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Pampoulie C, Berg PR, Jentoft S. Hidden but revealed: After years of genetic studies behavioural monitoring combined with genomics uncover new insight into the population dynamics of Atlantic cod in Icelandic waters. Evol Appl 2023; 16:223-233. [PMID: 36793686 PMCID: PMC9923494 DOI: 10.1111/eva.13471] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 05/29/2022] [Accepted: 08/18/2022] [Indexed: 11/27/2022] Open
Abstract
Stock structure is of paramount importance for sustainable management of exploited resources. In that context, genetic markers have been used for more than two decades to resolve spatial structure of marine exploited resources and to fully fathom stock dynamics and interactions. While genetic markers such as allozymes and RFLP dominated the debate in the early era of genetics, technology advances have provided scientists with new tools every decade to better assess stock discrimination and interactions (i.e. gene flow). Here, we provide a review of genetic studies performed to understand stock structure of Atlantic cod in Icelandic waters, from the early allozyme approaches to the genomic work currently carried out. We further highlight the importance of the generation of a chromosome-anchored genome assembly together with whole-genome population data, which drastically changed our perception of the possible management units to consider. After nearly 60 years of genetic investigation of Atlantic cod structure in Icelandic waters, genetic (and later genomic) data combined with behavioural monitoring using Data Storage Tags shifted the attention from geographical population structures to behavioural ecotypes. This review also demonstrates the need for future research to further disentangle the impact of these ecotypes (and gene flow among them) on the population structure of Atlantic cod in Icelandic waters. It also highlights the importance of whole-genome data to unravel unexpected within-species diversity related to chromosomal inversions and associated supergenes, which are important to consider for future development of sustainable management programmes of the species within the North Atlantic.
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Affiliation(s)
| | - Paul Ragnar Berg
- Norwegian Institute for Water ResearchOsloNorway
- Department of Natural Sciences, Centre for Coastal Research (CCR)University of AgderKristiansandNorway
| | - Sissel Jentoft
- Centre for Ecological and Evolutionary SynthesisOsloNorway
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2
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Puncher GN, Rowe S, Rose GA, Parent GJ, Wang Y, Pavey SA. Life-stage-dependent supergene haplotype frequencies and metapopulation neutral genetic patterns of Atlantic cod, Gadus morhua, from Canada's Northern cod stock region and adjacent areas. JOURNAL OF FISH BIOLOGY 2021; 98:817-828. [PMID: 33244791 DOI: 10.1111/jfb.14632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 11/16/2020] [Accepted: 11/24/2020] [Indexed: 06/11/2023]
Abstract
Among highly migratory fish species, nursery areas occupied by juveniles often differ from adult habitats. To better understand the spatial dynamics of Canada's Northern cod stock, juveniles caught off the east coast of Newfoundland and Labrador were compared to adults from the same region as well as individuals from other areas in Atlantic Canada using double-digest restriction site-associated DNA sequencing-derived single nucleotide polymorphisms. A reduced proportion of homozygotes with a chromosomal inversion located in linkage group 1 (LG1) was detected between juvenile and adult samples in the Northern cod stock region, potentially indicating age-dependent habitat use or ontogenetic selection for attributes associated with the many genes located in LG1. No selectively neutral genetic differences were found between samples from the Northern cod stock; nevertheless, significant differences were found between some of these samples and cod collected from St. Pierre Bank, Bay of Fundy, Browns Bank and the southern Scotian Shelf. Clustering analysis of variants at neutral loci provided evidence for three major genetic units: (a) the Newfoundland Atlantic Coast, (b) eastern and southern Gulf of St. Lawrence and Burgeo Bank and (c) the Bay of Fundy, Browns Bank and southern Scotian Shelf. Both adaptive and neutral population structure within the Northern cod stock should be considered by managers to promote demographic rebuilding of the stock.
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Affiliation(s)
- Gregory Neils Puncher
- Department of Biological Sciences, Canadian Rivers Institute, University of New Brunswick, Saint John, Canada
- Genomics Laboratory, Maurice-Lamontagne Institute, Fisheries and Oceans Canada, Mont-Joli, Canada
- Centre for Fisheries Ecosystems Research, Fisheries and Marine Institute, Memorial University of Newfoundland, St. John's, Canada
| | - Sherrylynn Rowe
- Centre for Fisheries Ecosystems Research, Fisheries and Marine Institute, Memorial University of Newfoundland, St. John's, Canada
| | - George A Rose
- Institute for the Oceans and Fisheries, University of British Columbia, Vancouver, Canada
| | - Geneviève J Parent
- Genomics Laboratory, Maurice-Lamontagne Institute, Fisheries and Oceans Canada, Mont-Joli, Canada
| | - Yanjun Wang
- Fisheries and Oceans Canada, St. Andrews Biological Station, St. Andrews, Canada
| | - Scott A Pavey
- Department of Biological Sciences, Canadian Rivers Institute, University of New Brunswick, Saint John, Canada
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Otterå H, Johansen T, Folkvord A, Dahle G, Solvang Bingh MK, Westgaard JI, Glover KA. The pantophysin gene and its relationship with survival in early life stages of Atlantic cod. ROYAL SOCIETY OPEN SCIENCE 2020; 7:191983. [PMID: 33204437 PMCID: PMC7657904 DOI: 10.1098/rsos.191983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 09/21/2020] [Indexed: 06/11/2023]
Abstract
Genetic markers are widely used in fisheries management around the world. While the genetic structure and markers selected are usually based on samples from the wild, very few controlled experiments have been carried out to investigate possible differences in influence on traits between markers. Here we examine the bi-allelic gene pantophysin (Pan I), widely used in the management of Atlantic cod, in a series of in vitro crosses under a range of temperatures. It has been proposed that this gene, or another tightly linked gene, may be under strong divergent selection. Resolving this issue is essential in order to interpret results when using this gene marker for stock management. We found no evidence of departure from the expected 1 : 2 : 1 Mendelian ratio for any of the three genotypes during the egg stage, while both the 6 and 12°C temperature regimes in tank experiments favoured the survival of the Pan IAA genotype. No difference in genotype survival was, however, found in a more natural mesocosm environment. Collectively, these results suggest that for the early life stages of Atlantic cod, and under the current experimental conditions, there is no strong consistent influence of Pan I genotype on survival. The results also emphasize the importance of varied experimental studies to verify the importance of environmental factors influencing genotype selection.
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Affiliation(s)
- Håkon Otterå
- Institute of Marine Research, POB 1870, 5817 Bergen, Norway
| | - Torild Johansen
- Institute of Marine Research, Tromsø Division, Framsenteret 9296 Tromsø, Norway
| | - Arild Folkvord
- Institute of Marine Research, POB 1870, 5817 Bergen, Norway
- Department of Biological Sciences, University of Bergen, Thormøhlensgt. 53, 5020Bergen
| | - Geir Dahle
- Institute of Marine Research, POB 1870, 5817 Bergen, Norway
| | | | - Jon-Ivar Westgaard
- Institute of Marine Research, Tromsø Division, Framsenteret 9296 Tromsø, Norway
| | - Kevin A. Glover
- Institute of Marine Research, POB 1870, 5817 Bergen, Norway
- Department of Biological Sciences, University of Bergen, Thormøhlensgt. 53, 5020Bergen
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4
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Frommel A, Hermann B, Michael K, Lucassen M, Clemmesen C, Hanel R, Reusch T. Differential gene expression patterns related to lipid metabolism in response to ocean acidification in larvae and juveniles of Atlantic cod. Comp Biochem Physiol A Mol Integr Physiol 2020; 247:110740. [DOI: 10.1016/j.cbpa.2020.110740] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 01/10/2023]
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Valen R, Karlsen R, Helvik JV. Environmental, population and life-stage plasticity in the visual system of Atlantic cod. ACTA ACUST UNITED AC 2018; 221:jeb.165191. [PMID: 29146770 DOI: 10.1242/jeb.165191] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 11/12/2017] [Indexed: 02/03/2023]
Abstract
The visual system is for many fishes essential in guiding behaviors, such as foraging, predator avoidance and mate choice. The marine environment is characterized by large spatio-temporal fluctuations in light intensity and spectral composition. However, visual capabilities are restricted by both space limitations set by eye size and by the genomic content of light-absorbing opsin genes. The rich array of visual opsins in teleosts may be used differentially to tune vision towards specific needs during ontogeny and to changing light. Yet, to what extent visual plasticity is a pre-programmed developmental event, or is triggered by photic environment, is unclear. Our previous studies on Atlantic cod revealed an evolutionary genomic loss of UV-sensitive sws1 and red-sensitive lws opsin families, while blue-sensitive sws2 and green-sensitive rh2 opsins had duplicated. The current study has taken an opsin expression approach to characterize visual plasticity in cod towards different spectral light during the larval stage, to maturation and extreme seasonal changes in the Barents Sea. Our data suggest that opsin plasticity in cod larvae is controlled by developmental programme rather than immediate light environment. The lack of expressional changes during maturation suggests a less important role for visual modulation related to mate choice. Although no seasonal effects on visual opsins were detected in migratory Northeast Arctic cod, the expressed opsin subset differed from the more stationary Norwegian coastal cod described in previous studies. Interestingly, these data provide the first indications of a population difference in actively used visual opsins associated with cod ecotypes.
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Affiliation(s)
- Ragnhild Valen
- Department of Biology, University of Bergen, NO-5020 Bergen, Norway
| | - Rita Karlsen
- Department of Biology, University of Bergen, NO-5020 Bergen, Norway
| | - Jon Vidar Helvik
- Department of Biology, University of Bergen, NO-5020 Bergen, Norway
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Valdersnes S, Nilsen BM, Breivik JF, Borge A, Maage A. Geographical trends of PFAS in cod livers along the Norwegian coast. PLoS One 2017; 12:e0177947. [PMID: 28531177 PMCID: PMC5439708 DOI: 10.1371/journal.pone.0177947] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 05/05/2017] [Indexed: 02/03/2023] Open
Abstract
The level of perfluorinated alkyl substances (PFAS) was determined in North East Arctic cod (Gadus morhua) liver samples from 15 Norwegian fjords and harbors. Five harbors in the eastern part of Norway, six harbors in the western part and four harbours in the northern part. A total of 200 samples were analyzed for 16 PFAS. Determination of PFAS were carried out by LC-MS/MS following sample clean up by solid phase extraction and ultracentrifugation. The predominating PFAS was PFOS, which was found to be higher than the level of quantification (1.5 μg kg-1 wet weight) in 72% of the samples. The highest level of PFOS found was 21.8 μg kg-1 wet weight in a sample from Kragerø in the eastern part of Norway. A significantly higher level of PFOS was found in the eastern fjords and harbors compared to fjords and harbors in the western and northern part of Norway. Within the northern fjords and harbors elevated PFOS levels were found in Narvik, which may indicate a local source there. Variations in PFOS of the cod livers thus reflect differences in levels of pollution between the areas.
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Affiliation(s)
- Stig Valdersnes
- National Institute of Nutrition and Seafood Research (NIFES), Nordnes, Bergen, Norway
| | - Bente M. Nilsen
- National Institute of Nutrition and Seafood Research (NIFES), Nordnes, Bergen, Norway
| | - Joar F. Breivik
- National Institute of Nutrition and Seafood Research (NIFES), Nordnes, Bergen, Norway
| | - Asbjørn Borge
- Institute of Marine Research, Nordnes, Bergen, Norway
| | - Amund Maage
- National Institute of Nutrition and Seafood Research (NIFES), Nordnes, Bergen, Norway
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7
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Berg PR, Star B, Pampoulie C, Sodeland M, Barth JMI, Knutsen H, Jakobsen KS, Jentoft S. Three chromosomal rearrangements promote genomic divergence between migratory and stationary ecotypes of Atlantic cod. Sci Rep 2016; 6:23246. [PMID: 26983361 PMCID: PMC4794648 DOI: 10.1038/srep23246] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 03/02/2016] [Indexed: 12/15/2022] Open
Abstract
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.
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Affiliation(s)
- Paul R Berg
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, N-0316 Oslo, Norway
| | - Bastiaan Star
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, N-0316 Oslo, Norway
| | | | - Marte Sodeland
- Institute of Marine Research, Flødevigen, N-4817 His, Norway.,Department of Natural Sciences, University of Agder, N-4604 Kristiansand, Norway
| | - Julia M I Barth
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, N-0316 Oslo, Norway
| | - Halvor Knutsen
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, N-0316 Oslo, Norway.,Institute of Marine Research, Flødevigen, N-4817 His, Norway.,Department of Natural Sciences, University of Agder, N-4604 Kristiansand, Norway
| | - Kjetill S Jakobsen
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, N-0316 Oslo, Norway
| | - Sissel Jentoft
- Centre for Ecological and Evolutionary Synthesis, Department of Biosciences, University of Oslo, N-0316 Oslo, Norway.,Department of Natural Sciences, University of Agder, N-4604 Kristiansand, Norway
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8
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Pampoulie C, Skirnisdottir S, Star B, Jentoft S, Jónsdóttir IG, Hjörleifsson E, Thorsteinsson V, Pálsson ÓK, Berg PR, Andersen Ø, Magnusdottir S, Helyar SJ, Daníelsdóttir AK. Rhodopsin Gene Polymorphism Associated with Divergent Light Environments in Atlantic Cod. Behav Genet 2015; 45:236-44. [DOI: 10.1007/s10519-014-9701-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 12/15/2014] [Indexed: 11/24/2022]
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Karlsen BO, Klingan K, Emblem Å, Jørgensen TE, Jueterbock A, Furmanek T, Hoarau G, Johansen SD, Nordeide JT, Moum T. Genomic divergence between the migratory and stationary ecotypes of Atlantic cod. Mol Ecol 2013; 22:5098-111. [DOI: 10.1111/mec.12454] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/30/2013] [Accepted: 07/09/2013] [Indexed: 01/15/2023]
Affiliation(s)
- Bård O. Karlsen
- Faculty of Biosciences and Aquaculture; University of Nordland; N-8049 Bodø Norway
- Department of Medical Biology; Faculty of Health Sciences; University of Tromsø; N-9037 Tromsø Norway
- Division of Molecular Diagnostics; Department of Laboratory Medicine; Nordland Hospital Trust; N-8092 Bodø Norway
| | - Kevin Klingan
- Faculty of Biosciences and Aquaculture; University of Nordland; N-8049 Bodø Norway
| | - Åse Emblem
- Department of Medical Biology; Faculty of Health Sciences; University of Tromsø; N-9037 Tromsø Norway
| | - Tor E. Jørgensen
- Faculty of Biosciences and Aquaculture; University of Nordland; N-8049 Bodø Norway
| | - Alexander Jueterbock
- Faculty of Biosciences and Aquaculture; University of Nordland; N-8049 Bodø Norway
| | - Tomasz Furmanek
- Institute of Marine Research; PO Box 1870 Nordnesgaten 50 5817 Bergen Norway
| | - Galice Hoarau
- Faculty of Biosciences and Aquaculture; University of Nordland; N-8049 Bodø Norway
| | - Steinar D. Johansen
- Faculty of Biosciences and Aquaculture; University of Nordland; N-8049 Bodø Norway
- Department of Medical Biology; Faculty of Health Sciences; University of Tromsø; N-9037 Tromsø Norway
| | - Jarle T. Nordeide
- Faculty of Biosciences and Aquaculture; University of Nordland; N-8049 Bodø Norway
| | - Truls Moum
- Faculty of Biosciences and Aquaculture; University of Nordland; N-8049 Bodø Norway
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10
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Ross SD, Behrens JW, Brander K, Methling C, Mork J. Haemoglobin genotypes in cod (Gadus morhua L): Their geographic distribution and physiological significance. Comp Biochem Physiol A Mol Integr Physiol 2013; 166:158-68. [DOI: 10.1016/j.cbpa.2013.05.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 05/21/2013] [Accepted: 05/24/2013] [Indexed: 11/26/2022]
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Grabowski TB, Boswell KM, McAdam BJ, Wells RJD, Marteinsdóttir G. Characterization of Atlantic cod spawning habitat and behavior in Icelandic coastal waters. PLoS One 2012; 7:e51321. [PMID: 23236471 PMCID: PMC3517460 DOI: 10.1371/journal.pone.0051321] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Accepted: 10/31/2012] [Indexed: 12/04/2022] Open
Abstract
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.
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Jung KM, Folkvord A, Kjesbu OS, Agnalt AL, Thorsen A, Sundby S. Egg buoyancy variability in local populations of Atlantic cod ( Gadus morhua). MARINE BIOLOGY 2012; 159:1969-1980. [PMID: 24391277 PMCID: PMC3873015 DOI: 10.1007/s00227-012-1984-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Accepted: 06/09/2012] [Indexed: 06/03/2023]
Abstract
Previous studies have found strong evidences for Atlantic cod (Gadus morhua) egg retention in fjords, which are caused by the combination of vertical salinity structure, estuarine circulation, and egg specific gravity, supporting small-scaled geographical differentiations of local populations. Here, we assess the variability in egg specific gravity for selected local populations of this species, that is, two fjord-spawning populations and one coastal-spawning population from Northern Norway (66-71°N/10-25°E). Eggs were naturally spawned by raised broodstocks (March to April 2009), and egg specific gravity was measured by a density-gradient column. The phenotype of egg specific gravity was similar among the three local populations. However, the associated variability was greater at the individual level than at the population level. The noted gradual decrease in specific gravity from gastrulation to hatching with an increase just before hatching could be a generic pattern in pelagic marine fish eggs. This study provides needed input to adequately understand and model fish egg dispersal.
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Affiliation(s)
- Kyung-Mi Jung
- Institute of Marine Research, P.O. Box 1870, Nordnes, 5817 Bergen, Norway
- Department of Biology, University of Bergen, P.O. Box 7800, 5020 Bergen, Norway
| | - Arild Folkvord
- Department of Biology, University of Bergen, P.O. Box 7800, 5020 Bergen, Norway
| | - Olav Sigurd Kjesbu
- Institute of Marine Research, P.O. Box 1870, Nordnes, 5817 Bergen, Norway
| | - Ann Lisbeth Agnalt
- Institute of Marine Research, P.O. Box 1870, Nordnes, 5817 Bergen, Norway
| | - Anders Thorsen
- Institute of Marine Research, P.O. Box 1870, Nordnes, 5817 Bergen, Norway
| | - Svein Sundby
- Institute of Marine Research, P.O. Box 1870, Nordnes, 5817 Bergen, Norway
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Evidence of segregated spawning in a single marine fish stock: sympatric divergence of ecotypes in Icelandic cod? PLoS One 2011; 6:e17528. [PMID: 21408180 PMCID: PMC3049785 DOI: 10.1371/journal.pone.0017528] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 02/03/2011] [Indexed: 11/19/2022] Open
Abstract
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.
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Are Vertical Behaviour Patterns Related to the Pantophysin Locus in the Atlantic Cod (Gadus morhua L.)? Behav Genet 2007; 38:76-81. [DOI: 10.1007/s10519-007-9175-y] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2007] [Accepted: 10/11/2007] [Indexed: 10/22/2022]
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15
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Evaluation of different cod viscera fractions and their seasonal variation used in a growth medium for lactic acid bacteria. Enzyme Microb Technol 2007. [DOI: 10.1016/j.enzmictec.2006.10.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Rudolfsen G, Figenschou L, Folstad I, Nordeide JT, Søreng E. Potential fitness benefits from mate selection in the Atlantic cod (Gadus morhua). J Evol Biol 2005; 18:172-9. [PMID: 15669974 DOI: 10.1111/j.1420-9101.2004.00778.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Little evidence of benefits from female mate choice has been found when males provide no parental care or resources. Yet, good genes models of sexual selection suggest that elaborated male sexual characters are reliable signals of mate quality and that the offspring of males with elaborate sexual ornaments will perform better than those of males with less elaborate ornaments. We used cod (Gadus morhua L.), an externally fertilizing species where males provide nothing but sperm, to examine the potential of optimal mate selection with respect to offspring survival. By applying in vitro fertilizations, we crossed eight females with nine males in all possible combinations and reared each of the 72 sib groups. We found that offspring survival was dependent on which female was mated with which male and that optimal mate selection has the potential to increase mean offspring survival from 31.9 to 55.6% (a 74% increase). However, the size of the male sexual ornaments and sperm quality (i.e. sperm velocity and sperm density) could not predict offspring survival. Thus, even if there may be large fitness benefits of mate selection, we might not yet have identified the male characteristics generating high offspring survival.
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Affiliation(s)
- G Rudolfsen
- Department of Evolution and Ecology, Institute of Biology, University of Tromsø, Tromsø, Norway.
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17
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Rowe S, Hutchings JA. The function of sound production by Atlantic cod as inferred from patterns of variation in drumming muscle mass. CAN J ZOOL 2004. [DOI: 10.1139/z04-119] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We quantified variation in the mass of drumming muscles (the sound-producing musculature) among individual Atlantic cod (Gadus morhua L., 1758) for comparison with other evidence on the role of sexual selection in the evolution of sound production by this species. Based on 913 cod sampled from the Western Scotian Shelf in 2001–2002, we found that males had drumming muscles that were larger than those of females and that increased in mass prior to spawning and declined thereafter. Drumming muscle mass was highly variable, particularly among males, and generally more variable than other morphological traits (somatic mass and body length). This pattern of drumming muscle variation is consistent with the hypothesis that drumming muscles are influenced by sexual selection and suggests that sound production by males during the spawning season has fitness benefits, perhaps through a role in mate competition. Drumming muscle mass of spawning males was also positively associated with body size, condition, and fertilization potential, suggesting that sound production may be an indicator of the size of the signaler and may reveal information about individual quality. In conjunction with previous studies of sound production by Atlantic cod, our study underscores the potential importance of sound production to cod spawning behaviour.
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18
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Rowe S, Hutchings JA. Mating systems and the conservation of commercially exploited marine fish. Trends Ecol Evol 2003. [DOI: 10.1016/j.tree.2003.09.004] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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