator population does not always impact on the survival of adult prey and that reduced recruitment can be a crucial

  5. ¹H, ¹³C and ¹⁵N resonance assignments and second structure information of Gad m 1: a β-parvalbumin allergen from Atlantic cod (Gadus morhua).

    PubMed

    Moraes, A H; Ackerbauer, D; Kostadinova, M; Bublin, M; Ferreira, F; Almeida, F C L; Breiteneder, H; Valente, A P

    2013-10-01

    Gad m 1 is the major allergen from Atlantic cod. It belongs to β-parvalbumin protein family and is characterized by the presence of two calcium-binding sites so called EF-hand motifs. β-Parvalbumins such as Gad m 1 are the most important fish allergens and their high cross-reactivity is the cause of the observed polysensitization to various fish species in allergic patients. Despite extensive efforts, the complete elucidation of β-parvalbumin-IgE complexes has not been achieved yet. Allergen structural studies are essential for the development of novel immunotherapy strategies, including vaccination with hypoallergenic derivatives and chimeric molecules. Here, we report for the first time the NMR study of a β-parvalbumin: Gad m 1. This report includes: (1)H, (13)C and (15)N resonance assignments of Gad m 1 as well as the second structure information based on the (13)C chemical shifts.

  6. Environmental genotoxicity and cytotoxicity in flounder (Platichthys flesus), herring (Clupea harengus) and Atlantic cod (Gadus morhua) from chemical munitions dumping zones in the southern Baltic Sea.

    PubMed

    Baršienė, Janina; Butrimavičienė, Laura; Grygiel, Wlodzimierz; Lang, Thomas; Michailovas, Aleksandras; Jackūnas, Tomas

    2014-05-01

    The data on environmental genotoxicity and cytotoxicity levels as well as on genotoxicity risk in flounder (Platichthys flesus), herring (Clupea harengus) and cod (Gadus morhua) collected in 2010-2012 at 42 stations located in chemical munitions dumping areas of the southern Baltic Sea are presented. The frequency of micronuclei, nuclear buds and nucleoplasmic bridges in erythrocytes was used as genotoxicity endpoint and the induction of fragmented-apoptotic, bi-nucleated and 8-shaped erythrocytes as cytotoxicity endpoint. The most significantly increased geno-cytotoxicity levels were determined in fish collected near known chemical munitions dumpsites. Extremely high genotoxicity risk for flounder were identified at 21 out of 24 stations, for herring at 29 out of 31 and for cod at 5 out of 10 stations studied. The reference level of genotoxicity was not recorded at any of the stations revealing that in the sampling area fish were affected generally.

  7. CHARACTERIZATION OF WESTERN NORTH ATLANTIC RIGHT WHALE SPRING FEEDING HABITAT

    EPA Science Inventory

    The Great South Channel region of the southwestern Gulf of Maine, between George's Bank and Cape Cod, is the primary spring feeding ground for the western North Atlantic population of the I northern right whale, E. glacialis .Since this whale is so endangered, it is critical to i...

  8. Population Structure of Humpback Whales from Their Breeding Grounds in the South Atlantic and Indian Oceans

    PubMed Central

    Rosenbaum, Howard C.; Pomilla, Cristina; Mendez, Martin; Leslie, Matthew S.; Best, Peter B.; Findlay, Ken P.; Minton, Gianna; Ersts, Peter J.; Collins, Timothy; Engel, Marcia H.; Bonatto, Sandro L.; Kotze, Deon P. G. H.; Meÿer, Mike; Barendse, Jaco; Thornton, Meredith; Razafindrakoto, Yvette; Ngouessono, Solange; Vely, Michel; Kiszka, Jeremy

    2009-01-01

    Although humpback whales are among the best-studied of the large whales, population boundaries in the Southern Hemisphere (SH) have remained largely untested. We assess population structure of SH humpback whales using 1,527 samples collected from whales at fourteen sampling sites within the Southwestern and Southeastern Atlantic, the Southwestern Indian Ocean, and Northern Indian Ocean (Breeding Stocks A, B, C and X, respectively). Evaluation of mtDNA population structure and migration rates was carried out under different statistical frameworks. Using all genetic evidence, the results suggest significant degrees of population structure between all ocean basins, with the Southwestern and Northern Indian Ocean most differentiated from each other. Effective migration rates were highest between the Southeastern Atlantic and the Southwestern Indian Ocean, followed by rates within the Southeastern Atlantic, and the lowest between the Southwestern and Northern Indian Ocean. At finer scales, very low gene flow was detected between the two neighbouring sub-regions in the Southeastern Atlantic, compared to high gene flow for whales within the Southwestern Indian Ocean. Our genetic results support the current management designations proposed by the International Whaling Commission of Breeding Stocks A, B, C, and X as four strongly structured populations. The population structure patterns found in this study are likely to have been influenced by a combination of long-term maternally directed fidelity of migratory destinations, along with other ecological and oceanographic features in the region. PMID:19812698

  9. Genetic discontinuity among regional populations of Lophelia pertusa in the North Atlantic Ocean

    USGS Publications Warehouse

    Morrison, C.L.; Ross, S.W.; Nizinski, M.S.; Brooke, S.; Jarnegren, J.; Waller, R.G.; Johnson, R.L.; King, T.L.

    2011-01-01

    Knowledge of the degree to which populations are connected through larval dispersal is imperative to effective management, yet little is known about larval dispersal ability or population connectivity in Lophelia pertusa, the dominant framework-forming coral on the continental slope in the North Atlantic Ocean. Using nine microsatellite DNA markers, we assessed the spatial scale and pattern of genetic connectivity across a large portion of the range of L. pertusa in the North Atlantic Ocean. A Bayesian modeling approach found four distinct genetic groupings corresponding to ocean regions: Gulf of Mexico, coastal southeastern U. S., New England Seamounts, and eastern North Atlantic Ocean. An isolation-by-distance pattern was supported across the study area. Estimates of pairwise population differentiation were greatest with the deepest populations, the New England Seamounts (average FST = 0.156). Differentiation was intermediate with the eastern North Atlantic populations (FST = 0.085), and smallest between southeastern U. S. and Gulf of Mexico populations (FST = 0.019), with evidence of admixture off the southeastern Florida peninsula. Connectivity across larger geographic distances within regions suggests that some larvae are broadly dispersed. Heterozygote deficiencies were detected within the majority of localities suggesting deviation from random mating. Gene flow between ocean regions appears restricted, thus, the most effective management scheme for L. pertusa involves regional reserve networks. ?? 2011 US Government.

  10. Genetic discontinuity among regional populations of Lophelia perfusa in the North Atlantic Ocean

    USGS Publications Warehouse

    Morrison, Cheryl L.

    2011-01-01

    Knowledge of the degree to which populations are connected through larval dispersal is imperative to effective management, yet little is known about larval dispersal ability or population connectivity in Lophelia pertusa, the dominant framework-forming coral on the continental slope in the North Atlantic Ocean. Using nine microsatellite DNA markers, we assessed the spatial scale and pattern of genetic connectivity across a large portion of the range of L. pertusa in the North Atlantic Ocean. A Bayesian modeling approach found four distinct genetic groupings corresponding to ocean regions: Gulf of Mexico, coastal southeastern U.S., New England Seamounts, and eastern North Atlantic Ocean. An isolation-by-distance pattern was supported across the study area. Estimates of pairwise population differentiation were greatest with the deepest populations, the New England Seamounts (average FST = 0.156). Differentiation was intermediate with the eastern North Atlantic populations (FST = 0.085), and smallest between southeastern U.S. and Gulf of Mexico populations (FST = 0.019), with evidence of admixture off the southeastern Florida peninsula. Connectivity across larger geographic distances within regions suggests that some larvae are broadly dispersed. Heterozygote deficiencies were detected within the majority of localities suggesting deviation from random mating. Gene flow between ocean regions appears restricted, thus, the most effective management scheme for L. pertusa involves regional reserve networks

  11. Sex dimorphic expression of five dmrt genes identified in the Atlantic cod genome. The fish-specific dmrt2b diverged from dmrt2a before the fish whole-genome duplication.

    PubMed

    Johnsen, Hanne; Andersen, Øivind

    2012-09-01

    The Doublesex and Mab-3 related transcription factors (Dmrt) are characterised by the zinc finger-like DM domain binding similar DNA sequences, but show different spatio-temporal expression patterns and functions throughout ontogenesis. Dmrt1 is the master regulator of sex determination in very distant metazoans, while Dmrt2 and Dmrt4 are of crucial importance in vertebrate somitogenesis and neurogenesis, respectively. To elucidate the evolutionary divergence of the fish dmrt genes, we examined the expression patterns and the chromosomal synteny of the five dmrt genes identified in the Atlantic cod genome. Quantitative PCR analyses of cod dmrt1, dmrt2a, dmrt3, dmrt4 and dmrt5 revealed distinct expression patterns in the embryo and larvae, and indicated conserved extragonadal functions during early development. Several dmrt genes seem to be involved in the sexual differentiation of gonads and brain, but the sex-dimorphic expression patterns differed substantially between teleosts, suggesting functional switch between Dmrt members. The dmrt2a-dmrt3-dmrt1 cluster was found to be located in a conserved syntenic region, and the flanking genes have become duplicated in teleosts and are closely linked in a paralogous region lacking the dmrt cluster. Similarly, the region containing the fish-specific dmrt2b gene was found to have a paralogous region without a dmrt2b duplicate in a separate linkage group in the teleost genomes. We propose that the teleost segments paralogous to the dmrt2a- and dmrt2b regions, respectively, were formed through the fish-specific whole genome duplication (3R), while dmrt2a and dmrt2b originated from the second round (2R) of whole genome duplication of the ancestral dmrt2. The dmrt2b paralog seems to have been lost in Atlantic cod as in tetrapods and may be a pseudogene in pufferfish, while dmrt2a and dmrt2b have acquired different functions in zebrafish. Contrasting with the retained duplicates of dmrt flanking genes, the massive losses of

  12. Hierarchical population structure and habitat differences in a highly mobile marine species: the Atlantic spotted dolphin.

    PubMed

    Viricel, Amélia; Rosel, Patricia E

    2014-10-01

    Recent molecular studies have shown that highly mobile species with continuous distributions can exhibit fine-scale population structure. In this context, we assessed genetic structure within a marine species with high dispersal potential, the Atlantic spotted dolphin (Stenella frontalis). Using 19 microsatellite loci and mitochondrial control region sequences, population structure was investigated in the western North Atlantic, the Gulf of Mexico and the Azores Islands. Analyses of the microsatellite data identified four distinct genetic clusters, which were supported by the control region sequences. The highest level of divergence was seen between two clusters corresponding to previously described morphotypes that inhabit oceanic and shelf waters. The combined morphological and genetic evidence suggests these two lineages are on distinct evolutionary trajectories and could be considered distinct subspecies despite their parapatry. Further analysis of the continental shelf cluster resulted in three groups: animals inhabiting shelf waters in the western North Atlantic, the eastern Gulf of Mexico and the western Gulf of Mexico. Analyses of environmental data indicate the four genetic clusters inhabit distinct habitats in terms of depth and sea surface temperature. Contemporary dispersal rate estimates suggest all of these populations should be considered as distinct management units. Conversely, no significant genetic differentiation was observed between S. frontalis from offshore waters of the western North Atlantic and the Azores, which are separated by approximately 4500 km. Overall, the hierarchical structure observed within the Atlantic spotted dolphin shows that the biogeography of the species is complex because it is not shaped solely by geographic distance.

  13. Latitudinal distribution of prokaryotic picoplankton populations in the Atlantic Ocean.

    PubMed

    Schattenhofer, Martha; Fuchs, Bernhard M; Amann, Rudolf; Zubkov, Mikhail V; Tarran, Glen A; Pernthaler, Jakob

    2009-08-01

    Members of the prokaryotic picoplankton are the main drivers of the biogeochemical cycles over large areas of the world's oceans. In order to ascertain changes in picoplankton composition in the euphotic and twilight zones at an ocean basin scale we determined the distribution of 11 marine bacterial and archaeal phyla in three different water layers along a transect across the Atlantic Ocean from South Africa (32.9 degrees S) to the UK (46.4 degrees N) during boreal spring. Depth profiles down to 500 m at 65 stations were analysed by catalysed reporter deposition fluorescence in situ hybridization (CARD-FISH) and automated epifluorescence microscopy. There was no obvious overall difference in microbial community composition between the surface water layer and the deep chlorophyll maximum (DCM) layer. There were, however, significant differences between the two photic water layers and the mesopelagic zone. SAR11 (35 +/- 9%) and Prochlorococcus (12 +/- 8%) together dominated the surface waters, whereas SAR11 and Crenarchaeota of the marine group I formed equal proportions of the picoplankton community below the DCM (both approximately 15%). However, due to their small cell sizes Crenarchaeota contributed distinctly less to total microbial biomass than SAR11 in this mesopelagic water layer. Bacteria from the uncultured Chloroflexi-related clade SAR202 occurred preferentially below the DCM (4-6%). Distinct latitudinal distribution patterns were found both in the photic zone and in the mesopelagic waters: in the photic zone, SAR11 was more abundant in the Northern Atlantic Ocean (up to 45%) than in the Southern Atlantic gyre (approximately 25%), the biomass of Prochlorococcus peaked in the tropical Atlantic Ocean, and Bacteroidetes and Gammaproteobacteria bloomed in the nutrient-rich northern temperate waters and in the Benguela upwelling. In mesopelagic waters, higher proportions of SAR202 were present in both central gyre regions, whereas Crenarchaeota were clearly

  14. Genetic diversity of Casearia sylvestris populations in remnants of the Atlantic Forest.

    PubMed

    Araujo, F L; Siqueira, M V B M; Grando, C; Viana, J P G; Pinheiro, J B; Alves-Pereira, A; Campos, J B; Brancalion, P H S; Zucchi, M I

    2017-01-23

    Guaçatonga (Casearia sylvestris) is a native plant of the Atlantic Forest, with high medicinal potential and relevance for reforestation programs. The aim of this study was to characterize, with microsatellite markers, two populations of C. sylvestris from remaining areas of the Atlantic Forest in the State of São Paulo. High allelic variation was found in both populations (NA = 101 and 117; AR = 12.5 and 14.4), although with high endogamy coefficients (f = 0.640 and 0.363). Estimates of genetic structure suggested the presence of considerable genetic divergence between the populations (FST = 0.103); however, there was no spatial genetic structure within the populations. Genetic divergence may have occurred due to decreased gene flow between the fragmented populations as the result of deforestation. The results of this study demonstrate the importance of genetic diversity and its characterization in native plants within remaining forest areas for the management and restoration of such areas.

  15. Cod Liver Oil

    MedlinePlus

    Cod liver oil can be obtained from eating fresh cod liver or by taking supplements. Cod liver oil is used for high cholesterol, high triglycerides, ... ear infections (otitis media). Some people put cod liver oil on their skin to speed wound healing. ...

  16. Trans-Atlantic responses of Calanus finmarchicus populations to basin-scale forcing associated with the North Atlantic Oscillation [review article

    NASA Astrophysics Data System (ADS)

    Greene, C. H.; Pershing, A. J.; Conversi, A.; Planque, B.; Hannah, C.; Sameoto, D.; Head, E.; Smith, P. C.; Reid, P. C.; Jossi, J.; Mountain, D.; Benfield, M. C.; Wiebe, P. H.; Durbin, E.

    2003-08-01

    Populations of the copepod species Calanus finmarchicus often dominate the springtime biomass and secondary production of shelf ecosystems throughout the North Atlantic Ocean. Recently, it has been hypothesised that interannual to interdecadal fluctuations observed in such populations are driven primarily by climate-associated changes in ocean circulation. Here, we compare evidence from the North Sea and Gulf of Maine/Western Scotian Shelf (GoM/WSS) linking fluctuations in C. finmarchicus abundance to changes in ocean circulation associated with the North Atlantic Oscillation (NAO). A particularly striking contrast emerges from this Trans-Atlantic comparison: whereas the North Sea C. finmarchicus population exhibits a negative correlation with the NAO index, the GoM/WSS population exhibits a more complex, positive association with the index. The physical processes underlying these contrasting population responses are discussed in the context of regional- to basin-scale circulation changes associated with the NAO.

  17. Population genetic structure of the abyssal grenadier (Coryphaenoides armatus) around the mid-Atlantic ridge

    NASA Astrophysics Data System (ADS)

    Ritchie, H.; Cousins, N. J.; Cregeen, S. J.; Piertney, S. B.

    2013-12-01

    Understanding the factors that affect the levels and distribution of genetic diversity in oceanic and deep sea environments is a central focus in marine population genetics. Whilst it has been considered that the oceans represent a homogenous environment that would facilitate dispersal and minimise population structure, it is now clear that topographical features and current patterns can influence the extent of spatial gene flow and promote significant population genetic divergence even at local scales. Here we examine patterns of population genetic structure among N. Atlantic populations of the cosmopolitan abyssal grenadier Coryphaenoides armatus in relation to two hypothesised barriers to gene flow-the mid-Atlantic Ridge and the Charlie-Gibbs Fracture Zone/Sub-Polar Front. A suite of microsatellite markers were developed to examine the spatial pattern of allelic variation among 210 individuals from ten sampling locations encompassing sites east and west of the MAR and north and south of the CGFZ, plus a geographically distinct sample of individuals from the Crozet Islands in the Indian Ocean. Considerable genetic diversity was detected among individuals (na=5-13 and HO=0.46-0.69 across populations) but with an overall lack of genetic divergence between populations. Pairwise estimates of divergence among NE Atlantic samples were small and non-significant (max FST=0.04) and Structure-based Bayesian analysis of genetic clusters returned no distinct population structure. The only indication of genetic structure was between the Atlantic and Indian Oceans, with FST estimates of ca. 0.05. Patterns of genetic diversity and divergence are discussed in relation to what has been resolved in Coryphaenoides congeners, and what is known about the life history and ecology of C. armatus.

  18. Population Structure and Dispersal Patterns within and between Atlantic and Mediterranean Populations of a Large-Range Pelagic Seabird

    PubMed Central

    Genovart, Meritxell; Thibault, Jean-Claude; Igual, José Manuel; Bauzà-Ribot, Maria del Mar; Rabouam, Corinne; Bretagnolle, Vincent

    2013-01-01

    Dispersal is critically linked to the demographic and evolutionary trajectories of populations, but in most seabird species it may be difficult to estimate. Using molecular tools, we explored population structure and the spatial dispersal pattern of a highly pelagic but philopatric seabird, the Cory's shearwater Calonectris diomedea. Microsatellite fragments were analysed from samples collected across almost the entire breeding range of the species. To help disentangle the taxonomic status of the two subspecies described, the Atlantic form C. d. borealis and the Mediterranean form C. d. diomedea, we analysed genetic divergence between subspecies and quantified both historical and recent migration rates between the Mediterranean and Atlantic basins. We also searched for evidence of isolation by distance (IBD) and addressed spatial patterns of gene flow. We found a low genetic structure in the Mediterranean basin. Conversely, strong genetic differentiation appeared in the Atlantic basin. Even if the species was mostly philopatric (97%), results suggest recent dispersal between basins, especially from the Atlantic to the Mediterranean (aprox. 10% of migrants/generation across the last two generations). Long-term gene flow analyses also suggested an historical exchange between basins (about 70 breeders/generation). Spatial analysis of genetic variation indicates that distance is not the main factor in shaping genetic structure in this species. Given our results we recommend gathering more data before concluded whether these taxa should be treated as two species or subspecies. PMID:23950986

  19. Fine-scale population structure in Atlantic salmon from Maine's Penobscot River drainage

    USGS Publications Warehouse

    Spidle, A.P.; Bane, Schill W.; Lubinski, B.A.; King, T.L.

    2001-01-01

    We report a survey of micro satellite DNA variation in Atlantic salmon from the unimpounded lower reaches of Maine's Penobscot River. Our analysis indicates that Atlantic salmon in the Penobscot River are distinct from other populations that have little or no history of human-mediated repopulation, including two of its tributaries, Cove Brook and Kenduskeag Stream, another Maine river, the Ducktrap, and Canada's Miramichi and Gander rivers. Significant heterogeneity was detected in allele frequency among all three subpopulations sampled in the Penobscot drainage. The high resolution of the 12-locus suite was quantified using maximum likelihood assignment tests, which correctly identified the source of 90.4-96.1% of individuals from within the Penobscot drainage. Current populations are clearly isolated from each other, however we are unable to determine from the present data whether the populations in Cove Brook and Kenduskeag Stream are recently diverged from populations stocked into the Penobscot River over the last century, or are aboriginal in origin. The degree of population structure identified in the Penobscot drainage is noteworthy in light of its lengthy history of systematic restocking, the geographic proximity of the subpopulations, and the extent of the differentiation. Similar population structure on this extremely limited geographic scale could exist among Atlantic salmon runs elsewhere in Maine and throughout the species' range and should be taken into account for future management decisions.

  20. Aryl hydrocarbon receptor protein and Cyp1A1 gene induction by LPS and phenanthrene in Atlantic cod (Gadus morhua) head kidney cells.

    PubMed

    Holen, Elisabeth; Olsvik, Pål Asgeir

    2014-10-01

    The objective of this study was to evaluate interactions between environmental toxicants and cod immune cells during inflammation. Phenanthrene is abundant in plant oils (rapeseed, palm, and soya oil) as compared to fish oils, and consequently constitute an undesirable element in plant replacement diets in aquaculture. Phenanthrene was added to head kidney cell cultures, alone or together with LPS (lipopolysaccharide) or poly I: C (polyinosinic acid: polycytidylic acid), and the responses were evaluated in terms of protein and gene expression. The results showed that LPS, poly I: C or phenanthrene, added to the cultures separately, induced aryl hydrocarbon receptor (AhR) protein expression. Phenanthrene treatment in combination with LPS induced AhR protein expression and Cyp1A1 gene transcription, which not was observed combining poly I: C and phenanthrene. Phenanthrene exposure up regulated the transcription of common stress and detoxification enzymes like catalase, caspase 3 and glutathione S-transferase alfa 3 subunit B (GSTAB3), while LPS exposure alone or combined with phenanthrene down regulated GSTAB3 and catalase in cod leukocytes. It seems clear that immune regulation and phenanthrene induced signaling pathways interact; transcriptional down regulation of detoxification and antioxidant enzymes by LPS could indicate that combating bacterial infections is the number one priority in these cells, and that AhR and Cyp1A1 is somehow involved in this signaling cascade. LPS seems to affect the mitogen activated protein kinases (MAPKs) pathways (P-p38 and ERK1/2) thus modulating the AhR protein and Cyp1A1 gene transcription, while phenanthrene possibly activates AhR by ligand binding.

  1. Transcriptional responses in juvenile Atlantic cod (Gadus morhua) after exposure to mercury-contaminated sediments obtained near the wreck of the German WW2 submarine U-864, and from Bergen Harbor, Western Norway.

    PubMed

    Olsvik, Pål A; Brattås, Marianne; Lie, Kai K; Goksøyr, Anders

    2011-04-01

    The main aim of the present work was to investigate the effects of mercury (Hg)-enriched sediments on fish. Sediments near the sunken German WW2 submarine U-864, which according to historical documents included 67 tons of metallic Hg in its cargo, are enriched of Hg leaking from the wreckage. Juvenile Atlantic cod (Gadus morhua) were exposed to two field-collected polluted sediments (U-864: inorganic Hg and Bergen Harbor (Vågen): inorganic Hg, PCB and PAH) or two comparable reference sediments for 5 weeks in the laboratory, and transcriptional responses evaluated in gills and liver. Gills of fish exposed to the Hg-enriched sunken WW2 submarine U-864 sediment contained four fold higher Hg levels compared to the control fish. An increase in Hg content in liver in the U-864 fish was also observed. The transcriptional results showed that calreticulin, HSP70 and heme oxygenase mRNA were significantly up-regulated in gills in fish exposed to the Hg-enriched sediments, whereas calreticulin, heme oxygenase, transferrin and WAP65 were significantly up-regulated and glutathione peroxidase 4B and zona pellucida 3 were significantly down-regulated in liver tissue. In gills and liver of cod exposed to the mixed-contaminated Vågen sediment, CYP1A showed the highest induction. In conclusion, the experiment shows that sediment-bound Hg is available to the fish and affects the transcription of oxidative stress responsive enzymes, suggesting that the Hg-enriched sediments may negatively affect the local wildlife. Furthermore, the mixed contaminated sediments of Vågen affected similar responses in addition to Ah-receptor mediated responses reflecting exposure to PAHs and PCBs.

  2. Footprints of directional selection in wild Atlantic salmon populations: evidence for parasite-driven evolution?

    PubMed

    Zueva, Ksenia J; Lumme, Jaakko; Veselov, Alexey E; Kent, Matthew P; Lien, Sigbjørn; Primmer, Craig R

    2014-01-01

    Mechanisms of host-parasite co-adaptation have long been of interest in evolutionary biology; however, determining the genetic basis of parasite resistance has been challenging. Current advances in genome technologies provide new opportunities for obtaining a genome-scale view of the action of parasite-driven natural selection in wild populations and thus facilitate the search for specific genomic regions underlying inter-population differences in pathogen response. European populations of Atlantic salmon (Salmo salar L.) exhibit natural variance in susceptibility levels to the ectoparasite Gyrodactylus salaris Malmberg 1957, ranging from resistance to extreme susceptibility, and are therefore a good model for studying the evolution of virulence and resistance. However, distinguishing the molecular signatures of genetic drift and environment-associated selection in small populations such as land-locked Atlantic salmon populations presents a challenge, specifically in the search for pathogen-driven selection. We used a novel genome-scan analysis approach that enabled us to i) identify signals of selection in salmon populations affected by varying levels of genetic drift and ii) separate potentially selected loci into the categories of pathogen (G. salaris)-driven selection and selection acting upon other environmental characteristics. A total of 4631 single nucleotide polymorphisms (SNPs) were screened in Atlantic salmon from 12 different northern European populations. We identified three genomic regions potentially affected by parasite-driven selection, as well as three regions presumably affected by salinity-driven directional selection. Functional annotation of candidate SNPs is consistent with the role of the detected genomic regions in immune defence and, implicitly, in osmoregulation. These results provide new insights into the genetic basis of pathogen susceptibility in Atlantic salmon and will enable future searches for the specific genes involved.

  3. Footprints of Directional Selection in Wild Atlantic Salmon Populations: Evidence for Parasite-Driven Evolution?

    PubMed Central

    Zueva, Ksenia J.; Lumme, Jaakko; Veselov, Alexey E.; Kent, Matthew P.; Lien, Sigbjørn; Primmer, Craig R.

    2014-01-01

    Mechanisms of host-parasite co-adaptation have long been of interest in evolutionary biology; however, determining the genetic basis of parasite resistance has been challenging. Current advances in genome technologies provide new opportunities for obtaining a genome-scale view of the action of parasite-driven natural selection in wild populations and thus facilitate the search for specific genomic regions underlying inter-population differences in pathogen response. European populations of Atlantic salmon (Salmo salar L.) exhibit natural variance in susceptibility levels to the ectoparasite Gyrodactylus salaris Malmberg 1957, ranging from resistance to extreme susceptibility, and are therefore a good model for studying the evolution of virulence and resistance. However, distinguishing the molecular signatures of genetic drift and environment-associated selection in small populations such as land-locked Atlantic salmon populations presents a challenge, specifically in the search for pathogen-driven selection. We used a novel genome-scan analysis approach that enabled us to i) identify signals of selection in salmon populations affected by varying levels of genetic drift and ii) separate potentially selected loci into the categories of pathogen (G. salaris)-driven selection and selection acting upon other environmental characteristics. A total of 4631 single nucleotide polymorphisms (SNPs) were screened in Atlantic salmon from 12 different northern European populations. We identified three genomic regions potentially affected by parasite-driven selection, as well as three regions presumably affected by salinity-driven directional selection. Functional annotation of candidate SNPs is consistent with the role of the detected genomic regions in immune defence and, implicitly, in osmoregulation. These results provide new insights into the genetic basis of pathogen susceptibility in Atlantic salmon and will enable future searches for the specific genes involved. PMID

  4. Population structure of Squatina guggenheim (Squatiniformes, Squatinidae) from the south-western Atlantic Ocean.

    PubMed

    Garcia, G; Pereyra, S; Gutierrez, V; Oviedo, S; Miller, P; Domingo, A

    2015-01-01

    Population genetic analyses based on both mitochondrial cytochrome b and the internal transcribed spacer 2 of recombinant (r)DNA genes were implemented to examine hypotheses of population differentiation in the angular angel shark Squatina guggenheim, one of the four most-widespread endemic species inhabiting coastal ecosystems in the south-western Atlantic Ocean. A total of 82 individuals of S. guggenheim from 10 sampling sites throughout the Río de la Plata mouth, its maritime front, the outer shelf at the subtropical confluence and the coastal areas of the south-west Atlantic Ocean, were included. The analysis of molecular variance (AMOVA) based on the second internal transcribed spacer (its-2) region supports that the samples from the outer shelf represent an isolated group from other sites. Historical gene flow in a coalescent-based approach revealed significant immigration and emigration asymmetry between sampling sites. Based on the low level of genetic diversity, the existence of a long-term population decline or a past recent population expansion following a population bottleneck could be proposed in S. guggenheim. This demographic differentiation suggests a degree of vulnerability to overexploitation in this endemic and endangered south-west Atlantic Ocean shark, given its longevity and low reproductive potential.

  5. Evidence of recent signatures of selection during domestication in an Atlantic salmon population.

    PubMed

    Gutierrez, A P; Yáñez, J M; Davidson, W S

    2016-04-01

    Selective breeding practices in Atlantic salmon aquaculture have been carried out intensively since the 1970s. Along with the phenotypic improvement of fish, we expect to observe genomic regions showing evidence of selection for traits related to growth and age at sexual maturation, as well as traits involved in the domestication process. This is mainly linked to the increase in the frequency of favourable alleles at loci that affect the traits of interest in the breeding population. In this study we searched for signatures of selection in the Cermaq Atlantic salmon broodstock, a Mowi strain, which was derived from wild Norwegian populations, and is now farmed in British Columbia, Canada. A 6.5K SNP array was used to genotype 202 fish from the Cermaq population, and the genotypes were compared with four wild populations from Norway. We used three methods based on FST values to detect signatures of selection. Forty four markers showing divergence in allele frequency were identified as outliers by the three detection methods, suggesting the presence of signatures of selection in the Cermaq population relative to their wild counterparts. Markers identified as outliers are associated with molecular functions that could be related to the selection for economically important traits (e.g., growth) as well as the domestication process (e.g., response to pathogens and environmental stressors). Of particular interest were three outlier markers that had been previously associated with grilsing (i.e., early sexual maturation) an undesirable trait, which has been heavily selected against in Atlantic salmon aquaculture. This study provides clear evidence of the presence of signatures of selection and domestication in a farmed Atlantic salmon population.

  6. Estimating effluent COD

    SciTech Connect

    Eckenfelder, W.W.; Landine, R.

    1995-06-01

    In many parts of the world, chemical oxygen demand (COD) is a primary effluent parameter. Unlike BOD, which considers only biodegradable organics, COD also includes non-degradable organics and non-degradable biological oxidation by-products, generally referred to as soluble microbial products (SMP). The SMP can vary from 2% to 10% of the influent degradable COD. If the technology is limited to biological treatment only, the degradable COD will be removed. Further reductions in COD will require physical chemical treatments such as activated carbon. Effluent COD values for several industrial wastewaters are presented. Effluent characteristics from the anaerobic treatment of industrial wastewaters are also discussed.

  7. The diversity of cyanomyovirus populations along a North-South Atlantic Ocean transect.

    PubMed

    Jameson, Eleanor; Mann, Nicholas H; Joint, Ian; Sambles, Christine; Mühling, Martin

    2011-11-01

    Viruses that infect the marine cyanobacterium Prochlorococcus have the potential to impact the growth, productivity, diversity and abundance of their hosts. In this study, changes in the microdiversity of cyanomyoviruses were investigated in 10 environmental samples taken along a North-South Atlantic Ocean transect using a myoviral-specific PCR-sequencing approach. Phylogenetic analyses of 630 viral g20 clones from this study, with 786 published g20 sequences, revealed that myoviral populations in the Atlantic Ocean had higher diversity than previously reported, with several novel putative g20 clades. Some of these clades were detected throughout the Atlantic Ocean. Multivariate statistical analyses did not reveal any significant correlations between myoviral diversity and environmental parameters, although myoviral diversity appeared to be lowest in samples collected from the north and south of the transect where Prochlorococcus diversity was also lowest. The results were correlated to the abundance and diversity of the co-occurring Prochlorococcus and Synechococcus populations, but revealed no significant correlations to either of the two potential host genera. This study provides evidence that cyanophages have extremely high and variable diversity and are distributed over large areas of the Atlantic Ocean.

  8. Correlation among commercial traits and the possible maternal effects for these traits in the reciprocal populations of Atlantic and Superior

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reciprocal populations of Atlantic and Superior were created with the objective of combining the desired traits of the two parents and selecting a new variety with similar characteristics as Atlantic but with improved internal quality. Both parents have contrasting characteristics for yield, specifi...

  9. North Atlantic phylogeography and large-scale population differentiation of the seagrass Zostera marina L.

    PubMed

    Olsen, Jeanine L; Stam, Wytze T; Coyer, James A; Reusch, Thorsten B H; Billingham, Martin; Boström, Christoffer; Calvert, Elizabeth; Christie, Hartvig; Granger, Stephen; la Lumière, Richard; Milchakova, Nataliya; Oudot-Le Secq, Marie-Pierre; Procaccini, Gabriele; Sanjabi, Bahram; Serrao, Ester; Veldsink, Jan; Widdicombe, Stephen; Wyllie-Echeverria, Sandy

    2004-07-01

    As the most widespread seagrass in temperate waters of the Northern Hemisphere, Zostera marina provides a unique opportunity to investigate the extent to which the historical legacy of the last glacial maximum (LGM18 000-10 000 years bp) is detectable in modern population genetic structure. We used sequences from the nuclear rDNA-internal transcribed spacer (ITS) and chloroplast matK-intron, and nine microsatellite loci to survey 49 populations (> 2000 individuals) from throughout the species' range. Minimal sequence variation between Pacific and Atlantic populations combined with biogeographical groupings derived from the microsatellite data, suggest that the trans-Arctic connection is currently open. The east Pacific and west Atlantic are more connected than either is to the east Atlantic. Allelic richness was almost two-fold higher in the Pacific. Populations from putative Atlantic refugia now represent the southern edges of the distribution and are not genetically diverse. Unexpectedly, the highest allelic diversity was observed in the North Sea-Wadden Sea-southwest Baltic region. Except for the Mediterranean and Black Seas, significant isolation-by-distance was found from ~150 to 5000 km. A transition from weak to strong isolation-by-distance occurred at ~150 km among northern European populations suggesting this scale as the natural limit for dispersal within the metapopulation. Links between historical and contemporary processes are discussed in terms of the projected effects of climate change on coastal marine plants. The identification of a high genetic diversity hotspot in Northern Europe provides a basis for restoration decisions.

  10. Habitat-driven population structure of bottlenose dolphins, Tursiops truncatus, in the North-East Atlantic.

    PubMed

    Louis, Marie; Viricel, Amélia; Lucas, Tamara; Peltier, Hélène; Alfonsi, Eric; Berrow, Simon; Brownlow, Andrew; Covelo, Pablo; Dabin, Willy; Deaville, Rob; de Stephanis, Renaud; Gally, François; Gauffier, Pauline; Penrose, Rod; Silva, Monica A; Guinet, Christophe; Simon-Bouhet, Benoit

    2014-02-01

    Despite no obvious barrier to gene flow, historical environmental processes and ecological specializations can lead to genetic differentiation in highly mobile animals. Ecotypes emerged in several large mammal species as a result of niche specializations and/or social organization. In the North-West Atlantic, two distinct bottlenose dolphin (Tursiops truncatus) ecotypes (i.e. 'coastal' and 'pelagic') have been identified. Here, we investigated the genetic population structure of North-East Atlantic (NEA) bottlenose dolphins on a large scale through the analysis of 381 biopsy-sampled or stranded animals using 25 microsatellites and a 682-bp portion of the mitochondrial control region. We shed light on the likely origin of stranded animals using a carcass drift prediction model. We showed, for the first time, that coastal and pelagic bottlenose dolphins were highly differentiated in the NEA. Finer-scale population structure was found within the two groups. We suggest that distinct founding events followed by parallel adaptation may have occurred independently from a large Atlantic pelagic population in the two sides of the basin. Divergence could be maintained by philopatry possibly as a result of foraging specializations and social organization. As coastal environments are under increasing anthropogenic pressures, small and isolated populations might be at risk and require appropriate conservation policies to preserve their habitats. While genetics can be a powerful first step to delineate ecotypes in protected and difficult to access taxa, ecotype distinction should be further documented through diet studies and the examination of cranial skull features associated with feeding.

  11. Alternative reproductive tactics increase effective population size and decrease inbreeding in wild Atlantic salmon

    PubMed Central

    Perrier, Charles; Normandeau, Éric; Dionne, Mélanie; Richard, Antoine; Bernatchez, Louis

    2014-01-01

    While nonanadromous males (stream-resident and/or mature male parr) contribute to reproduction in anadromous salmonids, little is known about their impacts on key population genetic parameters. Here, we evaluated the contribution of Atlantic salmon mature male parr to the effective number of breeders (Nb) using both demographic (variance in reproductive success) and genetic (linkage disequilibrium) methods, the number of alleles, and the relatedness among breeders. We used a recently published pedigree reconstruction of a wild anadromous Atlantic salmon population in which 2548 fry born in 2010 were assigned parentage to 144 anadromous female and 101 anadromous females that returned to the river to spawn in 2009 and to 462 mature male parr. Demographic and genetic methods revealed that mature male parr increased population Nb by 1.79 and 1.85 times, respectively. Moreover, mature male parr boosted the number of alleles found among progenies. Finally, mature male parr were in average less related to anadromous females than were anadromous males, likely because of asynchronous sexual maturation between mature male parr and anadromous fish of a given cohort. By increasing Nb and allelic richness, and by decreasing inbreeding, the reproductive contribution of mature male parr has important evolutionary and conservation implications for declining Atlantic salmon populations. PMID:25553070

  12. Population genomic analyses of early-phase Atlantic Salmon (Salmo salar) domestication/captive breeding

    PubMed Central

    Mäkinen, Hannu; Vasemägi, Anti; McGinnity, Philip; Cross, Tom F; Primmer, Craig R

    2015-01-01

    Domestication can have adverse genetic consequences, which may reduce the fitness of individuals once released back into the wild. Many wild Atlantic salmon (Salmo salarL.) populations are threatened by anthropogenic influences, and they are supplemented with captively bred fish. The Atlantic salmon is also widely used in selective breeding programs to increase the mean trait values for desired phenotypic traits. We analyzed a genomewide set of SNPs in three domesticated Atlantic salmon strains and their wild conspecifics to identify loci underlying domestication. The genetic differentiation between domesticated strains and wild populations was low (FST < 0.03), and domesticated strains harbored similar levels of genetic diversity compared to their wild conspecifics. Only a few loci showed footprints of selection, and these loci were located in different linkage groups among the different wild population/hatchery strain comparisons. Simulated scenarios indicated that differentiation in quantitative trait loci exceeded that in neutral markers during the early phases of divergence only when the difference in the phenotypic optimum between populations was large. This study indicates that detecting selection using standard approaches in the early phases of domestication might be challenging unless selection is strong and the traits under selection show simple inheritance patterns. PMID:25667605

  13. Genetic population structure of US atlantic coastal striped bass (Morone saxatilis).

    PubMed

    Gauthier, David T; Audemard, Corinne A; Carlsson, Jeanette E L; Darden, Tanya L; Denson, Michael R; Reece, Kimberly S; Carlsson, Jens

    2013-01-01

    Genetic population structure of anadromous striped bass along the US Atlantic coast was analyzed using 14 neutral nuclear DNA microsatellites. Young-of-the-year and adult striped bass (n = 1114) were sampled from Hudson River, Delaware River, Chesapeake Bay, North Carolina, and South Carolina. Analyses indicated clear population structure with significant genetic differentiation between all regions. Global multilocus F ST was estimated at 0.028 (P < 0.001). Population structure followed an isolation-by-distance model and temporal sampling indicated a stable population structure more than 2 years at all locations. Significant structure was absent within Hudson River, whereas weak but significant genetic differences were observed between northern and southern samples in Chesapeake Bay. The largest and smallest effective striped bass population sizes were found in Chesapeake Bay and South Carolina, respectively. Coalescence analysis indicated that the highest historical gene flow has been between Chesapeake Bay and Hudson River populations, and that exchange has not been unidirectional. Bayesian analysis of contemporary migration indicated that Chesapeake Bay serves as a major source of migrants for Atlantic coastal regions from Albemarle Sound northward. In addition to examining population genetic structure, the data acquired during this project were capable of serving as a baseline for assigning fish with unknown origin to source region.

  14. Extensive genetic diversity and rapid population differentiation during blooms of Alexandrium fundyense (Dinophyceae) in an isolated salt pond on Cape Cod, MA, USA

    PubMed Central

    Richlen, Mindy L; Erdner, Deana L; McCauley, Linda A R; Libera, Katie; Anderson, Donald M

    2012-01-01

    In Massachusetts, paralytic shellfish poisoning (PSP) is annually recurrent along the coastline, including within several small embayments on Cape Cod. One such system, the Nauset Marsh System (NMS), supports extensive marshes and a thriving shellfishing industry. Over the last decade, PSP in the NMS has grown significantly worse; however, the origins and dynamics of the toxic Alexandrium fundyense (Balech) populations that bloom within the NMS are not well known. This study examined a collection of 412 strains isolated from the NMS and the Gulf of Maine (GOM) in 2006–2007 to investigate the genetic characteristics of localized blooms and assess connectivity with coastal populations. Comparisons of genetic differentiation showed that A. fundyense blooms in the NMS exhibited extensive clonal diversity and were genetically distinct from populations in the GOM. In both project years, genetic differentiation was observed among temporal samples collected from the NMS, sometimes occurring on the order of approximately 7 days. The underlying reasons for temporal differentiation are unknown, but may be due, in part, to life-cycle characteristics unique to the populations in shallow embayments, or possibly driven by selection from parasitism and zooplankton grazing; these results highlight the need to investigate the role of selective forces in the genetic dynamics of bloom populations. The small geographic scale and limited connectivity of NMS salt ponds provide a novel system for investigating regulators of blooms, as well as the influence of selective forces on population structure, all of which are otherwise difficult or impossible to study in the adjacent open-coastal waters or within larger estuaries. PMID:23145343

  15. Population dynamics of ring-necked ducks in the Atlantic and Mississippi flyways

    USGS Publications Warehouse

    Conroy, M.J.

    1982-01-01

    Band-recovery data, harvest surveys, and spring and winter population surveys were used to estimate population parameters of ring-necked ducks (Aythya collaris). Mean annual survival rates of adult males (0.63 to 0.69) were higher (P < 0.05) than those of either adult females (0.48 to 0.58) or juveniles (0.31 to 0.41). Survival rates of winter-banded adult males were highest in the Mississippi Flyway (0.69), whereas those of females were highest in the Atlantic Flyway (0.58). Recovery rates varied little geographically, were similar for adult males and females, and were higher (P < 0.01) for juveniles. Survival rates of winter-banded adult males in the Mississippi Flyway were negatively correlated with annual harvest rate indices (r = -0.78, P < 0.01) and breeding population indices r = -0.68, P< 0.05). These results are contradictory, because the 1st correlation suggests an additive relationship between hunting and non-hunting mortality, whereas the 2nd suggests compensatory (density-dependent) mortality. Fall age-ratios of ring-necked ducks for 1961-80 were not significantly different between the Mississippi (1.29 young/adult) and the Atlantic (1.18 young/adult) Flyways. Estimated survival rates were used in conjunction with these age-ratios to project finite rates of increase at stable age distributions of approximately 1.0 for the Mississippi and the Atlantic Flyways. Mixing between the 2 Flyway populations and temporal variability in survival rates and age-ratios suggest a population with long-term stationarity but subject to large short-term fluctuations in growth rate. Breeding population surveys for 1960-80 corroborate these results, with breeding populations ranging from 200,000 to 800,000 ( = 500,000) but exhibiting no overall trends

  16. Population genetic structure in Atlantic and Pacific Ocean common murres (Uria aalge): Natural replicate tests of post-Pleistocene evolution

    USGS Publications Warehouse

    Morris-Pocock, J. A.; Taylor, S.A.; Birt, T.P.; Damus, M.; Piatt, J.F.; Warheit, K.I.; Friesen, V.L.

    2008-01-01

    Understanding the factors that influence population differentiation in temperate taxa can be difficult because the signatures of both historic and contemporary demographics are often reflected in population genetic patterns. Fortunately, analyses based on coalescent theory can help untangle the relative influence of these historic and contemporary factors. Common murres (Uria aalge) are vagile seabirds that breed in the boreal and low arctic waters of the Northern Hemisphere. Previous analyses revealed that Atlantic and Pacific populations are genetically distinct; however, less is known about population genetic structure within ocean basins. We employed the mitochondrial control region, four microsatellite loci and four intron loci to investigate population genetic structure throughout the range of common murres. As in previous studies, we found that Atlantic and Pacific populations diverged during the Pleistocene and do not currently exchange migrants. Therefore, Atlantic and Pacific murre populations can be used as natural replicates to test mechanisms of population differentiation. While we found little population genetic structure within the Pacific, we detected significant east-west structuring among Atlantic colonies. The degree that population genetic structure reflected contemporary population demographics also differed between ocean basins. Specifically, while the low levels of population differentiation in the Pacific are at least partially due to high levels of contemporary gene flow, the east-west structuring of populations within the Atlantic appears to be the result of historic fragmentation of populations rather than restricted contemporary gene flow. The contrasting results in the Atlantic and Pacific Oceans highlight the necessity of carefully considering multilocus nonequilibrium population genetic approaches when reconstructing the demographic history of temperate Northern Hemisphere taxa. ?? 2008 The Authors.

  17. The xenoestrogen, 4-nonylphenol, impaired steroidogenesis in previtellogenic oocyte culture of Atlantic cod (Gadus morhua) by targeting the StAR protein and P450scc expressions.

    PubMed

    Kortner, Trond M; Arukwe, Augustine

    2007-02-01

    The steroidogenic acute regulatory (StAR) protein and cytochrome P450-mediated cholesterol side-chain cleavage (P450scc) have been localized in most steroidogenic organs and are rapidly synthesized in response to acute tropic hormone stimulation. In this study, we present the development of cod previtellogenic oocyte in vitro culture system, histological and molecular methods for evaluating the effects of endocrine disruptors such as nonylphenol (NP) on steroid hormone levels, the StAR protein and P450scc. In addition, expression pattern of cyclin-B was studied, because of cyclin B's role as an indicator of oocyte growth in fish. The in vitro previtellogenic oocyte culture technique was based on an agarose floating method. Tissue was cultured in a humidified incubator at 10 degrees C for 4, 7, 14 and 21 d with different concentrations of nonylphenol (0 (control), 1, 10, 50 and 100 microM) dissolved in ethanol (0.3%). Gene expressions were detected using validated real-time polymerase chain reaction (PCR) with specific primers. Immunohistochemistry of the StAR protein and P450scc were performed using antisera prepared against synthetic peptide for both proteins. Estradiol-17beta (E2) and 11-ketotestosterone (11-KT) tissue levels were estimated using enzyme immunoassay. Our data show that nonylphenol produced a unique and consistent concentration-specific pattern of modulation for the StAR protein, P450scc and cyclin-B gene expression at day 14 after exposure. This pattern is generally described as increasing from 0 (control) to 1 and 10 microM, and decreased at 50 and 100 microM. The observed changes in the StAR protein, P450scc and cyclin-B levels showed a direct relationship with changes in 11-KT levels at day 14 after exposure. Cellular localization of StAR and P450scc were specific to the follicular cells of previtellogenic oocytes, but with no differences in staining intensities. No significant change in oocyte diameter was observed between the exposure groups

  18. Plankton effect on cod recruitment in the North Sea

    NASA Astrophysics Data System (ADS)

    Beaugrand, Grégory; Brander, Keith M.; Alistair Lindley, J.; Souissi, Sami; Reid, Philip C.

    2003-12-01

    The Atlantic cod (Gadus morhua L.) has been overexploited in the North Sea since the late 1960s and great concern has been expressed about the decline in cod biomass and recruitment. Here we show that, in addition to the effects of overfishing, fluctuations in plankton have resulted in long-term changes in cod recruitment in the North Sea (bottom-up control). Survival of larval cod is shown to depend on three key biological parameters of their prey: the mean size of prey, seasonal timing and abundance. We suggest a mechanism, involving the match/mismatch hypothesis, by which variability in temperature affects larval cod survival and conclude that rising temperature since the mid-1980s has modified the plankton ecosystem in a way that reduces the survival of young cod.

  19. Plankton effect on cod recruitment in the North Sea.

    PubMed

    Beaugrand, Grégory; Brander, Keith M; Alistair Lindley, J; Souissi, Sami; Reid, Philip C

    2003-12-11

    The Atlantic cod (Gadus morhua L.) has been overexploited in the North Sea since the late 1960s and great concern has been expressed about the decline in cod biomass and recruitment. Here we show that, in addition to the effects of overfishing, fluctuations in plankton have resulted in long-term changes in cod recruitment in the North Sea (bottom-up control). Survival of larval cod is shown to depend on three key biological parameters of their prey: the mean size of prey, seasonal timing and abundance. We suggest a mechanism, involving the match/mismatch hypothesis, by which variability in temperature affects larval cod survival and conclude that rising temperature since the mid-1980s has modified the plankton ecosystem in a way that reduces the survival of young cod.

  20. Slow adaptation in the face of rapid warming leads to collapse of the Gulf of Maine cod fishery.

    PubMed

    Pershing, Andrew J; Alexander, Michael A; Hernandez, Christina M; Kerr, Lisa A; Le Bris, Arnault; Mills, Katherine E; Nye, Janet A; Record, Nicholas R; Scannell, Hillary A; Scott, James D; Sherwood, Graham D; Thomas, Andrew C

    2015-11-13

    Several studies have documented fish populations changing in response to long-term warming. Over the past decade, sea surface temperatures in the Gulf of Maine increased faster than 99% of the global ocean. The warming, which was related to a northward shift in the Gulf Stream and to changes in the Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation, led to reduced recruitment and increased mortality in the region's Atlantic cod (Gadus morhua) stock. Failure to recognize the impact of warming on cod contributed to overfishing. Recovery of this fishery depends on sound management, but the size of the stock depends on future temperature conditions. The experience in the Gulf of Maine highlights the need to incorporate environmental factors into resource management.

  1. Role of egg predation by haddock in the decline of an Atlantic herring population

    PubMed Central

    Richardson, David E.; Hare, Jonathan A.; Fogarty, Michael J.; Link, Jason S.

    2011-01-01

    Theoretical studies suggest that the abrupt and substantial changes in the productivity of some fisheries species may be explained by predation-driven alternate stable states in their population levels. With this hypothesis, an increase in fishing or a natural perturbation can drive a population from an upper to a lower stable-equilibrium population level. After fishing is reduced or the perturbation ended, this low population level can persist due to the regulatory effect of the predator. Although established in theoretical studies, there is limited empirical support for predation-driven alternate stable states in exploited marine fish populations. We present evidence that egg predation by haddock (Melanogrammus aeglefinus) can cause alternate stable population levels in Georges Bank Atlantic herring (Clupea harengus). Egg predation by haddock explains a substantial decoupling of herring spawning stock biomass (an index of egg production) from observed larval herring abundance (an index of egg hatching). Estimated egg survival rates ranged from <2–70% from 1971 to 2005. A population model incorporating egg predation and herring fishing explains the major population trends of Georges Bank herring over four decades and predicts that, when the haddock population is high, seemingly conservative levels of fishing can still precipitate a severe decline in the herring population. These findings illustrate how efforts to rebuild fisheries can be undermined by not incorporating ecological interactions into fisheries models and management plans. PMID:21825166

  2. Role of egg predation by haddock in the decline of an Atlantic herring population.

    PubMed

    Richardson, David E; Hare, Jonathan A; Fogarty, Michael J; Link, Jason S

    2011-08-16

    Theoretical studies suggest that the abrupt and substantial changes in the productivity of some fisheries species may be explained by predation-driven alternate stable states in their population levels. With this hypothesis, an increase in fishing or a natural perturbation can drive a population from an upper to a lower stable-equilibrium population level. After fishing is reduced or the perturbation ended, this low population level can persist due to the regulatory effect of the predator. Although established in theoretical studies, there is limited empirical support for predation-driven alternate stable states in exploited marine fish populations. We present evidence that egg predation by haddock (Melanogrammus aeglefinus) can cause alternate stable population levels in Georges Bank Atlantic herring (Clupea harengus). Egg predation by haddock explains a substantial decoupling of herring spawning stock biomass (an index of egg production) from observed larval herring abundance (an index of egg hatching). Estimated egg survival rates ranged from <2-70% from 1971 to 2005. A population model incorporating egg predation and herring fishing explains the major population trends of Georges Bank herring over four decades and predicts that, when the haddock population is high, seemingly conservative levels of fishing can still precipitate a severe decline in the herring population. These findings illustrate how efforts to rebuild fisheries can be undermined by not incorporating ecological interactions into fisheries models and management plans.

  3. Stable isotopes provide insight into population structure and segregation in eastern North Atlantic sperm whales.

    PubMed

    Borrell, Asunción; Velásquez Vacca, Adriana; Pinela, Ana M; Kinze, Carl; Lockyer, Christina H; Vighi, Morgana; Aguilar, Alex

    2013-01-01

    In pelagic species inhabiting large oceans, genetic differentiation tends to be mild and populations devoid of structure. However, large cetaceans have provided many examples of structuring. Here we investigate whether the sperm whale, a pelagic species with large population sizes and reputedly highly mobile, shows indication of structuring in the eastern North Atlantic, an ocean basin in which a single population is believed to occur. To do so, we examined stable isotope values in sequential growth layer groups of teeth from individuals sampled in Denmark and NW Spain. In each layer we measured oxygen- isotope ratios (δ(18)O) in the inorganic component (hydroxyapatite), and nitrogen and carbon isotope ratios (δ(15)N: δ(13)C) in the organic component (primarily collagenous). We found significant differences between Denmark and NW Spain in δ(15)N and δ(18)O values in the layer deposited at age 3, considered to be the one best representing the baseline of the breeding ground, in δ(15)N, δ(13)C and δ(18)O values in the period up to age 20, and in the ontogenetic variation of δ(15)N and δ(18)O values. These differences evidence that diet composition, use of habitat and/or migratory destinations are dissimilar between whales from the two regions and suggest that the North Atlantic population of sperm whales is more structured than traditionally accepted.

  4. Who's your mama? Riverine hybridisation of threatened freshwater Trout Cod and Murray Cod.

    PubMed

    Couch, Alan J; Unmack, Peter J; Dyer, Fiona J; Lintermans, Mark

    2016-01-01

    Rates of hybridization and introgression are increasing dramatically worldwide because of translocations, restocking of organisms and habitat modifications; thus, determining whether hybridization is occuring after reintroducing extirpated congeneric species is commensurately important for conservation. Restocking programs are sometimes criticized because of the genetic consequences of hatchery-bred fish breeding with wild populations. These concerns are important to conservation restocking programs, including those from the Australian freshwater fish family, Percichthyidae. Two of the better known Australian Percichthyidae are the Murray Cod, Maccullochella peelii and Trout Cod, Maccullochella macquariensis which were formerly widespread over the Murray Darling Basin. In much of the Murrumbidgee River, Trout Cod and Murray Cod were sympatric until the late 1970s when Trout Cod were extirpated. Here we use genetic single nucleotide polymorphism (SNP) data together with mitochondrial sequences to examine hybridization and introgression between Murray Cod and Trout Cod in the upper Murrumbidgee River and consider implications for restocking programs. We have confirmed restocked riverine Trout Cod reproducing, but only as inter-specific matings, in the wild. We detected hybrid Trout Cod-Murray Cod in the Upper Murrumbidgee, recording the first hybrid larvae in the wild. Although hybrid larvae, juveniles and adults have been recorded in hatcheries and impoundments, and hybrid adults have been recorded in rivers previously, this is the first time fertile F1 have been recorded in a wild riverine population. The F1 backcrosses with Murray cod have also been found to be fertile. All backcrosses noted were with pure Murray Cod. Such introgression has not been recorded previously in these two species, and the imbalance in hybridization direction may have important implications for restocking programs.

  5. Potential for restoration of the Roanoke River population of Atlantic sturgeon

    USGS Publications Warehouse

    Armstrong, J.L.; Hightower, J.E.

    2002-01-01

    The Atlantic sturgeon (Acipenser oxyrinchus oxyrinchus) was historically abundant within Albemarie Sound and the Roanoke River in North Carolina, but declined dramatically in the late 1800s in response to intensive fishing. Recent evidence suggests that the population may be recovering, following a statewide prohibition on harvest in 1991. A recruitment index generally increased from 1992 through 2001. Estuarine habitat for juveniles appears to be suitable, resulting in mean growth rates for age 1 fish ranging from 0.59 to 0.81 mm day-1. A restoration goal of 7000-21 000 subadult and adult Atlantic sturgeon was developed for the Roanoke River, based on historical landings records. Bycatch mortality because of commercial gill-netting in Albermarle Sound could affect recovery. Telemetry and netting data indicate that juvenile Atlantic sturgeon in the sound are most abundant in shallow nearshore areas where commercial gill-netting is concentrated. However, immediate mortality rates from survey and commercial gill-netting in Albemarle Sound were only 0-2%. Additional field studies are needed to refine estimates of immediate- and longer-term mortality associated with gill-net bycatch.

  6. Populations genetic analysis of nuclear and mitochondrial loci in skin biopsies collected from central and northeastern North Atlantic humpback whales (Megaptera novaeangliae): population identity and migratory destinations.

    PubMed

    Larsen, A H; Sigurjónsson, J; Oien, N; Vikingsson, G; Palsbøll, P

    1996-11-22

    It has been speculated that humpback whales, Megaptera novaeangliae, from the northeastern North Atlantic breed in tropical waters off the coast of West Africa and therefore that they represent a separate breeding population from that which winters in the West Indies. We determined the genotype at six microsatellite loci as well as the sequence of the first 288 nucleotides in the mitochondrial control region of 133 skin biopsies collected from humpback whales in the central North Atlantic (Iceland and Jan Mayen) and the northeastern North Atlantic (Bear Island and the northern coast of Norway). We detected no significant deviations from Hardy-Weinberg proportions nor any differences in genotype frequencies between localities at the nuclear loci. However, the mitochondrial analyses revealed two distinct matrilineal aggregations: the central and the northeastern North Atlantic. Our findings were not compatible with the idea of a separate eastern North Atlantic breeding ground unless one has been established recently. The proposed alternative hypothesis of a common North Atlantic panmictic population (wintering primarily in the West Indies) in which individual whales display maternally directed site-fidelity to specific feeding grounds was supported by re-sightings of two northeastern North Atlantic humpback whales in the West Indies.

  7. High Connectivity among Blue Crab (Callinectes sapidus) Populations in the Western South Atlantic

    PubMed Central

    Kersanach, Ralf; Cortinhas, Maria Cristina Silva; Prata, Pedro Fernandes Sanmartin; Dumont, Luiz Felipe Cestari; Proietti, Maíra Carneiro; Maggioni, Rodrigo; D’Incao, Fernando

    2016-01-01

    Population connectivity in the blue crab Callinectes sapidus was evaluated along 740 km of the Western South Atlantic coast. Blue crabs are the most exploited portunid in Brazil. Despite their economic importance, few studies report their ecology or population structure. Here we sampled four estuarine areas in southern Brazil during winter 2013 and summer 2014 in order to evaluate diversity, gene flow and structure of these populations. Nine microsatellite markers were evaluated for 213 adult crabs, with identification of seven polymorphic loci and 183 alleles. Pairwise FST values indicated low population structure ranging from -0.00023 to 0.01755. A Mantel test revealed that the geographic distance does not influence genetic (r = -0.48), and structure/migration rates confirmed this, showing that even the populations located at the opposite extremities of our covered region presented low FST and exchanged migrants. These findings show that there is a significant amount of gene flow between blue crab populations in South Brazil, likely influenced by local current dynamics that allow the transport of a high number of larvae between estuaries. Considering the elevated gene flow, the populations can be considered a single genetic stock. However, further information on population size and dynamics, as well as fishery demands and impacts at different regions, are necessary for harvest management purposes. PMID:27064977

  8. High Connectivity among Blue Crab (Callinectes sapidus) Populations in the Western South Atlantic.

    PubMed

    Lacerda, Ana Luzia Figueiredo; Kersanach, Ralf; Cortinhas, Maria Cristina Silva; Prata, Pedro Fernandes Sanmartin; Dumont, Luiz Felipe Cestari; Proietti, Maíra Carneiro; Maggioni, Rodrigo; D'Incao, Fernando

    2016-01-01

    Population connectivity in the blue crab Callinectes sapidus was evaluated along 740 km of the Western South Atlantic coast. Blue crabs are the most exploited portunid in Brazil. Despite their economic importance, few studies report their ecology or population structure. Here we sampled four estuarine areas in southern Brazil during winter 2013 and summer 2014 in order to evaluate diversity, gene flow and structure of these populations. Nine microsatellite markers were evaluated for 213 adult crabs, with identification of seven polymorphic loci and 183 alleles. Pairwise FST values indicated low population structure ranging from -0.00023 to 0.01755. A Mantel test revealed that the geographic distance does not influence genetic (r = -0.48), and structure/migration rates confirmed this, showing that even the populations located at the opposite extremities of our covered region presented low FST and exchanged migrants. These findings show that there is a significant amount of gene flow between blue crab populations in South Brazil, likely influenced by local current dynamics that allow the transport of a high number of larvae between estuaries. Considering the elevated gene flow, the populations can be considered a single genetic stock. However, further information on population size and dynamics, as well as fishery demands and impacts at different regions, are necessary for harvest management purposes.

  9. Baseline studies of health status in north Atlantic Baleen whale populations

    SciTech Connect

    Lambertsen, R.H. )

    1988-09-01

    This study investigated the health status of fin and sei whale populations of the central North Atlantic to establish a baseline for comparison with stranded whales in more heavily contaminated coastal zones. Systematic necropsy examinations were conducted on 150 fin whales and 42 sei whales caught by commercial whalers off the west coast of Iceland. Gas chromatographic measurements showed detectable tissue levels of organochlorine pesticides, but these levels were low, ranging from 0.2 ppb (gamma-BHC) to 1540 ppb (p,p{prime} DDE). Relevant to the comparative evaluation of contaminant effects was the finding that both the fin and sei whale, despite very similar life histories, suffered from a distinct complement of natural disease problems. From the high incidence and contaminative route of transmission of the major parasitic diseases found, it is predicted that population-level health effects, including increments in mortality rate potentially caused by environmental contamination, will increase with population density.

  10. Influence of projected ocean warming on population growth potential in two North Atlantic copepod species

    NASA Astrophysics Data System (ADS)

    Stegert, Christoph; Ji, Rubao; Davis, Cabell S.

    2010-10-01

    Copepods of the genera Pseudocalanus and Centropages play an important role in the North Atlantic ecosystems and have distinctive spatial and temporal patterns depending on physiological adaptation to different environmental conditions. To examine the possible impact of climate change on these biogeographic patterns, potential population growth rate was computed for each species using IPCC projections of sea surface temperature together with chlorophyll distributions from SeaWiFS climatology and published laboratory data on temperature and food-dependent life-history parameters. The results indicate that the predicted temperature increase throughout the North Atlantic will cause temporal and spatial shifts in copepod species population growth potential. The Centropages population is projected to increase in mid-latitudinal shelf areas, e.g. the Gulf of Maine and the North Sea, due to shorter generation times and a longer growing season, while Pseudocalanus is predicted to be less abundant in these regions after 2050. These shifts potentially have a significant impact on the future demographics of pelagic fish species for which the copepods are the major food source.

  11. Modeling survival and movement of resident giant Canada goose populations in the Atlantic flyway

    USGS Publications Warehouse

    Miller, M.W.; Kendall, W.L.; Hestbeck, J.B.; Moser, Timothy J.; Lien, Ricky D.; VerCauterren, Kurt C.; Abraham, Kenneth F.; Andersen, David E.; Bruggink, John G.; Coluccy, John M.; Graber, David A.; Leafloor, James O.; Luukkonen, David R.; Trost, Robert E.

    2004-01-01

    Distribution of resident giant Canada geese (Branta canadensis maxima) has changed markedly in the Atlantic Flyway in recent decades. This change may be related to habitat variation or to changes in hunting regulations. We attempt to assess impacts of hunting regulations on survival, movement, and harvest rate of Canada goose populations from Maine to South Carolina. During 15 June-31 July 1991-1995, a total of 20,923 Canada geese were individually marked with unique metal leg bands and rubber neck collars. Capture-recapture, resighting, and recovery data will be used in a multi-state model of Canada goose populations in New England, the Mid-Atlantic, the Chesapeake Region, and the Carolinas. We plan to model annual survival, movement, and harvest rate as a function of harvest regulations while controlling for collar loss. Inferences will be drawn about the effects of harvest regulations on these parameters. Such inferences should be useful in management of resident Canada goose populations throughout the eastern United States.

  12. Genetic diversity, kinship analysis, and broodstock management of captive Atlantic sturgeon for population restoration

    USGS Publications Warehouse

    Henderson, A.P.; Spidle, A.P.; King, T.L.

    2005-01-01

    Captive Atlantic sturgeon Acipenser oxyrinchus considered for use as broodstock in a restoration program were genotyped using nuclear DNA microsatellites and compared to wild collections from the Hudson River, New York (source of parents of the captive sturgeon) and from Albemarle Sound, North Carolina. Because the potential broodfish were the progeny of a small number of parents, maintaining genetic diversity and minimizing inbreeding is essential to a successful breeding and supplementation program. The microsatellite loci used in this analysis generated unique multilocus genotypes for each of 136 Atlantic sturgeon. Analyses indicated significant genetic separation between the New York and North Carolina collections and correctly identified the potential broodstock as a subset of the Hudson River population. Pairwise genetic distance (-In proportion of shared alleles) between half and full siblings in the potential broodfish was as great as 1.386, a value exceeded by only 36% of the sampled broodfish pairs available for mating. Because the current broodstock population does not seem to have deviated far from their ancestral population in the Hudson River, progeny from that broodstock, or the parents themselves, would seem to be genetically suitable for release back into the Hudson River.

  13. Predictability of multispecies competitive interactions in three populations of Atlantic salmon Salmo salar.

    PubMed

    Houde, A L S; Wilson, C C; Neff, B D

    2015-04-01

    Juvenile Atlantic salmon Salmo salar from three allopatric populations (LaHave, Sebago and Saint-Jean) were placed into artificial streams with combinations of four non-native salmonids: brown trout Salmo trutta, rainbow trout Oncorhynchus mykiss, Chinook salmon Oncorhynchus tshawytscha and coho salmon Oncorhynchus kisutch. Non-additive effects, as evidenced by lower performance than predicted from weighted summed two-species competition trials, were detected for S. salar fork length (LF ) and mass, but not for survival, condition factor or riffle use. These data support emerging theory on niche overlap and species richness as factors that can lead to non-additive competition effects.

  14. Population-Scale Foraging Segregation in an Apex Predator of the North Atlantic

    PubMed Central

    Paiva, Vitor H.; Fagundes, Ana I.; Romão, Vera; Gouveia, Cátia; Ramos, Jaime A.

    2016-01-01

    In this work we investigated the between-colony spatial, behavioural and trophic segregation of two sub-populations of the elusive Macaronesian shearwaters Puffinus baroli breeding only ~340 km apart in Cima Islet (Porto Santo Island) and Selvagem Grande Island. Global location sensing (gls) loggers were used in combination with the trophic ecology of tracked individuals, inferred from the isotopic signatures of wing feathers. Results suggest that these two Macaronesian shearwater sub-populations do segregate during the non-breeding period in some ‘sub-population-specific’ regions, by responding to different oceanographic characteristics (habitat modelling). Within these disparate areas, both sub-populations behave differently (at-sea activity) and prey on disparate trophic niches (stable isotope analysis). One hypothesis would be that each sub-population have evolved and adapted to feed on particular and ‘sub-population-specific’ resources, and the segregation observed at the three different levels (spatial, behavioural and trophic) might be in fact a result of such adaptation, from the emergence of ‘cultural foraging patterns’. Finally, when comparing to the results of former studies reporting on the spatial, behavioural and trophic choices of Macaronesian shearwater populations breeding on Azores and Canary Islands, we realized the high ecological plasticity of this species inhabiting and foraging over the North-East Atlantic Ocean. PMID:27003687

  15. Population-Scale Foraging Segregation in an Apex Predator of the North Atlantic.

    PubMed

    Paiva, Vitor H; Fagundes, Ana I; Romão, Vera; Gouveia, Cátia; Ramos, Jaime A

    2016-01-01

    In this work we investigated the between-colony spatial, behavioural and trophic segregation of two sub-populations of the elusive Macaronesian shearwaters Puffinus baroli breeding only ~340 km apart in Cima Islet (Porto Santo Island) and Selvagem Grande Island. Global location sensing (gls) loggers were used in combination with the trophic ecology of tracked individuals, inferred from the isotopic signatures of wing feathers. Results suggest that these two Macaronesian shearwater sub-populations do segregate during the non-breeding period in some 'sub-population-specific' regions, by responding to different oceanographic characteristics (habitat modelling). Within these disparate areas, both sub-populations behave differently (at-sea activity) and prey on disparate trophic niches (stable isotope analysis). One hypothesis would be that each sub-population have evolved and adapted to feed on particular and 'sub-population-specific' resources, and the segregation observed at the three different levels (spatial, behavioural and trophic) might be in fact a result of such adaptation, from the emergence of 'cultural foraging patterns'. Finally, when comparing to the results of former studies reporting on the spatial, behavioural and trophic choices of Macaronesian shearwater populations breeding on Azores and Canary Islands, we realized the high ecological plasticity of this species inhabiting and foraging over the North-East Atlantic Ocean.

  16. Who’s your mama? Riverine hybridisation of threatened freshwater Trout Cod and Murray Cod

    PubMed Central

    Unmack, Peter J.; Dyer, Fiona J.; Lintermans, Mark

    2016-01-01

    Rates of hybridization and introgression are increasing dramatically worldwide because of translocations, restocking of organisms and habitat modifications; thus, determining whether hybridization is occuring after reintroducing extirpated congeneric species is commensurately important for conservation. Restocking programs are sometimes criticized because of the genetic consequences of hatchery-bred fish breeding with wild populations. These concerns are important to conservation restocking programs, including those from the Australian freshwater fish family, Percichthyidae. Two of the better known Australian Percichthyidae are the Murray Cod, Maccullochella peelii and Trout Cod, Maccullochella macquariensis which were formerly widespread over the Murray Darling Basin. In much of the Murrumbidgee River, Trout Cod and Murray Cod were sympatric until the late 1970s when Trout Cod were extirpated. Here we use genetic single nucleotide polymorphism (SNP) data together with mitochondrial sequences to examine hybridization and introgression between Murray Cod and Trout Cod in the upper Murrumbidgee River and consider implications for restocking programs. We have confirmed restocked riverine Trout Cod reproducing, but only as inter-specific matings, in the wild. We detected hybrid Trout Cod–Murray Cod in the Upper Murrumbidgee, recording the first hybrid larvae in the wild. Although hybrid larvae, juveniles and adults have been recorded in hatcheries and impoundments, and hybrid adults have been recorded in rivers previously, this is the first time fertile F1 have been recorded in a wild riverine population. The F1 backcrosses with Murray cod have also been found to be fertile. All backcrosses noted were with pure Murray Cod. Such introgression has not been recorded previously in these two species, and the imbalance in hybridization direction may have important implications for restocking programs. PMID:27812407

  17. Evidence of segregated spawning in a single marine fish stock: Sympatric divergence of ecotypes in icelandic cod?

    USGS Publications Warehouse

    Grabowski, T.B.; Thorsteinsson, Vilhjalmur; McAdam, B.J.; Marteinsdottir, G.

    2011-01-01

    There is increasing recognition of intraspecific diversity and population structure within marine fish species, yet there is little direct evidence of the isolating mechanisms that maintain it or documentation of its ecological extent. We analyzed depth and temperature histories collected by electronic data storage tags retrieved from 104 Atlantic cod at liberty ???1 year to evaluate a possible isolating mechanisms maintaining population structure within the Icelandic cod stock. This stock consists of two distinct behavioral types, resident coastal cod and migratory frontal cod, each occurring within two geographically distinct populations. Despite being captured together on the same spawning grounds, we show the behavioral types seem reproductively isolated by fine-scale differences in spawning habitat selection, primarily depth. Additionally, the different groups occupied distinct seasonal thermal and bathymetric niches that generally demonstrated low levels of overlap throughout the year. Our results indicate that isolating mechanisms, such as differential habitat selection during spawning, might contribute to maintaining diversity and fine-scale population structure in broadcast-spawning marine fishes.

  18. Verification of SNPs Associated with Growth Traits in Two Populations of Farmed Atlantic Salmon

    PubMed Central

    Tsai, Hsin Y.; Hamilton, Alastair; Guy, Derrick R.; Tinch, Alan E.; Bishop, Steve C.; Houston, Ross D.

    2015-01-01

    Understanding the relationship between genetic variants and traits of economic importance in aquaculture species is pertinent to selective breeding programmes. High-throughput sequencing technologies have enabled the discovery of large numbers of SNPs in Atlantic salmon, and high density SNP arrays now exist. A previous genome-wide association study (GWAS) using a high density SNP array (132K SNPs) has revealed the polygenic nature of early growth traits in salmon, but has also identified candidate SNPs showing suggestive associations with these traits. The aim of this study was to test the association of the candidate growth-associated SNPs in a separate population of farmed Atlantic salmon to verify their effects. Identifying SNP-trait associations in two populations provides evidence that the associations are true and robust. Using a large cohort (N = 1152), we successfully genotyped eight candidate SNPs from the previous GWAS, two of which were significantly associated with several growth and fillet traits measured at harvest. The genes proximal to these SNPs were identified by alignment to the salmon reference genome and are discussed in the context of their potential role in underpinning genetic variation in salmon growth. PMID:26703584

  19. Assessing footprints of selection in commercial Atlantic salmon populations using microsatellite data.

    PubMed

    Martinez, V; Dettleff, P; Lopez, P; Fernandez, G; Jedlicki, A; Yañez, J M; Davidson, W S

    2013-04-01

    Relatively large rates of response to traits of economic importance have been observed in different selection experiments in salmon. Several QTL have been mapped in the salmon genome, explaining unprecedented levels of phenotypic variation. Owing to the relatively large selection intensity, individual loci may be indirectly selected, leaving molecular footprints of selection, together with increased inbreeding, as its likely relatives will share the selected loci. We used population differentiation and levels of linkage disequilibrium in chromosomes known to be harbouring QTL for body weight, infectious pancreatic necrosis resistance and infectious salmon anaemia resistance to assess the recent selection history at the genomic level in Atlantic salmon. The results clearly suggest that the marker SSA0343BSFU on chromosome 3 (body weight QTL) showed strong evidence of directional selection. It is intriguing that this marker is physically mapped to a region near the coding sequence of DVL2 , making it an ideal candidate gene to explain the rapid evolutionary response of this chromosome to selection for growth in Salmo salar. Weak evidence of diversifying selection was observed in the QTL associated with infectious pancreatic necrosis and infectious salmon anaemia resistance. Overall, this study showed that artificial selection has produced important changes in the Atlantic salmon genome, validating QTL in commercial salmon populations used for production purposes according to the recent selection history.

  20. Verification of SNPs Associated with Growth Traits in Two Populations of Farmed Atlantic Salmon.

    PubMed

    Tsai, Hsin Y; Hamilton, Alastair; Guy, Derrick R; Tinch, Alan E; Bishop, Steve C; Houston, Ross D

    2015-12-22

    Understanding the relationship between genetic variants and traits of economic importance in aquaculture species is pertinent to selective breeding programmes. High-throughput sequencing technologies have enabled the discovery of large numbers of SNPs in Atlantic salmon, and high density SNP arrays now exist. A previous genome-wide association study (GWAS) using a high density SNP array (132K SNPs) has revealed the polygenic nature of early growth traits in salmon, but has also identified candidate SNPs showing suggestive associations with these traits. The aim of this study was to test the association of the candidate growth-associated SNPs in a separate population of farmed Atlantic salmon to verify their effects. Identifying SNP-trait associations in two populations provides evidence that the associations are true and robust. Using a large cohort (N = 1152), we successfully genotyped eight candidate SNPs from the previous GWAS, two of which were significantly associated with several growth and fillet traits measured at harvest. The genes proximal to these SNPs were identified by alignment to the salmon reference genome and are discussed in the context of their potential role in underpinning genetic variation in salmon growth.

  1. Historical Arctic Logbooks Provide Insights into Past Diets and Climatic Responses of Cod.

    PubMed

    Townhill, Bryony L; Maxwell, David; Engelhard, Georg H; Simpson, Stephen D; Pinnegar, John K

    2015-01-01

    Gadus morhua (Atlantic cod) stocks in the Barents Sea are currently at levels not seen since the 1950s. Causes for the population increase last century, and understanding of whether such large numbers will be maintained in the future, are unclear. To explore this, we digitised and interrogated historical cod catch and diet datasets from the Barents Sea. Seventeen years of catch data and 12 years of prey data spanning 1930-1959 cover unexplored spatial and temporal ranges, and importantly capture the end of a previous warm period, when temperatures were similar to those currently being experienced. This study aimed to evaluate cod catch per unit effort and prey frequency in relation to spatial, temporal and environmental variables. There was substantial spatio-temporal heterogeneity in catches through the time series. The highest catches were generally in the 1930s and 1940s, although at some localities more cod were recorded late in the 1950s. Generalized Additive Models showed that environmental, spatial and temporal variables are all valuable descriptors of cod catches, with the highest occurring from 15-45°E longitude and 73-77°N latitude, at bottom temperatures between 2 and 4°C and at depths between 150 and 250 m. Cod diets were highly variable during the study period, with frequent changes in the relative frequencies of different prey species, particularly Mallotus villosus (capelin). Environmental variables were particularly good at describing the importance of capelin and Clupea harengus (herring) in the diet. These new analyses support existing knowledge about how the ecology of the region is controlled by climatic variability. When viewed in combination with more recent data, these historical relationships will be valuable in forecasting the future of Barents Sea fisheries, and in understanding how environments and ecosystems may respond.

  2. Historical Arctic Logbooks Provide Insights into Past Diets and Climatic Responses of Cod

    PubMed Central

    Townhill, Bryony L.; Maxwell, David; Engelhard, Georg H.; Simpson, Stephen D.; Pinnegar, John K.

    2015-01-01

    Gadus morhua (Atlantic cod) stocks in the Barents Sea are currently at levels not seen since the 1950s. Causes for the population increase last century, and understanding of whether such large numbers will be maintained in the future, are unclear. To explore this, we digitised and interrogated historical cod catch and diet datasets from the Barents Sea. Seventeen years of catch data and 12 years of prey data spanning 1930–1959 cover unexplored spatial and temporal ranges, and importantly capture the end of a previous warm period, when temperatures were similar to those currently being experienced. This study aimed to evaluate cod catch per unit effort and prey frequency in relation to spatial, temporal and environmental variables. There was substantial spatio-temporal heterogeneity in catches through the time series. The highest catches were generally in the 1930s and 1940s, although at some localities more cod were recorded late in the 1950s. Generalized Additive Models showed that environmental, spatial and temporal variables are all valuable descriptors of cod catches, with the highest occurring from 15–45°E longitude and 73–77°N latitude, at bottom temperatures between 2 and 4°C and at depths between 150 and 250 m. Cod diets were highly variable during the study period, with frequent changes in the relative frequencies of different prey species, particularly Mallotus villosus (capelin). Environmental variables were particularly good at describing the importance of capelin and Clupea harengus (herring) in the diet. These new analyses support existing knowledge about how the ecology of the region is controlled by climatic variability. When viewed in combination with more recent data, these historical relationships will be valuable in forecasting the future of Barents Sea fisheries, and in understanding how environments and ecosystems may respond. PMID:26331271

  3. Modelling the effects of stranding on the Atlantic salmon population in the Dale River, Norway.

    PubMed

    Sauterleute, Julian F; Hedger, Richard D; Hauer, Christoph; Pulg, Ulrich; Skoglund, Helge; Sundt-Hansen, Line E; Bakken, Tor Haakon; Ugedal, Ola

    2016-12-15

    Rapid dewatering in rivers as a consequence of hydropower operations may cause stranding of juvenile fish and have a negative impact on fish populations. We implemented stranding into an Atlantic salmon population model in order to evaluate long-term effects on the population in the Dale River, Western Norway. Furthermore, we assessed the sensitivity of the stranding model to dewatered area in comparison to biological parameters, and compared different methods for calculating wetted area, the main abiotic input parameter to the population model. Five scenarios were simulated dependent on fish life-stage, season and light level. Our simulation results showed largest negative effect on the population abundance for hydropeaking during winter daylight. Salmon smolt production had highest sensitivity to the stranding mortality of older juvenile fish, suggesting that stranding of fish at these life-stages is likely to have greater population impacts than that of earlier life-stages. Downstream retention effects on the ramping velocity were found to be negligible in the stranding model, but are suggested to be important in the context of mitigation measure design.

  4. Forecasting the Major Influences of Predation and Environment on Cod Recovery in the Northern Gulf of St. Lawrence

    PubMed Central

    Bousquet, Nicolas; Chassot, Emmanuel; Duplisea, Daniel E.; Hammill, Mike O.

    2014-01-01

    The northern Gulf of St. Lawrence (NGSL) stock of Atlantic cod (Gadus morhua), historically the second largest cod population in the Western Atlantic, has known a severe collapse during the early 1990 s and is currently considered as endangered by the Committee on the Status of Endangered Wildlife in Canada. As for many fish populations over the world which are currently being heavily exploited or overfished, urgent management actions in the form of recovery plans are needed for restoring this stock to sustainable levels. Stochastic projections based on a statistical population model incorporating predation were conducted over a period of 30 years (2010–2040) to assess the expected outcomes of alternative fishing strategies on the stock recovery under different scenarios of harp seal (Pagophilus groenlandicus) abundance and environmental conditions. This sensitivity study shows that water temperature is key in the rebuilding of the NGSL cod stock. Model projections suggest that maintaining the current management practice under cooler water temperatures is likely to maintain the species in an endangered status. Under current or warmer conditions in the Gulf of St. Lawrence, partial recovery might only be achieved by significant reductions in both fishing and predation pressure. In the medium-term, a management strategy that reduces catch could be favoured over a complete moratorium so as to minimize socio-economic impacts on the industry. PMID:24523852

  5. Forecasting the major influences of predation and environment on cod recovery in the northern Gulf of St. Lawrence.

    PubMed

    Bousquet, Nicolas; Chassot, Emmanuel; Duplisea, Daniel E; Hammill, Mike O

    2014-01-01

    The northern Gulf of St. Lawrence (NGSL) stock of Atlantic cod (Gadus morhua), historically the second largest cod population in the Western Atlantic, has known a severe collapse during the early 1990 s and is currently considered as endangered by the Committee on the Status of Endangered Wildlife in Canada. As for many fish populations over the world which are currently being heavily exploited or overfished, urgent management actions in the form of recovery plans are needed for restoring this stock to sustainable levels. Stochastic projections based on a statistical population model incorporating predation were conducted over a period of 30 years (2010-2040) to assess the expected outcomes of alternative fishing strategies on the stock recovery under different scenarios of harp seal (Pagophilus groenlandicus) abundance and environmental conditions. This sensitivity study shows that water temperature is key in the rebuilding of the NGSL cod stock. Model projections suggest that maintaining the current management practice under cooler water temperatures is likely to maintain the species in an endangered status. Under current or warmer conditions in the Gulf of St. Lawrence, partial recovery might only be achieved by significant reductions in both fishing and predation pressure. In the medium-term, a management strategy that reduces catch could be favoured over a complete moratorium so as to minimize socio-economic impacts on the industry.

  6. DNA barcoding for detecting market substitution in salted cod fillets and battered cod chunks.

    PubMed

    Di Pinto, Angela; Di Pinto, Pietro; Terio, Valentina; Bozzo, Giancarlo; Bonerba, Elisabetta; Ceci, Edmondo; Tantillo, Giuseppina

    2013-12-01

    The Italian Ministry of Agricultural, Food and Forestry Policies (MiPAAF) Decree dated 31 January 2008, which reports the Italian name for fish species of commercial interest, establishes that baccalà can be obtained exclusively from G. macrocephalus (Pacific cod) and G. morhua (Atlantic cod). This paper describes the COI-based DNA identification system to verify the substitution or misbranding of gadoid fish species and, consequently, its concordance with the labels on salted cod fillets shown as baccalà and on battered cod chunks labelled as bocconcini di baccalà. The analysis of interpretable sequences revealed that 55/65 dried salted cod fillet samples were detected as belonging to the family Gadidae, while 10/65 samples appeared to belong to the Lotidae family, while among battered cod chunks labelled as bocconcini di baccalà, the post-sequencing data analysis shows that the labels were completely wrong, with 28/40 samples from Pollachius virens and 12/40 samples from Brosme brosme. The substitution rate for products labelled on the market as baccalà in this study raises significant issues relating to food safety and consumer protection.

  7. Population structure and gene flow of the Atlantic walrus (Odobenus rosmarus rosmarus) in the eastern Atlantic Arctic based on mitochondrial DNA and microsatellite variation.

    PubMed

    Andersen, L W; Born, E W; Gjertz, I; Wiig, O; Holm, L E; Bendixen, C

    1998-10-01

    The population structure of the Atlantic walrus, Odobenus rosmarus rosmarus, was studied using 11 polymorphic microsatellites and restriction fragment length polymorphism detected in the NADH-dehydrogenase ND1, ND2 and ND3/4 segments in mtDNA. A total of 105 walrus samples were analysed from northwest (NW) Greenland, east (E) Greenland, Svalbard and Franz Joseph Land. Two of the 10 haplotypes detected in the four samples were diagnostic for the NW Greenland sample, which implied that the group of walruses in this area is evolutionary distinct from walruses in the other three areas. One individual sampled in E Greenland exhibited a Pacific haplotype, which proved a connection between the Pacific walrus and walruses in eastern Greenland. The Franz Joseph Land, Svalbard and E Greenland samples shared the most common haplotype, indicating very little differentiation at the mtDNA level. Gene flow (Nm) estimates among the four areas indicated a very restricted exchange of female genes between NW Greenland and the more eastern Atlantic Arctic samples, and a closer relationship between the three samples composing the eastern Atlantic Arctic. The genetic variation at 11 polymorphic microsatellite loci grouped individuals into three populations, NW Greenland, E Greenland and a common Franz Joseph Land-Svalbard population, which were connected by moderate gene flow.

  8. First record of intestinal parasites in a wild population of jaguar in the Brazilian Atlantic Forest.

    PubMed

    Srbek-Araujo, Ana Carolina; Santos, Juliana Lúcia Costa; Almeida, Viviane Medeiros de; Guimarães, Marcos Pezzi; Chiarello, Adriano Garcia

    2014-01-01

    Small and isolated wildlife populations may be more susceptible to disease, which makes illness an important issue to investigate regarding the conservation of large carnivores. Here, we present the results of the first investigation of intestinal parasites in one of the last remaining populations of jaguars in the Brazilian Atlantic Forest. We studied parasites from fecal samples using three different techniques for parasitological examination: floatation in saturated sodium chloride solution, sedimentation and formalin-ether centrifugation. Intestinal parasites were detected in 70% of the analyzed samples, and seven taxa (mean = 3.7 taxa/sample) were identified. All the groups of parasites that were identified have been recorded in previous jaguar studies. However, the records of Class Trematoda and nematodes Trichuridae are the first evidence of these groups of worms in free-ranging jaguars in Brazil. Although our results do not provide conclusive evidence on the health of this jaguar population, given its very small size (approximately 20 animals) we stress the need to properly understand the dynamics of disease in this wild population and to evaluate the risk of contracting new diseases from domestic species inhabiting the neighboring areas. These represent imperative actions for the successful conservation of this threatened population of jaguar.

  9. Large-scale distribution of microbial and viral populations in the South Atlantic Ocean.

    PubMed

    De Corte, Daniele; Sintes, Eva; Yokokawa, Taichi; Lekunberri, Itziar; Herndl, Gerhard J

    2016-04-01

    Viruses are abundant, diverse and dynamic components of the marine environments and play a significant role in the ocean biogeochemical cycles. To assess potential variations in the relation between viruses and microbes in different geographic regions and depths, viral and microbial abundance and production were determined throughout the water column along a latitudinal transect in the South Atlantic Ocean. Path analysis was used to examine the relationships between several abiotic and biotic parameters and the different microbial and viral populations distinguished by flow cytometry. The depth-integrated contribution of microbial and viral abundance to the total microbial and viral biomass differed significantly among the different provinces. Additionally, the virus-to-microbe ratio increased with depth and decreased laterally towards the more productive regions. Our data revealed that the abundance of phytoplankton and microbes is the main controlling factor of the viral populations in the euphotic and mesopelagic layers, whereas in the bathypelagic realm, viral abundance was only weakly related to the biotic and abiotic variables. The relative contribution of the three viral populations distinguished by flow cytometry showed a clear geographical pattern throughout the water column, suggesting that these populations are composed of distinct taxa able to infect specific hosts. Overall, our data indicate the presence of distinct microbial patterns along the latitudinal transect. This variability is not limited to the euphotic layer but also detectable in the meso- and bathypelagic layers.

  10. Genetic architecture of survival and fitness-related traits in two populations of Atlantic salmon

    PubMed Central

    Houde, A LS; Wilson, C C; Neff, B D

    2013-01-01

    The additive genetic effects of traits can be used to predict evolutionary trajectories, such as responses to selection. Non-additive genetic and maternal environmental effects can also change evolutionary trajectories and influence phenotypes, but these effects have received less attention by researchers. We partitioned the phenotypic variance of survival and fitness-related traits into additive genetic, non-additive genetic and maternal environmental effects using a full-factorial breeding design within two allopatric populations of Atlantic salmon (Salmo salar). Maternal environmental effects were large at early life stages, but decreased during development, with non-additive genetic effects being most significant at later juvenile stages (alevin and fry). Non-additive genetic effects were also, on average, larger than additive genetic effects. The populations, generally, did not differ in the trait values or inferred genetic architecture of the traits. Any differences between the populations for trait values could be explained by maternal environmental effects. We discuss whether the similarities in architectures of these populations is the result of natural selection across a common juvenile environment. PMID:23942281

  11. Large‐scale distribution of microbial and viral populations in the South Atlantic Ocean

    PubMed Central

    Sintes, Eva; Yokokawa, Taichi; Lekunberri, Itziar; Herndl, Gerhard J.

    2016-01-01

    Summary Viruses are abundant, diverse and dynamic components of the marine environments and play a significant role in the ocean biogeochemical cycles. To assess potential variations in the relation between viruses and microbes in different geographic regions and depths, viral and microbial abundance and production were determined throughout the water column along a latitudinal transect in the South Atlantic Ocean. Path analysis was used to examine the relationships between several abiotic and biotic parameters and the different microbial and viral populations distinguished by flow cytometry. The depth‐integrated contribution of microbial and viral abundance to the total microbial and viral biomass differed significantly among the different provinces. Additionally, the virus‐to‐microbe ratio increased with depth and decreased laterally towards the more productive regions. Our data revealed that the abundance of phytoplankton and microbes is the main controlling factor of the viral populations in the euphotic and mesopelagic layers, whereas in the bathypelagic realm, viral abundance was only weakly related to the biotic and abiotic variables. The relative contribution of the three viral populations distinguished by flow cytometry showed a clear geographical pattern throughout the water column, suggesting that these populations are composed of distinct taxa able to infect specific hosts. Overall, our data indicate the presence of distinct microbial patterns along the latitudinal transect. This variability is not limited to the euphotic layer but also detectable in the meso‐ and bathypelagic layers. PMID:26765966

  12. The between-population genetic architecture of growth, maturation, and plasticity in Atlantic salmon.

    PubMed

    Debes, Paul Vincent; Fraser, Dylan John; Yates, Matthew; Hutchings, Jeffrey A

    2014-04-01

    The between-population genetic architecture for growth and maturation has not been examined in detail for many animal species despite its central importance in understanding hybrid fitness. We studied the genetic architecture of population divergence in: (i) maturation probabilities at the same age; (ii) size at age and growth, while accounting for maturity status and sex; and (iii) growth plasticity in response to environmental factors, using divergent wild and domesticated Atlantic salmon (Salmo salar). Our work examined two populations and their multigenerational hybrids in a common experimental arrangement in which salinity and quantity of suspended sediments were manipulated to mimic naturally occurring environmental variation. Average specific growth rates across environments differed among crosses, maturity groups, and cross-by-maturity groups, but a growth-rate reduction in the presence of suspended sediments was equal for all groups. Our results revealed both additive and nonadditive outbreeding effects for size at age and for growth rates that differed with life stage, as well as the presence of different sex- and size-specific maturation probabilities between populations. The major implication of our work is that estimates of the genetic architecture of growth and maturation can be biased if one does not simultaneously account for temporal changes in growth and for different maturation probabilities between populations. Namely, these correlated traits interact differently within each population and between sexes and among generations, due to nonadditive effects and a level of independence in the genetic control for traits. Our results emphasize the challenges to investigating and predicting phenotypic changes resulting from between-population outbreeding.

  13. Organochlorine exposure and bioaccumulation in the endangered northwest Atlantic right whale (Eubalaena glacialis) population

    SciTech Connect

    Weisbrod, A.V.; Shea, D.; Moore, M.J.; Stegeman, J.J.

    2000-03-01

    Exposure to toxicants is one factor hypothesized to influence population growth of the northern right whale. Organochlorines in right whale skin, feces, and prey were measured and used to identify factors influencing exposure and bioaccumulation. Concentrations of 30 polychlorinated biphenyls (PCBs) and 20 pesticides in skin biopsies were consistent with other baleenopterids. Concentrations in feces and prey were two orders of magnitude less than in biopsies. In principal component analysis, organochlorines in biopsies matched those from Bay of Fundy, Canada, zooplankton, whereas feces were like Cape Cod, USA, copepods. Year of biopsy collection was the principal factor associated with differential accumulation of nonmetabolizable PCBs, 4,4{prime}-DDE, and dieldrin. Biopsies collected during winter had lower concentrations of lipid and metabolizable compounds than biopsies collected during summer. Concentrations of metabolizable PCBs increased with age in males. The bioaccumulation patterns implied that blubber burdens change annually because of the ingestion of different prey or prey from distinct locations and the release of some organochlorines stored in blubber during lipid depletion in winter. Because biopsy concentrations were lower than those found in marine mammals affected by PCBs and DDTs, the authors do not have evidence that the endangered whales bioaccumulate hazardous concentrations of organochlorines.

  14. Life-history traits and population decline of the Atlantic mackerel Scomber scombrusin the Adriatic Sea.

    PubMed

    Meneghesso, C; Riginella, E; La Mesa, M; Donato, F; Mazzoldi, C

    2013-11-01

    This study investigated demographic structure and reproductive characteristics of the Atlantic mackerel Scomber scombrus, in relation to landing trends in the northern-central Adriatic Sea. Results highlighted the occurrence of only small-sized and young-age individuals, and a marked decline from the 1990s to the present in maximum age (from 8 to 3 years) and total length (L(T); from 420 to 360 mm). Fecundity ranged between 40,000 and 190,000 eggs, and was related to female L(T). High levels of atresia implied lower values of actual fecundity. Sexual maturity was attained by 72·8% of individuals in their first year of life at 200 mm. The reduction in maximum L(T) resulted in a marked decline in the population egg production, while the reduction in maximum age implied that females participated in fewer spawning events.

  15. Geologic history of Cape Cod, Massachusetts

    USGS Publications Warehouse

    ,

    1976-01-01

    Cape Cod, a sandy peninsula built mostly during the Ice Age, juts into the Atlantic Ocean like a crooked arm. Because of its exposed location, Cape Cod was visited by many early explorers. Although clear-cut evidence is lacking, the Vikings may have sighted this land about 1,000 years ago. It was visited by Samuel de Champlain in 1605, and his detailed descriptions and charts have helped present-day scientists to determine the rate of growth of Nauset Beach marsh and Nauset spit. Bartholomew Gosnold, a lesser known explorer, settled for a short time on the Elizabeth Islands to the southwest and gave Cape Cod its name in 1602. The Pilgrims first landed in America on the tip of Lower Cape Cod after they were turned back from their more southerly destination by shoals between Cape Cod and Nantucket Island. On Cape Cod they found potable water and food and had their first fight with the natives. The Pilgrims, however, decided that this land was too isolated, too exposed, and too sandy to support them, and they sailed across Cape Cod Bay to establish Plymouth. These features remain today. Small villages are separated by large areas of forest, dune, beach, and marsh. This unspoiled natural beauty makes Cape Cod one of the most favored vacation areas for the people living in the thickly settled Northeastern States. Cape Cod is of particular interest to geologists because it was formed by glaciers very recently in terms of geologic time. During the Great Ice Age, (the Pleistocene Epoch which began 2 to 3 million years ago), glaciers advanced from the north into the temperate regions of the Earth. Glacial ice covered the land at least four times. Each advance was accompanied by a worldwide lowering of sea level because the source of the ice was water from the seas. When the glaciers melted, the climate and sea level were probably much like they are today. In fact, some scientists believe that the Earth is presently between glacial episodes and that ice once again will

  16. Mechanistic insights into the effects of climate change on larval cod.

    PubMed

    Kristiansen, Trond; Stock, Charles; Drinkwater, Kenneth F; Curchitser, Enrique N

    2014-05-01

    Understanding the biophysical mechanisms that shape variability in fisheries recruitment is critical for estimating the effects of climate change on fisheries. In this study, we used an Earth System Model (ESM) and a mechanistic individual-based model (IBM) for larval fish to analyze how climate change may impact the growth and survival of larval cod in the North Atlantic. We focused our analysis on five regions that span the current geographical range of cod and are known to contain important spawning populations. Under the SRES A2 (high emissions) scenario, the ESM-projected surface ocean temperatures are expected to increase by >1 °C for 3 of the 5 regions, and stratification is expected to increase at all sites between 1950-1999 and 2050-2099. This enhanced stratification is projected to decrease large (>5 μm ESD) phytoplankton productivity and mesozooplankton biomass at all 5 sites. Higher temperatures are projected to increase larval metabolic costs, which combined with decreased food resources will reduce larval weight, increase the probability of larvae dying from starvation and increase larval exposure to visual and invertebrate predators at most sites. If current concentrations of piscivore and invertebrate predators are maintained, larval survival is projected to decrease at all five sites by 2050-2099. In contrast to past observed responses to climate variability in which warm anomalies led to better recruitment in cold-water stocks, our simulations indicated that reduced prey availability under climate change may cause a reduction in larval survival despite higher temperatures in these regions. In the lower prey environment projected under climate change, higher metabolic costs due to higher temperatures outweigh the advantages of higher growth potential, leading to negative effects on northern cod stocks. Our results provide an important first large-scale assessment of the impacts of climate change on larval cod in the North Atlantic.

  17. Effects of warm water intrusions on populations of macrozooplankton on Georges Bank, Northwest Atlantic

    NASA Astrophysics Data System (ADS)

    Brown, Harmon; Bollens, Stephen M.; Madin, Laurence P.; Horgan, Erich F.

    2005-01-01

    As part of the Georges Bank/North West Atlantic GLOBEC (Global Ocean Ecosystems Dynamics) Program, macrozooplankton and micronekton were collected on 30 Broad Scale Survey Cruises between January-June, 1995-1999, using a 10 m 2 MOCNESS (3 mm mesh). The objective of this study is to examine the effects of warm water intrusions on populations of macrozooplankton, namely Salpa spp., Phronima spp., Neomysis americana, and Crangon septemspinosa, on Georges Bank. Salpa spp. and Phronima spp. showed a large degree of horizontal co-occurrence, being found predominantly in Upper Slope/Gulf Stream Water and Georges Bank/Gulf of Maine Water. Abundances of these taxa showed striking interannual variability, and were only abundant on the southern flank and in the Northeast Channel in late spring/early summer of 1995 and 1999, periods during which AVHRR imagery and hydrographic data showed the presence of warm water intrusions. These intrusions seemed to have little effect on the distribution of other macrozooplankton (e.g., N. americana and C. septemspinosa). Warm water intrusions can directly affect Salpa spp. and Phronima spp. populations by advecting them onto Georges Bank, although other, more resident populations, especially those inside the 100 m isobath, seem to be little affected by such intrusions.

  18. Lack of genetic structure in greylag goose (Anser anser) populations along the European Atlantic flyway

    PubMed Central

    Pellegrino, Irene; Follestad, Arne; Boos, Mathieu

    2015-01-01

    Greylag goose populations are steadily increasing in north-western Europe. Although individuals breeding in the Netherlands have been considered mainly sedentary birds, those from Scandinavia or northern Germany fly towards their winter quarters, namely over France as far as Spain. This study aimed to determine the genetic structure of these birds, and to evaluate how goose populations mix. We used mitochondrial DNA and microsatellites from individuals distributed throughout the European Atlantic flyway, from breeding sites in Norway and the Netherlands to stopover and wintering sites in northern and south-western France. The mtDNA marker (CR1 D-Loop, 288 bp sequence, 144 ind.) showed 23 different haplotypes. The genetic distances amongst individuals sampled in Norway, northern France and the Netherlands were low (range 0.012–0.013). Individuals in south-western France showed a slightly higher genetic distance compared to all other sampling areas (ranges 0.018–0.022). The NJ tree does not show evidence of any single clades grouping together all individuals from the same geographic area. Besides, individuals from each site are found in different branches. Bayesian clustering procedures on 14 microsatellites (169 individuals) did not detect any geographically distinct cluster, and a high genetic admixture was recorded in all studied areas except for the individuals from the breeding sites in Norway, which were genetically very close. Estimation of migration rates through Bayesian inference confirms the scenario for the current mixing of goose populations. PMID:26339543

  19. Could seals prevent cod recovery in the Baltic Sea?

    PubMed

    MacKenzie, Brian R; Eero, Margit; Ojaveer, Henn

    2011-05-09

    Fish populations are increasingly affected by multiple human and natural impacts including exploitation, eutrophication, habitat alteration and climate change. As a result many collapsed populations may have to recover in ecosystems whose structure and functioning differ from those in which they were formerly productive and supported sustainable fisheries. Here we investigate how a cod (Gadus morhua) population in the Baltic Sea whose biomass was reduced due to a combination of high exploitation and deteriorating environmental conditions might recover and develop in the 21st century in an ecosystem that likely will change due to both the already started recovery of a cod predator, the grey seal Halichoerus grypus, and projected climate impacts. Simulation modelling, assuming increased seal predation, fishing levels consistent with management plan targets and stable salinity, shows that the cod population could reach high levels well above the long-term average. Scenarios with similar seal and fishing levels but with 15% lower salinity suggest that the Baltic will still be able to support a cod population which can sustain a fishery, but biomass and yields will be lower. At present knowledge of cod and seal interactions, seal predation was found to have much lower impact on cod recovery, compared to the effects of exploitation and salinity. These results suggest that dual management objectives (recovery of both seal and cod populations) are realistic but success in achieving these goals will also depend on how climate change affects cod recruitment.

  20. Could Seals Prevent Cod Recovery in the Baltic Sea?

    PubMed Central

    MacKenzie, Brian R.; Eero, Margit; Ojaveer, Henn

    2011-01-01

    Fish populations are increasingly affected by multiple human and natural impacts including exploitation, eutrophication, habitat alteration and climate change. As a result many collapsed populations may have to recover in ecosystems whose structure and functioning differ from those in which they were formerly productive and supported sustainable fisheries. Here we investigate how a cod (Gadus morhua) population in the Baltic Sea whose biomass was reduced due to a combination of high exploitation and deteriorating environmental conditions might recover and develop in the 21st century in an ecosystem that likely will change due to both the already started recovery of a cod predator, the grey seal Halichoerus grypus, and projected climate impacts. Simulation modelling, assuming increased seal predation, fishing levels consistent with management plan targets and stable salinity, shows that the cod population could reach high levels well above the long-term average. Scenarios with similar seal and fishing levels but with 15% lower salinity suggest that the Baltic will still be able to support a cod population which can sustain a fishery, but biomass and yields will be lower. At present knowledge of cod and seal interactions, seal predation was found to have much lower impact on cod recovery, compared to the effects of exploitation and salinity. These results suggest that dual management objectives (recovery of both seal and cod populations) are realistic but success in achieving these goals will also depend on how climate change affects cod recruitment. PMID:21573062

  1. Demographic consequences of population subdivision on the long-furred woolly mouse opossum ( Micoureus paraguayanus) from the Atlantic Forest

    NASA Astrophysics Data System (ADS)

    Brito, Daniel; da Fonseca, Gustavo A. B.

    2007-01-01

    Habitat destruction and fragmentation severely affected the Atlantic Forest. Formerly contiguous populations may become subdivided into a larger number of smaller populations, threatening their long-term persistence. The computer package VORTEX was used to simulate the consequences of habitat fragmentation and population subdivision on Micoureus paraguayanus, an endemic arboreal marsupial of the Atlantic Forest. Scenarios simulated hypothetical populations of 100 and 2000 animals being partitioned into 1-10 populations, linked by varying rates of inter-patch dispersal, and also evaluated male-biased dispersal. Results demonstrated that a single population was more stable than an ensemble of populations of equal size, irrespective of dispersal rate. Small populations (10-20 individuals) exhibited high instability due to demographic stochasticity, and were characterized by high rates of extinction, smaller values for metapopulation growth and larger fluctuations in population size and growth rate. Dispersal effects on metapopulation persistence were related to the size of the populations and to the sexes that were capable of dispersing. Male-biased dispersal had no noticeable effects on metapopulation extinction dynamics, whereas scenarios modelling dispersal by both sexes positively affected metapopulation dynamics through higher growth rates, smaller fluctuations in growth rate, larger final metapopulation sizes and lower probabilities of extinction. The present study highlights the complex relationships between metapopulation size, population subdivision, habitat fragmentation, rate of inter-patch dispersal and sex-biased dispersal and indicates the importance of gaining a better understanding of dispersal and its interactions with correlations between disturbance events.

  2. Patterns of genetic diversity of the cryptogenic red alga Polysiphonia morrowii (Ceramiales, Rhodophyta) suggest multiple origins of the Atlantic populations.

    PubMed

    Geoffroy, Alexandre; Destombe, Christophe; Kim, Byeongseok; Mauger, Stéphane; Raffo, María Paula; Kim, Myung Sook; Le Gall, Line

    2016-08-01

    The red alga Polysiphonia morrowii, native to the North Pacific (Northeast Asia), has recently been reported worldwide. To determine the origin of the French and Argentine populations of this introduced species, we compared samples from these two areas with samples collected in Korea and at Hakodate, Japan, the type locality of the species. Combined analyses of chloroplastic (rbcL) and mitochondrial (cox1) DNA revealed that the French and Argentine populations are closely related and differ substantially from the Korean and Japanese populations. The genetic structure of P. morrowii populations from South Atlantic and North Atlantic, which showed high haplotype diversity compared with populations from the North Pacific, suggested the occurrence of multiple introduction events from areas outside of the so-called native regions. Although similar, the French and Argentine populations are not genetically identical. Thus, the genetic structure of these two introduced areas may have been modified by cryptic and recurrent introduction events directly from Asia or from other introduced areas that act as introduction relays. In addition, the large number of private cytoplasmic types identified in the two introduced regions strongly suggests that local populations of P. morrowii existed before the recent detection of these invasions. Our results suggest that the most likely scenario is that the source population(s) of the French and Argentine populations was not located only in the North Pacific and/or that P. morrowii is a cryptogenic species.

  3. Statistical approaches to paternity analysis in natural populations and applications to the North Atlantic humpback whale.

    PubMed

    Nielsen, R; Mattila, D K; Clapham, P J; Palsbøll, P J

    2001-04-01

    We present a new method for paternity analysis in natural populations that is based on genotypic data that can take the sampling fraction of putative parents into account. The method allows paternity assignment to be performed in a decision theoretic framework. Simulations are performed to evaluate the utility and robustness of the method and to assess how many loci are necessary for reliable paternity inference. In addition we present a method for testing hypotheses regarding relative reproductive success of different ecologically or behaviorally defined groups as well as a new method for estimating the current population size of males from genotypic data. This method is an extension of the fractional paternity method to the case where only a proportion of all putative fathers have been sampled. It can also be applied to provide abundance estimates of the number of breeding males from genetic data. Throughout, the methods were applied to genotypic data collected from North Atlantic humpback whales (Megaptera novaeangliae) to test if the males that appear dominant during the mating season have a higher reproductive success than the subdominant males.

  4. Lagged influence of North Atlantic Oscillation on population dynamics of a Mediterranean terrestrial salamander.

    PubMed

    Salvidio, Sebastiano; Oneto, Fabrizio; Ottonello, Dario; Pastorino, Mauro V

    2016-04-01

    The North Atlantic Oscillation (NAO) is a large-scale climatic pattern that strongly influences the atmospheric circulation in the northern Hemisphere and by consequence the long-term variability of marine and terrestrial ecosystem over great part of northern Europe and western Mediterranean. In the Mediterranean, the effects of the NAO on vertebrates has been studied mainly on bird populations but was rarely analysed in ectothermic animals, and in particular in amphibians. In this study, we investigated the relationships between winter, spring and summer NAO indexes and the long-term population dynamics of the plethodontid salamander Speleomantes strinatii. This terrestrial salamander was monitored inside an artificial cave in NW Italy for 24 consecutive years. The relationships between seasonal NAO indexes and the salamander dynamics were assessed by cross-correlation function (CCF) analysis, after prewhitening the time series by autoregressive moving average statistical modelling. Results of CCF analyses indicated that the salamander abundance varied in relation to the one-year ahead winter NAO (P = 0.018), while no relationships were found with spring and summer indexes. These results strengthen some previous findings that suggested a high sensitivity of temperate terrestrial amphibians to wintertime climatic conditions.

  5. Lagged influence of North Atlantic Oscillation on population dynamics of a Mediterranean terrestrial salamander

    NASA Astrophysics Data System (ADS)

    Salvidio, Sebastiano; Oneto, Fabrizio; Ottonello, Dario; Pastorino, Mauro V.

    2016-04-01

    The North Atlantic Oscillation (NAO) is a large-scale climatic pattern that strongly influences the atmospheric circulation in the northern Hemisphere and by consequence the long-term variability of marine and terrestrial ecosystem over great part of northern Europe and western Mediterranean. In the Mediterranean, the effects of the NAO on vertebrates has been studied mainly on bird populations but was rarely analysed in ectothermic animals, and in particular in amphibians. In this study, we investigated the relationships between winter, spring and summer NAO indexes and the long-term population dynamics of the plethodontid salamander Speleomantes strinatii. This terrestrial salamander was monitored inside an artificial cave in NW Italy for 24 consecutive years. The relationships between seasonal NAO indexes and the salamander dynamics were assessed by cross-correlation function (CCF) analysis, after prewhitening the time series by autoregressive moving average statistical modelling. Results of CCF analyses indicated that the salamander abundance varied in relation to the one-year ahead winter NAO ( P = 0.018), while no relationships were found with spring and summer indexes. These results strengthen some previous findings that suggested a high sensitivity of temperate terrestrial amphibians to wintertime climatic conditions.

  6. Statistical approaches to paternity analysis in natural populations and applications to the North Atlantic humpback whale.

    PubMed Central

    Nielsen, R; Mattila, D K; Clapham, P J; Palsbøll, P J

    2001-01-01

    We present a new method for paternity analysis in natural populations that is based on genotypic data that can take the sampling fraction of putative parents into account. The method allows paternity assignment to be performed in a decision theoretic framework. Simulations are performed to evaluate the utility and robustness of the method and to assess how many loci are necessary for reliable paternity inference. In addition we present a method for testing hypotheses regarding relative reproductive success of different ecologically or behaviorally defined groups as well as a new method for estimating the current population size of males from genotypic data. This method is an extension of the fractional paternity method to the case where only a proportion of all putative fathers have been sampled. It can also be applied to provide abundance estimates of the number of breeding males from genetic data. Throughout, the methods were applied to genotypic data collected from North Atlantic humpback whales (Megaptera novaeangliae) to test if the males that appear dominant during the mating season have a higher reproductive success than the subdominant males. PMID:11290722

  7. Comparison of mitochondrial DNA control region sequence and microsatellite DNA analyses in estimating population structure and gene flow rates in Atlantic sturgeon Acipenser oxyrinchus

    USGS Publications Warehouse

    Wirgin, I.; Waldman, J.; Stabile, J.; Lubinski, B.; King, T.

    2002-01-01

    Atlantic sturgeon Acipenser oxyrinchus is large, long-lived, and anadromous with subspecies distributed along the Atlantic (A. oxyrinchus oxyrinchus) and Gulf of Mexico (A. o. desotoi) coasts of North America. Although it is not certain if extirpation of some population units has occurred, because of anthropogenic influences abundances of all populations are low compared with historical levels. Informed management of A. oxyrinchus demands a detailed knowledge of its population structure, levels of genetic diversity, and likelihood to home to natal rivers. We compared the use of mitochondrial DNA (mtDNA) control region sequence and microsatellite nuclear DNA (nDNA) analyses in identifying the stock structure and homing fidelity of Atlantic and Gulf coast populations of A. oxyrinchus. The approaches were concordant in that they revealed moderate to high levels of genetic diversity and suggested that populations of Atlantic sturgeon are highly structured. At least six genetically distinct management units were detected using the two approaches among the rivers surveyed. Mitochondrial DNA sequences revealed a significant cline in haplotype diversity along the Atlantic coast with monomorphism observed in Canadian populations. High levels of nDNA diversity were also observed among populations along the Atlantic coast, including the two Canadian populations, probably resulting from the more rapid rate of mutational and evolutionary change at microsatellite loci. Estimates of gene flow among populations were similar between both approaches with the exception that because of mtDNA monomorphism in Canadian populations, gene flow estimates between them were unobtainable. Analyses of both genomes provided high resolution and confidence in characterizing the population structure of Atlantic sturgeon. Microsatellite analysis was particularly informative in delineating population structure in rivers that were recently glaciated and may prove diagnostic in rivers that are

  8. Inclusion of South American samples reveals new population structuring of the blacktip shark (Carcharhinus limbatus) in the western Atlantic

    PubMed Central

    Sodré, Davidson; Rodrigues-Filho, Luis F.S.; Souza, Rosália F.C.; Rêgo, Péricles S.; Schneider, Horacio; Sampaio, Iracilda; Vallinoto, Marcelo

    2012-01-01

    Carcharhinus limbatus has a cosmopolitan distribution and marked genetic structuring, mainly because of its philopatric behavior. However, analysis of this structuring has not previously included South American populations. In the present study, we analyzed a sample of adult individuals collected on the northern coast of Brazil and compared the sequences of the mitochondrial control region with those of populations already genotyped. Relatively high haplotype diversity (12 haplotypes, genetic diversity of 0.796) was observed, similar to that in other populations but with a much larger number of private alleles. In contrast to populations studied previously, which were represented by neonates, the pronounced allelic variability found in the South American individuals may have resulted from migrations from other populations in the region that have yet to be genotyped. This population was also genetically distinct from the other Atlantic populations (Fst > 0.8), probably because of female philopatry, and apparently separated from the northwestern Atlantic group 1.39 million years ago. These findings indicate that the C. limbatus population from northern Brazil is genetically distinct from all other populations and should be considered as a different management unit for the protection of stocks. PMID:23271935

  9. New view of population genetics of zooplankton: RAD-seq analysis reveals population structure of the North Atlantic planktonic copepod Centropages typicus.

    PubMed

    Blanco-Bercial, L; Bucklin, A

    2016-04-01

    Detection of population genetic structure of zooplankton at medium-to-small spatial scales in the absence of physical barriers has remained challenging and controversial. The large population sizes and high rates of gene flow characteristic of zooplankton have made resolution of geographical differentiation very difficult, especially when using few genetic markers and assuming equilibrium conditions. Next-generation sequencing now allows simultaneous sampling of hundreds to thousands of genetic markers; new analytical approaches allow studies under nonequilibrium conditions and directional migration. Samples of the North Atlantic Ocean planktonic copepod, Centropages typicus, were analysed using restriction site-associated DNA (RAD) sequencing on a PROTON platform. Although prior studies revealed no genetic differentiation of populations across the geographical range of the species, analysis of RAD tags showed significant structure across the North Atlantic Ocean. We also compared the likelihood for models of connectivity among NW Atlantic populations under various directional flow scenarios that replicate oceanographic conditions of the sampled domain. High-density marker sampling with RAD sequencing markedly outperformed other technical and analytical approaches in detection of population genetic structure and characterization of connectivity of this high geneflow zooplankton species.

  10. 1H NMR metabolic profiling of cod (Gadus morhua) larvae: potential effects of temperature and diet composition during early developmental stages

    PubMed Central

    Chauton, Matilde Skogen; Galloway, Trina Falck; Kjørsvik, Elin; Størseth, Trond Røvik; Puvanendran, Velmurugu; van der Meeren, Terje; Karlsen, Ørjan; Rønnestad, Ivar; Hamre, Kristin

    2015-01-01

    ABSTRACT Marine aquaculture offers a great source of protein for the increasing human population, and farming of, for example, Atlantic salmon is a global industry. Atlantic cod farming however, is an example of a promising industry where the potential is not yet realized. Research has revealed that a major bottleneck to successful farming of cod is poor quality of the larvae and juveniles. A large research program was designed to increase our understanding of how environmental factors such as temperature and nutrition affects cod larvae development. Data on larvae growth and development were used together with nuclear magnetic resonance. The NMR data indicated that the temperature influenced the metabolome of the larvae; differences were related to osmolytes such as betaine/TMAO, the amino acid taurine, and creatine and lactate which reflect muscle activity. The larvae were fed Artemia from stage 2, and this was probably reflected in a high taurine content of older larvae. Larvae fed with copepods in the nutrition experiment also displayed a high taurine content, together with higher creatine and betaine/TMAO content. Data on the cod larvae metabolome should be coupled to data on gene expression, in order to identify events which are regulated on the genetic level versus regulation resulting from temperature or nutrition during development, to fully understand how the environment affects larval development. PMID:26545964

  11. Genomic prediction in an admixed population of Atlantic salmon (Salmo salar)

    PubMed Central

    Ødegård, Jørgen; Moen, Thomas; Santi, Nina; Korsvoll, Sven A.; Kjøglum, Sissel; Meuwissen, Theo H. E.

    2014-01-01

    Reliability of genomic selection (GS) models was tested in an admixed population of Atlantic salmon, originating from crossing of several wild subpopulations. The models included ordinary genomic BLUP models (GBLUP), using genome-wide SNP markers of varying densities (1–220 k), a genomic identity-by-descent model (IBD-GS), using linkage analysis of sparse genome-wide markers, as well as a classical pedigree-based model. Reliabilities of the models were compared through 5-fold cross-validation. The traits studied were salmon lice (Lepeophtheirus salmonis) resistance (LR), measured as (log) density on the skin and fillet color (FC), with respective estimated heritabilities of 0.14 and 0.43. All genomic models outperformed the classical pedigree-based model, for both traits and at all marker densities. However, the relative improvement differed considerably between traits, models and marker densities. For the highly heritable FC, the IBD-GS had similar reliability as GBLUP at high marker densities (>22 k). In contrast, for the lowly heritable LR, IBD-GS was clearly inferior to GBLUP, irrespective of marker density. Hence, GBLUP was robust to marker density for the lowly heritable LR, but sensitive to marker density for the highly heritable FC. We hypothesize that this phenomenon may be explained by historical admixture of different founder populations, expected to reduce short-range lice density (LD) and induce long-range LD. The relative importance of LD/relationship information is expected to decrease/increase with increasing heritability of the trait. Still, using the ordinary GBLUP, the typical long-range LD of an admixed population may be effectively captured by sparse markers, while efficient utilization of relationship information may require denser markers (e.g., 22 k or more). PMID:25484890

  12. Relationships between nesting populations of wading birds and habitat features along the Atlantic Coast

    USGS Publications Warehouse

    Erwin, R.M.; Spendelow, J.A.; Geissler, P.H.; Williams, B.K.; Whitman, William R.; Meredith, William H.

    1987-01-01

    Using previously published atlas data for 122 mixed-species wading bird colonies on islands along the Atlantic coast (Maine to Florida, 1976-77), we examined relationships between population sizes of 11 species of egrets, herons, ibises, and wood storks (Mycteria americana) and nine habitat variables. On nautical charts, we measured four island characteristics (area, length, width, shape), three isolation factors (distances to nearest island, mainland, and a water barrier),, and two variables related to potential feeding habitat within 5 km of the center of the colony (wetland area and land-water interface, i.e., the linear distance between the marsh/upland and all water bodies within the same 5-km radius). One univariable and five multivariable .procedures were used to determine which habitat features were best related to population size .(all species combined). Multicollinearity problems among the variables limited interpretation for most procedures. Both univariable and the multivariable procedures indicated that land-water interface was the most important of the nine variables, but for all models, less than 10% of the total variance was explained (rz is less than 0.10). The size of the colony was not related to the amount of wetland area (within 5-km).per se. Colony data showed better 'structure' when examined on the basis of geographic and disturbance gradients. Population sizes of colonies near man-altered habitats were compared with those surrounded by relatively natural habitats in three geographic zones: north, middle, and south. Significant differences were found in colony size among the three zones (south largest) and between disturbance types. Surprisingly, in all three zones, colonies near man-altered areas were larger on average than those near more natural habitats in this region. A possible reason for this difference is suggested.

  13. Development and application of a density dependent matrix population model for Atlantic killifish (Fundulus heteroclitus)

    EPA Science Inventory

    Ranging along the Atlantic coast from US Florida to the Maritime Provinces of Canada, the Atlantic killifish (Fundulus heteroclitus) is an important and well-studied model organism for understanding the effects of pollutants and other stressors in estuarine and marine ecosystems....

  14. Elemental composition of natural populations of key microbial groups in Atlantic waters.

    PubMed

    Grob, Carolina; Ostrowski, Martin; Holland, Ross J; Heldal, Mikal; Norland, Svein; Erichsen, Egil S; Blindauer, Claudia; Martin, Adrian P; Zubkov, Mikhail V; Scanlan, David J

    2013-11-01

    Intracellular carbon (C), nitrogen (N) and phosphorus (P) content of marine phytoplankton and bacterioplankton can vary according to cell requirements or physiological acclimation to growth under nutrient limited conditions. Although such variation in macronutrient content is well known for cultured organisms, there is a dearth of data from natural populations that reside under a range of environmental conditions. Here, we compare C, N and P content of Synechococcus, Prochlorococcus, low nucleic acid (LNA) content bacterioplankton and small plastidic protists inhabiting surface waters of the North and South subtropical gyres and the Equatorial Region of the Atlantic Ocean. While intracellular C:N ratios ranged between 3.5 and 6, i.e. below the Redfield ratio of 6.6, all the C:P and N:P ratios were up to 10 times higher than the corresponding Redfield ratio of 106 and 16, respectively, reaching and in some cases exceeding maximum values reported in the literature. Similar C:P or N:P ratios in areas with different concentrations of inorganic phosphorus suggests that this is not just a response to the prevailing environmental conditions but an indication of the extremely low P content of these oceanic microbes.

  15. Comparative study of organohalogen contamination between two populations of Eastern Atlantic loggerhead sea turtles (Caretta caretta).

    PubMed

    Camacho, María; Boada, Luis D; Orós, Jorge; López, Pedro; Zumbado, Manuel; Almeida-González, Maira; Luzardo, Octavio P

    2013-12-01

    We evaluated the presence of 37 organohalogen contaminants in plasma samples from 162 juvenile and 197 adult loggerhead turtles (Caretta caretta) from the archipelagos of the Canary Islands and Cape Verde, respectively, and compared the contamination profiles found. We detected five organochlorine pesticides (OCP) and 16 polychlorinated biphenyls (PCBs). The concentrations of the two groups of contaminants were higher in turtles from the Canary Islands (OCPs, 1.04 vs. 0.37 ng/mL; PCBs, 1.92 vs. 0.08 ng/mL). We also observed a different profile of PCB contamination between the two populations. In addition, there was a negative correlation between body size and the total concentration of PCBs in the Canary Islands turtles, but not in turtles from Cape Verde. The present study presents the first data on the organochlorine contaminants (OCs) of live turtles from Canary Islands. In addition, we perform a comparison of the levels and profiles of OCs between these two different groups of loggerhead sea turtles from the Eastern Atlantic.

  16. Human population and socioeconomic modulators of conservation performance in 788 Amazonian and Atlantic Forest reserves.

    PubMed

    de Marques, Ana Alice B; Schneider, Mauricio; Peres, Carlos A

    2016-01-01

    Protected areas form a quintessential component of the global strategy to perpetuate tropical biodiversity within relatively undisturbed wildlands, but they are becoming increasingly isolated by rapid agricultural encroachment. Here we consider a network of 788 forest protected areas (PAs) in the world's largest tropical country to examine the degree to which they remain intact, and their responses to multiple biophysical and socioeconomic variables potentially affecting natural habitat loss under varying contexts of rural development. PAs within the complex Brazilian National System of Conservation Units (SNUC) are broken down into two main classes-strictly protected and sustainable use. Collectively, these account for 22.6% of the forest biomes within Brazil's national territory, primarily within the Amazon and the Atlantic Forest, but are widely variable in size, ecoregional representation, management strategy, and the degree to which they are threatened by human activities both within and outside reserve boundaries. In particular, we examine the variation in habitat conversion rates in both strictly protected and sustainable use reserves as a function of the internal and external human population density, and levels of land-use revenue in adjacent human-dominated landscapes. Our results show that PAs surrounded by heavily settled agro-pastoral landscapes face much greater challenges in retaining their natural vegetation, and that strictly protected areas are considerably less degraded than sustainable use reserves, which can rival levels of habitat degradation within adjacent 10-km buffer areas outside.

  17. Human population and socioeconomic modulators of conservation performance in 788 Amazonian and Atlantic Forest reserves

    PubMed Central

    Schneider, Mauricio; Peres, Carlos A.

    2016-01-01

    Protected areas form a quintessential component of the global strategy to perpetuate tropical biodiversity within relatively undisturbed wildlands, but they are becoming increasingly isolated by rapid agricultural encroachment. Here we consider a network of 788 forest protected areas (PAs) in the world’s largest tropical country to examine the degree to which they remain intact, and their responses to multiple biophysical and socioeconomic variables potentially affecting natural habitat loss under varying contexts of rural development. PAs within the complex Brazilian National System of Conservation Units (SNUC) are broken down into two main classes—strictly protected and sustainable use. Collectively, these account for 22.6% of the forest biomes within Brazil’s national territory, primarily within the Amazon and the Atlantic Forest, but are widely variable in size, ecoregional representation, management strategy, and the degree to which they are threatened by human activities both within and outside reserve boundaries. In particular, we examine the variation in habitat conversion rates in both strictly protected and sustainable use reserves as a function of the internal and external human population density, and levels of land-use revenue in adjacent human-dominated landscapes. Our results show that PAs surrounded by heavily settled agro-pastoral landscapes face much greater challenges in retaining their natural vegetation, and that strictly protected areas are considerably less degraded than sustainable use reserves, which can rival levels of habitat degradation within adjacent 10-km buffer areas outside. PMID:27478703

  18. Created versus natural coastal islands: Atlantic waterbird populations, habitat choices, and management implications

    USGS Publications Warehouse

    Erwin, R.M.; Allen, D.H.; Jenkins, D.

    2003-01-01

    Nesting colonial waterbirds along the Atlantic Coast of the United States face a number of landscape-level threats including human disturbance, mammalian predator expansion, and habitat alteration. There have been changes from 1977 to the mid-1990s in use of nesting habitats and populations of a number of seabird species of concern in the region, including black skimmers Rynchops niger Linnaeaus, common terns Sterna hirundo Linnaeaus, gull-billed terns Sterna nilotica Linnaeaus, least terns Sterna antillarum Lesson, royal terns Sterna maxima Boddaert, and sandwich terns Sterna sandvicensis Cabot. These species form colonies primarily on the following habitat types: large, sandy barrier or shoal islands, natural estuarine or bay islands (mostly marsh), man-made islands of dredged deposition materials (from navigation channels), and the mainland. Significant changes in the use of the dredged material islands have occurred for these species in New Jersey and North Carolina, but not in Virginia. Population declines and changes in bird habitat use appear to be at least partially associated with the conditions and management of the existing dredged material islands, coastal policy changes associated with creating new dredged material islands, and competing demands for sand for beach augmentation by coastal communities. As these and other coastal habitats become less suitable for colonial waterbirds, other manmade sites, such as bridges and buildings have become increasingly more important. In regions with intense recreational demands, coastal wildlife managers need to take a more aggressive role in managing natural and man-made habitats areas and as stakeholders in the decision-making process involving dredged materials and beach sand allocation.

  19. Testing hypotheses of population structuring in the Northeast Atlantic Ocean and Mediterranean Sea using the common cuttlefish Sepia officinalis.

    PubMed

    Pérez-Losada, Marcos; Nolte, Mark J; Crandall, Keith A; Shaw, Paul W

    2007-07-01

    Population structuring in species inhabiting marine environments such as the Northeast Atlantic Ocean (NEA) and Mediterranean Sea (MS) has usually been explained based on past and present physical barriers to gene flow and isolation by distance (IBD). Here, we examined the relative importance of these factors on population structuring of the common cuttlefish Sepia officinalis by using methods of phylogenetic inference and hypothesis testing coupled with coalescent and classical population genetic parameter estimation. Individuals from 10 Atlantic and 15 Mediterranean sites were sequenced for 659 bp of the mitochondrial COI gene (259 sequences). IBD seems to be the main factor driving present and past genetic structuring of Sepia populations across the NEA-MS, both at large and small geographical scales. Such an evolutionary process agrees well with some of the biological features characterizing this cuttlefish species (short migrations, nektobenthic habit, benthic eggs hatching directly to benthic juveniles). Despite the many barriers to migration/gene flow suggested in the NEA-MS region, genetic population fragmentation due to past isolation of water masses (Pleistocene; 0.56 million years ago) and/or present-day oceanographic currents was only detected between the Aegean-Ionian and western Mediterranean Seas. Restricted gene flow associated with the Almería-Oran hydrographic front was also suggested between southern and eastern Spanish populations. Distinct population boundaries could not be clearly determined, except for the Aegean-Ionian stock. Two Atlantic and five Mediterranean samples showed evidence of current decline in genetic diversity, which may indicate over-exploitation of Sepia in both marine regions.

  20. Genetic stock identification of Atlantic salmon (Salmo salar) populations in the southern part of the European range

    PubMed Central

    2010-01-01

    Background Anadromous migratory fish species such as Atlantic salmon (Salmo salar) have significant economic, cultural and ecological importance, but present a complex case for management and conservation due to the range of their migration. Atlantic salmon exist in rivers across the North Atlantic, returning to their river of birth with a high degree of accuracy; however, despite continuing efforts and improvements in in-river conservation, they are in steep decline across their range. Salmon from rivers across Europe migrate along similar routes, where they have, historically, been subject to commercial netting. This mixed stock exploitation has the potential to devastate weak and declining populations where they are exploited indiscriminately. Despite various tagging and marking studies, the effect of marine exploitation and the marine element of the salmon lifecycle in general, remain the "black-box" of salmon management. In a number of Pacific salmonid species and in several regions within the range of the Atlantic salmon, genetic stock identification and mixed stock analysis have been used successfully to quantify exploitation rates and identify the natal origins of fish outside their home waters - to date this has not been attempted for Atlantic salmon in the south of their European range. Results To facilitate mixed stock analysis (MSA) of Atlantic salmon, we have produced a baseline of genetic data for salmon populations originating from the largest rivers from Spain to northern Scotland, a region in which declines have been particularly marked. Using 12 microsatellites, 3,730 individual fish from 57 river catchments have been genotyped. Detailed patterns of population genetic diversity of Atlantic salmon at a sub-continent-wide level have been evaluated, demonstrating the existence of regional genetic signatures. Critically, these appear to be independent of more commonly recognised terrestrial biogeographical and political boundaries, allowing reporting

  1. Population structure of Zostera marina (eelgrass) on the western Atlantic coast is characterized by poor connectivity and inbreeding.

    PubMed

    Campanella, James J; Bologna, Paul A; Smalley, John V; Rosenzweig, Eric B; Smith, Stephanie M

    2010-01-01

    Zostera marina (eelgrass) can be found in the North Atlantic on the coast of Europe and on the east and west coasts of North America. Over the last 30 years, this once robust species has been reduced to sparse patchy populations due to disease and anthropogenic effects. In order to better understand the consequences of this devastation on the population genetics of the species, we have analyzed the population structure of western Atlantic Z. marina, employing microsatellite DNA polymorphisms. Although high fixation index values suggest moderate genetic differentiation among most of the Z. marina sites, population diversity was low. This lack of diversity was supported by a general dearth of observable heterozygotes in these sites; mean observed heterozygosity values (0.14-0.46) were lower than the mean expected heterozygosity values (0.57-0.81). Additionally, the mean F(IS) (coefficient of local inbreeding) values in these sites were positive, again indicating a surfeit of homozygotes. Allelic richness suggests that Chesapeake Bay has the greatest internal genetic diversity of the sites studied. Inbreeding seems prevalent in these American populations, suggesting possible reproductive fitness problems in the future. There is evidence of demographic bottlenecking and particularly low genetic diversity in Long Island. Northern Maine had the highest effective population size, suggesting a possible use in future restoration projects.

  2. Changes in the genetic structure of Atlantic salmon populations over four decades reveal substantial impacts of stocking and potential resiliency

    PubMed Central

    Perrier, Charles; Guyomard, René; Bagliniere, Jean-Luc; Nikolic, Natacha; Evanno, Guillaume

    2013-01-01

    While the stocking of captive-bred fish has been occurring for decades and has had substantial immediate genetic and evolutionary impacts on wild populations, its long-term consequences have only been weakly investigated. Here, we conducted a spatiotemporal analysis of 1428 Atlantic salmon sampled from 1965 to 2006 in 25 populations throughout France to investigate the influence of stocking on the neutral genetic structure in wild Atlantic salmon (Salmo salar) populations. On the basis of the analysis of 11 microsatellite loci, we found that the overall genetic structure among populations dramatically decreased over the period studied. Admixture rates among populations were highly variable, ranging from a nearly undetectable contribution from donor stocks to total replacement of the native gene pool, suggesting extremely variable impacts of stocking. Depending on population, admixture rates either increased, remained stable, or decreased in samples collected between 1998 and 2006 compared to samples from 1965 to 1987, suggesting either rising, long-lasting or short-term impacts of stocking. We discuss the potential mechanisms contributing to this variability, including the reduced fitness of stocked fish and persistence of wild locally adapted individuals. PMID:23919174

  3. Assessing the impact of bycatch on dolphin populations: the case of the common dolphin in the eastern North Atlantic.

    PubMed

    Mannocci, Laura; Dabin, Willy; Augeraud-Véron, Emmanuelle; Dupuy, Jean-François; Barbraud, Christophe; Ridoux, Vincent

    2012-01-01

    Fisheries interactions have been implicated in the decline of many marine vertebrates worldwide. In the eastern North Atlantic, at least 1000 common dolphins (Delphinus delphis) are bycaught each year, particularly in pelagic pair-trawls. We have assessed the resulting impact of bycatch on this population using a demographic modeling approach. We relied on a sample of females stranded along the French Atlantic and western Channel coasts. Strandings represent an extensive source of demographic information to monitor our study population. Necropsy analysis provided an estimate of individual age and reproductive state. Then we estimated effective survivorship (including natural and human-induced mortality), age at first reproduction and pregnancy rates. Reproductive parameters were consistent with literature, but effective survivorship was unexpectedly low. Demographic parameters were then used as inputs in two models. A constant parameter matrix proposed an effective growth rate of -5.5±0.5%, corresponding to the current situation (including bycatch mortality). Subsequently, deterministic projections suggested that the population would be reduced to 20% of its current size in 30 years and would be extinct in 100 years. The demographic invariant model suggested a maximum growth rate of +4.5±0.09%, corresponding to the optimal demographic situation. Then, a risk analysis incorporating Potential Biological Removal (PBR), based on two plausible scenarii for stock structure suggested that bycatch level was unsustainable for the neritic population of the Bay of Biscay under a two-stock scenario. In depth assessment of stock structure and improved observer programs to provide scientifically robust bycatch estimates are needed. Effective conservation measures would be reducing bycatch to less than 50% of the current level in the neritic stock to reach PBR. Our approach provided indicators of the status and trajectory of the common dolphin population in the eastern North

  4. Assessing the Impact of Bycatch on Dolphin Populations: The Case of the Common Dolphin in the Eastern North Atlantic

    PubMed Central

    Mannocci, Laura; Dabin, Willy; Augeraud-Véron, Emmanuelle; Dupuy, Jean-François; Barbraud, Christophe; Ridoux, Vincent

    2012-01-01

    Fisheries interactions have been implicated in the decline of many marine vertebrates worldwide. In the eastern North Atlantic, at least 1000 common dolphins (Delphinus delphis) are bycaught each year, particularly in pelagic pair-trawls. We have assessed the resulting impact of bycatch on this population using a demographic modeling approach. We relied on a sample of females stranded along the French Atlantic and western Channel coasts. Strandings represent an extensive source of demographic information to monitor our study population. Necropsy analysis provided an estimate of individual age and reproductive state. Then we estimated effective survivorship (including natural and human-induced mortality), age at first reproduction and pregnancy rates. Reproductive parameters were consistent with literature, but effective survivorship was unexpectedly low. Demographic parameters were then used as inputs in two models. A constant parameter matrix proposed an effective growth rate of −5.5±0.5%, corresponding to the current situation (including bycatch mortality). Subsequently, deterministic projections suggested that the population would be reduced to 20% of its current size in 30 years and would be extinct in 100 years. The demographic invariant model suggested a maximum growth rate of +4.5±0.09%, corresponding to the optimal demographic situation. Then, a risk analysis incorporating Potential Biological Removal (PBR), based on two plausible scenarii for stock structure suggested that bycatch level was unsustainable for the neritic population of the Bay of Biscay under a two-stock scenario. In depth assessment of stock structure and improved observer programs to provide scientifically robust bycatch estimates are needed. Effective conservation measures would be reducing bycatch to less than 50% of the current level in the neritic stock to reach PBR. Our approach provided indicators of the status and trajectory of the common dolphin population in the eastern North

  5. Combining waterfowl and breeding bird survey data to estimate wood duck breeding population size in the Atlantic Flyway

    USGS Publications Warehouse

    Guthrie Zimmerman,; Sauer, John; Fleming, Kathy; Link, William; Pamela R. Garrettson,

    2015-01-01

    We combined data from the Atlantic Flyway Breeding Waterfowl Survey (AFBWS) and the North American Breeding Bird Survey (BBS) to estimate the number of wood ducks (Aix sponsa) in the United States portion of the Atlantic Flyway from 1993 to 2013. The AFBWS is a plot-based survey that covers most of the northern and central portions of the Flyway; when analyzed with adjustments for survey time of day effects, these data can be used to estimate population size. The BBS provides an index of wood duck abundance along roadside routes. Although factors influencing change in BBS counts over time can be controlled in BBS analysis, BBS indices alone cannot be used to derive population size estimates. We used AFBWS data to scale BBS indices for Bird Conservation Regions (BCR), basing the scaling factors on the ratio of estimated AFBWS population sizes to regional BBS indices for portions of BCRs that were common to both surveys. We summed scaled BBS results for portions of the Flyway not covered by the AFBWS with AFBWS population estimates to estimate a mean yearly total of 1,295,875 (mean 95% CI: 1,013,940–1,727,922) wood ducks. Scaling factors varied among BCRs from 16.7 to 148.0; the mean scaling factor was 68.9 (mean 95% CI: 53.5–90.9). Flyway-wide, population estimates from the combined analysis were consistent with alternative estimates derived from harvest data, and also provide population estimates within states and BCRs. We recommend their use in harvest and habitat management within the Atlantic Flyway.

  6. Recent Demographic History and Present Fine-Scale Structure in the Northwest Atlantic Leatherback (Dermochelys coriacea) Turtle Population

    PubMed Central

    Molfetti, Érica; Torres Vilaça, Sibelle; Georges, Jean-Yves; Plot, Virginie; Delcroix, Eric; Le Scao, Rozen; Lavergne, Anne; Barrioz, Sébastien; dos Santos, Fabrício Rodrigues; de Thoisy, Benoît

    2013-01-01

    The leatherback turtle Dermochelys coriacea is the most widely distributed sea turtle species in the world. It exhibits complex life traits: female homing and migration, migrations of juveniles and males that remain poorly known, and a strong climatic influence on resources, breeding success and sex-ratio. It is consequently challenging to understand population dynamics. Leatherbacks are critically endangered, yet the group from the Northwest Atlantic is currently considered to be under lower risk than other populations while hosting some of the largest rookeries. Here, we investigated the genetic diversity and the demographic history of contrasted rookeries from this group, namely two large nesting populations in French Guiana, and a smaller one in the French West Indies. We used 10 microsatellite loci, of which four are newly isolated, and mitochondrial DNA sequences of the control region and cytochrome b. Both mitochondrial and nuclear markers revealed that the Northwest Atlantic stock of leatherbacks derives from a single ancestral origin, but show current genetic structuration at the scale of nesting sites, with the maintenance of migrants amongst rookeries. Low nuclear genetic diversities are related to founder effects that followed consequent bottlenecks during the late Pleistocene/Holocene. Most probably in response to climatic oscillations, with a possible influence of early human hunting, female effective population sizes collapsed from 2 million to 200. Evidence of founder effects and high numbers of migrants make it possible to reconsider the population dynamics of the species, formerly considered as a metapopulation model: we propose a more relaxed island model, which we expect to be a key element in the currently observed recovering of populations. Although these Northwest Atlantic rookeries should be considered as a single evolutionary unit, we stress that local conservation efforts remain necessary since each nesting site hosts part of the genetic

  7. EDC RESEARCH AT EPA ATLANTIC ECOLOGY DIVISION: DO ENVIRONMENTAL EDCS IMPACT FISH POPULATIONS

    EPA Science Inventory

    The Atlantic Ecology Division, Office of Research and Development, EP A is a marine laboratory situated on Narragansett Bay, Rhode Island. Researchers at AED are investigating the effects endocrine disrupting chemicals (EDCs) in the aquatic environment might have on reproductive ...

  8. Comparison of genetic diversity in the recently founded Connecticut River Atlantic salmon population to that of its primary donor stock, Maine's Penobscot River

    USGS Publications Warehouse

    Spidle, A.P.; King, T.L.; Letcher, B.H.

    2004-01-01

    Anadromous Atlantic salmon returning to the Connecticut River (CR) from 1996 to 1999 were assayed for variability at nine microsatellite DNA loci. Heterozygosity and allele frequencies were compared to the anadromous Atlantic salmon returning to Maine's Penobscot River from 1998 to 2000. The Penobscot River was the primary source of the salmon used to found the previously extirpated population in the Connecticut River. While there were no significant differences in heterozygosity between the source population and the Connecticut River sea-run spawners, microsatellite allele frequencies were significantly different between the populations. Two techniques of estimating effective population size (Ne) suggested a healthy level of genetic variation in the Connecticut River population of anadromous Atlantic salmon. This is significant because the sea-run population is maintained almost entirely through hatchery production. Healthy ratios of Ne to N indicate that hatchery production has not resulted in excessive inbreeding to date. ?? 2003 Elsevier B.V. All rights reserved.

  9. Molecular Assessment of Mating Strategies in a Population of Atlantic Spotted Dolphins

    PubMed Central

    Green, Michelle L.; Herzing, Denise L.; Baldwin, John D.

    2015-01-01

    Similar to other small cetacean species, Atlantic spotted dolphins (Stenella frontalis) have been the object of concentrated behavioral study. Although mating and courtship behaviors occur often and the social structure of the population is well-studied, the genetic mating system of the species is unknown. To assess the genetic mating system, we genotyped females and their progeny at ten microsatellite loci. Genotype analysis provided estimates of the minimum number of male sires necessary to account for the allelic diversity observed among the progeny. Using the estimates of male sires, we determined whether females mated with the same or different males during independent estrus events. Using Gerud2.0, a minimum of two males was necessary to account for the genetic variation seen among progeny arrays of all tested females. ML-Relate assigned the most likely relationship between offspring pairs; half or full sibling. Relationship analysis supported the conservative male estimates of Gerud2.0 but in some cases, half or full sibling relationships between offspring could not be fully resolved. Integrating the results from Gerud2.0, ML-Relate with previous observational and paternity data, we constructed two-, three-, and four-male pedigree models for each genotyped female. Because increased genetic diversity of offspring may explain multi-male mating, we assessed the internal genetic relatedness of each offspring’s genotype to determine whether parent pairs of offspring were closely related. We found varying levels of internal relatedness ranging from unrelated to closely related (range -0.136–0.321). Because there are several hypothesized explanations for multi-male mating, we assessed our data to determine the most plausible explanation for multi-male mating in our study system. Our study indicated females may benefit from mating with multiple males by passing genes for long-term viability to their young. PMID:25692972

  10. Genetic relationships between Atlantic and Pacific populations of the notothenioid fish Eleginops maclovinus: the footprints of Quaternary glaciations in Patagonia

    PubMed Central

    Ceballos, S G; Lessa, E P; Licandeo, R; Fernández, D A

    2016-01-01

    The genetic relationships between the Pacific and the Atlantic populations of marine coastal biota in Southern South America have been analyzed in few studies, most of them relying on a single mitochondrial locus. We analyzed 10 polymorphic microsatellite loci, isolated from a dinucleotide-enriched Eleginops maclovinus genomic library, in a total of 240 individuals (48 from each of 5 sampled sites: 2 Atlantic, 2 Pacific and 1 in Beagle Channel). The results were contrasted against a previous work on the same species with mitochondrial DNA (mtDNA). Observed heterozygosity within localities ranged from 0.85 to 0.88 with the highest overall number of alleles observed at the northernmost locality on the Pacific side (Concepción), but no clear geographic pattern arose from the data. On the other hand, the number of private alleles was negatively correlated with latitude (Spearman's rs test, P=0.017). Among-population variance was low but significant (1.35% P<0.0001, analysis of molecular variance (AMOVA)) and low genetic differentiation between populations was observed (pairwise FST values ranged from 0 to 0.021). A Mantel test revealed a significant correlation between geographic distances and FST (r=0.56, P=0.047). This could be partially accounted by the Atlantic versus Pacific population differentiation detected in three different analyses (STRUCTURE, SAMOVA (Spatial Analysis of MOlecular VAriance) and a population phylogeny). The observed pattern is compatible with a history of separation into two glacial refugia that was better captured by the multilocus microsatellite data than by the mtDNA analysis. PMID:26696136

  11. Basin-scale population genetic structure of the planktonic copepod Calanus finmarchicus in the North Atlantic Ocean

    NASA Astrophysics Data System (ADS)

    Unal, Ebru; Bucklin, Ann

    2010-10-01

    Pelagic marine invertebrates have extensive potential for gene flow, although barriers to gene flow and entrainment in ocean currents may lead to reproductive isolation or drift, and thus to genetic differentiation of populations. The planktonic calanoid copepod Calanus finmarchicus shows significant geographic variation in life history traits across subarctic zones of the N. Atlantic Ocean. Population genetic analysis of C. finmarchicus examined allelic variation at 24 single nucleotide polymorphic (SNP) sites in three nuclear protein-coding genes: citrate synthase, heat-shock protein-70, and AMP-activated protein kinase. Samples were collected during 2005 from 10 areas representing the Northwest (NW), North Central (NC), and Northeast (NE) Atlantic gyres. Hypotheses of two or more distinct populations of C. finmarchicus were examined based on SNP variation within the three genes analyzed both separately and together using AMOVA ( Arlequin Ver. 3.11), CLUMPP (Ver. 1.1), GENALEX (Ver. 6.2), Genepop (Ver. 4.0.10), and Structure (Ver. 2.3). All analyses revealed evidence of small but significant differentiation among areas within gyres (e.g., FSC = 0.0306, p < 0.0001 for two populations; FSC = 0.0344, p < 0.0001 for three populations; pairwise FST values for all 10 areas ranged from 0.0000 to 0.2400), which may reflect ecologically-important, short-term (on the order of months) variation driven by geographic variation in life history traits. Support for underlying large-scale differentiation, which may reflect persistent barriers to gene flow associated with entrainment in ocean gyres, was provided by various analyses, with numbers of distinct C. finmarchicus populations ranging from two to four. Analysis of molecular variation supported two populations, while clustering and population assignment supported two, three, or four populations. The Barents Sea sample was especially distinctive: one test using AMOVA was non-significant among gyres without this sample and

  12. Mixed-stock analysis in green turtles Chelonia mydas: mtDNA decipher current connections among west Atlantic populations.

    PubMed

    Costa Jordao, Juliana; Bondioli, Ana Cristina Vigliar; Almeida-Toledo, Lurdes Foresti de; Bilo, Karin; Berzins, Rachel; Le Maho, Yvon; Chevallier, Damien; de Thoisy, Benoit

    2017-03-01

    The green turtle Chelonia mydas undertakes wide-ranging migrations between feeding and nesting sites, resulting in mixing and isolation of genetic stocks. We used mtDNA control region to characterize the genetic composition, population structure, and natal origins of C. mydas in the West Atlantic Ocean, at one feeding ground (State of Rio de Janeiro, Brazil), and three Caribbean nesting grounds (French Guiana, Guadeloupe, and Suriname). The feeding ground presented considerable frequency of common haplotypes from the South Atlantic, whereas the nesting sites presented a major contribution of the most common haplotype from the Caribbean. MSA revealed multiple origins of individuals at the feeding ground, notably from Ascension Island, Guinea Bissau, and French Guiana. This study enables a better understanding of the dispersion patterns and highlights the importance of connecting both nesting and feeding areas. Effective conservation initiatives need to encompass these ecologically and geographically distinct sites as well as those corridors connecting them.

  13. Prehistoric versus modern Baltic Sea cod fisheries: selectivity across the millennia

    PubMed Central

    Limburg, Karin E; Walther, Yvonne; Hong, Bongghi; Olson, Carina; Storå, Jan

    2008-01-01

    Combining Stone Age and modern data provides unique insights for management, extending beyond contemporary problems and shifting baselines. Using fish chronometric parts, we compared demographic characteristics of exploited cod populations from the Neolithic Period (4500 BP) to the modern highly exploited fishery in the central Baltic Sea. We found that Neolithic cod were larger (mean 56.4 cm, 95% confidence interval (CI)±0.9) than modern fish (weighted mean length in catch =49.5±0.2 cm in 1995, 48.2±0.2 cm in 2003), and older (mean ages =4.7±0.11, 3.1±0.02 and 3.6±0.02 years for Neolithic, 1995, and 2003 fisheries, respectively). Fishery-independent surveys in 1995 and 2003 show that mean sizes in the stock are 16–17 cm smaller than reflected in the fishery, and mean ages approximately 1–1.5 years younger. Modelled von Bertalanffy growth and back-calculated lengths indicated that Neolithic cod grew to smaller asymptotic lengths, but were larger at younger ages, implying rapid early growth. Very small Neolithic cod were absent and large individuals were rare as in modern times. This could be owing to selective harvests, the absence of small and large fish in the area or a combination. Comparing modern and prehistoric times, fishery selection is evident, but apparently not as great as in the North Atlantic proper. PMID:18755680

  14. Metazoan parasite infection in the swordfish, Xiphias gladius, from the Mediterranean Sea and comparison with Atlantic populations: implications for its stock characterization.

    PubMed

    Mattiucci, Simonetta; Garcia, Alexandra; Cipriani, Paolo; Santos, Miguel Neves; Nascetti, Giuseppe; Cimmaruta, Roberta

    2014-01-01

    Thirteen parasite taxa were identified in the Mediterranean swordfish by morphological and genetic/molecular methods. The comparison of the identified parasite taxa and parasitic infection values observed in the Mediterranean swordfish showed statistically significant differences with respect to those reported for its Atlantic populations. A stepwise Linear Discriminant Analysis of the individual fish examined showed a separation among three groups: one including fish from the Mediterranean Sea (CTS, STS, and IOS); one consisting of fish from the Central South (CS), Eastern Tropical (ET), and Equatorial (TEQ) Atlantic; and a third comprising the fish sampled from the North-West Atlantic (NW); the CN Atlantic sample was more similar to the first group rather than to the other Atlantic ones. The nematodes Hysterothylacium petteri and Anisakis pegreffii were the species that contributed most to the characterization of the Mediterranean swordfish samples with respect to these Atlantic ones. Anisakis brevispiculata, A. physeteris, A. paggiae, Anisakis sp. 2, Hysterothylacium incurvum, Hepatoxylon trichiuri, Sphyriocephalus viridis, and their high infection levels were associated with the swordfish from the Central and the Southern Atlantic areas. Finally, H. corrugatum, A. simplex (s.s.), Rhadinorhynchus pristis, and Bolbosoma vasculosum were related to the fish from the North-West (NW) Atlantic area. These results indicate that some parasites, particularly Anisakis spp. larvae identified by genetic markers, could be used as "biological tags" and support the existence of a Mediterranean swordfish stock.

  15. Metazoan parasite infection in the swordfish, Xiphias gladius, from the Mediterranean Sea and comparison with Atlantic populations: implications for its stock characterization

    PubMed Central

    Mattiucci, Simonetta; Garcia, Alexandra; Cipriani, Paolo; Santos, Miguel Neves; Nascetti, Giuseppe; Cimmaruta, Roberta

    2014-01-01

    Thirteen parasite taxa were identified in the Mediterranean swordfish by morphological and genetic/molecular methods. The comparison of the identified parasite taxa and parasitic infection values observed in the Mediterranean swordfish showed statistically significant differences with respect to those reported for its Atlantic populations. A stepwise Linear Discriminant Analysis of the individual fish examined showed a separation among three groups: one including fish from the Mediterranean Sea (CTS, STS, and IOS); one consisting of fish from the Central South (CS), Eastern Tropical (ET), and Equatorial (TEQ) Atlantic; and a third comprising the fish sampled from the North-West Atlantic (NW); the CN Atlantic sample was more similar to the first group rather than to the other Atlantic ones. The nematodes Hysterothylacium petteri and Anisakis pegreffii were the species that contributed most to the characterization of the Mediterranean swordfish samples with respect to these Atlantic ones. Anisakis brevispiculata, A. physeteris, A. paggiae, Anisakis sp. 2, Hysterothylacium incurvum, Hepatoxylon trichiuri, Sphyriocephalus viridis, and their high infection levels were associated with the swordfish from the Central and the Southern Atlantic areas. Finally, H. corrugatum, A. simplex (s.s.), Rhadinorhynchus pristis, and Bolbosoma vasculosum were related to the fish from the North-West (NW) Atlantic area. These results indicate that some parasites, particularly Anisakis spp. larvae identified by genetic markers, could be used as “biological tags” and support the existence of a Mediterranean swordfish stock. PMID:25057787

  16. Vicariance and marine migration in continental island populations of a frog endemic to the Atlantic Coastal forest

    PubMed Central

    Duryea, M C; Zamudio, K R; Brasileiro, C A

    2015-01-01

    The theory of island biogeography is most often studied in the context of oceanic islands where all island inhabitants are descendants from founding events involving migration from mainland source populations. Far fewer studies have considered predictions of island biogeography in the case of continental islands, where island formation typically splits continuous populations and thus vicariance also contributes to the diversity of island populations. We examined one such case on continental islands in southeastern Brazil, to determine how classic island biogeography predictions and past vicariance explain the population genetic diversity of Thoropa taophora, a frog endemic to the Atlantic Coastal Forest. We used nuclear microsatellite markers to examine the genetic diversity of coastal and island populations of this species. We found that island isolation has a role in shaping the genetic diversity of continental island species, with island populations being significantly less diverse than coastal populations. However, area of the island and distance from coast had no significant effect on genetic diversity. We also found no significant differences between migration among coastal populations and migration to and from islands. We discuss how vicariance and the effects of continued migration between coastal and island populations interact to shape evolutionary patterns on continental islands. PMID:25920672

  17. Vicariance and marine migration in continental island populations of a frog endemic to the Atlantic Coastal forest.

    PubMed

    Duryea, M C; Zamudio, K R; Brasileiro, C A

    2015-09-01

    The theory of island biogeography is most often studied in the context of oceanic islands where all island inhabitants are descendants from founding events involving migration from mainland source populations. Far fewer studies have considered predictions of island biogeography in the case of continental islands, where island formation typically splits continuous populations and thus vicariance also contributes to the diversity of island populations. We examined one such case on continental islands in southeastern Brazil, to determine how classic island biogeography predictions and past vicariance explain the population genetic diversity of Thoropa taophora, a frog endemic to the Atlantic Coastal Forest. We used nuclear microsatellite markers to examine the genetic diversity of coastal and island populations of this species. We found that island isolation has a role in shaping the genetic diversity of continental island species, with island populations being significantly less diverse than coastal populations. However, area of the island and distance from coast had no significant effect on genetic diversity. We also found no significant differences between migration among coastal populations and migration to and from islands. We discuss how vicariance and the effects of continued migration between coastal and island populations interact to shape evolutionary patterns on continental islands.

  18. Spatio-temporal population structuring and genetic diversity retention in depleted Atlantic Bluefin tuna of the Mediterranean Sea

    PubMed Central

    Riccioni, Giulia; Landi, Monica; Ferrara, Giorgia; Milano, Ilaria; Cariani, Alessia; Zane, Lorenzo; Sella, Massimo; Barbujani, Guido; Tinti, Fausto

    2010-01-01

    Fishery genetics have greatly changed our understanding of population dynamics and structuring in marine fish. In this study, we show that the Atlantic Bluefin tuna (ABFT, Thunnus thynnus), an oceanic predatory species exhibiting highly migratory behavior, large population size, and high potential for dispersal during early life stages, displays significant genetic differences over space and time, both at the fine and large scales of variation. We compared microsatellite variation of contemporary (n = 256) and historical (n = 99) biological samples of ABFTs of the central-western Mediterranean Sea, the latter dating back to the early 20th century. Measures of genetic differentiation and a general heterozygote deficit suggest that differences exist among population samples, both now and 96–80 years ago. Thus, ABFTs do not represent a single panmictic population in the Mediterranean Sea. Statistics designed to infer changes in population size, both from current and past genetic variation, suggest that some Mediterranean ABFT populations, although still not severely reduced in their genetic potential, might have suffered from demographic declines. The short-term estimates of effective population size are straddled on the minimum threshold (effective population size = 500) indicated to maintain genetic diversity and evolutionary potential across several generations in natural populations. PMID:20080643

  19. Age, growth, and mortality of introduced flathead catfish in Atlantic rivers and a review of other populations

    USGS Publications Warehouse

    Kwak, T.J.; Pine, William E.; Waters, D.S.

    2006-01-01

    Knowledge of individual growth and mortality rates of an introduced fish population is required to determine the success and degree of establishment as well as to predict the fish's impact on native fauna. The age and growth of flathead catfish Pylodictis olivaris have been studied extensively in the species' native and introduced ranges, and estimates have varied widely. We quantified individual growth rates and age structure of three introduced flathead catfish populations in North Carolina's Atlantic slope rivers using sagittal otoliths, determined trends in growth rates over time, compared these estimates among rivers in native and introduced ranges, and determined total mortality rates for each population. Growth was significantly faster in the Northeast Cape Fear River (NECFR) than in the Lumber and Neuse rivers. Fish in the NECFR grew to a total length of 700 mm by age 7, whereas fish in the Neuse and Lumber river populations reached this length by 8 and 10 years, respectively. The growth rates of fish in all three rivers were consistently higher than those of native riverine populations, similar to those of native reservoir populations, and slower than those of other introduced riverine populations. In general, recent cohorts (1998-2001 year-classes) in these three rivers exhibited slower growth among all ages than did cohorts previous to the 1998 year-class. The annual total mortality rate was similar among the three rivers, ranging from 0.16 to 0.20. These mortality estimates are considerably lower than those from the Missouri and Mississippi rivers, suggesting relatively low fishing mortality for these introduced populations. Overall, flathead catfish populations in reservoirs grow faster than those in rivers, the growth rates of introduced populations exceed those of native populations, and eastern United States populations grow faster than those in western states. Such trends constitute critical information for understanding and managing local

  20. Testing the Rio Doce as a riverine barrier in shaping the Atlantic rainforest population divergence in the rodent Akodon cursor

    PubMed Central

    2010-01-01

    Akodon cursor occurs in dense rainforest from northern (8° S) to southern (26° S) states along the Atlantic coast of Brazil. Previous karyological and molecular data revealed two major clades, one including northern (8-15° S) and the other southern (19-26° S) populations. The center of geographic distribution (15-20° S), which included the state of Espírito Santo, was identified as a potential vicariance region. Since river barriers are among the most discussed models in the study of Neotropical diversification, we examined whether the Rio Doce (19° S) plays an important role in shaping the population genetic divergence of A. cursor by including samples from Espírito Santo in the analysis. Our results showed that the northern-southern division region in Atlantic forest was no coincidence with the presence of the Rio Doce by refuting the hypothesis that this river is an effective barrier to gene flow between populations. Instead, we found evidence that isolation by geographical distance shaped the phylogeographical structure in the southern lineage. However, there is uncertainty about effectiveness of the processes involved and further studies based on wider sampling are needed. PMID:21637592

  1. MtDNA haplogroup analysis of black Brazilian and sub-Saharan populations: implications for the Atlantic slave trade.

    PubMed

    Silva, Wilson Araújo; Bortolini, Maria Cátira; Schneider, Maria Paula Cruz; Marrero, Andrea; Elion, Jacques; Krishnamoorthy, Rajagopal; Zago, Marco Antonio

    2006-02-01

    Seventy individuals from two African and four black Brazilian populations were studied for the first hypervariable segment of mtDNA. To delineate a more complete phylogeographic scenario of the African mtDNA haplogroups in Brazil and to provide additional information on the nature of the Atlantic slave trade, we analyzed our data together with previously published data. The results indicate different sources of African slaves for the four major Brazilian regions. In addition, the data revealed patterns that differ from those expected on the basis of historical registers, thus suggesting the role of ethnic sex differences in the slave trade.

  2. Submarine Hydrogeological Data from Cape Cod National Seashore

    USGS Publications Warehouse

    Cross, VeeAnn A.; Bratton, John F.; Crusius, John; Colman, John A.; McCobb, Timothy D.

    2008-01-01

    In order to test hypotheses about ground water flow under and into estuaries and the Atlantic Ocean, geophysical surveys, geophysical probing, submarine ground-water sampling, and sediment coring were conducted by U.S. Geological Survey (USGS) scientists at Cape Cod National Seashore (CCNS) in Massachusetts from 2004 through 2006. This USGS Open-File Report presents the data collected as a result of these field efforts.

  3. Gulf of Mexico Ecological Forecasting - Atlantic Bluefin Tuna Population Assessment and Management using Synthetic Aperture Radar (SAR) Data

    NASA Astrophysics Data System (ADS)

    Laygo, K.; Jones, I.; Huerta, J.; Holt, B.

    2010-12-01

    Atlantic Bluefin Tuna (Thunnus thynnus) is one of the largest vertebrates in the world and is in high demand in sushi markets. It is a highly political species and is managed internationally by the International Commission for the Conservation of Atlantic Tuna. The Gulf of Mexico and the Mediterranean Sea are the only two known spawning sites in the world. However, there is a large variance in estimates of adult Atlantic Tuna spawning. This research focuses on extending Earth science research results to existing decision-making systems, National Oceanic and Atmospheric Administration (NOAA) and the National Marine Fisheries Service (NMFS)for population assessment and management of Atlantic Bluefin Tuna. The research team is a multi-sector and multi-disciplinary team composed of government (NOAA_NMFS), academic (University of South Florida Institute for Marine Remote Sensing) and commercial (Roffer’s Ocean Fishing Forecasting Service, Inc.) institutions. Their goal is to reduce the variance in the estimates of adult Bluefin Tuna spawning stock abundance in the Gulf of Mexico (GOM). Therefore, this paper will be derived from the innovative use of several earth orbiting satellites focusing on the use of synthetic aperture radar (SAR) data to identify Sargassum, which is a floating marine algae that may be relevant to the presence of Bluefin Tuna aggregations. The SAR imagery will be examined in combination with MODIS and MERIS Chlorophyll-a products to detect fine-scale surface current shear, eddy and frontal features, as well as biological slicks due to the presence of Sargassum. In addition, wind records from NOAA buoy data will be studied to analyze wind patterns in the Gulf of Mexico. The fine-resolution, all-weather capabilities of SAR provide a valuable complement to optical/IR sensors, which are often impacted by cloud cover. This study will provide an assessment of whether or not SAR can contribute to decision support efforts relevant to commercial fisheries

  4. Trans-Atlantic exchanges have shaped the population structure of the Lyme disease agent Borrelia burgdorferi sensu stricto

    PubMed Central

    Castillo-Ramírez, S.; Fingerle, V.; Jungnick, S.; Straubinger, R. K.; Krebs, S.; Blum, H.; Meinel, D. M.; Hofmann, H.; Guertler, P.; Sing, A.; Margos, G.

    2016-01-01

    The origin and population structure of Borrelia burgdorferi sensu stricto (s.s.), the agent of Lyme disease, remain obscure. This tick-transmitted bacterial species occurs in both North America and Europe. We sequenced 17 European isolates (representing the most frequently found sequence types in Europe) and compared these with 17 North American strains. We show that trans-Atlantic exchanges have occurred in the evolutionary history of this species and that a European origin of B. burgdorferi s.s. is marginally more likely than a USA origin. The data further suggest that some European human patients may have acquired their infection in North America. We found three distinct genetically differentiated groups: i) the outgroup species Borrelia bissettii, ii) two divergent strains from Europe, and iii) a group composed of strains from both the USA and Europe. Phylogenetic analysis indicated that different genotypes were likely to have been introduced several times into the same area. Our results demonstrate that irrespective of whether B. burgdorferi s.s. originated in Europe or the USA, later trans-Atlantic exchange(s) have occurred and have shaped the population structure of this genospecies. This study clearly shows the utility of next generation sequencing to obtain a better understanding of the phylogeography of this bacterial species. PMID:26955886

  5. Population Genetic Structure of the Magnificent Frigatebird Fregata magnificens (Aves, Suliformes) Breeding Colonies in the Western Atlantic Ocean.

    PubMed

    Nuss, Andressa; Carlos, Caio J; Moreno, Ignacio B; Fagundes, Nelson J R

    2016-01-01

    The Magnificent Frigatebird Fregata magnificens has a pantropical distribution, nesting on islands along the Atlantic and Pacific coasts. In the Caribbean, there is little genetic structure among colonies; however, the genetic structure among the colonies off Brazil and its relationship with those in the Caribbean are unknown. In this study, we used mtDNA and microsatellite markers to infer population structure and evolutionary history in a sample of F. magnificens individuals collected in Brazil, Grand Connétable (French Guyana), and Barbuda. Virtually all Brazilian individuals had the same mtDNA haplotype. There was no haplotype sharing between Brazil and the Caribbean, though Grand Connétable shared haplotypes with both regions. A Bayesian clustering analysis using microsatellite data found two genetic clusters: one associated with Barbuda and the other with the Brazilian populations. Grand Connétable was more similar to Barbuda but had ancestry from both clusters, corroborating its "intermediate" position. The Caribbean and Grand Connétable populations showed higher genetic diversity and effective population size compared to the Brazilian population. Overall, our results are in good agreement with an effect of marine winds in isolating the Brazilian meta-population.

  6. Population Genetic Structure of the Magnificent Frigatebird Fregata magnificens (Aves, Suliformes) Breeding Colonies in the Western Atlantic Ocean

    PubMed Central

    Nuss, Andressa; Carlos, Caio J.; Moreno, Ignacio B.; Fagundes, Nelson J. R.

    2016-01-01

    The Magnificent Frigatebird Fregata magnificens has a pantropical distribution, nesting on islands along the Atlantic and Pacific coasts. In the Caribbean, there is little genetic structure among colonies; however, the genetic structure among the colonies off Brazil and its relationship with those in the Caribbean are unknown. In this study, we used mtDNA and microsatellite markers to infer population structure and evolutionary history in a sample of F. magnificens individuals collected in Brazil, Grand Connétable (French Guyana), and Barbuda. Virtually all Brazilian individuals had the same mtDNA haplotype. There was no haplotype sharing between Brazil and the Caribbean, though Grand Connétable shared haplotypes with both regions. A Bayesian clustering analysis using microsatellite data found two genetic clusters: one associated with Barbuda and the other with the Brazilian populations. Grand Connétable was more similar to Barbuda but had ancestry from both clusters, corroborating its “intermediate” position. The Caribbean and Grand Connétable populations showed higher genetic diversity and effective population size compared to the Brazilian population. Overall, our results are in good agreement with an effect of marine winds in isolating the Brazilian meta-population. PMID:26901878

  7. Population dynamics and secondary production of the cockle Cerastoderma edule: A comparison between Merja Zerga (Moroccan Atlantic Coast) and Arcachon Bay (French Atlantic Coast)

    NASA Astrophysics Data System (ADS)

    Gam, Mériame; de Montaudouin, Xavier; Bazairi, Hocein

    2010-04-01

    temperature. This study showed that population dynamics of cockles at the southern limit of this distribution fell in the range of what was observed elsewhere in the North-Eastern Atlantic coast. Most factors that were involved in population regulation (intraspecific competition, predation and sediment dynamics) were not strictly dependent on latitude. The direct role of temperature (latitude dependent factor) was not obvious. Variation in temperature could explain the recruitment delay between Arcachon and Merja Zerga and the low maximum shell length at Merja Zerga.

  8. A genetic overview of Atlantic coastal populations from Europe and North-West Africa based on a 17 X-STR panel.

    PubMed

    Prieto-Fernández, Endika; Díaz-de Usera, Ana; Baeta, Miriam; Núñez, Carolina; Chbel, Faiza; Nadifi, Sellama; Rouault, Karen; Férec, Claude; Hardiman, Orla; Pinheiro, Fátima; de Pancorbo, Marian M

    2017-03-01

    The forensic use of X-STRs requires the creation of allele and haplotype frequency databases in the populations where they are going to be used. Recently, an updated Spanish allele and haplotype frequency database for the new 17 X-STR panel has been created, being the only database available up to now for this new multiplex. In order to broaden the forensic applicability of the 17 X-STR panel, 513 individuals from four different populations located on the Atlantic Coast of Europe and North-West Africa have been studied, i.e. Brittany (France), Ireland, northern Portugal, and Casablanca (Morocco). Allele and haplotype frequency databases, as well as parameters of forensic interest for these populations are presented. The obtained results showed that the 17 X-STR panel constitutes a highly discriminative tool for forensic identification and kinship testing in the studied populations. Furthermore, we aimed to study if these populations located on the Atlantic coast actually share alike allele and haplotype frequency distributions since they have experienced genetic exchanges throughout history. This would allow creating larger forensic databases that include several genetically similar populations for its use in forensic casework. For this purpose, pairwise FST genetic distances between the analyzed populations and others from the Atlantic Coast previously studied with the 17 X-STR panel or the ten coincident markers included in the decaplex of the GHEP-ISFG were estimated. Our results suggest that certain nearby populations located on the European Atlantic coast could have underwent episodes of genetic interchange as they have not shown statistically significant differentiation between them. However, the population of Casablanca showed significant differentiation with the majority of the European populations. Likewise, the autochthonous Basque Country and Brittany populations have shown distinctive allele frequency distributions between them. Therefore, these

  9. Aspects of the hormonal regulation of appetite in fish with emphasis on goldfish, Atlantic cod and winter flounder: notes on actions and responses to nutritional, environmental and reproductive changes.

    PubMed

    Volkoff, Hélène; Xu, Meiyu; MacDonald, Erin; Hoskins, Leah

    2009-05-01

    In vertebrates including fish, food intake regulation involves intricate networks of hormones produced by both brain and peripheral tissues. Under optimum conditions, nutritional intake is adequate for basal metabolic needs, growth, development, reproduction, and deposition of energy stores. As fish represent a very diverse group, different fish species live in very different environments and are exposed to variations in a wide range of factors, including not only internal factors, such as nutritional/metabolic status and reproductive events but also environmental factors, such as temperature and photoperiod. These physiological responses often include changes in appetite that might occur through modulations of the gene expression and action of feeding-regulating hormones. Despite recent advances, our current understanding of the regulation of feeding in fish is still limited and based primarily on studies involving a few fish species. This review will give a brief overview of our current knowledge of the regulation of feeding by three central (NPY, OX and CART) and two peripheral (ghrelin and GRP) appetite-related factors in a freshwater species, the goldfish (Carassius auratus) and two marine species, cod (Gadus morhua) and winter flounder (Pleuronectes americanus).

  10. Biophysical and Population Genetic Models Predict the Presence of "Phantom" Stepping Stones Connecting Mid-Atlantic Ridge Vent Ecosystems.

    PubMed

    Breusing, Corinna; Biastoch, Arne; Drews, Annika; Metaxas, Anna; Jollivet, Didier; Vrijenhoek, Robert C; Bayer, Till; Melzner, Frank; Sayavedra, Lizbeth; Petersen, Jillian M; Dubilier, Nicole; Schilhabel, Markus B; Rosenstiel, Philip; Reusch, Thorsten B H

    2016-09-12

    Deep-sea hydrothermal vents are patchily distributed ecosystems inhabited by specialized animal populations that are textbook meta-populations. Many vent-associated species have free-swimming, dispersive larvae that can establish connections between remote populations. However, connectivity patterns among hydrothermal vents are still poorly understood because the deep sea is undersampled, the molecular tools used to date are of limited resolution, and larval dispersal is difficult to measure directly. A better knowledge of connectivity is urgently needed to develop sound environmental management plans for deep-sea mining. Here, we investigated larval dispersal and contemporary connectivity of ecologically important vent mussels (Bathymodiolus spp.) from the Mid-Atlantic Ridge by using high-resolution ocean modeling and population genetic methods. Even when assuming a long pelagic larval duration, our physical model of larval drift suggested that arrival at localities more than 150 km from the source site is unlikely and that dispersal between populations requires intermediate habitats ("phantom" stepping stones). Dispersal patterns showed strong spatiotemporal variability, making predictions of population connectivity challenging. The assumption that mussel populations are only connected via additional stepping stones was supported by contemporary migration rates based on neutral genetic markers. Analyses of population structure confirmed the presence of two southern and two hybridizing northern mussel lineages that exhibited a substantial, though incomplete, genetic differentiation. Our study provides insights into how vent animals can disperse between widely separated vent habitats and shows that recolonization of perturbed vent sites will be subject to chance events, unless connectivity is explicitly considered in the selection of conservation areas.

  11. Atlantic wolf-fish Anarhichas lupus population diversity: growth and maturation.

    PubMed

    Gunnarsson, Á

    2014-02-01

    Biological data from 1125 female Atlantic wolf-fish Anarhichas lupus were collected during 2002-2006 at their main spawning and fishing grounds in Iceland. The results demonstrated substantial annual variation in growth and maturity of female A. lupus. The fast growing females mature earlier than the slow growing ones. In addition, females mature at a larger size and greater age in warmer temperatures than colder ones. There was a strong negative relationship between temperature and growth, which may indicate that the sea temperature west of Iceland has risen above the optimum for growth of female A. lupus and thereby reduced the reproductive potential of the species.

  12. Space Radar Image of Cape Cod, Massachusetts

    NASA Technical Reports Server (NTRS)

    1994-01-01

    This spaceborne radar image shows the famous 'hook' of Cape Cod, Massachusetts. The Cape, which juts out into the Atlantic Ocean about 100 kilometers (62 miles) southeast of Boston, actually consists of sandy debris left behind by the great continental ice sheets when they last retreated from southern New England about 20,000 years ago. Today's landscape consists of sandy forests, fields of scrub oak and other bushes and grasses, salt marshes, freshwater ponds, as well as the famous beaches and sand dunes. In this image, thickly forested areas appear green, marshes are dark blue, ponds and sandy areas are black, and developed areas are mostly pink. The dark L-shape in the lower center is the airport runways in Hyannis, the Cape's largest town. The dark X-shape left of the center is Otis Air Force Base. The Cape Cod Canal, above and left of center, connects Buzzards Bay on the left with Cape Cod Bay on the right. The northern tip of the island of Martha's Vineyard is seen in the lower left. The tip of the Cape, in the upper right, includes the community of Provincetown, which appears pink, and the protected National Seashore areas of sand dunes that parallel the Atlantic coast east of Provincetown. Scientists are using radar images like this one to study delicate coastal environments and the effects of human activities on the ecosystem and landscape. This image was acquired by Spaceborne Imaging Radar-C/X-band Synthetic Aperture Radar (SIR-C/X-SAR) onboard the space shuttle Endeavour on April 15, 1994. The image is 81.7 kilometers by 43.1 kilometers (50.7 miles by 26.7 miles) and is centered at 41.8 degrees north latitude, 70.3 degrees west longitude. North is toward the upper right. The colors are assigned to different radar frequencies and polarizations of the radar as follows: red is L-band, horizontally transmitted and received; green is C-band, horizontally transmitted, vertically received; and blue is C-band, horizontally transmitted and received. SIR

  13. Sand fly population dynamics and cutaneous leishmaniasis among soldiers in an Atlantic forest remnant in northeastern Brazil.

    PubMed

    Dantas-Torres, Filipe; Sales, Kamila Gaudêncio da Silva; Miranda, Débora Elienai de Oliveira; da Silva, Fernando José; Figueredo, Luciana Aguiar; de Melo, Fábio Lopes; de Brito, Maria Edileuza Felinto; Andrade, Maria Sandra; Brandão-Filho, Sinval P

    2017-02-27

    Outbreaks of cutaneous leishmaniasis are relatively common among soldiers involved in nocturnal activities in tropical forests. We investigated the population dynamics of sand flies in a military training camp located in a remnant of Atlantic rainforest in northeastern Brazil, where outbreaks of cutaneous leishmaniasis have sporadically been described. From July 2012 to July 2014, light traps were monthly placed in 10 collection sites, being nine sites located near the forest edge and one near a horse stable. Light traps operated from 5:00 pm to 6:00 am, during four consecutive nights. Leishmania infection in sand flies was assessed using a fast real-time PCR assay. Cases of cutaneous leishmaniasis among soldiers were also investigated. In total, 24,606 sand flies belonging to 25 species were identified. Males (n = 12,683) predominated over females (n = 11,923). Sand flies were present during all months, being more numerous in March (n = 1,691) and April 2013 (n = 3,324). Lutzomyia choti (72.9%) was the most abundant species, followed by Lutzomyia longispina (13.8%), Lutzomyia complexa (5.3%), representing together >90% of the sand flies collected. Forty cases of cutaneous leishmaniasis were recorded among soldiers from January 2012 to December 2014. Leishmania isolates were obtained from eight patients and were all characterized as Leishmania braziliensis. Soldiers and anyone overnighting in Atlantic rainforest remnants should adopt preventative measures such as the use of repellents on bare skin or clothes and insecticide-treated tents.

  14. High dispersal potential has maintained long-term population stability in the North Atlantic copepod Calanus finmarchicus

    PubMed Central

    Provan, Jim; Beatty, Gemma E.; Keating, Sianan L.; Maggs, Christine A.; Savidge, Graham

    2008-01-01

    The cool-water copepod Calanus finmarchicus is a key species in North Atlantic marine ecosystems since it represents an important food resource for the developmental stages of several fish of major economic value. Over the last 40 years, however, data from the Continuous Plankton Recorder survey have highlighted a 70 per cent reduction in C. finmarchicus biomass, coupled with a gradual northward shift in the species's distribution, which have both been linked with climate change. To determine the potential for C. finmarchicus to track changes in habitat availability and maintain stable effective population sizes, we have assessed levels of gene flow and dispersal in current populations, as well as using a coalescent approach together with palaeodistribution modelling to elucidate the historical population demography of the species over previous changes in Earth's climate. Our findings indicate high levels of dispersal and a constant effective population size over the period 359 000–566 000 BP and suggest that C. finmarchicus possesses the capacity to track changes in available habitat, a feature that may be of crucial importance to the species's ability to cope with the current period of global climate change. PMID:18812293

  15. Bathymetric and geographic population structure in the pan-Atlantic deep-sea bivalve Deminucula atacellana (Schenck, 1939).

    PubMed

    Zardus, John D; Etter, Ron J; Chase, Michael R; Rex, Michael A; Boyle, Elizabeth E

    2006-03-01

    The deep-sea soft-sediment environment hosts a diverse and highly endemic fauna of uncertain origin. We know little about how this fauna evolved because geographic patterns of genetic variation, the essential information for inferring patterns of population differentiation and speciation are poorly understood. Using formalin-fixed specimens from archival collections, we quantify patterns of genetic variation in the protobranch bivalve Deminucula atacellana, a species widespread throughout the Atlantic Ocean at bathyal and abyssal depths. Samples were taken from 18 localities in the North American, West European and Argentine basins. A hypervariable region of mitochondrial 16S rDNA was amplified by polymerase chain reaction (PCR) and sequenced from 130 individuals revealing 21 haplotypes. Except for several important exceptions, haplotypes are unique to each basin. Overall gene diversity is high (h = 0.73) with pronounced population structure (Phi(ST) = 0.877) and highly significant geographic associations (P < 0.0001). Sequences cluster into four major clades corresponding to differences in geography and depth. Genetic divergence was much greater among populations at different depths within the same basin, than among those at similar depths but separated by thousands of kilometres. Isolation by distance probably explains much of the interbasin variation. Depth-related divergence may reflect historical patterns of colonization or strong environmental selective gradients. Broadly distributed deep-sea organisms can possess highly genetically divergent populations, despite the lack of any morphological divergence.

  16. Population Genomics Reveals Seahorses (Hippocampus erectus) of the Western Mid-Atlantic Coast to Be Residents Rather than Vagrants

    PubMed Central

    Boehm, J. T.; Waldman, John; Robinson, John D.; Hickerson, Michael J.

    2015-01-01

    Understanding population structure and areas of demographic persistence and transients is critical for effective species management. However, direct observational evidence to address the geographic scale and delineation of ephemeral or persistent populations for many marine fishes is limited. The Lined seahorse (Hippocampus erectus) can be commonly found in three western Atlantic zoogeographic provinces, though inhabitants of the temperate northern Virginia Province are often considered tropical vagrants that only arrive during warm seasons from the southern provinces and perish as temperatures decline. Although genetics can locate regions of historical population persistence and isolation, previous evidence of Virginia Province persistence is only provisional due to limited genetic sampling (i.e., mitochondrial DNA and five nuclear loci). To test alternative hypotheses of historical persistence versus the ephemerality of a northern Virginia Province population we used a RADseq generated dataset consisting of 11,708 single nucleotide polymorphisms (SNP) sampled from individuals collected from the eastern Gulf of Mexico to Long Island, NY. Concordant results from genomic analyses all infer three genetically divergent subpopulations, and strongly support Virginia Province inhabitants as a genetically diverged and a historically persistent ancestral gene pool. These results suggest that individuals that emerge in coastal areas during the warm season can be considered “local” and supports offshore migration during the colder months. This research demonstrates how a large number of genes sampled across a geographical range can capture the diversity of coalescent histories (across loci) while inferring population history. Moreover, these results clearly demonstrate the utility of population genomic data to infer peripheral subpopulation persistence in difficult-to-observe species. PMID:25629166

  17. Potential Population Consequences of Active Sonar Disturbance in Atlantic Herring: Estimating the Maximum Risk.

    PubMed

    Sivle, Lise Doksæter; Kvadsheim, Petter Helgevold; Ainslie, Michael

    2016-01-01

    Effects of noise on fish populations may be predicted by the population consequence of acoustic disturbance (PCAD) model. We have predicted the potential risk of population disturbance when the highest sound exposure level (SEL) at which adult herring do not respond to naval sonar (SEL(0)) is exceeded. When the population density is low (feeding), the risk is low even at high sonar source levels and long-duration exercises (>24 h). With densely packed populations (overwintering), a sonar exercise might expose the entire population to levels >SEL(0) within a 24-h exercise period. However, the disturbance will be short and the response threshold used here is highly conservative. It is therefore unlikely that naval sonar will significantly impact the herring population.

  18. Ontogenesis of gonadal aromatase gene expression in atlantic silverside (Menidia menidia) populations with genetic and temperature-dependent sex determination.

    PubMed

    Duffy, Tara A; Picha, Matthew E; Won, Eugene T; Borski, Russell J; McElroy, Anne E; Conover, David O

    2010-08-01

    Cytochrome P450 aromatase (P450arom), an enzyme that converts testosterone to 17beta-estradiol, is an important mediator of sex determination in teleosts with genetic sex determination (GSD) and temperature-dependent sex determination (TSD). We compared the ontogenetic expression of P450arom in two populations of Atlantic silversides, Menidia menidia, which exhibit TSD (South Carolina) or GSD (Nova Scotia, Canada) using quantitative, real-time polymerase chain reaction (qRT-PCR). Embryos and newly hatched larvae were reared at an intermediate sex ratio-producing temperature (21 degrees C), and older larvae and juveniles were reared at temperatures that feminize (15 degrees C) and masculinize (28 degrees C) to assess the temperature response of P450arom during development. Before sex determination, embryos and newly-hatched larvae displayed negligible P450arom expression, indicating minimal upregulation of this gene before sex determination. Gene expression increased in both populations during sex differentiation. Nova Scotia fish with GSD exhibited presumptive male- and female-like expression levels during early sex differentiation that were not influenced by temperature. South Carolina fish displayed low levels of expression at 28 degrees C with significantly heightened expression in some individuals at 15 degrees C, indicating that P450arom is temperature sensitive in the population with TSD. Populations also differed in the timing and maximal levels of P450arom expression, with fish from Nova Scotia exhibiting both the highest and earliest increase in expression in presumptive females. Our results support the hypothesis that P450arom is involved in female sex differentiation in this species, but is only responsive to temperature in M. menidia populations that exhibit TSD.

  19. Genetic isolation by distance among populations of the netted dog whelk Nassarius reticulatus (L.) along the European Atlantic coastline.

    PubMed

    Couceiro, Lucía; Barreiro, Rodolfo; Ruiz, José M; Sotka, Erik E

    2007-01-01

    Estimates of the average distances by which marine larvae disperse are generally poorly described, despite the central role that larval dispersal plays in the demographic connectivity of populations across geographic space. Here, we describe the population genetic structure and average dispersal distance of the netted dog whelk Nassarius reticulatus (L.) (Mollusca, Gastropoda, Prosobranchia), a widespread member of European intertidal communities, using DNA sequence variation in a fragment of the mitochondrial gene cytochrome c oxidase subunit I (COI). An analysis of 156 individuals from 6 locations spread across approximately 1700 km of the European Atlantic coastline revealed weak and nonsignificant population structure (overall Phi(ST) = 0.00013). However, pairwise Phi(ST) values revealed a slight but significant increase in genetic isolation with geographic distance (IBD), suggesting that populations are not panmictic across the sampled geographic range. If we assume that the isolation by distance is maintained by a stable, stepping stone model of gene flow, then the slope of the IBD is consistent with an average larval dispersal distance of approximately 70 km per generation. The spatial scale of larval dispersal in N. reticulatus is consistent with the life cycle of the species (planktotrophic veliger lasting 30-60 days before competent to settle). A mismatch analysis of the COI sequences revealed a signature of an ancient demographic expansion that began 61 500-160,000 years ago, well before the most recent Pleistocene glaciation event. The greatest levels of genetic diversity occur within the middle latitudes of the whelk's geographic range, consistent with the notion that historic populations of N. reticulatus might have expanded northward and southward from the centrally located Bay of Biscay.

  20. Genetic variation at aryl hydrocarbon receptor (AHR) loci in populations of Atlantic killifish (Fundulus heteroclitus) inhabiting polluted and reference habitats

    PubMed Central

    2014-01-01

    Background The non-migratory killifish Fundulus heteroclitus inhabits clean and polluted environments interspersed throughout its range along the Atlantic coast of North America. Several populations of this species have successfully adapted to environments contaminated with toxic aromatic hydrocarbon pollutants such as polychlorinated biphenyls (PCBs). Previous studies suggest that the mechanism of resistance to these and other “dioxin-like compounds” (DLCs) may involve reduced signaling through the aryl hydrocarbon receptor (AHR) pathway. Here we investigated gene diversity and evidence for positive selection at three AHR-related loci (AHR1, AHR2, AHRR) in F. heteroclitus by comparing alleles from seven locations ranging over 600 km along the northeastern US, including extremely polluted and reference estuaries, with a focus on New Bedford Harbor (MA, USA), a PCB Superfund site, and nearby reference sites. Results We identified 98 single nucleotide polymorphisms within three AHR-related loci among all populations, including synonymous and nonsynonymous substitutions. Haplotype distributions were spatially segregated and F-statistics suggested strong population genetic structure at these loci, consistent with previous studies showing strong population genetic structure at other F. heteroclitus loci. Genetic diversity at these three loci was not significantly different in contaminated sites as compared to reference sites. However, for AHR2 the New Bedford Harbor population had significant FST values in comparison to the nearest reference populations. Tests for positive selection revealed ten nonsynonymous polymorphisms in AHR1 and four in AHR2. Four nonsynonymous SNPs in AHR1 and three in AHR2 showed large differences in base frequency between New Bedford Harbor and its reference site. Tests for isolation-by-distance revealed evidence for non-neutral change at the AHR2 locus. Conclusion Together, these data suggest that F. heteroclitus populations in reference

  1. Sand fly population dynamics and cutaneous leishmaniasis among soldiers in an Atlantic forest remnant in northeastern Brazil

    PubMed Central

    Sales, Kamila Gaudêncio da Silva; Miranda, Débora Elienai de Oliveira; da Silva, Fernando José; Figueredo, Luciana Aguiar; de Melo, Fábio Lopes; de Brito, Maria Edileuza Felinto; Andrade, Maria Sandra; Brandão-Filho, Sinval Pinto

    2017-01-01

    Outbreaks of cutaneous leishmaniasis are relatively common among soldiers involved in nocturnal activities in tropical forests. We investigated the population dynamics of sand flies in a military training camp located in a remnant of Atlantic rainforest in northeastern Brazil, where outbreaks of cutaneous leishmaniasis have sporadically been described. From July 2012 to July 2014, light traps were monthly placed in 10 collection sites, being nine sites located near the forest edge and one near a sheep and goat stable. Light traps operated from 5:00 pm to 6:00 am, during four consecutive nights. Leishmania infection in sand flies was assessed using a fast real-time PCR assay. Cases of cutaneous leishmaniasis among soldiers were also investigated. In total, 24,606 sand flies belonging to 25 species were identified. Males (n = 12,683) predominated over females (n = 11,923). Sand flies were present during all months, being more numerous in March (n = 1,691) and April 2013 (n = 3,324). Lutzomyia choti (72.9%) was the most abundant species, followed by Lutzomyia longispina (13.8%), Lutzomyia complexa (5.3%), representing together >90% of the sand flies collected. Forty cases of cutaneous leishmaniasis were recorded among soldiers from January 2012 to December 2014. Leishmania isolates were obtained from eight patients and were all characterized as Leishmania braziliensis. Soldiers and anyone overnighting in Atlantic rainforest remnants should adopt preventative measures such as the use of repellents on bare skin or clothes and insecticide-treated tents. PMID:28241005

  2. Ecological, morphological and genetic divergence of sympatric North Atlantic killer whale populations.

    PubMed

    Foote, Andrew D; Newton, Jason; Piertney, Stuart B; Willerslev, Eske; Gilbert, M Thomas P

    2009-12-01

    Ecological divergence has a central role in speciation and is therefore an important source of biodiversity. Studying the micro-evolutionary processes of ecological diversification at its early stages provides an opportunity for investigating the causative mechanisms and ecological conditions promoting divergence. Here we use morphological traits, nitrogen stable isotope ratios and tooth wear to characterize two disparate types of North Atlantic killer whale. We find a highly specialist type, which reaches up to 8.5 m in length and a generalist type which reaches up to 6.6 m in length. There is a single fixed genetic difference in the mtDNA control region between these types, indicating integrity of groupings and a shallow divergence. Phylogenetic analysis indicates this divergence is independent of similar ecological divergences in the Pacific and Antarctic. Niche-width in the generalist type is more strongly influenced by between-individual variation rather than within-individual variation in the composition of the diet. This first step to divergent specialization on different ecological resources provides a rare example of the ecological conditions at the early stages of adaptive radiation.

  3. Acoustically Induced Streaming Flows near a Model Cod Otolith and their Potential Implications for Fish Hearing

    SciTech Connect

    Kotas, Charlotte W; Rogers, Peter; Yoda, Minami

    2011-01-01

    The ears of fishes are remarkable sensors for the small acoustic disturbances associated with underwater sound. For example, each ear of the Atlantic cod (Gadus morhua) has three dense bony bodies (otoliths) surrounded by fluid and tissue, and detects sounds at frequencies from 30 to 500 Hz. Atlantic cod have also been shown to localize sounds. However, how their ears perform these functions is not fully understood. Steady streaming, or time-independent, flows near a 350% scale model Atlantic cod otolith immersed in a viscous fluid were studied to determine if these fluid flows contain acoustically relevant information that could be detected by the ear s sensory hair cells. The otolith was oscillated sinusoidally at various orientations at frequencies of 8 24 Hz, corresponding to an actual frequency range of 280 830 Hz. Phaselocked particle pathline visualizations of the resulting flows give velocity, vorticity, and rate of strain fields over a single plane of this mainly two-dimensional flow. Although the streaming flows contain acoustically relevant information, the displacements due to these flows are likely too small to explain Atlantic cod hearing abilities near threshold. The results, however, may suggest a possible mechanism for detection of ultrasound in some fish species.

  4. A comparison between egg trancriptomes of cod and salmon reveals species-specific traits in eggs for each species.

    PubMed

    Wargelius, Anna; Furmanek, Tomasz; Montfort, Jérôme; Le Cam, Aurélie; Kleppe, Lene; Juanchich, Amelie; Edvardsen, Rolf B; Taranger, Geir Lasse; Bobe, Julien

    2015-05-01

    Fish in use in aquaculture display large variation in gamete biology. To reach better understanding around this issue, this study aims at identifying if species specific "egg life history traits" can be hidden in the unfertilized egg. This was done by investigating egg transcriptome differences between Atlantic salmon and Atlantic cod. Salmon and cod eggs were selected due to their largely differencing phenotypes. An oligo microarray analysis was performed on ovulated eggs from cod (n = 8) and salmon (n = 7). The arrays were normalized to a similar spectrum for both arrays. Both arrays were re-annotated with SWISS-Prot and KEGG genes to retrieve an official gene symbol and an orthologous KEGG annotation, in salmon and cod arrays this represented 14,009 and 7,437 genes respectively. The probe linked to the highest gene expression for that particular KEGG annotation was used to compare expression between species. Differential expression was calculated for genes that had an annotation with score >300, resulting in a total of 2,457 KEGG annotations (genes) being differently expressed between the species (FD > 2). This analysis revealed that immune, signal transduction and excretory related pathways were overrepresented in salmon compared to cod. The most overrepresented pathways in cod were related to regulation of genetic information processing and metabolism. To conclude this analysis clearly point at some distinct transcriptome repertoires for cod and salmon and that these differences may explain some of the species-specific biological features for salmon and cod eggs.

  5. Estimating population abundance and mapping distribution of wintering sea ducks in coastal waters of the mid-Atlantic

    USGS Publications Warehouse

    Koneff, M.D.; Royle, J. Andrew; Forsell, D.J.; Wortham, J.S.; Boomer, G.S.; Perry, M.C.

    2005-01-01

    Survey design for wintering scoters (Melanitta sp.) and other sea ducks that occur in offshore waters is challenging because these species have large ranges, are subject to distributional shifts among years and within a season, and can occur in aggregations. Interest in winter sea duck population abundance surveys has grown in recent years. This interest stems from concern over the population status of some sea ducks, limitations of extant breeding waterfowl survey programs in North America and logistical challenges and costs of conducting surveys in northern breeding regions, high winter area philopatry in some species and potential conservation implications, and increasing concern over offshore development and other threats to sea duck wintering habitats. The efficiency and practicality of statistically-rigorous monitoring strategies for mobile, aggregated wintering sea duck populations have not been sufficiently investigated. This study evaluated a 2-phase adaptive stratified strip transect sampling plan to estimate wintering population size of scoters, long-tailed ducks (Clangua hyemalis), and other sea ducks and provide information on distribution. The sampling plan results in an optimal allocation of a fixed sampling effort among offshore strata in the U.S. mid-Atlantic coast region. Phase I transect selection probabilities were based on historic distribution and abundance data, while Phase 2 selection probabilities were based on observations made during Phase 1 flights. Distance sampling methods were used to estimate detection rates. Environmental variables thought to affect detection rates were recorded during the survey and post-stratification and covariate modeling were investigated to reduce the effect of heterogeneity on detection estimation. We assessed cost-precision tradeoffs under a number of fixed-cost sampling scenarios using Monte Carlo simulation. We discuss advantages and limitations of this sampling design for estimating wintering sea duck

  6. Population Structure of the Rockpool Blenny Entomacrodus vomerinus Shows Source-Sink Dynamics among Ecoregions in the Tropical Southwestern Atlantic

    PubMed Central

    Lima, Sergio M. Q.; Mendes, Liana F.; Torres, Rodrigo A.; Pereira, Ricardo J.

    2016-01-01

    The Tropical Southwestern Atlantic is characterized by prominent ecosystems with large-scale oceanographic complexity. Yet, the evolutionary processes underlying genetic differentiation and connectivity in this region remain largely unknown. Entomacrodus vomerinus (Valenciennes, 1836) is a demersal fish with planktonic larvae endemic to this marine province, inhabiting shallow tidal pools in continental and oceanic reef environments. We evaluated the population structure, genetic diversity and gene flow of E. vomerinus using mitochondrial data (CYTB and COI) and nuclear (rhodopsin, RHO) DNA sequences. We sampled a total of 85 individuals, comprising 46 from three oceanic archipelagos with varying distance from the coast (São Pedro and São Paulo—SS, Fernando de Noronha—FE and Rocas Atoll—RA) and 39 from two localities in northeastern Brazilian coast (Rio Grande do Norte—RN and Bahia—BA). Multilocus analysis revealed the presence of three Evolutionarily Significant Units—ESUs (SS, FE+RA, and RN+BA), which are in accordance with distinct marine ecoregions. Coalescent analyses showed that the central ESU has a larger effective population size than the other two, suggesting strong asymmetries in the genetic diversity across the species range. Moreover, they showed that gene flow is highly asymmetric, suggesting a source-sink dynamics from the central ESU into the remaining ones, in agreement with oceanic currents. Together, these results provide insights in the evolutionary mechanisms facilitating diversification in this marine province. PMID:27309356

  7. Population dynamics of Gyrodactylus salaris (Monogenea) infecting Atlantic salmon, Salmo salar, parr in the river Batnfjordselva, Norway.

    PubMed

    Appleby, C; Mo, T A

    1997-02-01

    Population dynamics of Gyrodactylus salaris on 5 year classes of Atlantic salmon, Salmo salar, in the river Batnfjordselva in Norway was studied from April 1991 to June 1994. Prevalence was 100% on all year classes throughout the study period, except for a marked decline in winter and spring of 1992. Median abundance generally increased during summer and peaked in September/October at levels between 400 and 1,300 parasites. The lowest number of parasites was observed during winter and spring. The seasonal dynamics in the first year of the study differed markedly from the remainder of the study, abundance peaked already in June/July on 1+ and 2+ fish the first year, but decreased throughout summer and peaked again in autumn. A collapse in the G. salaris population was observed in the winter of 1991/1992, with prevalence being 0-40% on all year classes. Parr aged 2 yr harbored significantly fewer parasites than younger parr during the winter months. Parasite intensity on precocious males was significantly higher than on sexually immature males and females. Gyrodactylus salaris was found on the fins (76%), gill filaments (15%), and head/body (9%). During the last 2 yr of the study the gills were increasingly infected, with 40% of the parasites found on gills in some samples.

  8. Population Structure of the Rockpool Blenny Entomacrodus vomerinus Shows Source-Sink Dynamics among Ecoregions in the Tropical Southwestern Atlantic.

    PubMed

    Neves, Jessika M M; Lima, Sergio M Q; Mendes, Liana F; Torres, Rodrigo A; Pereira, Ricardo J; Mott, Tamí

    2016-01-01

    The Tropical Southwestern Atlantic is characterized by prominent ecosystems with large-scale oceanographic complexity. Yet, the evolutionary processes underlying genetic differentiation and connectivity in this region remain largely unknown. Entomacrodus vomerinus (Valenciennes, 1836) is a demersal fish with planktonic larvae endemic to this marine province, inhabiting shallow tidal pools in continental and oceanic reef environments. We evaluated the population structure, genetic diversity and gene flow of E. vomerinus using mitochondrial data (CYTB and COI) and nuclear (rhodopsin, RHO) DNA sequences. We sampled a total of 85 individuals, comprising 46 from three oceanic archipelagos with varying distance from the coast (São Pedro and São Paulo-SS, Fernando de Noronha-FE and Rocas Atoll-RA) and 39 from two localities in northeastern Brazilian coast (Rio Grande do Norte-RN and Bahia-BA). Multilocus analysis revealed the presence of three Evolutionarily Significant Units-ESUs (SS, FE+RA, and RN+BA), which are in accordance with distinct marine ecoregions. Coalescent analyses showed that the central ESU has a larger effective population size than the other two, suggesting strong asymmetries in the genetic diversity across the species range. Moreover, they showed that gene flow is highly asymmetric, suggesting a source-sink dynamics from the central ESU into the remaining ones, in agreement with oceanic currents. Together, these results provide insights in the evolutionary mechanisms facilitating diversification in this marine province.

  9. Bamboo thickets alter the demographic structure of Euterpe edulis population: A keystone, threatened palm species of the Atlantic forest

    NASA Astrophysics Data System (ADS)

    Rother, Débora Cristina; Rodrigues, Ricardo Ribeiro; Pizo, Marco Aurélio

    2016-01-01

    The rapid spread of bamboos can strongly affect forest structure by interfering plant regeneration and reducing local biodiversity. Considering that bamboos exert a negative influence on the plant community, our main goal was to investigate how this influence manifests at the population level. We compared the demographic structure of the threatened palm Euterpe edulis between bamboo and non-bamboo dominated patches within the Atlantic forest. In the study site, the native bamboo Guadua tagoara has created a marked patchiness and heterogeneity in the vegetation. Plots were set up randomly in bamboo and non-bamboo patches and the heights of all E. edulis individuals were measured. Data from canopy openness and litter depth were collected for both patches. Greater number of E. edulis was recorded in bamboo patches. However, frequency distribution of the height classes differed between patches revealing a predominance of seedling and sapling I classes in bamboo patches, in comparison to a more evenly distribution of height classes in non-bamboo patches. The canopy in bamboo patches was more open and the litter depth was thicker. Our analyses evidenced G. tagoara is functioning as a demographic bottleneck of natural population of E. edulis by arresting its later stages of regeneration and in high densities that bamboos may limit recruitment of this palm species.

  10. [The demography of an Atlantic island population. Grand Canary, 1680-1850].

    PubMed

    Macias Hernandez, A M

    1991-01-01

    The author applies inverse projection methods to data from baptism and death records for the parishes of the island of Grand Canary from 1680 up to the cholera epidemic of 1851. The relationships among the economy, migration, and other demographic parameters for this isolated population are assessed. He concludes that the island population was not greatly affected by emigration to the Americas until the late eighteenth century, and that a high birth rate combined with low levels of mortality wreaked havoc with the local economy.

  11. What can otolith shape analysis tell us about population structure of the European sardine, Sardina pilchardus, from Atlantic and Mediterranean waters?

    NASA Astrophysics Data System (ADS)

    Jemaa, Sharif; Bacha, Mahmoud; Khalaf, Gaby; Dessailly, David; Rabhi, Khalef; Amara, Rachid

    2015-02-01

    The European sardine, Sardina pilchardus, exhibits a complex population structure, which has produced conflicting results in previous genetic studies. Despite its importance in the fisheries industry, stock delineation for management and conservation purposes is still a matter of debate throughout the distribution range of the species. This study examines whether otolith shapes are more efficient than genetic markers to detect population structure in pelagic species with large population sizes. Sardines were analyzed from 15 sampling localities in the Northeast Atlantic and Mediterranean Sea covering almost the whole distribution range of the species. A combination of otolith shape indices and elliptic Fourier descriptors was investigated by multivariate statistical procedures. Within the studied area, three distinct groups were identified with an overall correct classification of 77%. Group A: northern Mediterranean Sea and Gulf of Gabès; group B: Atlantic Morocco-south Alboran-Algero-provençal coasts; and group C: European Atlantic coast. The Almeria-Oran front and the Gibraltar strait are not an efficient barrier for sardine population separation as there seems to be exchanges between populations of the south-western Mediterranean Sea and those of the Moroccan Atlantic Ocean coast or Gulf of Cadiz. The results are discussed in relation to environmental conditions, oceanographic features, and physical barriers to dispersal in the study area, and compared with those obtained by previous genetic, morphometric, and meristic data. For pelagic species with high gene flow, present results highlighted the need to take into account the identification of phenotypic stocks to ensure sustainable fishery benefits and efficient conservation as they may have unique demographic properties and responses to exploitation.

  12. Population Genetic Structure of the Bonnethead Shark, Sphyrna tiburo, from the Western North Atlantic Ocean Based on mtDNA Sequences.

    PubMed

    Escatel-Luna, Elena; Adams, Douglas H; Uribe-Alcocer, Manuel; Islas-Villanueva, Valentina; Díaz-Jaimes, Píndaro

    2015-01-01

    The population genetic structure of 251 bonnethead sharks, Sphyrna tiburo, from estuarine and nearshore ocean waters of the Western North Atlantic Ocean (WNA), was assessed using sequences of the mitochondrial DNA-control region. Highly significant genetic differences were observed among bonnetheads from 3 WNA regions; Atlantic coast of Florida, Gulf coast of Florida, and southwestern Gulf of Mexico (analysis of molecular variance, ΦCT = 0.137; P=0.001). Within the Gulf coast of Florida region, small but significant genetic differences were observed between bonnetheads from neighboring estuaries. These overall patterns were consistent with known latitudinal and inshore-offshore movements that occur seasonally for this species within US waters, and with the residency patterns and high site fidelity to feeding/nursery grounds reported in estuaries along the Atlantic coast of Florida and South Carolina. Historical demography also supported the occurrence of past population expansions occurring during Pleistocene glacial-interglacial cycles that caused drastic reductions in bonnethead population size, as a consequence of the eustatic processes that affected the Florida peninsula. This is the first population genetics study for bonnetheads to report genetic divergence among core abundance areas in US and Mexican waters of the WNA. These results, coupled with recent advances in knowledge regarding regional differences in life-history parameters of this species, are critical for defining management units to guide future management strategies for bonnetheads within US waters and across international boundaries into Mexico.

  13. Population structure of Atlantic mackerel inferred from RAD-seq-derived SNP markers: effects of sequence clustering parameters and hierarchical SNP selection.

    PubMed

    Rodríguez-Ezpeleta, Naiara; Bradbury, Ian R; Mendibil, Iñaki; Álvarez, Paula; Cotano, Unai; Irigoien, Xabier

    2016-07-01

    Restriction-site-associated DNA sequencing (RAD-seq) and related methods are revolutionizing the field of population genomics in nonmodel organisms as they allow generating an unprecedented number of single nucleotide polymorphisms (SNPs) even when no genomic information is available. Yet, RAD-seq data analyses rely on assumptions on nature and number of nucleotide variants present in a single locus, the choice of which may lead to an under- or overestimated number of SNPs and/or to incorrectly called genotypes. Using the Atlantic mackerel (Scomber scombrus L.) and a close relative, the Atlantic chub mackerel (Scomber colias), as case study, here we explore the sensitivity of population structure inferences to two crucial aspects in RAD-seq data analysis: the maximum number of mismatches allowed to merge reads into a locus and the relatedness of the individuals used for genotype calling and SNP selection. Our study resolves the population structure of the Atlantic mackerel, but, most importantly, provides insights into the effects of alternative RAD-seq data analysis strategies on population structure inferences that are directly applicable to other species.

  14. Performance of promising clones from Atlantic x Superior and Superior x Snowden populations evaluated in several locations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Atlantic is the standard variety for chipping from the field or very short-term cold storage. It has traits desired by the chip industry such as uniformity, high specific gravity and high yield. However, Atlantic tubers are susceptible to common scab and internal defects such as internal brown spot,...

  15. Seasonal Variation in Population Abundance and Chytrid Infection in Stream-Dwelling Frogs of the Brazilian Atlantic Forest

    PubMed Central

    Ruggeri, Joice; Longo, Ana V.; Gaiarsa, Marília P.; Alencar, Laura R. V.; Lambertini, Carolina; Leite, Domingos S.; Carvalho-e-Silva, Sergio P.; Zamudio, Kelly R.; Toledo, Luís Felipe; Martins, Marcio

    2015-01-01

    Enigmatic amphibian declines were first reported in southern and southeastern Brazil in the late 1980s and included several species of stream-dwelling anurans (families Hylodidae and Cycloramphidae). At that time, we were unaware of the amphibian-killing fungus Batrachochytrium dendrobatidis (Bd); therefore, pollution, habitat loss, fragmentation and unusual climatic events were hypothesized as primary causes of these declines. We now know that multiple lineages of Bd have infected amphibians of the Brazilian Atlantic forest for over a century, yet declines have not been associated specifically with Bd outbreaks. Because stream-dwelling anurans occupy an environmental hotspot ideal for disease transmission, we investigated temporal variation in population and infection dynamics of three stream-adapted species (Hylodes asper, H. phyllodes, and Cycloramphus boraceiensis) on the northern coast of São Paulo state, Brazil. We surveyed standardized transects along streams for four years, and show that fluctuations in the number of frogs correlate with specific climatic variables that also increase the likelihood of Bd infections. In addition, we found that Bd infection probability in C. boraceiensis, a nocturnal species, was significantly higher than in Hylodes spp., which are diurnal, suggesting that the nocturnal activity may either facilitate Bd zoospore transmission or increase susceptibility of hosts. Our findings indicate that, despite long-term persistence of Bd in Brazil, some hosts persist with seasonally variable infections, and thus future persistence in the face of climate change will depend on the relative effect of those changes on frog recruitment and pathogen proliferation. PMID:26161777

  16. Microsatellite and mitochondrial DNA analyses of Atlantic bluefin tuna (Thunnus thynnus thynnus) population structure in the Mediterranean Sea.

    PubMed

    Carlsson, Jens; McDowell, Jan R; Díaz-Jaimes, Píndaro; Carlsson, Jeanette E L; Boles, Sandra B; Gold, John R; Graves, John E

    2004-11-01

    Genetic variation was surveyed at nine microsatellite loci and the mitochondrial control region (868 bp) to test for the presence of genetic stock structure in young-of-the-year Atlantic bluefin tuna (Thunnus thynnus thynnus) from the Mediterranean Sea. Bluefin tuna were sampled over a period of 5 years from the Balearic and Tyrrhenian seas in the western basin of the Mediterranean Sea, and from the southern Ionian Sea in the eastern basin of the Mediterranean Sea. Analyses of multilocus microsatellite genotypes and mitochondrial control region sequences revealed no significant heterogeneity among collections taken from the same location in different years; however, significant spatial genetic heterogeneity was observed across all samples for both microsatellite markers and mitochondrial control region sequences (FST=0.0023, P=0.038 and PhiST=0.0233, P=0.000, respectively). Significant genetic differentiation between the Tyrrhenian and Ionian collections was found for both microsatellite and mitochondrial markers (FST=0.0087, P=0.015 and PhiST=0.0367, P=0.030, respectively). These results suggest the possibility of a genetically discrete population in the eastern basin of the Mediterranean Sea.

  17. Acquired resistance to Ah receptor agonists in a population of Atlantic killifish (Fundulus heteroclitus) inhabiting a marine superfund site: in vivo and in vitro studies on the inducibility of xenobiotic metabolizing enzymes.

    PubMed

    Bello, S M; Franks, D G; Stegeman, J J; Hahn, M E

    2001-03-01

    New Bedford Harbor (NBH), MA, is a federal Superfund site that is heavily contaminated with polychlorinated biphenyls (PCBs) and other halogenated aromatic hydrocarbons (HAHs), including some potent aryl hydrocarbon receptor (AhR) agonists. A population of Atlantic killifish (Fundulus heteroclitus) continues to inhabit this site, despite accumulating extraordinarily high concentrations of PCBs (272 microg/g dry weight). To determine if NBH killifish have developed resistance to HAHs that act through the AhR, we examined the inducibility of cytochrome P4501A1 (CYP1A1), UDP glucuronosyl transferase (UGT), and glutathione S-transferase (GST) in fish from NBH and a reference site, Scorton Creek (SC, Cape Cod, MA; PCB concentrations 0.177 microg/g dry weight). 2,3,7,8-Tetrachlorodibenzofuran (TCDF) induced CYP1A1 mRNA, protein, and activity in SC fish in all tissues examined (liver, heart, gut, gill, kidney, spleen, and gonad). In contrast, NBH fish expressed low levels of CYP1A1 and showed no induction of CYP1A1 mRNA, protein, or activity by TCDF, or induction that was lower in magnitude or required higher doses of inducer. p-Nitrophenol UGT activity was not induced by TCDF in either population, while GST activity with 1-chloro-2,4-dinitrobenzene as substrate was induced only in NBH fish in one experiment. Inducibility of CYP1A1 by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or beta-naphthoflavone (BNF) was measured in primary hepatocyte cultures prepared from SC and NBH fish. TCDD induced CYP1A1 activity (ethoxyresorufin O-deethylase) to the same degree in hepatocytes from both populations, demonstrating the functionality of the AhR signaling pathway in NBH fish. However, hepatocytes from NBH fish were 14-fold less sensitive to TCDD than were those from SC fish. The nonhalogenated AhR agonist BNF also induced CYP1A1 in cells from both populations, although with only a 3-fold difference in sensitivity (NBH < SC). These results indicate that chronic exposure to high

  18. Short Term Effects of Particle Exposure on Hospital Admissions in the Mid-Atlantic States: A Population Estimate

    PubMed Central

    Kloog, Itai; Nordio, Francesco; Zanobetti, Antonella; Coull, Brent A.; Koutrakis, Petros; Schwartz, Joel D.

    2014-01-01

    Background Many studies report significant associations between PM2.5 (particulate matter <2.5 micrometers) and hospital admissions. These studies mostly rely on a limited number of monitors which introduces exposure error, and excludes rural and suburban populations from locations where monitors are not available, reducing generalizability and potentially creating selection bias. Methods Using prediction models developed by our group, daily PM2.5 exposure was estimated across the Mid-Atlantic (Washington D.C., and the states of Delaware, Maryland, New Jersey, Pennsylvania, Virginia, New York and West Virginia). We then investigated the short-term effects of PM2.5 exposures on emergency hospital admissions of the elderly in the Mid-Atlantic region.We performed case-crossover analysis for each admission type, matching on day of the week, month and year and defined the hazard period as lag01 (a moving average of day of admission exposure and previous day exposure). Results We observed associations between short-term exposure to PM2.5 and hospitalization for all outcomes examined. For example, for every 10-µg/m3 increase in short-term PM 2.5 there was a 2.2% increase in respiratory diseases admissions (95% CI = 1.9 to 2.6), and a 0.78% increase in cardiovascular disease (CVD) admission rate (95% CI = 0.5 to 1.0). We found differences in risk for CVD admissions between people living in rural and urban areas. For every10-µg/m3 increase in PM 2.5 exposure in the ‘rural’ group there was a 1.0% increase (95% CI = 0.6 to 1.5), while for the ‘urban’ group the increase was 0.7% (95% CI = 0.4 to 1.0). Conclusions Our findings showed that PM2.5 exposure was associated with hospital admissions for all respiratory, cardio vascular disease, stroke, ischemic heart disease and chronic obstructive pulmonary disease admissions. In addition, we demonstrate that our AOD (Aerosol Optical Depth) based exposure models can be successfully applied to epidemiological

  19. Health assessment of wild lowland tapir (Tapirus terrestris) populations in the Atlantic Forest and Pantanal biomes, Brazil (1996-2012).

    PubMed

    Medici, Emília Patrícia; Mangini, Paulo Rogerio; Fernandes-Santos, Renata Carolina

    2014-10-01

    Abstract The lowland tapir (Tapirus terrestris) is found in South America and is listed as Vulnerable to Extinction by the International Union for Conservation of Nature, Red List of Threatened Species. Health issues, particularly infectious diseases, are potential threats for the species. Health information from 65 wild tapirs from two Brazilian biomes, Atlantic Forest (AF) and Pantanal (PA), were collected during a long-term study (1996-2012). The study included physic, hematologic and biochemical evaluations, microbiologic cultures, urinalysis, and serologic analyses for antibodies against 13 infectious agents (viral and bacterial). The AF and PA tapirs were significantly different for several hematologic and biochemical parameters. Ten bacteria taxa were identified in the AF and 26 in the PA. Antibodies against five viruses were detected: Bluetongue virus, eastern equine encephalitis virus, western equine encephalitis virus, infectious bovine rhinotracheitis virus, and porcine parvovirus. A high prevalence of exposure to Leptospira interrogans (10 serovars: Autumnalis, Bratislava, Canicola, Copenhageni, Grippotyphosa, Hardjo, Hebdomadis, Icterohaemorrhagiae, Pomona, and Pyrogenes) was detected in both the AF and PA sites. A greater diversity of serovars and higher antibody titers were found in the PA. Statistically significant differences between sites were found for L. interrogans, equine encephalitis virus, and porcine parvovirus. Based on physical evaluations, both AF and PA populations were healthy. The differences in the overall health profile of the AF and PA tapir populations appear to be associated with environmental factors and infectious diseases ecology. The extensive datasets on hematology, biochemistry, urinalysis, and microbiology results from this paper can be used as reference values for wild tapirs.

  20. 76 FR 18778 - Cape Cod National Seashore; South Wellfleet, MA; Cape Cod National Seashore Advisory Commission

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    ... National Park Service Cape Cod National Seashore; South Wellfleet, MA; Cape Cod National Seashore Advisory..., 86 Stat. 770, 5 U.S.C. App 1, Section 10) of a meeting of the Cape Cod National Seashore Advisory Commission. DATES: The meeting of the Cape Cod National Seashore Advisory Commission will be held on May...

  1. 77 FR 9699 - Cape Cod National Seashore Advisory Commission; Cape Cod National Seashore, South Wellfleet, MA

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    ... National Park Service Cape Cod National Seashore Advisory Commission; Cape Cod National Seashore, South... Stat. 770, 5 U.S.C. App 1, Section 10) of a meeting of the Cape Cod National Seashore Advisory Commission. DATES: The meeting of the Cape Cod National Seashore Advisory Commission will be held on March...

  2. 76 FR 8768 - Cape Cod National Seashore, South Wellfleet, MA; Cape Cod National Seashore Advisory Commission

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    ... National Park Service Cape Cod National Seashore, South Wellfleet, MA; Cape Cod National Seashore Advisory... Stat. 770, 5 U.S.C. App 1, Section 10) of a meeting of the Cape Cod National Seashore Advisory Commission. DATES: The meeting of the Cape Cod National Seashore Advisory Commission will be held on March...

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    ... National Park Service Cape Cod National Seashore; South Wellfleet, MA; Cape Cod National Seashore Advisory.... 770, 5 U.S.C. App 1, Section 10) of a meeting of the Cape Cod National Seashore Advisory Commission. DATES: The meeting of the Cape Cod National Seashore Advisory Commission will be held on September...

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    ... National Park Service Cape Cod National Seashore, South Wellfleet, MA; Cape Cod National Seashore Advisory... Stat. 770, 5 U.S.C. App 1, Section 10) of a meeting of the Cape Cod National Seashore Advisory Commission. DATES: The meeting of the Cape Cod National Seashore Advisory Commission will be held on...

  5. 76 FR 81965 - Cape Cod National Seashore Advisory Commission; Cape Cod National Seashore, South Wellfleet, MA

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    ... National Park Service Cape Cod National Seashore Advisory Commission; Cape Cod National Seashore, South... Stat. 770, 5 U.S.C. App 1, Section 10) of a meeting of the Cape Cod National Seashore Advisory Commission. DATES: The meeting of the Cape Cod National Seashore Advisory Commission will be held on...

  6. 75 FR 34479 - Cape Cod National Seashore; South Wellfleet, MA; Cape Cod National Seashore Advisory Commission

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    ... National Park Service Cape Cod National Seashore; South Wellfleet, MA; Cape Cod National Seashore Advisory... Stat. 770, 5 U.S.C. App 1, Section 10) of a meeting of the Cape Cod National Seashore Advisory Commission. DATES: The meeting of the Cape Cod National Seashore Advisory Commission will be held on July...

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    ... Cape Cod National Seashore, South Wellfleet, MA; Cape Cod National Seashore Advisory Commission AGENCY.... App 1, Section 10) of a meeting of the Cape Cod National Seashore Advisory Commission. DATES: The meeting of the Cape Cod National Seashore Advisory Commission will be held on March 22, 2010 at 1...

  8. 75 FR 77900 - Cape Cod National Seashore, South Wellfleet, MA; Cape Cod National Seashore Advisory Commission

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    ... National Park Service Cape Cod National Seashore, South Wellfleet, MA; Cape Cod National Seashore Advisory... Stat. 770, 5 U.S.C. App 1, Section 10) of a meeting of the Cape Cod National Seashore Advisory Commission. DATES: The meeting of the Cape Cod National Seashore Advisory Commission will be held on...

  9. 75 FR 48990 - Cape Cod National Seashore; South Wellfleet, MA; Cape Cod National Seashore Advisory Commission

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  10. 75 FR 63854 - Cape Cod National Seashore, South Wellfleet, MA; Cape Cod National Seashore Advisory Commission

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  11. 75 FR 20380 - Cape Cod National Seashore; South Wellfleet, Massachusetts; Cape Cod National Seashore Advisory...

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  12. Genetic variability and heterogeneity of Venezuelan equine encephalitis virus vector Ochlerotatus taeniorhynchus (Diptera: Culicidae) populations of the Colombian Atlantic coast, based on microsatellite loci.

    PubMed

    Bello, F; Becerra, V

    2009-09-29

    In Colombia, the mosquito Ochlerotatus taeniorhynchus has been identified as an efficient vector of the epidemic-epizootic Venezuelan equine encephalitis virus. We evaluated the genetic variability and heterogeneity of this mosquito in Colombian populations using eight microsatellite DNA loci. Two hundred and ten mosquito specimens collected from seven populations of the Colombian Atlantic coast (San Bernardo del Viento, Coveñas, Cartagena, Barranquilla, Ciénaga, Dibulla, and Riohacha) were analyzed. We found five polymorphic microsatellite loci, with 19 alleles giving 62.5% polymorphism; the mean number of alleles per locus was 3.8. The mean expected heterogeneity ranged from 0.568 to 0.660. Most of the polymorphic microsatellite loci were in Hardy-Weinberg disequilibrium, due to both deficit and excess of heterozygotes. The Fst statistic gave a total value of 0.0369, reflecting low genetic differentiation among the populations and, as a consequence, a low degree of structuring among them, while gene flow was high (Nm = 6.52); these findings point to genetic homogeneity among these populations. There was no significant linkage disequilibrium between genotype pairs of the various populations. We concluded that this mosquito is distributed in local populations along the Colombian Atlantic coast; these findings will be useful for developing strategies for controlling this vector.

  13. Complex pattern of genetic structuring in the Atlantic salmon (Salmo salar L.) of the River Foyle system in northwest Ireland: disentangling the evolutionary signal from population stochasticity

    PubMed Central

    Ensing, Dennis; Prodöhl, Paulo A; McGinnity, Philip; Boylan, Patrick; O'Maoiléidigh, Niall; Crozier, Walter W

    2011-01-01

    Little is known about the microevolutionary processes shaping within river population genetic structure of aquatic organisms characterized by high levels of homing and spawning site fidelity. Using a microsatellite panel, we observed complex and highly significant levels of intrariver population genetic substructure and Isolation-by-Distance, in the Atlantic salmon stock of a large river system. Two evolutionary models have been considered explaining mechanisms promoting genetic substructuring in Atlantic salmon, the member-vagrant and metapopulation models. We show that both models can be simultaneously used to explain patterns and levels of population structuring within the Foyle system. We show that anthropogenic factors have had a large influence on contemporary population structure observed. In an analytical development, we found that the frequently used estimator of genetic differentiation, FST, routinely underestimated genetic differentiation by a factor three to four compared to the equivalent statistic Jost's Dest (Jost 2008). These statistics also showed a near-perfect correlation. Despite ongoing discussions regarding the usefulness of “adjusted”FST statistics, we argue that these could be useful to identify and quantify qualitative differences between populations, which are important from management and conservation perspectives as an indicator of existence of biologically significant variation among tributary populations or a warning of critical environmental damage. PMID:22393506

  14. Three Decades of Farmed Escapees in the Wild: A Spatio-Temporal Analysis of Atlantic Salmon Population Genetic Structure throughout Norway

    PubMed Central

    Glover, Kevin A.; Quintela, María; Wennevik, Vidar; Besnier, François; Sørvik, Anne G. E.; Skaala, Øystein

    2012-01-01

    Each year, hundreds of thousands of domesticated farmed Atlantic salmon escape into the wild. In Norway, which is the world’s largest commercial producer, many native Atlantic salmon populations have experienced large numbers of escapees on the spawning grounds for the past 15–30 years. In order to study the potential genetic impact, we conducted a spatio-temporal analysis of 3049 fish from 21 populations throughout Norway, sampled in the period 1970–2010. Based upon the analysis of 22 microsatellites, individual admixture, FST and increased allelic richness revealed temporal genetic changes in six of the populations. These changes were highly significant in four of them. For example, 76% and 100% of the fish comprising the contemporary samples for the rivers Vosso and Opo were excluded from their respective historical samples at P = 0.001. Based upon several genetic parameters, including simulations, genetic drift was excluded as the primary cause of the observed genetic changes. In the remaining 15 populations, some of which had also been exposed to high numbers of escapees, clear genetic changes were not detected. Significant population genetic structuring was observed among the 21 populations in the historical (global FST = 0.038) and contemporary data sets (global FST = 0.030), although significantly reduced with time (P = 0.008). This reduction was especially distinct when looking at the six populations displaying temporal changes (global FST dropped from 0.058 to 0.039, P = 0.006). We draw two main conclusions: 1. The majority of the historical population genetic structure throughout Norway still appears to be retained, suggesting a low to modest overall success of farmed escapees in the wild; 2. Genetic introgression of farmed escapees in native salmon populations has been strongly population-dependent, and it appears to be linked with the density of the native population. PMID:22916215

  15. DNA barcoding reveals species level divergence between populations of the microhylid frog genus Arcovomer (Anura: Microhylidae) in the Atlantic Rainforest of southeastern Brazil.

    PubMed

    Jennings, W Bryan; Wogel, Henrique; Bilate, Marcos; Salles, Rodrigo de O L; Buckup, Paulo A

    2016-09-01

    The microhylid frogs belonging to the genus Arcovomer have been reported from lowland Atlantic Rainforest in the Brazilian states of Espírito Santo, Rio de Janeiro, and São Paulo. Here, we use DNA barcoding to assess levels of genetic divergence between apparently isolated populations in Espírito Santo and Rio de Janeiro. Our mtDNA data consisting of cytochrome oxidase subunit I (COI) nucleotide sequences reveals 13.2% uncorrected and 30.4% TIM2 + I + Γ corrected genetic divergences between these two populations. This level of divergence exceeds the suggested 10% uncorrected divergence threshold for elevating amphibian populations to candidate species using this marker, which implies that the Espírito Santo population is a species distinct from Arcovomer passarellii. Calibration of our model-corrected sequence divergence estimates suggests that the time of population divergence falls between 12 and 29 million years ago.

  16. Insights about the genetic diversity and population structure of an offshore group of common bottlenose dolphins (Tursiops truncatus) in the Mid-Atlantic.

    PubMed

    Castilho, C S; Pedone-Valdez, F; Bertuol, F; Fruet, P; Genoves, R C; Di Tullio, J C; Caon, G; Hoffmann, L S; Freitas, T R O

    2015-04-15

    Although the genus Tursiops has a worldwide distribution and is globally well-studied, some dolphin populations continue to face high risks of decline. Hence, it is necessary to assess the genetic diversity and structure of this genus to properly assess its conservation status and to implement appropriate management actions. In Brazil, genetic studies on this group remain rare, particularly for populations inhabiting offshore waters. Saint Peter and Saint Paul Archipelago (SPSPA) is a small group of islands located in the Mid- Atlantic Ridge, where recent studies of the Tursiops truncatus group indicate that individuals are resident throughout the year around the archipelago, exhibiting considerable site fidelity. A previous study with this group indicated that the individuals form an isolated population. To test this hypothesis, and describe the genetic diversity of SPSPA individuals, we assessed 12 microsatellite loci and a portion of the mitochondrial control region. Bayesian analysis revealed that SPSPA bottlenose dolphins form a unique population. In a phylogeographic perspective, we found that individuals from SPSPA shared mtDNA haplotypes with inshore and offshore individuals from North Atlantic, suggesting that they are not currently isolated from their conspecifics. Mirroring mtDNA findings, microsatellite analysis revealed that most of the pairs of individuals sampled seem to be unrelated (83.8%) and no indication of inbreeding, what would be expected if a small population such as SPSPA was reproductively isolated.

  17. Invasion of the red seaweed Heterosiphonia japonica spans biogeographic provinces in the Western North Atlantic Ocean.

    PubMed

    Newton, Christine; Bracken, Matthew E S; McConville, Megan; Rodrigue, Katherine; Thornber, Carol S

    2013-01-01

    The recent invasion of the red alga Heterosiphonia japonica in the western North Atlantic Ocean has provided a unique opportunity to study invasion dynamics across a biogeographical barrier. Native to the western North Pacific Ocean, initial collections in 2007 and 2009 restricted the western North Atlantic range of this invader to Rhode Island, USA. However, through subtidal community surveys, we document the presence of Heterosiphonia in coastal waters from Maine to New York, USA, a distance of more than 700 km. This geographical distribution spans a well-known biogeographical barrier at Cape Cod, Massachusetts. Despite significant differences in subtidal community structure north and south of Cape Cod, Heterosiphonia was found at all but two sites surveyed in both biogeographic provinces, suggesting that this invader is capable of rapid expansion over broad geographic ranges. Across all sites surveyed, Heterosiphonia comprised 14% of the subtidal benthic community. However, average abundances of nearly 80% were found at some locations. As a drifting macrophyte, Heterosiphonia was found as intertidal wrack in abundances of up to 65% of the biomass washed up along beaches surveyed. Our surveys suggest that the high abundance of Heterosiphonia has already led to marked changes in subtidal community structure; we found significantly lower species richness in recipient communities with higher Heterosiphona abundances. Based on temperature and salinity tolerances of the European populations, we believe Heterosiphonia has the potential to invade and alter subtidal communities from Florida to Newfoundland in the western North Atlantic.

  18. Invasion of the Red Seaweed Heterosiphonia japonica Spans Biogeographic Provinces in the Western North Atlantic Ocean

    PubMed Central

    Newton, Christine; Bracken, Matthew E. S.; McConville, Megan; Rodrigue, Katherine; Thornber, Carol S.

    2013-01-01

    The recent invasion of the red alga Heterosiphonia japonica in the western North Atlantic Ocean has provided a unique opportunity to study invasion dynamics across a biogeographical barrier. Native to the western North Pacific Ocean, initial collections in 2007 and 2009 restricted the western North Atlantic range of this invader to Rhode Island, USA. However, through subtidal community surveys, we document the presence of Heterosiphonia in coastal waters from Maine to New York, USA, a distance of more than 700 km. This geographical distribution spans a well-known biogeographical barrier at Cape Cod, Massachusetts. Despite significant differences in subtidal community structure north and south of Cape Cod, Heterosiphonia was found at all but two sites surveyed in both biogeographic provinces, suggesting that this invader is capable of rapid expansion over broad geographic ranges. Across all sites surveyed, Heterosiphonia comprised 14% of the subtidal benthic community. However, average abundances of nearly 80% were found at some locations. As a drifting macrophyte, Heterosiphonia was found as intertidal wrack in abundances of up to 65% of the biomass washed up along beaches surveyed. Our surveys suggest that the high abundance of Heterosiphonia has already led to marked changes in subtidal community structure; we found significantly lower species richness in recipient communities with higher Heterosiphona abundances. Based on temperature and salinity tolerances of the European populations, we believe Heterosiphonia has the potential to invade and alter subtidal communities from Florida to Newfoundland in the western North Atlantic. PMID:23638018

  19. An evaluation of introgression of Atlantic coast striped bass mitochondrial DNA in a Gulf of Mexico population using formalin-preserved museum collections.

    PubMed

    Wirgin, I; Maceda, L; Stabile, J; Mesing, C

    1997-10-01

    Striped bass Morone saxatilis populations in drainages along the Gulf of Mexico coast (Gulf) were depleted in the 1950s and 1960s, probably because of anthropogenic influences. It is believed that only the Apalachicola-Chattahoochee-Flint (A-C-F) river system continually supported a naturally reproducing population of Gulf lineage. Striped bass juveniles of Atlantic coast (Atlantic) ancestry were introduced to restore population abundances in the A-C-F from the late 1960s to the mid 1970s and in many other Gulf rivers from the 1960s to the present. We previously identified mtDNA polymorphisms that were unique to approximately 60% of striped bass from the A-C-F and which confirmed the continued successful natural reproduction of striped bass of Gulf maternal ancestry within the system. However, the genetic relatedness of the extant A-C-F population to 'pure' Gulf striped bass was not addressed. In this study, we determined the frequency of a diagnostic mtDNA XbaI polymorphism in samples of 'pure' Gulf striped bass that were collected from the A-C-F prior to the introduction of Atlantic fish, that were obtained from museum collections, and that were originally preserved in formalin. PCR primers were developed that allowed for amplification of a 191-bp mtDNA fragment that contained the diagnostic XbaI restriction site. Using RFLP and direct sequence analyses of the PCR amplicons, we found no significant differences in mtDNA XbaI genotype frequencies between the archived samples and extant A-C-F samples collected over a 15-year period. This indicates that significant maternally mediated introgression of Atlantic mtDNA genomes into the A-C-F gene pool has not occurred. Additionally, we found no evidence of the unique Gulf mtDNA genotype in striped bass from extant populations in Texas, Louisiana and the Mississippi River. These results highlight the importance of the A-C-F as a repository of striped bass to restore extirpated Gulf populations and the potential use of

  20. Organochlorines including polychlorinated biphenyls in muscle, liver, and ovaries of cod, Gadus morhua

    SciTech Connect

    Hellou, J.; Warren, W.G.; Payne, J.F. )

    1993-11-01

    Twenty-three specific organochlorine contaminants and polychlorinated biphenyls (PCBs), measured as three Aroclor standards were analyzed in muscle, liver, and ovaries of cod, Gadus morhua, collected in the Northwest Atlantic. In general, contaminants were undetectable in muscle tissue, while concentrations were 10 times lower in ovaries than liver (wet weight). Comparison of results to other locations indicated a similarity between the ratio of the concentrations of p,p'-DDE, p,p'-DDD and p,p'-DDT, in liver of cod from the northern North Sea and from the Northwest Atlantic, although with lower levels in the present study. The ratio of alpha-HCH and gamma-HCH was between that of the central and northern North Sea. Similar ratios tend to indicate similar residence times in the atmosphere, from source to sampling area. Comparison of sigma PCB and sigma DDT in the liver of cod from various geographical locations showed the following general trend in concentrations: Arctic, Northwest Atlantic, West Atlantic, Norway < North Baltic, Nova Scotia, North Sea < South Baltic. It was observed that if the liver concentration of one compound was low (high), there was a tendency for all compounds to be low (high). Cluster analysis of organochlorines in liver pointed to the presence of four basic clusters, which could reflect similar physical chemical properties within a group. Concentrations of organochlorines in ovaries were below levels expected to affect egg and larval viability.

  1. 75 FR 5541 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-03

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod for Processing by the Inshore...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific cod by vessels catching Pacific cod for... Pacific cod apportioned to vessels catching Pacific cod for processing by the inshore component of...

  2. 75 FR 10441 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-08

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod for Processing by the Offshore...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific cod by vessels catching Pacific cod for... Pacific cod apportioned to vessels catching Pacific cod for processing by the offshore component of...

  3. 75 FR 8839 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-26

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod for Processing by the Offshore...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific cod by vessels catching Pacific cod for... Pacific cod apportioned to vessels catching Pacific cod for processing by the offshore component of...

  4. 75 FR 7976 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod for Processing by the Inshore...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific cod by vessels catching Pacific cod for... Pacific cod apportioned to vessels catching Pacific cod for processing by the inshore component of...

  5. Mortality trends of stranded marine mammals on Cape Cod and southeastern Massachusetts, USA, 2000 to 2006.

    PubMed

    Bogomolni, Andrea L; Pugliares, Katie R; Sharp, Sarah M; Patchett, Kristen; Harry, Charles T; LaRocque, Jane M; Touhey, Kathleen M; Moore, Michael

    2010-01-25

    To understand the cause of death of 405 marine mammals stranded on Cape Cod and southeastern Massachusetts between 2000 and 2006, a system for coding final diagnosis was developed and categorized as (1) disease, (2) human interaction, (3) mass-stranded with no significant findings, (4) single-stranded with no significant findings, (5) rock and/or sand ingestion, (6) predatory attack, (7) failure to thrive or dependent calf or pup, or (8) other. The cause of death for 91 animals could not be determined. For the 314 animals that could be assigned a cause of death, gross and histological pathology results and ancillary testing indicated that disease was the leading cause of mortality in the region, affecting 116/314 (37%) of cases. Human interaction, including harassment, entanglement, and vessel collision, fatally affected 31/314 (10%) of all animals. Human interaction accounted for 13/29 (45%) of all determined gray seal Halichoerus grypus mortalities. Mass strandings were most likely to occur in northeastern Cape Cod Bay; 97/106 (92%) of mass stranded animals necropsied presented with no significant pathological findings. Mass strandings were the leading cause of death in 3 of the 4 small cetacean species: 46/67 (69%) of Atlantic white-sided dolphin Lagenorhynchus acutus, 15/21 (71%) of long-finned pilot whale Globicephala melas, and 33/54 (61%) of short-beaked common dolphin Delphinus delphis. These baseline data are critical for understanding marine mammal population health and mortality trends, which in turn have significant conservation and management implications. They not only afford a better retrospective analysis of strandings, but ultimately have application for improving current and future response to live animal stranding.

  6. Genetic and phenotypic changes in an Atlantic salmon population supplemented with non-local individuals: a longitudinal study over 21 years

    PubMed Central

    Le Cam, Sabrina; Perrier, Charles; Besnard, Anne-Laure; Bernatchez, Louis; Evanno, Guillaume

    2015-01-01

    While introductions and supplementations using non-native and potentially domesticated individuals may have dramatic evolutionary effects on wild populations, few studies documented the evolution of genetic diversity and life-history traits in supplemented populations. Here, we investigated year-to-year changes from 1989 to 2009 in genetic admixture at 15 microsatellite loci and in phenotypic traits in an Atlantic salmon (Salmo salar) population stocked during the first decade of this period with two genetically and phenotypically distinct source populations. We detected a pattern of temporally increasing introgressive hybridization between the stocked population and both source populations. The proportion of fish returning to the river after a single winter at sea (versus several ones) was higher in fish assigned to the main source population than in local individuals. Moreover, during the first decade of the study, both single-sea-winter and multi-sea-winter (MSW) fish assigned to the main source population were smaller than local fish. During the second decade of the study, MSW fish defined as hybrids were lighter and smaller than fish from parental populations, suggesting outbreeding depression. Overall, this study suggests that supplementation with non-local individuals may alter not only the genetic diversity of wild populations but also life-history traits of adaptive significance. PMID:25608883

  7. AHR-related activities in a creosote-adapted population of adult atlantic killifish, Fundulus heteroclitus, two decades post-EPA superfund status at the Atlantic Wood Site, Portsmouth, VA USA.

    PubMed

    Wojdylo, Josephine V; Vogelbein, Wolfgang; Bain, Lisa J; Rice, Charles D

    2016-08-01

    Atlantic killifish, Fundulus heteroclitus, are adapted to creosote-based PAHs at the US EPA Superfund site known as Atlantic Wood (AW) on the southern branch of the Elizabeth River, VA USA. Subsequent to the discovery of the AW population in the early 1990s, these fish were shown to be recalcitrant to CYP1A induction by PAHs under experimental conditions, and even to the time of this study, killifish embryos collected from the AW site are resistant to developmental deformities typically associated with exposure to PAHs in reference fish. Historically, however, 90 +% of the adult killifish at this site have proliferative hepatic lesions including cancer of varying severity. Several PAHs at this site are known to be ligands for the aryl hydrocarbon receptor (AHR). In this study, AHR-related activities in AW fish collected between 2011 and 2013 were re-examined nearly 2 decades after first discovery. This study shows that CYP1A mRNA expression is three-fold higher in intestines of AW killifish compared to a reference population. Using immunohistochemistry, CYP1A staining in intestines was uniformly positive compared to negative staining in reference fish. Livers of AW killifish were examined by IHC to show that CYP1A and AHR2 protein expression reflect lesions-specific patterns, probably representing differences in intrinsic cellular physiology of the spectrum of proliferative lesions comprising the hepatocarcinogenic process. We also found that COX2 mRNA expression levels were higher in AW fish livers compared to those in the reference population, suggesting a state of chronic inflammation. Overall, these findings suggest that adult AW fish are responsive to AHR signaling, and do express CYP1A and AHR2 proteins in intestines at a level above what was observed in the reference population.

  8. Population genetics of the American eel (Anguilla rostrata): FST = 0 and North Atlantic Oscillation effects on demographic fluctuations of a panmictic species.

    PubMed

    Côté, Caroline L; Gagnaire, Pierre-Alexandre; Bourret, Vincent; Verreault, Guy; Castonguay, Martin; Bernatchez, Louis

    2013-04-01

    We performed population genetic analyses on the American eel (Anguilla rostrata) with three main objectives. First, we conducted the most comprehensive analysis of neutral genetic population structure to date to revisit the null hypothesis of panmixia in this species. Second, we used this data to provide the first estimates of contemporary effective population size (Ne ) and to document temporal variation in effective number of breeders (Nb ) in American eel. Third, we tested for statistical associations between temporal variation in the North Atlantic Oscillation (NAO), the effective number of breeders and two indices of recruit abundance. A total of 2142 eels from 32 sampling locations were genotyped with 18 microsatellite loci. All measures of differentiation were essentially zero, and no evidence for significant spatial or temporal genetic differentiation was found. The panmixia hypothesis should thus be accepted for this species. Nb estimates varied by a factor of 23 among 12 cohorts, from 473 to 10,999. The effective population size Ne was estimated at 10,532 (95% CI, 9312-11,752). This study also showed that genetically based demographic indices, namely Nb and allelic richness (Ar), can be used as surrogates for the abundance of breeders and recruits, which were both shown to be positively influenced by variation during high (positive) NAO phases. Thus, long-term genetic monitoring of American glass eels at several sites along the North American Atlantic coast would represent a powerful and efficient complement to census monitoring to track demographic fluctuations and better understand their causes.

  9. The annual marine feeding aggregation of Atlantic sturgeon Acipenser oxyrinchus in the inner Bay of Fundy: population characteristics and movement.

    PubMed

    Dadswell, M J; Wehrell, S A; Spares, A D; Mclean, M F; Beardsall, J W; Logan-Chesney, L M; Nau, G S; Ceapa, C; Redden, A M; Stokesbury, M J W

    2016-10-01

    Atlantic sturgeon Acipenser oxyrinchus aggregate to feed from May to October in Minas Basin (45° N; 64° W), a large, cul-de-sac embayment of the inner Bay of Fundy. The aggregation consists mainly of migrants from the Saint John, NB and Kennebec Rivers, ME (99%). During 2004-2015, 4393 A. oxyrinchus were taken as by-catch by commercial fish trawlers or at intertidal fishing weirs, and 1453 were marked and/or sampled and released. Fork length (LF ) ranged from 458 to 2670 mm, but 72·5% were <1500 mm. Mass (M) ranged from 0·5 to 58·0 kg. The mass-length relationship for fish ≤50 kg was log10 M = 3·32log10 LF - 5·71. Observed growth of unsexed A. oxyrinchus recaptured after 1-8 years indicated fish of 90-179 cm LF grew c. 2-4 cm a year. Ages obtained from pectoral spines were from 4 to 54 years. The Von Bertalanffy growth model predicted K = 0·01 and L∞ = 5209 mm LF . Estimated annual mortality was 9·5-10·9%. Aggregation sizes in 2008 and 2013 were 8804 and 9244 individuals, respectively. Fish exhibited high fidelity for yearly return to Minas Basin and population estimates indicated the total at-sea number utilizing the Basin increased from c. 10 700 in 2010 to c. 37 500 in 2015. Abundance in the Basin was greatest along the north shore in spring and along the south shore in summer, suggesting clockwise movement following the residual current structure. Marked individuals were recaptured in other bays of the inner Bay of Fundy, north to Gaspé, Quebec, and south to New Jersey, U.S.A., with 26 recoveries from the Saint John River, NB, spawning run. Fish marked at other Canadian and U.S. sites were also recovered in Minas Basin. Since all A. oxyrinchus migrate into and out of the Basin annually they will be at risk of mortality if planned tidal power turbines are installed in Minas Passage.

  10. Conservation genomics of anadromous Atlantic salmon across its North American range: outlier loci identify the same patterns of population structure as neutral loci.

    PubMed

    Moore, Jean-Sébastien; Bourret, Vincent; Dionne, Mélanie; Bradbury, Ian; O'Reilly, Patrick; Kent, Matthew; Chaput, Gérald; Bernatchez, Louis

    2014-12-01

    Anadromous Atlantic salmon (Salmo salar) is a species of major conservation and management concern in North America, where population abundance has been declining over the past 30 years. Effective conservation actions require the delineation of conservation units to appropriately reflect the spatial scale of intraspecific variation and local adaptation. Towards this goal, we used the most comprehensive genetic and genomic database for Atlantic salmon to date, covering the entire North American range of the species. The database included microsatellite data from 9142 individuals from 149 sampling locations and data from a medium-density SNP array providing genotypes for >3000 SNPs for 50 sampling locations. We used neutral and putatively selected loci to integrate adaptive information in the definition of conservation units. Bayesian clustering with the microsatellite data set and with neutral SNPs identified regional groupings largely consistent with previously published regional assessments. The use of outlier SNPs did not result in major differences in the regional groupings, suggesting that neutral markers can reflect the geographic scale of local adaptation despite not being under selection. We also performed assignment tests to compare power obtained from microsatellites, neutral SNPs and outlier SNPs. Using SNP data substantially improved power compared to microsatellites, and an assignment success of 97% to the population of origin and of 100% to the region of origin was achieved when all SNP loci were used. Using outlier SNPs only resulted in minor improvements to assignment success to the population of origin but improved regional assignment. We discuss the implications of these new genetic resources for the conservation and management of Atlantic salmon in North America.

  11. Calcium from salmon and cod bone is well absorbed in young healthy men: a double-blinded randomised crossover design

    PubMed Central

    2010-01-01

    Background Calcium (Ca) - fortified foods are likely to play an important role in helping the consumer achieve an adequate Ca intake, especially for persons with a low intake of dairy products. Fish bones have a high Ca content, and huge quantities of this raw material are available as a by-product from the fish industry. Previously, emphasis has been on producing high quality products from fish by-products by use of bacterial proteases. However, documentation of the nutritional value of the enzymatically rinsed Ca-rich bone fraction remains unexplored. The objective of the present study was to assess the bioavailability of calcium in bones of Atlantic salmon (oily fish) and Atlantic cod (lean fish) in a double-blinded randomised crossover design. Methods Ca absorption was measured in 10 healthy young men using 47Ca whole body counting after ingestion of a test meal extrinsically labelled with the 47Ca isotope. The three test meals contained 800 mg of Ca from three different calcium sources: cod bones, salmon bones and control (CaCO3). Results Mean Ca absorption (± SEE) from the three different Ca sources were 21.9 ± 1.7%, 22.5 ± 1.7% and 27.4 ± 1.8% for cod bones, salmon bones, and control (CaCO3), respectively. Conclusion We conclude that bones from Atlantic salmon and Atlantic cod are suitable as natural Ca sources in e.g. functional foods or as supplements. PMID:20646299

  12. Comment on "Slow adaptation in the face of rapid warming leads to collapse of the Gulf of Maine cod fishery".

    PubMed

    Palmer, Michael C; Deroba, Jonathan J; Legault, Christopher M; Brooks, Elizabeth N

    2016-04-22

    Pershing et al (Reports, 13 November, p. 809) concluded that failure to account for temperature in the assessment and management of Gulf of Maine Atlantic cod caused overfishing. We argue that the "extra mortality" calculation driving this conclusion is an artifact. Environmental factors affect all stocks, but attribution of additional mortality to temperature alone by Pershing et al is unsupported by the data.

  13. Host size-dependent anisakid infection in Baltic cod Gadus morhua associated with differential food preferences.

    PubMed

    Zuo, Shaozhi; Huwer, Bastian; Bahlool, Qusay; Al-Jubury, Azmi; Daugbjerg Christensen, Nanna; Korbut, Rozalia; Kania, Per; Buchmann, Kurt

    2016-06-15

    A significant increase in the infection level of Baltic cod Gadus morhua with the anisakid nematode larvae Contracaecum osculatum and Pseudoterranova decipiens has been recorded during recent years due to the expanding local population of grey seals Halichoerus grypus, which act as final hosts for these parasites. Here, we report from an investigation of 368 cod (total length [TL] 6-49 cm; caught in ICES Subdivision 25) that the infection level of juvenile cod (TL 6-30 cm) with larvae of C. osculatum and P. decipiens is absent or very low, whereas it increases drastically in larger cod (TL 31-48 cm). A third nematode Hysterothylacium aduncum was rarely found. The study indicates that the prey animals for large cod act as transport hosts for the parasite larvae. Analyses of stomach contents of cod caught in the same area (2007-2014) showed that small benthic organisms (including polychaetes Harmothoë sarsi) are preferred food items by small cod, the isopod Saduria entomon is taken by all size classes, and sprat Sprattus sprattus are common prey items for cod larger than 30 cm. Parasitological investigations (microscopic and molecular analyses) of H. sarsi (100 specimens) and S. entomon (40 specimens) did not reveal infection in these invertebrates, but 11.6% of sprat (265 specimens examined) was shown to be infected with 1-8 C. osculatum third stage larvae per fish. Analyses of sprat stomach contents confirmed that copepods and cladocerans are the main food items of sprat. These observations suggest that the C. osculatum life cycle in the Baltic Sea includes grey seals as final hosts, sprat as the first transport host and cod as second transport host. It may be speculated that sprat obtain infection by feeding on copepods and/or cladocerans, which could serve as the first intermediate hosts. One cannot exclude the possibility that the size-dependent C. osculatum infection of cod may contribute (indirectly or directly) to the differential mortality of larger cod

  14. 75 FR 64957 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-21

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod for Processing by the Offshore...; closure. ] SUMMARY: NMFS is prohibiting directed fishing for Pacific cod by vessels catching Pacific cod... to vessels catching Pacific cod for processing by the offshore component of the Western...

  15. 75 FR 56016 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-15

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod for Processing by the Inshore...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific cod by vessels catching Pacific cod for... catching Pacific cod for processing by the inshore component of the Central Regulatory Area of the...

  16. 75 FR 63402 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-15

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod for Processing by the Inshore...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific cod by vessels catching Pacific cod for... catching Pacific cod for processing by the inshore component of the Western Regulatory Area of the...

  17. 75 FR 64956 - Fisheries of the Exclusive Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-21

    ... Economic Zone Off Alaska; Pacific Cod by Vessels Catching Pacific Cod for Processing by the Offshore...; closure. SUMMARY: NMFS is prohibiting directed fishing for Pacific cod by vessels catching Pacific cod for... catching Pacific cod for processing by the offshore component of the Central Regulatory Area of the...

  18. Breeding and moulting locations and migration patterns of the Atlantic population of Steller's eiders Polysticta stelleri as determined from satellite telemetry

    USGS Publications Warehouse

    Petersen, M.R.; Bustnes, J.O.; Systad, G.H.

    2006-01-01

    This study was designed to determine the spring, summer, autumn, and early winter distribution, migration routes, and timing of migration of the Atlantic population of Steller's eiders Polysticta stelleri. Satellite transmitters were implanted in 20 eiders captured in April 2001 at Vads??, Norway, and their locations were determined from 5 May 2001 to 6 February 2002. Regions where birds concentrated from spring until returning to wintering areas included coastal waters from western Finnmark, Norway, to the eastern Taymyr Peninsula, Russia. Novaya Zemlya, Russia, particularly the Mollera Bay region, was used extensively during spring staging, moult, and autumn staging; regions of the Kola, Kanin, and Gydanskiy peninsulas, Russia, were used extensively during spring and moult migrations. Steller's eiders migrated across the Barents and Kara seas and along the Kara Sea and Kola Peninsula coastal waters to nesting, moulting, and wintering areas. The majority of marked eiders (9 of 15) were flightless in near-shore waters along the west side of Novaya Zemlya. Eiders were also flightless in northern Norway and along the Kanin and at Kola Peninsula coasts. We compare and contrast natural history characteristics of the Atlantic and Pacific populations and discuss evolutionary and ecological factors influencing their distribution. © Journal of Avian Biology.

  19. Fitness reduction and potential extinction of wild populations of Atlantic salmon, Salmo salar, as a result of interactions with escaped farm salmon.

    PubMed Central

    McGinnity, Philip; Prodöhl, Paulo; Ferguson, Andy; Hynes, Rosaleen; Maoiléidigh, Niall O; Baker, Natalie; Cotter, Deirdre; O'Hea, Brendan; Cooke, Declan; Rogan, Ger; Taggart, John; Cross, Tom

    2003-01-01

    The high level of escapes from Atlantic salmon farms, up to two million fishes per year in the North Atlantic, has raised concern about the potential impact on wild populations. We report on a two-generation experiment examining the estimated lifetime successes, relative to wild natives, of farm, F(1) and F(2) hybrids and BC(1) backcrosses to wild and farm salmon. Offspring of farm and "hybrids" (i.e. all F(1), F(2) and BC(1) groups) showed reduced survival compared with wild salmon but grew faster as juveniles and displaced wild parr, which as a group were significantly smaller. Where suitable habitat for these emigrant parr is absent, this competition would result in reduced wild smolt production. In the experimental conditions, where emigrants survived downstream, the relative estimated lifetime success ranged from 2% (farm) to 89% (BC(1) wild) of that of wild salmon, indicating additive genetic variation for survival. Wild salmon primarily returned to fresh water after one sea winter (1SW) but farm and 'hybrids' produced proportionately more 2SW salmon. However, lower overall survival means that this would result in reduced recruitment despite increased 2SW fecundity. We thus demonstrate that interaction of farm with wild salmon results in lowered fitness, with repeated escapes causing cumulative fitness depression and potentially an extinction vortex in vulnerable populations. PMID:14667333

  20. Latitudinal-Related Variation in Wintering Population Trends of Greylag Geese (Anser Anser) along the Atlantic Flyway: A Response to Climate Change?

    PubMed Central

    Ramo, Cristina; Amat, Juan A.; Nilsson, Leif; Schricke, Vincent; Rodríguez-Alonso, Mariano; Gómez-Crespo, Enrique; Jubete, Fernando; Navedo, Juan G.; Masero, José A.; Palacios, Jesús; Boos, Mathieu; Green, Andy J.

    2015-01-01

    The unusually high quality of census data for large waterbirds in Europe facilitates the study of how population change varies across a broad geographical range and relates to global change. The wintering population of the greylag goose Anser anser in the Atlantic flyway spanning between Sweden and Spain has increased from 120 000 to 610 000 individuals over the past three decades, and expanded its wintering range northwards. Although population sizes recorded in January have increased in all seven countries in the wintering range, we found a pronounced northwards latitudinal effect in which the rate of increase is higher at greater latitudes, causing a constant shift in the centre of gravity for the spatial distribution of wintering geese. Local winter temperatures have a strong influence on goose numbers but in a manner that is also dependent on latitude, with the partial effect of temperature (while controlling for the increasing population trend between years) being negative at the south end and positive at the north end of the flyway. Contrary to assumptions in the literature, the expansion of crops exploited by greylag geese has made little contribution to the increases in population size. Only in one case (expansion of winter cereals in Denmark) did we find evidence of an effect of changing land use. The expanding and shifting greylag population is likely to have increasing impacts on habitats in northern Europe during the course of this century. PMID:26465601

  1. Exploring neutral and adaptive processes in expanding populations of gilthead sea bream, Sparus aurata L., in the North-East Atlantic

    PubMed Central

    Coscia, I; Vogiatzi, E; Kotoulas, G; Tsigenopoulos, C S; Mariani, S

    2012-01-01

    Recent studies in empirical population genetics have highlighted the importance of taking into account both neutral and adaptive genetic variation in characterizing microevolutionary dynamics. Here, we explore the genetic population structure and the footprints of selection in four populations of the warm-temperate coastal fish, the gilthead sea bream (Sparus aurata), whose recent northward expansion has been linked to climate change. Samples were collected at four Atlantic locations, including Spain, Portugal, France and the South of Ireland, and genetically assayed using a suite of species-specific markers, including 15 putatively neutral microsatellites and 23 expressed sequence tag-linked markers, as well as a portion of the mitochondrial DNA (mtDNA) control region. Two of the putatively neutral markers, Bld-10 and Ad-10, bore signatures of strong directional selection, particularly in the newly established Irish population, although the potential ‘surfing effect' of rare alleles at the edge of the expansion front was also considered. Analyses after the removal of these loci suggest low but significant population structure likely affected by some degree of gene flow counteracting random genetic drift. No signal of historic divergence was detected at mtDNA. BLAST searches conducted with all 38 markers used failed to identify specific genomic regions associated to adaptive functions. However, the availability of genomic resources for this commercially valuable species is rapidly increasing, bringing us closer to the understanding of the interplay between selective and neutral evolutionary forces, shaping population divergence of an expanding species in a heterogeneous milieu. PMID:22126850

  2. Mitochondrial DNA phylogeography and population history of Meladema diving beetles on the Atlantic Islands and in the Mediterranean basin (Coleoptera, Dytiscidae).

    PubMed

    Ribera, I; Bilton, D T; Vogler, A P

    2003-01-01

    The phylogeny and population history of Meladema diving beetles (Coleoptera, Dytiscidae) were examined using mitochondrial DNA sequence from 16S ribosomal RNA and cytochrome oxidase I genes in 51 individuals from 22 populations of the three extant species (M. imbricata endemic to the western Canary Islands, M. lanio endemic to Madeira and M. coriacea widespread in the Western Mediterranean and on the western Canaries), using a combination of phylogenetic and nested clade analyses. Four main lineages are observed within Meladema, representing the three recognized species plus Corsican populations of M. coriacea. Phylogenetic analyses demonstrate the sister relationship of the two Atlantic Island taxa, and suggest the possible paraphyly of M. coriacea. A molecular clock approach reveals that speciation within the genus occurred in the Early Pleistocene, indicating that the Atlantic Island endemics are not Tertiary relict taxa as had been proposed previously. Our results point to past population bottlenecks in all four lineages, with recent (Late-Middle Pleistocene) range expansion in non-Corsican M. coriacea and M. imbricata. Within the Canary Islands, M. imbricata seems to have independently colonized La Gomera and La Palma from Tenerife (although a colonization of La Palma from La Gomera cannot be discarded), and M. coriacea has independently colonized Tenerife and Gran Canaria from separate mainland lineages. In the Mediterranean basin this species apparently colonized Corsica on a single occasion, relatively early in its evolutionary history (Early Pleistocene), and has colonized Mallorca recently on multiple occasions. On the only island where M. coriacea and M. imbricata are broadly sympatric (Tenerife), we report evidence of bidirectional hybridization between the two species.

  3. Diversity and genetic connectivity among populations of a threatened tree (Dalbergia nigra) in a recently fragmented landscape of the Brazilian Atlantic Forest.

    PubMed

    Resende, Luciana Cunha; Ribeiro, Renata Acácio; Lovato, Maria Bernadete

    2011-09-01

    In this study we evaluated the influence of recent landscape fragmentation on the dynamics of remnant fragments from the Brazilian Atlantic Forest. This biome is one of the richest in the world and has been extensively deforested and fragmented. We sampled five populations of the threatened Dalbergia nigra, a tree endemic to the Brazilian Atlantic Forest, two located in a large reserve of continuous forest and three in fragments of different sizes and levels of disturbance. In order to assess historical changes, considering the longevity of the analyzed species, 119 adults and 116 saplings were genotyped for six microsatellite loci. Lower levels of genetic diversity were found in the most impacted fragments when compared to the most preserved population located inside the reserve, and there was significant genetic structure among the populations studied (pairwise F(ST) = 0.031-0.152; pairwise D(EST) = 0.039-0.301). However, genetic structure among saplings (F ST) = 0.056; D(EST) = 0.231) was significantly lower than among adults (F(ST) = 0.088; D(EST) = 0.275). Estimates of contemporary gene flow based on assignment tests corroborated this result, suggesting that fragmentation led to an increase in gene flow. This connectivity among remnant fragments could mitigate the loss of genetic diversity through a metapopulation dynamic, but the high rate of habitat loss and the unknown long-term genetic effects add uncertainty. These results, taken together with the presence of private alleles in disturbed populations, highlight the importance of preserving the extant fragments.

  4. Alternative adaptive immunity strategies: coelacanth, cod and shark immunity.

    PubMed

    Buonocore, Francesco; Gerdol, Marco

    2016-01-01

    The advent of high throughput sequencing has permitted to investigate the genome and the transcriptome of novel non-model species with unprecedented depth. This technological advance provided a better understanding of the evolution of adaptive immune genes in gnathostomes, revealing several unexpected features in different fish species which are of particular interest. In the present paper, we review the current understanding of the adaptive immune system of the coelacanth, the elephant shark and the Atlantic cod. The study of coelacanth, the only living extant of the long thought to be extinct Sarcopterygian lineage, is fundamental to bring new insights on the evolution of the immune system in higher vertebrates. Surprisingly, coelacanths are the only known jawed vertebrates to lack IgM, whereas two IgD/W loci are present. Cartilaginous fish are of great interest due to their basal position in the vertebrate tree of life; the genome of the elephant shark revealed the lack of several important immune genes related to T cell functions, which suggest the existence of a primordial set of TH1-like cells. Finally, the Atlantic cod lacks a functional major histocompatibility II complex, but balances this evolutionary loss with the expansion of specific gene families, including MHC I, Toll-like receptors and antimicrobial peptides. Overall, these data point out that several fish species present an unconventional adaptive immune system, but the loss of important immune genes is balanced by adaptive evolutionary strategies which still guarantee the establishment of an efficient immune response against the pathogens they have to fight during their life.

  5. High Levels of Genetic Connectivity among Populations of Yellowtail Snapper, Ocyurus chrysurus (Lutjanidae – Perciformes), in the Western South Atlantic Revealed through Multilocus Analysis

    PubMed Central

    da Silva, Raimundo; Veneza, Ivana; Sampaio, Iracilda; Araripe, Juliana; Schneider, Horacio; Gomes, Grazielle

    2015-01-01

    In the present study, five loci (mitochondrial and nuclear) were sequenced to determine the genetic diversity, population structure, and demographic history of populations of the yellowtail snapper, Ocyurus chrysurus, found along the coast of the western South Atlantic. O. chrysurus is a lutjanid species that is commonly associated with coral reefs and exhibits an ample geographic distribution, and it can therefore be considered a good model for the investigation of phylogeographic patterns and genetic connectivity in marine environments. The results reflected a marked congruence between the mitochondrial and nuclear markers as well as intense gene flow among the analyzed populations, which represent a single genetic stock along the entire coast of Brazil between the states of Pará and Espírito Santo. Our data also showed high levels of genetic diversity in the species (mainly mtDNA), as well a major historic population expansion, which most likely coincided with the sea level oscillations at the end of the Pleistocene. In addition, this species is intensively exploited by commercial fisheries, and data on the genetic structure of its populations will be essential for the development of effective conservation and management plans. PMID:25769032

  6. High levels of genetic connectivity among populations of yellowtail snapper, Ocyurus chrysurus (Lutjanidae-Perciformes), in the western South Atlantic revealed through multilocus analysis.

    PubMed

    da Silva, Raimundo; Veneza, Ivana; Sampaio, Iracilda; Araripe, Juliana; Schneider, Horacio; Gomes, Grazielle

    2015-01-01

    In the present study, five loci (mitochondrial and nuclear) were sequenced to determine the genetic diversity, population structure, and demographic history of populations of the yellowtail snapper, Ocyurus chrysurus, found along the coast of the western South Atlantic. O. chrysurus is a lutjanid species that is commonly associated with coral reefs and exhibits an ample geographic distribution, and it can therefore be considered a good model for the investigation of phylogeographic patterns and genetic connectivity in marine environments. The results reflected a marked congruence between the mitochondrial and nuclear markers as well as intense gene flow among the analyzed populations, which represent a single genetic stock along the entire coast of Brazil between the states of Pará and Espírito Santo. Our data also showed high levels of genetic diversity in the species (mainly mtDNA), as well a major historic population expansion, which most likely coincided with the sea level oscillations at the end of the Pleistocene. In addition, this species is intensively exploited by commercial fisheries, and data on the genetic structure of its populations will be essential for the development of effective conservation and management plans.

  7. On the ecology of Calanus finmarchicus in the Subarctic North Atlantic: A comparison of population dynamics and environmental conditions in areas of the Labrador Sea-Labrador/Newfoundland Shelf and Norwegian Sea Atlantic and Coastal Waters

    NASA Astrophysics Data System (ADS)

    Head, Erica J. H.; Melle, Webjørn; Pepin, Pierre; Bagøien, Espen; Broms, Cecilie

    2013-07-01

    The Norwegian Sea is generally warmer than the Labrador Sea because it is influenced more by Atlantic Water inflows from the south, whereas the latter receives relatively larger inputs of Arctic Water from the north. Despite its more northerly location, the spring bloom generally starts earlier in the Norwegian Sea. Within each of the two seas, however, there are regional and interannual differences in temperature and the timing of the spring bloom. The responses of Calanus finmarchicus populations to these differences in environmental conditions include differences in physical characteristics (e.g. female size), physiological rates (egg production rates) and seasonal cycles of abundance. Females are generally larger in the Labrador Sea and have higher egg production rates for a given chlorophyll concentration than do those in the Norwegian Sea. Within and among areas in both seas, as temperatures increase and spring blooms tend to occur earlier, C. finmarchicus start to reproduce earlier, the new generation develops faster, and in some areas a second generation ensues. In areas where near surface temperatures are relatively high in summer and/or where phytoplankton growth rates are relatively low in summer or autumn, reproduction and development cease, and C. finmarchicus desert the surface layers for their overwintering depths. This occurs in the Norwegian Sea in summer and in the central Labrador Sea in autumn. By contrast, in areas where near surface temperatures remain cool in summer and where phytoplankton growth persists through the autumn, reproduction and development can continue through summer and autumn, probably until winter vertical mixing prevents phytoplankton growth. This occurs on the southern Newfoundland Shelf. Even in areas where the growth season is prolonged, however, a proportion of the first generation, and probably subsequent generations, descends to overwinter. If the size of the overwintering population is used as an index of net

  8. Population dynamics of Vibrio and Pseudomonas species isolated from farmed Tasmanian Atlantic salmon (Salmo salar L.): a seasonal study.

    PubMed

    Hatje, Eva; Neuman, Christina; Stevenson, Hollie; Bowman, John P; Katouli, Mohammad

    2014-11-01

    Vibrio and Pseudomonas species have been shown to be part of the normal microbiota of Atlantic salmon (Salmo salar L.), with some strains causing disease in fish. The factors affecting their prevalence and persistence in the salmon gut, however, have not been well studied. In this study, we collected 340 Vibrio and 150 Pseudomonas isolates from the hindgut of farmed Tasmanian Atlantic salmon, fed with two commercially available diets. Samples were collected every 6-8 weeks between July 2011 and May 2012. Isolates from selective agar were initially identified using biochemical tests and confirmed using genus-specific primers and 16S ribosomal RNA (16S rRNA) sequencing. Random amplified polymorphic DNA (RAPD) PCR was used to type both Pseudomonas and Vibrio; the latter was further typed using a biochemical fingerprinting method (PhP-RV plates). We observed low species diversity with strains comprising Vibrio ichthyoenteri/Vibrio scophthalmi, Vibrio crassostreae/Vibrio splendidus, Aliivibrio finisterrensis, Photobacterium phosphoreum and Pseudomonas fragi. Out of 340 Vibrio isolates, 238 (70 %) belonged to 21 clonal types and were found predominantly during summer when water temperatures reached 15 to 21 °C. Of these, the four major clonal types were found in multiple samples (70 %). P. fragi, on the other hand, was only found during the colder water temperatures and belonged to 18 clonal types. The presence of both groups of bacteria and their clonal types were independent of the fish diets used, suggesting that the water temperature was the main factor of the prevalence and persistence of these bacteria in the gut of Atlantic salmon.

  9. Low concentrations of sodium hypochlorite affect population dynamics in Gyrodactylus salaris (Malmberg, 1957): practical guidelines for the treatment of the Atlantic salmon, Salmo salar L. parasite.

    PubMed

    Hagen, A G; Hytterød, S; Olstad, K

    2014-12-01

    Atlantic salmon, Salmo salar L. parr (age 1+), infected by the monogenean ectoparasite Gyrodactylus salaris (Malmberg, 1957), were exposed to chlorine (Cl)-enriched water at three different concentrations: Cllow (0-5 μg Cl L(-1) ), Clmedium (18 μg Cl L(-1) ) and Clhigh (50 μg Cl L(-1) ). There was a negative correlation between G. salaris infections and the hypochlorite concentrations added. The parasite infection was eliminated by day 6-8 and day 2-4 in the groups Clmedium and Clhigh , respectively, while inhibition of G. salaris population growth was observed in the Cllow group. An important note to this matter, however, is that the G. salaris specimens observed at day 6 in Clmedium and at day 2 in Clhigh were all considered dead by subjective judgement. No mortality in the salmon parr was observed during the first 8 days of the experiment, demonstrating that Cl has a stronger effect on G. salaris than on the salmonid host. The differences in sensitivity between the parasite and the Atlantic salmon indicate that hypochlorite has a potential use as a parasiticide with a therapeutic margin. The low-dose sensitivity may imply that Cl pollution in urban areas may pose a greater risk towards biodiversity than previously assumed.

  10. Co-exposure to metals modulates CYP1A mRNA inducibility in Atlantic tomcod Microgadus tomcod from two populations.

    PubMed

    Sorrentino, C; Roy, N K; Courtenay, S C; Wirgin, I

    2005-11-10

    Populations from urbanized and industrialized sites are often exposed to mixtures of chemical contaminants including aromatic hydrocarbons (AHs) and heavy metals. The effects of mixtures of these contaminants on these populations are largely unknown. The Hudson River Estuary is highly contaminated with a variety of AHs including, PCBs and PAHs, and metals, and its population of Atlantic tomcod Microgadus tomcod bioaccumulates those which are persistent. The Hudson River's tomcod population exhibits resistance to persistent AHs as exemplified by significantly decreased inducibility of hepatic cytochrome P4501A (CYP1A) mRNA. We used hepatic CYP1A mRNA inducibility in tomcod from the Hudson River and a sensitive population to investigate the effects of acute co-exposure to metals on aryl hydrocarbon receptor (AHR)-mediated gene expression. Adult tomcod from the Hudson River and the cleaner Miramichi River were i.p. injected with one dose of benzo[a]pyrene (B[a]P) or coplanar PCB77 and graded doses of four metals, As, Cd, Cr, and Ni, and levels of hepatic CYP1A mRNA and protein were assayed. We observed no effects of metals treatment on basal levels of hepatic CYP1A mRNA expression, but all four metals significantly reduced CYP1A mRNA inducibility in tomcod from one or both populations. The magnitude of the inhibition of CYP1A mRNA inducibility differed among the metals and fish from the two populations. Also, the profile of the metals modulation of induced CYP1A mRNA showed differences that depended on the time after treatment of sacrifice. Our results demonstrate that co-exposure to several metals can impact inducible, but not basal levels of CYP1A expression and perhaps other toxicities mediated by the AHR.

  11. Genetic polymorphism and its potential relation to environmental stress in five populations of the European flounder Platichthys flesus, along the French Atlantic coast.

    PubMed

    Marchand, J; Evrard, E; Guinand, B; Cachot, J; Quiniou, L; Laroche, J

    2010-08-01

    In this study, new DNA markers were explored for the flounder Platichthys flesus. cDNA and genomic sequences of the genes encoding the glyceraldehyde-3-phosphate-deshydrogenase (GAPDH), the cytosolic creatine kinase (CK), the prostaglandin D synthase (PGDS) and the betaine homocysteine methyltransferase (BHMT) were characterized. The tumour suppressor p53 gene structure was already described. A PCR-SSCP (Single Strand Conformation Polymorphism) analysis was finally conducted to study the genetic polymorphism of different populations of flounders collected along the French Atlantic coast. Four highly contaminated French estuaries (Seine, Vilaine, Loire and Gironde) were sampled and compared to a reference estuary (Ster) to explore possible selective effect of the environment on specific allelic frequencies. Our results showed that two loci p53 and PGDS, could be potential markers of chemical stress: p53A allele frequency increased in contaminated systems compared to the reference system. In the Vilaine estuary, PGDS polymorphism could be related to pesticide stress.

  12. Influence of the North Atlantic oceanograghic and climatic parameters on the Spanish European Eel population recruitment: relationships in the past and for a future climate change

    NASA Astrophysics Data System (ADS)

    Ribalaygua, Jaime; Pórtoles, Javier; Monjo, Robert; Díaz, Estíbaliz; Korta, María; Chust, Guillem

    2016-04-01

    The status of the European eel population is critical.; the annual recruitment of glass eel to European waters in 2015 is 1.2% of the 1960-1979 level in the 'North Sea' area, and 8.4% in the rest of Europe (ICES 2015) . There are a number of anthropogenic impacts potentially affecting eel population including commercial exploitation, habitat loss, dam and weir construction, hydropower, pumping stations and surface water abstractions. Furthermore, the first eel stages and larval migration and marine survival are heavily influenced by oceanic and climatic factors since the species breeds in the Sargasso Sea and migrates to the continental shelf of the Atlantic coast of Europe and North Africa. Therefore, the study of the relations between recruitment and oceanic conditions may allow to study the potential effect of climatic change on the future eel recruitment and therefore stock. In the present study, the relation between glass eel recruitment and oceanic and climatic factors has been studied. Historic glass eel catches data beginning in the 50s from two Mediterranean and two Atlantic estuaries have been used as a proxy of recruitment. The relation of catches with the main oceanographic and climatic factors identified in the literature was established using an ocean reanalysis, the Simple Ocean Data Assimilation (SODA) and determined which variables are significantly related to the number of catches. The analysis shows significant relationships between catches and oceanic (Surface Downward Stress, Sea Water Temperature and Sea Water Velocity) and atmospheric (NAO Index, AMO Index) variables. Subsequently, we applied the results of three climate models (GFDL-ESM2M, CanESM2 and CNRM-CM5), associated with the Coupled Model Intercomparison Project Phase 5 (CMIP5) under two simulations of climate change (RCP4.5 and RCP8.5), both associated with the 5th Assessment Report of the IPCC, for possible future influences on the eel. This research was funded by the Spanish

  13. Assessment of a land-locked Atlantic salmon (Salmo salar L.) population as a potential genetic resource with a focus on long-chain polyunsaturated fatty acid biosynthesis.

    PubMed

    Betancor, M B; Olsen, R E; Solstorm, D; Skulstad, O F; Tocher, D R

    2016-03-01

    The natural food for Atlantic salmon (Salmo salar) in freshwater has relatively lower levels of omega-3 (n-3) long-chain polyunsaturated fatty acids (LC-PUFA) than found in prey for post-smolt salmon in seawater. Land-locked salmon such as the Gullspång population feed exclusively on freshwater type lipids during its entire life cycle, a successful adaptation derived from divergent evolution. Studying land-locked populations may provide insights into the molecular and genetic control mechanisms that determine and regulate n-3 LC-PUFA biosynthesis and retention in Atlantic salmon. A two factorial study was performed comparing land-locked and farmed salmon parr fed diets formulated with fish or rapeseed oil for 8 weeks. The land-locked parr had higher capacity to synthesise n-3 LC-PUFA as indicated by higher expression and activity of desaturase and elongase enzymes. The data suggested that the land-locked salmon had reduced sensitivity to dietary fatty acid composition and that dietary docosahexaenoic acid (DHA) did not appear to suppress expression of LC-PUFA biosynthetic genes or activity of the biosynthesis pathway, probably an evolutionary adaptation to a natural diet lower in DHA. Increased biosynthetic activity did not translate to enhanced n-3 LC-PUFA contents in the flesh and diet was the only factor affecting this parameter. Additionally, high lipogenic and glycolytic potentials were found in land-locked salmon, together with decreased lipolysis which in turn could indicate increased use of carbohydrates as an energy source and a sparing of lipid.

  14. Plasma levels of pollutants are much higher in loggerhead turtle populations from the Adriatic Sea than in those from open waters (Eastern Atlantic Ocean).

    PubMed

    Bucchia, Matteo; Camacho, María; Santos, Marcelo R D; Boada, Luis D; Roncada, Paola; Mateo, Rafael; Ortiz-Santaliestra, Manuel E; Rodríguez-Estival, Jaime; Zumbado, Manuel; Orós, Jorge; Henríquez-Hernández, Luis A; García-Álvarez, Natalia; Luzardo, Octavio P

    2015-08-01

    In this paper we determined the levels of 63 environmental contaminants, including organic (PCBs, organochlorine pesticides, and PAHs) and inorganic (As, Cd, Cu, Pb, Hg and Zn) compounds in the blood of loggerhead turtles (Caretta caretta) from two comparable populations that inhabit distinct geographic areas: the Adriatic Sea (Mediterranean basin) and the Canary Islands (Eastern Atlantic Ocean). All animals were sampled at the end of a period of rehabilitation in centers of wildlife recovery, before being released back into the wild, so they can be considered to be in good health condition. The dual purpose of this paper is to provide reliable data on the current levels of contamination of this species in these geographic areas, and secondly to compare the results of both populations, as it has been reported that marine biota inhabiting the Mediterranean basin is exposed to much higher pollution levels than that which inhabit in other areas of the planet. According to our results it is found that current levels of contamination by organic compounds are considerably higher in Adriatic turtles than in the Atlantic ones (∑PCBs, 28.45 vs. 1.12ng/ml; ∑OCPs, 1.63 vs. 0.19ng/ml; ∑PAHs, 13.39 vs. 4.91ng/ml; p<0.001 in all cases). This is the first time that levels of PAHs are reported in the Adriatic loggerheads. With respect to inorganic contaminants, although the differences were not as great, the Adriatic turtles appear to have higher levels of some of the most toxic elements such as mercury (5.74 vs. 7.59μg/ml, p<0.01). The results of this study confirm that the concentrations are larger in turtles from the Mediterranean, probably related to the high degree of anthropogenic pressure in this basin, and thus they are more likely to suffer adverse effects related to contaminants.

  15. Predicting the Potential for Natural Recovery of Atlantic Salmon (Salmo salar L.) Populations following the Introduction of Gyrodactylus salaris Malmberg, 1957 (Monogenea).

    PubMed

    Denholm, Scott J; Hoyle, Andrew S; Shinn, Andrew P; Paladini, Giuseppe; Taylor, Nick G H; Norman, Rachel A

    2016-01-01

    Gyrodactylus salaris (Monogenea, Platyhelminthes) is a notifiable freshwater pathogen responsible for causing catastrophic damage to wild Atlantic salmon stocks, most notably in Norway. In some strains of Baltic salmon (e.g., from the river Neva) however, the impact is greatly reduced due to some form of innate resistance that regulates parasite numbers, resulting in fewer host mortalities. Gyrodactylus salaris is known from 17 European states; its status in a further 35 states remains unknown; the UK, the Republic of Ireland and certain watersheds in Finland are free of the parasite. Thus, the parasite poses a serious threat if it emerges in Atlantic salmon rearing regions throughout Europe. At present, infections are generally controlled via extreme measures such as the treatment of entire river catchments with the biocide rotenone, in order to remove all hosts, before restocking with the original genetic stock. The use of rotenone in this way in EU countries is unlikely as it would be in contravention of the Water Framework Directive. Not only are such treatments economically and environmentally costly, they also eradicate the potential for any host/parasite evolutionary process to occur. Based on previous studies, UK salmon stocks have been shown to be highly susceptible to infection, analogous to Norwegian stocks. The present study investigates the impact of a G. salaris outbreak within a naïve salmon population in order to determine long-term consequences of infection and the likelihood of coexistence. Simulation of the salmon/ G. salaris system was carried out via a deterministic mathematical modelling approach to examine the dynamics of host-pathogen interactions. Results indicated that in order for highly susceptible Atlantic strains to evolve a resistance, both a moderate-strong deceleratingly costly trade-off on birth rate and a lower overall cost of the immune response are required. The present study provides insights into the potential long term

  16. Predicting the Potential for Natural Recovery of Atlantic Salmon (Salmo salar L.) Populations following the Introduction of Gyrodactylus salaris Malmberg, 1957 (Monogenea)

    PubMed Central

    Shinn, Andrew P.; Paladini, Giuseppe; Taylor, Nick G. H.; Norman, Rachel A.

    2016-01-01

    Gyrodactylus salaris (Monogenea, Platyhelminthes) is a notifiable freshwater pathogen responsible for causing catastrophic damage to wild Atlantic salmon stocks, most notably in Norway. In some strains of Baltic salmon (e.g., from the river Neva) however, the impact is greatly reduced due to some form of innate resistance that regulates parasite numbers, resulting in fewer host mortalities. Gyrodactylus salaris is known from 17 European states; its status in a further 35 states remains unknown; the UK, the Republic of Ireland and certain watersheds in Finland are free of the parasite. Thus, the parasite poses a serious threat if it emerges in Atlantic salmon rearing regions throughout Europe. At present, infections are generally controlled via extreme measures such as the treatment of entire river catchments with the biocide rotenone, in order to remove all hosts, before restocking with the original genetic stock. The use of rotenone in this way in EU countries is unlikely as it would be in contravention of the Water Framework Directive. Not only are such treatments economically and environmentally costly, they also eradicate the potential for any host/parasite evolutionary process to occur. Based on previous studies, UK salmon stocks have been shown to be highly susceptible to infection, analogous to Norwegian stocks. The present study investigates the impact of a G. salaris outbreak within a naïve salmon population in order to determine long-term consequences of infection and the likelihood of coexistence. Simulation of the salmon/ G. salaris system was carried out via a deterministic mathematical modelling approach to examine the dynamics of host-pathogen interactions. Results indicated that in order for highly susceptible Atlantic strains to evolve a resistance, both a moderate-strong deceleratingly costly trade-off on birth rate and a lower overall cost of the immune response are required. The present study provides insights into the potential long term

  17. Impact of naturally spawning captive-bred Atlantic salmon on wild populations: depressed recruitment and increased risk of climate-mediated extinction.

    PubMed

    McGinnity, Philip; Jennings, Eleanor; DeEyto, Elvira; Allott, Norman; Samuelsson, Patrick; Rogan, Gerard; Whelan, Ken; Cross, Tom

    2009-10-22

    The assessment report of the 4th International Panel on Climate Change confirms that global warming is strongly affecting biological systems and that 20-30% of species risk extinction from projected future increases in temperature. It is essential that any measures taken to conserve individual species and their constituent populations against climate-mediated declines are appropriate. The release of captive bred animals to augment wild populations is a widespread management strategy for many species but has proven controversial. Using a regression model based on a 37-year study of wild and sea ranched Atlantic salmon (Salmo salar) spawning together in the wild, we show that the escape of captive bred animals into the wild can substantially depress recruitment and more specifically disrupt the capacity of natural populations to adapt to higher winter water temperatures associated with climate variability. We speculate the mechanisms underlying this seasonal response and suggest that an explanation based on bio-energetic processes with physiological responses synchronized by photoperiod is plausible. Furthermore, we predict, by running the model forward using projected future climate scenarios, that these cultured fish substantially increase the risk of extinction for the studied population within 20 generations. In contrast, we show that positive outcomes to climate change are possible if captive bred animals are prevented from breeding in the wild. Rather than imposing an additional genetic load on wild populations by releasing maladapted captive bred animals, we propose that conservation efforts should focus on optimizing conditions for adaptation to occur by reducing exploitation and protecting critical habitats. Our findings are likely to hold true for most poikilothermic species where captive breeding programmes are used in population management.

  18. The effect of habitat fragmentation on the genetic structure of a top predator: loss of diversity and high differentiation among remnant populations of Atlantic Forest jaguars (Panthera onca).

    PubMed

    Haag, T; Santos, A S; Sana, D A; Morato, R G; Cullen, L; Crawshaw, P G; De Angelo, C; Di Bitetti, M S; Salzano, F M; Eizirik, E

    2010-11-01

    Habitat fragmentation may disrupt original patterns of gene flow and lead to drift-induced differentiation among local population units. Top predators such as the jaguar may be particularly susceptible to this effect, given their low population densities, leading to small effective sizes in local fragments. On the other hand, the jaguar's high dispersal capabilities and relatively long generation time might counteract this process, slowing the effect of drift on local populations over the time frame of decades or centuries. In this study, we have addressed this issue by investigating the genetic structure of jaguars in a recently fragmented Atlantic Forest region, aiming to test whether loss of diversity and differentiation among local populations are detectable, and whether they can be attributed to the recent effect of drift. We used 13 microsatellite loci to characterize the genetic diversity present in four remnant populations, and observed marked differentiation among them, with evidence of recent allelic loss in local areas. Although some migrant and admixed individuals were identified, our results indicate that recent large-scale habitat removal and fragmentation among these areas has been sufficiently strong to promote differentiation induced by drift and loss of alleles at each site. Low estimated effective sizes supported the inference that genetic drift could have caused this effect within a short time frame. These results indicate that jaguars' ability to effectively disperse across the human-dominated landscapes that separate the fragments is currently very limited, and that each fragment contains a small, isolated population that is already suffering from the effects of genetic drift.

  19. Detecting population structure in a high gene-flow species, Atlantic herring (Clupea harengus): direct, simultaneous evaluation of neutral vs putatively selected loci.

    PubMed

    André, C; Larsson, L C; Laikre, L; Bekkevold, D; Brigham, J; Carvalho, G R; Dahlgren, T G; Hutchinson, W F; Mariani, S; Mudde, K; Ruzzante, D E; Ryman, N

    2011-02-01

    In many marine fish species, genetic population structure is typically weak because populations are large, evolutionarily young and have a high potential for gene flow. We tested whether genetic markers influenced by natural selection are more efficient than the presumed neutral genetic markers to detect population structure in Atlantic herring (Clupea harengus), a migratory pelagic species with large effective population sizes. We compared the spatial and temporal patterns of divergence and statistical power of three traditional genetic marker types, microsatellites, allozymes and mitochondrial DNA, with one microsatellite locus, Cpa112, previously shown to be influenced by divergent selection associated with salinity, and one locus located in the major histocompatibility complex class IIA (MHC-IIA) gene, using the same individuals across analyses. Samples were collected in 2002 and 2003 at two locations in the North Sea, one location in the Skagerrak and one location in the low-saline Baltic Sea. Levels of divergence for putatively neutral markers were generally low, with the exception of single outlier locus/sample combinations; microsatellites were the most statistically powerful markers under neutral expectations. We found no evidence of selection acting on the MHC locus. Cpa112, however, was highly divergent in the Baltic samples. Simulations addressing the statistical power for detecting population divergence showed that when using Cpa112 alone, compared with using eight presumed neutral microsatellite loci, sample sizes could be reduced by up to a tenth while still retaining high statistical power. Our results show that the loci influenced by selection can serve as powerful markers for detecting population structure in high gene-flow marine fish species.

  20. 78 FR 41305 - Collect on Delivery (COD)-Service Features

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-10

    ... 111 Collect on Delivery (COD)--Service Features AGENCY: Postal Service TM . ACTION: Final rule... for Collect on Delivery (COD) articles, expand the acceptable payment methods for COD articles, and provide current options for the redirecting of COD articles. DATES: Effective date: July 28, 2013. ]...

  1. 78 FR 32612 - Collect on Delivery (COD)-Service Features

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-31

    ... 111 Collect on Delivery (COD)--Service Features AGENCY: Postal Service\\TM\\. ACTION: Proposed rule... the automatic holding period for Collect on Delivery (COD) articles, expand the acceptable payment methods for COD articles, and provide current options for the redirecting of COD mailpieces. DATES:...

  2. The dangers of ignoring stock complexity in fishery management: the case of the North Sea cod.

    PubMed

    Hutchinson, William F

    2008-12-23

    The plight of the marine fisheries is attracting increasing attention as unsustainably high exploitation levels, exacerbated by more extreme climatic conditions, are driving stocks to the point of collapse. The North Atlantic cod (Gadus morhua), a species which until recently formed a major component of the demersal fisheries, has undergone significant declines across its range. The North Sea stock is typical of many, with a spawning stock biomass that has remained below the safe biological limit since 2000 and recruitment levels near the lowest on record. Cod within the North Sea are currently managed as a single stock, and yet mounting empirical evidence supports the existence of a metapopulation of regionally variable, genetically distinct, sub-stocks. Applying the same management strategies to multiple stocks that differ in their resilience to exploitation inevitably results in the overfishing and likely collapse of the weaker components. Indeed, recent studies have identified two North Sea spawning stocks that have undergone disproportionally large collapses with very substantial reductions in egg production. Similarly affected cod stocks in the northwest Atlantic have shown little evidence of recovery, despite fishery closures. The possible implications of ignoring sub-structuring within management units for biocomplexity, local adaptation and ecosystem stability are considered.

  3. Molecular classification of an elasmobranch angiotensin receptor: quantification of angiotensin receptor and natriuretic peptide receptor mRNAs in saltwater and freshwater populations of the Atlantic stingray.

    PubMed

    Evans, Andrew N; Henning, Toni; Gelsleichter, James; Nunez, B Scott

    2010-12-01

    Among the most conserved osmoregulatory hormone systems in vertebrates are the renin-angiotensin system (RAS) and the natriuretic peptides (NPs). We examined the RAS and NP system in the euryhaline Atlantic stingray, Dasyatis sabina (Lesueur). To determine the relative sensitivity of target organs to these hormonal systems, we isolated cDNA sequences encoding the D. sabina angiotensin receptor (AT) and natriuretic peptide type-B receptor (NPR-B). We then determined the tissue-specific expression of their mRNAs in saltwater D. sabina from local Texas waters and an isolated freshwater population in Lake Monroe, Florida. AT mRNA was most abundant in interrenal tissue from both populations. NPR-B mRNA was most abundant in rectal gland tissue from both populations, and also highly abundant in the kidney of saltwater D. sabina. This study is the first to report the sequence of an elasmobranch angiotensin receptor, and phylogenetic analysis indicates that the D. sabina receptor is more similar to AT(1) vs. AT(2) proteins. This classification is further supported by molecular analysis of AT(1) and AT(2) proteins demonstrating conservation of AT(1)-specific amino acid residues and motifs in D. sabina AT. Molecular classification of the elasmobranch angiotensin receptor as an AT(1)-like protein provides fundamental insight into the evolution of the vertebrate RAS.

  4. Isolation of microsatellite markers and analysis of genetic diversity among east Atlantic populations of the sword razor shell Ensis siliqua: a tool for population management.

    PubMed

    Arias-Pérez, Alberto; Fernández-Tajes, Juan; Gaspar, Miguel B; Méndez, Josefina

    2012-06-01

    The sword razor shell Ensis siliqua (Linnaeus, 1758) is found mainly from Norway to the Atlantic coast of the Iberian Peninsula. It is intensively caught in Europe, being highly appreciated as seafood. To help in its conservation and management, five microsatellite markers were isolated and genetic variation was analyzed in samples from Ireland, Spain, and Portugal. The highly significant differentiation (θ = 0.287, P < 0.001) observed was mainly due to differences between samples from Irish and Iberian Peninsula localities, except Aveiro (its sample resembled the Irish samples, and it may be predominantly self-recruiting). These groups of samples showed significant differences in allelic richness that could be related to harvesting intensity. Moreover, microsatellites detected low but significant differentiation between Iberian localities (Celeiro and Olhão), and Aveiro differed significantly from Strangford Lough. Overall, results suggest that two independently evolving regions exist and that management strategies should be designed for each region.

  5. Temporal variation of genetic composition in Atlantic salmon populations from the Western White Sea Basin: influence of anthropogenic factors?

    PubMed Central

    2013-01-01

    Background Studies of the temporal patterns of population genetic structure assist in evaluating the consequences of demographic and environmental changes on population stability and persistence. In this study, we evaluated the level of temporal genetic variation in 16 anadromous and 2 freshwater salmon populations from the Western White Sea Basin (Russia) using samples collected between 1995 and 2008. To assess whether the genetic stability was affected by human activity, we also evaluated the effect of fishing pressure on the temporal genetic variation in this region. Results We found that the genetic structure of salmon populations in this region was relatively stable over a period of 1.5 to 2.5 generations. However, the level of temporal variation varied among geographical regions: anadromous salmon of the Kola Peninsula exhibited a higher stability compared to that of the anadromous and freshwater salmon from the Karelian White Sea coast. This discrepancy was most likely attributed to the higher census, and therefore effective, population sizes of the populations inhabiting the rivers of the Kola Peninsula compared to salmon of the Karelian White Sea coast. Importantly, changes in the genetic diversity observed in a few anadromous populations were best explained by the increased level of fishing pressure in these populations rather than environmental variation or the negative effects of hatchery escapees. The observed population genetic patterns of isolation by distance remained consistent among earlier and more recent samples, which support the stability of the genetic structure over the period studied. Conclusions Given the increasing level of fishing pressure in the Western White Sea Basin and the higher level of temporal variation in populations exhibiting small census and effective population sizes, further genetic monitoring in this region is recommended, particularly on populations from the Karelian rivers. PMID:24053319

  6. 76 FR 63564 - Pacific Cod by Vessels Harvesting Pacific Cod for Processing by the Inshore Component in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-13

    ... Atmospheric Administration 50 CFR Part 679 [Docket No. 101126522-0640-02] RIN 0648-XA759 Pacific Cod by Vessels Harvesting Pacific Cod for Processing by the Inshore Component in the Central Regulatory Area of... for Pacific cod by vessels harvesting Pacific cod for processing by the inshore component in...

  7. 76 FR 80266 - Pacific Cod by Vessels Catching Pacific Cod for Processing by the Inshore Component of the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... Administration 50 CFR Part 679 [Docket No. 101126522-0640-02] RIN 0648-XA886 Pacific Cod by Vessels Catching Pacific Cod for Processing by the Inshore Component of the Central Regulatory Area of the Gulf of Alaska... Pacific cod by vessels catching Pacific cod for processing by the inshore component in the...

  8. Substrate mediates consumer control of salt marsh cordgrass on Cape Cod, New England.

    PubMed

    Bertness, Mark D; Holdredge, Christine; Altieri, Andrew H

    2009-08-01

    Cordgrass die-offs in Cape Cod, Massachusetts, USA, salt marshes have challenged the view that the primary production of New England salt marshes is controlled by physical factors. These die-offs have increased dramatically over the last decade and are caused by the common herbivorous marsh crab Sesarma reticulatum, but other factors that control crab impacts remain unclear. We examined the influence of plant nutrient supply and disturbances on Sesarma herbivory by fertilizing plots and creating experimental disturbances, since previous studies have revealed that they mediate the intensity of herbivory in other Western Atlantic marshes. Neither nutrient enrichment nor experimental disturbances affected crab grazing intensity despite their strong effects in other marsh systems. Within and among Cape Cod salt marshes, however, Sesarma burrows are concentrated on peat substrate. Surveys of 10 Cape Cod marshes revealed that burrow density, depth, and complexity are all much higher on peat than on sand or mud substrate, and paralleling these patterns, crab abundance, herbivore pressure, and the expansion of die-off areas are markedly higher on peat than on other substrates. Complementing work hypothesizing that predator release is triggering increased crab herbivory in Cape Cod marshes, these results suggest that cordgrass die-offs are constrained to the peat substrate commonly found on the leading edge of marshes and that the vulnerability of New England salt marshes to crab herbivory and future die-offs may be predictable.

  9. LATITUDINAL GRADIENTS IN BENTHIC COMMUNITY COMPOSITION IN WESTERN ATLANTIC ESTUARIES

    EPA Science Inventory

    The community structure of benthic macroinvertebrates from estuaries along the Atlantic coast of North America from Cape Cod, MA, to Biscayne Bay, FL, were compared. Benthic data were collected over a 5 year period (1990 to 1995) by the U.S. Environmental Protection Agency's Envi...

  10. Holocene re-colonisation, central-marginal distribution and habitat specialisation shape population genetic patterns within an Atlantic European grass species.

    PubMed

    Harter, D E V; Jentsch, A; Durka, W

    2015-05-01

    Corynephorus canescens (L.) P.Beauv. is an outbreeding, short-lived and wind-dispersed grass species, highly specialised on scattered and disturbance-dependent habitats of open sandy sites. Its distribution ranges from the Iberian Peninsula over Atlantic regions of Western and Central Europe, but excludes the two other classical European glacial refuge regions on the Apennine and Balkan Peninsulas. To investigate genetic patterns of this uncommon combination of ecological and biogeographic species characteristics, we analysed AFLP variation among 49 populations throughout the European distribution range, expecting (i) patterns of SW European glacial refugia and post-glacial expansion to the NE; (ii) decreasing genetic diversity from central to marginal populations; and (iii) interacting effects of high gene flow and disturbance-driven genetic drift. Decreasing genetic diversity from SW to NE and distinct gene pool clustering imply refugia on the Iberian Peninsula and in western France, from where range expansion originated towards the NE. High genetic diversity within and moderate genetic differentiation among populations, and a significant pattern of isolation-by-distance indicate a gene flow drift equilibrium within C. canescens, probably due to its restriction to scattered and dynamic habitats and limited dispersal distances. These features, as well as the re-colonisation history, were found to affect genetic diversity gradients from central to marginal populations. Our study emphasises the need for including the specific ecology into analyses of species (re-)colonisation histories and range centre-margin analyses. To account for discontinuous distributions, new indices of marginality were tested for their suitability in studies of centre-periphery gradients.

  11. Latitudinal patterns in the life-history traits of three isolated Atlantic populations of the deep-water shrimp Plesionika edwardsii (Decapoda, Pandalidae)

    NASA Astrophysics Data System (ADS)

    González, José A.; Pajuelo, José G.; Triay-Portella, Raül; Ruiz-Díaz, Raquel; Delgado, João; Góis, Ana R.; Martins, Albertino

    2016-11-01

    Patterns in the life-history traits of the pandalid shrimp Plesionika edwardsii are studied for the first time in three isolated Atlantic populations (Madeira, Canaries and Cape Verde Islands) to gain an understanding of their latitudinal variations. The maximum carapace size of the populations studied, as well as the maximum weight, showed clear latitudinal patterns. The patterns observed may be a consequence of the temperature experienced by shrimps during development, 1.37 ° C higher in the Canaries and 5.96 ° C higher in the Cape Verde Islands than in Madeira. These temperature differences among populations may have induced phenotypic plasticity because the observed final body size decreased as the temperature increased. A latitudinal north-south pattern was also observed in the maximum size of ovigerous females, with larger sizes found in the Madeira area and lower sizes observed in the Cape Verde Islands. A similar pattern was observed in the brood size and maximum egg size. Females of P. edwardsii produced smaller eggs in the Cape Verde Islands than did those at the higher latitude in Madeira. P. edwardsii was larger at sexual maturity in Madeira than in the Cape Verde Islands. The relative size at sexual maturity is not affected by latitude or environmental factors and is the same in the three areas studied, varying slightly between 0.568 and 0.585. P. edwardsii had a long reproductive season with ovigerous females observed all year round, although latitudinal variations were observed. Seasonally, there were more ovigerous females in spring and summer in Madeira and from winter to summer in the Cape Verde Islands. P. edwardsii showed a latitudinal pattern in size, with asymptotic size and growth rate showing a latitudinal compensation gradient as a result of an increased growth performance in the Madeira population compared to that of the Cape Verde Islands.

  12. Multiregional periodic matrix for modeling the population dynamics of sardine (Sardina pilchardus) along the moroccan atlantic coast: management elements for fisheries.

    PubMed

    Serghini, Mansour; Boutayeb, Abdesslam; Auger, Pierre; Charouki, Najib; Ramzi, Azeddine; Ettahiri, Omar; Tchuente, Maurice

    2009-12-01

    In this paper, we present a deterministic time discrete mathematical model based on multiregional periodic matrices to describe the dynamics of Sardina pilchardus in the Central Atlantic area of the Moroccan coast. This model deals with two stages (immature and mature) and three spatial zones where sardines are supposed to migrate from one zone to another. The population dynamics is described by an autonomous recurrence equation N(t + 1) = A.N(t), where A is a positive matrix whose entries are estimated using data collected during biannual acoustic surveys carried out from 2001 to 2003 onboard the Norwegian research vessel "Dr Fridtjof Nansen". The dominant eigenvalue lambda of A that gives the long-term growth rate of fish population is smaller than one. This agrees with the stock decrease observed in the data collected. We show that lambda is highly sensitive to the recruitment rate and much less sensitive to the reproduction rate. These results can clearly be used to define an efficient scenario in order to fight for instance against a stock decrease.

  13. Streamflow Flashiness in the Mid-Atlantic Region: A Historical Analysis of Flashiness and Population Density, Imperviousness and Urban Development

    EPA Science Inventory

    The relationship between stream flashiness and watershed-scale estimates of percent imperviousness, urban development, and population density were used in an historic landscape analysis at the individual watershed spatial scale. GIS technology was employed to spatially associate...

  14. Chemical quality of ground water on Cape Cod, Massachusetts

    USGS Publications Warehouse

    Frimpter, M.H.; Gay, F.B.

    1979-01-01

    Cape Cod is a 440 square mile hook-shaped peninsula which extends 40 miles into the Atlantic. Freshwater in Pleistocene sand and gravel deposits is the source of supply for nearly 100 municipal and thousands of private domestic wells. Most ground water on Cape Cod is of good chemical quality for drinking and other uses. It is characteristically low in dissolved solids and is soft. In 90 percent of the samples analyzed, dissolved solids were less than 100 mg/l (milligrams per liter) and pH was less than 7.0. Highway deicing salt, sea-water flooding due to storms , and saltwater intrusion due to ground-water withdrawal are sources of sodium chloride contamination. Chloride concentrations have increased from 20 to 140 mg/l, owing to saltwater intrusion at Provincetown 's wells in Truro. In Yarmouth, contaminated ground water near a salt-storage area contained as much as 1,800 mg/l chloride. Heavy metals, insecticides, and herbicides were not found at concentrations above the U.S. Environmental Protection Agency 's recommended limits for public drinking-water supplies, but iron and manganese in some samples exceeded those limits. Ninety percent of 84 samples analyzed for nitrate reported as nitrogen contained less than 1.3 mg/l and 80 percent contained 0.5 mg/l or less of nitrate as nitrogen. Water containing nitrogen in excess of 0.5 mg/l has probably been affected by municipal or domestic sewage or fertilizer, and water with less than this amount may have been affected by them. (Woodard-USGS)

  15. An Oscillating Jet in the Cape Cod Bay

    NASA Astrophysics Data System (ADS)

    Poulin, F. J.; Flierl, G. R.

    2004-05-01

    During the spring months, the Cape Cod Bay is a roaming ground for the North Atlantic right whale, perhaps the most endangered whale species in the world. The whales are observed to travel along the topographic steps that run parallel to the shore, eating plankton patches that form in the coastal water. In this region, off the coast of Provincetown, there is an oscillatory current with the same period as that of the ambient tides. The location of the current and its periodicity suggest that the topography and tides play fundamental roles in generating the jet. This current, depending on its velocity profile, may become unstable and generate vortices. It is likely that the local surface convergences and divergences in the tidal flows and vortices are related to the aggregation of the copepods (Calanus Finmarchicus), which are the right whale's primary food source. Understanding the dynamics of this jet is essential to predicting the spatial and temporal patterns of the codepods, which will in turn help us understand the likely locations and feeding history of the whales. In this talk we discuss results of the first phase of this study, that of the oscillatory jet in the Cape Cod Bay. This jet is rather complicated since it involves complex topography and coastlines, bottom and lateral friction, stratification and numerous other effects. Rather than study this system in fine detail, we investigate an idealized model that captures the essential features. In the context of this model, we first compute possible profiles for the oscillating jet. We then solve the linear stability problem to determine how the growth rates depend on the various parameters. Finally, and most importantly, we study the nonlinear problem to observe the time evolution of the instability process along with its equilibration. This provides some insight into how the instabilities are related to fluid transport across the shelf.

  16. Combined venomics, venom gland transcriptomics, bioactivities, and antivenomics of two Bothrops jararaca populations from geographic isolated regions within the Brazilian Atlantic rainforest.

    PubMed

    Gonçalves-Machado, Larissa; Pla, Davinia; Sanz, Libia; Jorge, Roberta Jeane B; Leitão-De-Araújo, Moema; Alves, Maria Lúcia M; Alvares, Diego Janisch; De Miranda, Joari; Nowatzki, Jenifer; de Morais-Zani, Karen; Fernandes, Wilson; Tanaka-Azevedo, Anita Mitico; Fernández, Julián; Zingali, Russolina B; Gutiérrez, José María; Corrêa-Netto, Carlos; Calvete, Juan J

    2016-03-01

    Bothrops jararaca is a slender and semi-arboreal medically relevant pit viper species endemic to tropical and subtropical forests in southern Brazil, Paraguay, and northern Argentina (Misiones). Within its geographic range, it is often abundant and is an important cause of snakebite. Although no subspecies are currently recognized, geographic analyses have revealed the existence of two well-supported B. jararaca clades that diverged during the Pliocene ~3.8Mya and currently display a southeastern (SE) and a southern (S) Atlantic rainforest (Mata Atlântica) distribution. The spectrum, geographic variability, and ontogenetic changes of the venom proteomes of snakes from these two B. jararaca phylogroups were investigated applying a combined venom gland transcriptomic and venomic analysis. Comparisons of the venom proteomes and transcriptomes of B. jararaca from the SE and S geographic regions revealed notable interpopulational variability that may be due to the different levels of population-specific transcriptional regulation, including, in the case of the southern population, a marked ontogenetic venom compositional change involving the upregulation of the myotoxic PLA2 homolog, bothropstoxin-I. This population-specific marker can be used to estimate the proportion of venom from the southern population present in the B. jararaca venom pool used for the Brazilian soro antibotrópico (SAB) antivenom production. On the other hand, the southeastern population-specific D49-PLA2 molecules, BinTX-I and BinTX-II, lend support to the notion that the mainland ancestor of Bothrops insularis was originated within the same population that gave rise to the current SE B. jararaca phylogroup, and that this insular species endemic to Queimada Grande Island (Brazil) expresses a pedomorphic venom phenotype. Mirroring their compositional divergence, the two geographic B. jararaca venom pools showed distinct bioactivity profiles. However, the SAB antivenom manufactured in Vital Brazil

  17. Analysis of a PAH-degrading bacterial population in subsurface sediments on the Mid-Atlantic Ridge

    NASA Astrophysics Data System (ADS)

    Shao, Zongze; Cui, Zhisong; Dong, Chunming; Lai, Qiliang; Chen, Liang

    2010-05-01

    Little is known about the types and concentrations of polycyclic aromatic hydrocarbons (PAHs) existing in the deep-sea subsurface environment, which is believed to be cold, oligothrophic and of high static pressure. PAHs in the upper layers of the water column are unavoidably subjected to degradation while they are deposited to the sea floor and become embedded in the deep-sea sediment. In this report, a high concentration of PAHs was discovered in the sediment 2.7 m beneath the bottom surface at a water depth of 3962 m on the Mid-Atlantic Ridge (MAR). The total concentration of PAHs was 445 ng (g dry wt sediment) -1. Among the seven detected PAHs, the concentrations of phenanthrene (222 ng g -1) and fluorene (79 ng g -1) were relatively high. In addition, PAH-degrading bacteria were found within the sediments. As in a previously detected site on the MAR, in the PAH-enriched region of this site, a bacterium of the genus Cycloclasticus was found to be the predominant isolate detected by PCR-DGGE analysis. In addition, bacteria of the Halomonas, Marinobacter, Alcanivorax, Thalassospira and Maricaulis genera, were also included in the PAH-degrading community. In summary, a high concentration of PAHs was detected in the subsurface of the deep-sea sediment, and once again, the Cycloclasticus bacterium was confirmed to be a ubiquitous marine PAH degrader even in the subsurface marine environment. Considering the abundance of PAHs therein, biodegradation is thus thought to be inactive, probably because of the low temperature, limited oxygen and/or limited nutrients.

  18. Cod (Gadus morhua) muscle proteome cataloging using 1D-PAGE protein separation, nano-liquid chromatography peptide fractionation, and linear trap quadrupole (LTQ) mass spectrometry.

    PubMed

    Gebriel, Mohammed; Uleberg, Kai-Erik; Larssen, Eivind; Bjørnstad, Anne Hjelle; Sivertsvik, Morten; Møller, Simon Geir

    2010-12-08

    Because Atlantic cod (Gadus morhua) has high economic value and its protein-rich muscle tissue is a food source, an increased understanding of the effects and consequences of environmental, nutritional, biological, and industrial factors on meat quality is necessary. To gain insight into cod muscle tissue protein composition, a large-scale proteomics approach has been used. One-dimensional polyacrylamide gel electrophoresis, nanoflow liquid chromatography peptide separation, and linear trap quadrupole mass spectrometry were used to identify 4804 peptides, which retrieved 9113 cod expressed sequence tags (ESTs), which in turn were mapped to 446 unique proteins. The same data set identified 3924 proteins from the zebrafish protein database, which highlights the complementary value of the two approaches. The generated data sets will act as a foundation for studies related to physiological status assessment of cod under different environmental conditions, screening for diseases, and biomarker identification for assessment of fish quality during industrial processing and preservation.

  19. A modified method for COD determination of solid waste, using a commercial COD kit and an adapted disposable weighing support.

    PubMed

    André, L; Pauss, A; Ribeiro, T

    2017-03-01

    The chemical oxygen demand (COD) is an essential parameter in waste management, particularly when monitoring wet anaerobic digestion processes. An adapted method to determine COD was developed for solid waste (total solids >15%). This method used commercial COD tubes and did not require sample dilution. A homemade plastic weighing support was used to transfer the solid sample into COD tubes. Potassium hydrogen phthalate and glucose used as standards showed an excellent repeatability. A small underestimation of the theoretical COD value (standard values around 5% lower than theoretical values) was also observed, mainly due to the intrinsic COD of the weighing support and to measurement uncertainties. The adapted COD method was tested using various solid wastes in the range of 1-8 mgCOD, determining the COD of dried and ground cellulose, cattle manure, straw and a mixed-substrate sample. This new adapted method could be used to monitor and design dry anaerobic digestion processes.

  20. Reproductive development of female plum curculio, conotrachelus nenuphar (Herbst) in the mid-atlantic: Presence of multivoltine populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The plum curculio, Conotrachelus nenuphar (Herbst), is a key pest of pome and stone fruit throughout eastern and central North America. There are two strains of plum curculio, the univoltine ‘northern’ strain and the multivoltine ‘southern’ strain. Voltinism associated with populations located in ...

  1. Abundance and distribution of Arctic cod (Boreogadus saida) and other pelagic fishes over the U.S. Continental Shelf of the Northern Bering and Chukchi Seas

    NASA Astrophysics Data System (ADS)

    De Robertis, Alex; Taylor, Kevin; Wilson, Christopher D.; Farley, Edward V.

    2017-01-01

    We conducted acoustic-trawl (AT) surveys of the northern Bering and Chukchi Seas during ice-free periods in 2012 and 2013. The mixed species assemblages in the study area required refinement of standard AT survey methods, and adjustment of trawl catches for the effects of trawl selectivity. Sensitivity analyses indicate that the AT abundance estimates are relatively robust to the assumptions of the analysis. These surveys indicate that midwater fishes are dominated by age-0 Arctic cod (Boreogadus saida), age-0 saffron cod (Eleginus gracilis), capelin (Mallotus villosus), and Pacific herring (Clupea pallasii). In both years, age-0 Arctic cod were distributed principally ≥69.5 °N, age-0 saffron cod were abundant in coastal areas between 66.5 and 69.5 °N, and Pacific herring were distributed south of 67 °N. These three fishes exhibited consistent associations with temperature, salinity and bottom depth: e.g., age-0 Arctic cod were abundant at lower mean water column temperatures than saffron cod. In contrast, capelin were distributed throughout the study area, and were not consistently associated with environmental measures. There was a geographic trend in body length, with smaller Arctic cod, saffron cod and capelin in northern areas, but smaller herring in the south. Arctic cod, saffron cod, herring and capelin were all >2 times more abundant in 2013 than 2012. Sizeable populations of age-0 Arctic cod were observed in the northern Chukchi Sea, which suggests that this area is an important nursery ground. However, relatively few older Arctic cod were observed in this and other surveys of the area, which suggests that either overwinter mortality of age-0 Arctic cod is high, and/or these fish are not retained on the Chukchi shelf.

  2. Impact of forest fragment size on the population structure of three palm species (Arecaceae) in the Brazilian Atlantic rainforest.

    PubMed

    Portela, Rita de Cássia Quitete; dos Santos, Flavio Antonio Maes

    2014-06-01

    The main threats to natural populations in terrestrial ecosystems have been widly recognized to be the habitat fragmentation and the exploitation of forest products. In this study, we compared the density of th