1
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Chang SL, Ward HGM, Elliott LD, Russello MA. Genotyping-in-Thousands by sequencing panel development and application for high-resolution monitoring of introgressive hybridization within sockeye salmon. Sci Rep 2022; 12:3441. [PMID: 35236892 PMCID: PMC8891347 DOI: 10.1038/s41598-022-07309-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 02/17/2022] [Indexed: 11/09/2022] Open
Abstract
Stocking programs have been widely implemented to re-establish extirpated fish species to their historical ranges; when employed in species with complex life histories, such management activities should include careful consideration of resulting hybridization dynamics with resident stocks and corresponding outcomes on recovery initiatives. Genetic monitoring can be instrumental for quantifying the extent of introgression over time, however conventional markers typically have limited power for the identification of advanced hybrid classes, especially at the intra-specific level. Here, we demonstrate a workflow for developing, evaluating and deploying a Genotyping-in-Thousands by Sequencing (GT-seq) SNP panel with the power to detect advanced hybrid classes to assess the extent and trajectory of intra-specific hybridization, using the sockeye salmon (Oncorhynchus nerka) stocking program in Skaha Lake, British Columbia as a case study. Previous analyses detected significant levels of hybridization between the anadromous (sockeye) and freshwater resident (kokanee) forms of O. nerka, but were restricted to assigning individuals to pure-stock or “hybrid”. Simulation analyses indicated our GT-seq panel had high accuracy, efficiency and power (> 94.5%) of assignment to pure-stock sockeye salmon/kokanee, F1, F2, and B2 backcross-sockeye/kokanee. Re-analysis of 2016/2017 spawners previously analyzed using TaqMan® assays and otolith microchemistry revealed shifts in assignment of some hybrids to adjacent pure-stock or B2 backcross classes, while new assignment of 2019 spawners revealed hybrids comprised 31% of the population, ~ 74% of which were B2 backcross or F2. Overall, the GT-seq panel development workflow presented here could be applied to virtually any system where genetic stock identification and intra-specific hybridization are important management parameters.
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Affiliation(s)
- Sarah L Chang
- Department of Biology, University of British Columbia, Kelowna, BC, Canada
| | - Hillary G M Ward
- Lands and Natural Resource Operations and Rural Development, British Columbia Ministry of Forests, Penticton, BC, Canada
| | - Lucas D Elliott
- Department of Biology, University of British Columbia, Kelowna, BC, Canada.,UiT The Arctic University of Norway, Tromsø, Norway
| | - Michael A Russello
- Department of Biology, University of British Columbia, Kelowna, BC, Canada.
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2
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Perry WB, Solberg MF, Brodie C, Medina AC, Pillay KG, Egerton A, Harvey A, Creer S, Llewellyn M, Taylor M, Carvalho G, Glover KA. Disentangling the effects of sex, life history and genetic background in Atlantic salmon: growth, heart and liver under common garden conditions. ROYAL SOCIETY OPEN SCIENCE 2020; 7:200811. [PMID: 33204455 PMCID: PMC7657880 DOI: 10.1098/rsos.200811] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 09/17/2020] [Indexed: 06/11/2023]
Abstract
Livestock domestication has long been a part of agriculture, estimated to have first occurred approximately 10 000 years ago. Despite the plethora of traits studied, there is little understanding of the possible impacts domestication has had on internal organs, which are key determinants of survival. Moreover, the genetic basis of observed associated changes in artificial environments is still puzzling. Here we examine impacts of captivity on two organs in Atlantic salmon (Salar salar) that have been domesticated for approximately 50 years: heart and liver, in addition to growth. We studied multiple families of wild, domesticated, F1 and F2 hybrid, and backcrossed strains of S. salar in replicated common garden tanks during the freshwater and marine stages of development. Heart and liver weight were investigated, along with heart morphology metrics examined in just the wild, domesticated and F1 hybrid strains (heart height and width). Growth was positively linked with the proportion of the domesticated strain, and recombination in F2 hybrids (and the potential disruption of co-adapted gene complexes) did not influence growth. Despite the influence of domestication on growth, we found no evidence for domestication-driven divergence in heart or liver morphology. However, sexual dimorphism was detected in heart morphology, and after controlling for body size, females exhibited significantly larger heart weight and heart width when compared with males. Wild females also had an increased heart height when compared with wild males, and this was not observed in any other strain. Females sampled in saltwater showed significantly larger heart height with rounder hearts, than saltwater males. Collectively, these results demonstrate an additive basis of growth and, despite a strong influence of domestication on growth, no clear evidence of changes in heart or liver morphology associated with domestication was identified.
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Affiliation(s)
- William Bernard Perry
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Monica F. Solberg
- Population Genetics Research Group, Institute of Marine Research, PO Box 1870, Nordnes 5817, Bergen, Norway
| | - Christopher Brodie
- Mariani Molecular Ecology Laboratory, School of Natural Sciences and Psychology, Liverpool John Moores University, Liverpool L3 5UX, UK
| | - Angela C. Medina
- School of Microbiology, Food Science and Technology Building University College Cork, Cork T12 TP07, Ireland
| | - Kirthana G. Pillay
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Anna Egerton
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Alison Harvey
- Population Genetics Research Group, Institute of Marine Research, PO Box 1870, Nordnes 5817, Bergen, Norway
| | - Simon Creer
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Martin Llewellyn
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Martin Taylor
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Gary Carvalho
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Kevin A. Glover
- Population Genetics Research Group, Institute of Marine Research, PO Box 1870, Nordnes 5817, Bergen, Norway
- Institute of Biology, University of Bergen, Bergen, Norway
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3
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Bicskei B, Taggart JB, Bron JE, Glover KA. Transcriptomic comparison of communally reared wild, domesticated and hybrid Atlantic salmon fry under stress and control conditions. BMC Genet 2020; 21:57. [PMID: 32471356 PMCID: PMC7257211 DOI: 10.1186/s12863-020-00858-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 05/12/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Domestication is the process by which organisms become adapted to the human-controlled environment. Since the selection pressures that act upon cultured and natural populations differ, adaptations that favour life in the domesticated environment are unlikely to be advantageous in the wild. Elucidation of the differences between wild and domesticated Atlantic salmon may provide insights into some of the genomic changes occurring during domestication, and, help to predict the evolutionary consequences of farmed salmon escapees interbreeding with wild conspecifics. In this study the transcriptome of the offspring of wild and domesticated Atlantic salmon were compared using a common-garden experiment under standard hatchery conditions and in response to an applied crowding stressor. RESULTS Transcriptomic differences between wild and domesticated crosses were largely consistent between the control and stress conditions, and included down-regulation of environmental information processing, immune and nervous system pathways and up-regulation of genetic information processing, carbohydrate metabolism, lipid metabolism and digestive and endocrine system pathways in the domesticated fish relative to their wild counterparts, likely reflective of different selection pressures acting in wild and cultured populations. Many stress responsive functions were also shared between crosses and included down-regulation of cellular processes and genetic information processing and up-regulation of some metabolic pathways, lipid and energy in particular. The latter may be indicative of mobilization and reallocation of energy resources in response to stress. However, functional analysis indicated that a number of pathways behave differently between domesticated and wild salmon in response to stress. Reciprocal F1 hybrids permitted investigation of inheritance patterns that govern transcriptomic differences between these genetically divergent crosses. Additivity and maternal dominance accounted for approximately 42 and 25% of all differences under control conditions for both hybrids respectively. However, the inheritance of genes differentially expressed between crosses under stress was less consistent between reciprocal hybrids, potentially reflecting maternal environmental effects. CONCLUSION We conclude that there are transcriptomic differences between the domesticated and wild salmon strains studied here, reflecting the different selection pressures operating on them. Our results indicate that stress may affect certain biological functions differently in wild, domesticated and hybrid crosses and these should be further investigated.
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Affiliation(s)
- Beatrix Bicskei
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA UK
| | - John B. Taggart
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA UK
| | - James E. Bron
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK9 4LA UK
| | - Kevin A. Glover
- Institute of Marine Research, Bergen, Norway
- Department of Biology, University of Bergen, Bergen, Norway
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4
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Besnier F, Solberg MF, Harvey AC, Carvalho GR, Bekkevold D, Taylor MI, Creer S, Nielsen EE, Skaala Ø, Ayllon F, Dahle G, Glover KA. Epistatic regulation of growth in Atlantic salmon revealed: a QTL study performed on the domesticated-wild interface. BMC Genet 2020; 21:13. [PMID: 32033538 PMCID: PMC7006396 DOI: 10.1186/s12863-020-0816-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Accepted: 01/28/2020] [Indexed: 12/23/2022] Open
Abstract
Background Quantitative traits are typically considered to be under additive genetic control. Although there are indications that non-additive factors have the potential to contribute to trait variation, experimental demonstration remains scarce. Here, we investigated the genetic basis of growth in Atlantic salmon by exploiting the high level of genetic diversity and trait expression among domesticated, hybrid and wild populations. Results After rearing fish in common-garden experiments under aquaculture conditions, we performed a variance component analysis in four mapping populations totaling ~ 7000 individuals from six wild, two domesticated and three F1 wild/domesticated hybrid strains. Across the four independent datasets, genome-wide significant quantitative trait loci (QTLs) associated with weight and length were detected on a total of 18 chromosomes, reflecting the polygenic nature of growth. Significant QTLs correlated with both length and weight were detected on chromosomes 2, 6 and 9 in multiple datasets. Significantly, epistatic QTLs were detected in all datasets. Discussion The observed interactions demonstrated that the phenotypic effect of inheriting an allele deviated between half-sib families. Gene-by-gene interactions were also suggested, where the combined effect of two loci resulted in a genetic effect upon phenotypic variance, while no genetic effect was detected when the two loci were considered separately. To our knowledge, this is the first documentation of epistasis in a quantitative trait in Atlantic salmon. These novel results are of relevance for breeding programs, and for predicting the evolutionary consequences of domestication-introgression in wild populations.
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Affiliation(s)
- Francois Besnier
- Population Genetics Research group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway.
| | - Monica F Solberg
- Population Genetics Research group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - Alison C Harvey
- Population Genetics Research group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway.,Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Deiniol Road, Bangor, LL57 2UW, UK
| | - Gary R Carvalho
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Deiniol Road, Bangor, LL57 2UW, UK
| | - Dorte Bekkevold
- Section for Marine Living Resources, National Institute of Aquatic Resources, Technical University of Denmark, Vejlsøvej 39, 8600, Silkeborg, Denmark
| | - Martin I Taylor
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Simon Creer
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Bangor University, Deiniol Road, Bangor, LL57 2UW, UK
| | - Einar E Nielsen
- Section for Marine Living Resources, National Institute of Aquatic Resources, Technical University of Denmark, Vejlsøvej 39, 8600, Silkeborg, Denmark
| | - Øystein Skaala
- Population Genetics Research group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - Fernando Ayllon
- Population Genetics Research group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - Geir Dahle
- Population Genetics Research group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway.,Sea Lice Research Centre, Department of Biology, University of Bergen, Bergen, Norway
| | - Kevin A Glover
- Population Genetics Research group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway.,Sea Lice Research Centre, Department of Biology, University of Bergen, Bergen, Norway
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5
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Solberg MF, Robertsen G, Sundt-Hansen LE, Hindar K, Glover KA. Domestication leads to increased predation susceptibility. Sci Rep 2020; 10:1929. [PMID: 32029847 PMCID: PMC7005312 DOI: 10.1038/s41598-020-58661-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 01/19/2020] [Indexed: 12/18/2022] Open
Abstract
Domestication involves adapting animals to the human-controlled environment. Genetic changes occurring during the domestication process may manifest themselves in phenotypes that render domesticated animals maladaptive for life in the wild. Domesticated Atlantic salmon frequently interbreed with wild conspecifics, and their offspring display reduced survival in the wild. However, the mechanism(s) contributing to their lower survival in the wild remains a subject of conjecture. Here, we document higher susceptibility to predation by brown trout in fast-growing domesticated salmon, as compared to their slow-growing wild conspecifics, demonstrating that directional selection for increased growth comes at a cost of decreased survival when under the risk of predation, as predicted by the growth/predation risk trade-off. Despite earlier documentation of altered risk-taking behavior, this study demonstrates for the first time that domestication of Atlantic salmon has lead to increased predation susceptibility, and that this consitutes a mechanism underpinning the observed survial differences in the wild.
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Affiliation(s)
- Monica F Solberg
- Institute of Marine Research, P.O. Box 1870 Nordnes, NO, 5817, Bergen, Norway.
| | - Grethe Robertsen
- Norwegian Institute for Nature Research (NINA), P.O. Box 5685 Torgarden, NO, 7485, Trondheim, Norway
| | - Line E Sundt-Hansen
- Norwegian Institute for Nature Research (NINA), P.O. Box 5685 Torgarden, NO, 7485, Trondheim, Norway
| | - Kjetil Hindar
- Norwegian Institute for Nature Research (NINA), P.O. Box 5685 Torgarden, NO, 7485, Trondheim, Norway
| | - Kevin A Glover
- Institute of Marine Research, P.O. Box 1870 Nordnes, NO, 5817, Bergen, Norway.,Department of Biology, University of Bergen, Bergen, Norway
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6
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Abstract
Salmon were among the first nonmodel species for which systematic population genetic studies of natural populations were conducted, often to support management and conservation. The genomics revolution has improved our understanding of the evolutionary ecology of salmon in two major ways: (a) Large increases in the numbers of genetic markers (from dozens to 104-106) provide greater power for traditional analyses, such as the delineation of population structure, hybridization, and population assignment, and (b) qualitatively new insights that were not possible with traditional genetic methods can be achieved by leveraging detailed information about the structure and function of the genome. Studies of the first type have been more common to date, largely because it has taken time for the necessary tools to be developed to fully understand the complex salmon genome. We expect that the next decade will witness many new studies that take full advantage of salmonid genomic resources.
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Affiliation(s)
- Robin S Waples
- Northwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, Washington 98112, USA;
| | - Kerry A Naish
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, Washington 98195-5020, USA;
| | - Craig R Primmer
- Organismal & Evolutionary Biology Research Program and Biotechnology Institute, University of Helsinki, 00014 Helsinki, Finland;
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7
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Wennevik V, Quintela M, Skaala Ø, Verspoor E, Prusov S, Glover KA. Population genetic analysis reveals a geographically limited transition zone between two genetically distinct Atlantic salmon lineages in Norway. Ecol Evol 2019; 9:6901-6921. [PMID: 31380023 PMCID: PMC6662299 DOI: 10.1002/ece3.5258] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 04/24/2019] [Accepted: 04/26/2019] [Indexed: 12/17/2022] Open
Abstract
Atlantic salmon is characterized by a high degree of population genetic structure throughout its native range. However, while populations inhabiting rivers in Norway and Russia make up a significant proportion of salmon in the Atlantic, thus far, genetic studies in this region have only encompassed low to modest numbers of populations. Here, we provide the first "in-depth" investigation of population genetic structuring in the species in this region. Analysis of 18 microsatellites on >9,000 fish from 115 rivers revealed highly significant population genetic structure throughout, following a hierarchical pattern. The highest and clearest level of division separated populations north and south of the Lofoten region in northern Norway. In this region, only a few populations displayed intermediate genetic profiles, strongly indicating a geographically limited transition zone. This was further supported by a dedicated cline analysis. Population genetic structure was also characterized by a pattern of isolation by distance. A decline in overall genetic diversity was observed from the south to the north, and two of the microsatellites showed a clear decrease in number of alleles across the observed transition zone. Together, these analyses support results from previous studies, that salmon in Norway originate from two main genetic lineages, one from the Barents-White Sea refugium that recolonized northern Norwegian and adjacent Russian rivers, and one from the eastern Atlantic that recolonized the rest of Norway. Furthermore, our results indicate that local conditions in the limited geographic transition zone between the two observed lineages, characterized by open coastline with no obvious barriers to gene flow, are strong enough to maintain the genetic differentiation between them.
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Affiliation(s)
| | | | | | - Eric Verspoor
- Rivers and Lochs Institute, Inverness CollegeUniversity of the Highlands and IslandsInvernessUK
| | - Sergey Prusov
- The Knipovich Polar Research Institute of Marine Fisheries and Oceanography (PINRO)MurmanskRussia
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8
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Skaala Ø, Besnier F, Borgstrøm R, Barlaup B, Sørvik AG, Normann E, Østebø BI, Hansen MM, Glover KA. An extensive common-garden study with domesticated and wild Atlantic salmon in the wild reveals impact on smolt production and shifts in fitness traits. Evol Appl 2019; 12:1001-1016. [PMID: 31080511 PMCID: PMC6503829 DOI: 10.1111/eva.12777] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 01/18/2019] [Accepted: 01/19/2019] [Indexed: 01/15/2023] Open
Abstract
Interactions between domesticated escapees and wild conspecifics represent a threat to the genetic integrity and fitness of native populations. For Atlantic salmon, the recurrent presence of large numbers of domesticated escapees in the wild makes it necessary to better understand their impacts on native populations. We planted 254,400 eggs from 75 families of domesticated, F1-hybrid, and wild salmon in a river containing up- and downstream traps. Additionally, 41,630 hatchery smolts of the same pedigrees were released into the river. Over 8 years, 6,669 out-migrating smolts and 356 returning adults were recaptured and identified to their families of origin with DNA. In comparison with wild salmon, domesticated fish had substantially lower egg to smolt survival (1.8% vs. 3.8% across cohorts), they migrated earlier in the year (11.8 days earlier across years), but they only displayed marginally larger smolt sizes and marginally lower smolt ages. Upon return to freshwater, domesticated salmon were substantially larger at age than wild salmon (2.4 vs. 2.0, 4.8 vs. 3.2, and 8.5 vs. 5.6 kg across sexes for 1, 2, and 3 sea-winter fish) and displayed substantially lower released smolt to adult survival (0.41% vs. 0.94% across releases). Overall, egg-to-returning adult survival ratios were 1:0.76:0.30 and 1:0.44:0.21 for wild:F1-hybrid:domesticated salmon, respectively, using two different types of data. This study represents the most updated and extensive analysis of domesticated, hybrid, and wild salmon in the wild and provides the first documentation of a clear genetic difference in the timing of smolt migration-an adaptive trait presumed to be linked with optimal timing of entry to seawater. We conclude that spawning and hybridization of domesticated escapees can lead to (i) reduced wild smolt output and therefore wild adult abundance, through resource competition in freshwater, (ii) reduced total adult abundance due to freshwater competition and reduced marine survival of domesticated salmon, and (iii) maladaptive changes in phenotypic traits.
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Affiliation(s)
| | | | - Reidar Borgstrøm
- Faculty of Environmental Sciences and Natural Resource ManagementÅsNorway
| | | | | | | | | | - Michael Møller Hansen
- Institute of Marine ResearchNordnes, BergenNorway
- Department of BioscienceAarhus UniversityAarhus CDenmark
| | - Kevin Alan Glover
- Institute of Marine ResearchNordnes, BergenNorway
- Department of Biological SciencesUniversity of BergenBergenNorway
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9
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Toews SD, Wellband KW, Dixon B, Heath DD. Variation in juvenile Chinook salmon (Oncorhynchus tshawytscha) transcription profiles among and within eight population crosses from British Columbia, Canada. Mol Ecol 2019; 28:1890-1903. [DOI: 10.1111/mec.15025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 01/02/2019] [Accepted: 01/07/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Shelby D. Toews
- Great Lakes Institute for Environmental Research University of Windsor Windsor Ontario Canada
| | - Kyle W. Wellband
- Great Lakes Institute for Environmental Research University of Windsor Windsor Ontario Canada
- Institute de Biologie Intégrative et des SystèmesUniversité LavalQuébec Québec Canada
| | - Brian Dixon
- Department of Biology University of Waterloo Waterloo Ontario Canada
| | - Daniel D. Heath
- Great Lakes Institute for Environmental Research University of Windsor Windsor Ontario Canada
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10
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Perry WB, Solberg MF, Besnier F, Dyrhovden L, Matre IH, Fjelldal PG, Ayllon F, Creer S, Llewellyn M, Taylor MI, Carvalho G, Glover KA. Evolutionary drivers of kype size in Atlantic salmon ( Salmo salar): domestication, age and genetics. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190021. [PMID: 31183145 PMCID: PMC6502380 DOI: 10.1098/rsos.190021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Accepted: 03/20/2019] [Indexed: 06/09/2023]
Abstract
The diversity of reproduction and associated mating patterns in Atlantic salmon (Salmo salar) has long captivated evolutionary biologists. Salmo salar exhibit strategies involving migration, bold mating behaviours and radical morphological and physiological change. One such radical change is the elongation and curvature of the lower jaw in sexually mature males into a hook-like appendage called the kype. The kype is a secondary sexual characteristic used in mating hierarchies and a prime candidate for sexual selection. As one of the core global aquaculture fish species, however, mate choice, and thus sexual selection, has been replaced by industrial artificial fertilization seeking to develop more commercially viable strains. Removal of mate choice provides a unique opportunity to examine the kype over successive generations in the absence of sexual selection. Here we use a large-scale common-garden experiment, incorporating six experimental strains (wild, farmed and wild × farmed hybrids), experiencing one to three sea winters, to assess the impact of age and genetic background. After controlling for allometry, fork length-adjusted kype height (AKH) was significantly reduced in the domesticated strain in comparison to two wild strains. Furthermore, genetic variation at a locus on linkage group SSA1 was associated with kype height, and a locus on linkage group SSA23 was associated with fork length-adjusted kype length (AKL). The reduction in fork length-AKH in domesticated salmon suggests that the kype is of importance in mate choice and that it has decreased due to relaxation of sexual selection. Fork length-AKL showed an increase in domesticated individuals, highlighting that it may not be an important cue in mate choice. These results give us insight into the evolutionary significance of the kype, as well as implications of genetic induced phenotypic change caused by domesticated individuals escaping into the natural environment.
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Affiliation(s)
- William Bernard Perry
- Molecular Ecology and Fisheries Genetics Laboratory, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Monica Favnebøe Solberg
- Population Genetics Research Group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817 Bergen, Norway
| | - Francois Besnier
- Population Genetics Research Group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817 Bergen, Norway
| | - Lise Dyrhovden
- Matre Research Station, Institute of Marine Research, Matredal, Norway
| | - Ivar Helge Matre
- Matre Research Station, Institute of Marine Research, Matredal, Norway
| | - Per Gunnar Fjelldal
- Population Genetics Research Group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817 Bergen, Norway
| | - Fernando Ayllon
- Population Genetics Research Group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817 Bergen, Norway
| | - Simon Creer
- Molecular Ecology and Fisheries Genetics Laboratory, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Martin Llewellyn
- Institute of Biodiversity, Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Martin I. Taylor
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
| | - Gary Carvalho
- Molecular Ecology and Fisheries Genetics Laboratory, School of Natural Sciences, Bangor University, Bangor, Gwynedd LL57 2UW, UK
| | - Kevin Alan Glover
- Population Genetics Research Group, Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817 Bergen, Norway
- Institute of Biology, University of Bergen, N-5020 Bergen, Norway
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11
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Glover KA, Solberg MF, Besnier F, Skaala Ø. Cryptic introgression: evidence that selection and plasticity mask the full phenotypic potential of domesticated Atlantic salmon in the wild. Sci Rep 2018; 8:13966. [PMID: 30228303 PMCID: PMC6143624 DOI: 10.1038/s41598-018-32467-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 09/03/2018] [Indexed: 01/13/2023] Open
Abstract
Domesticated Atlantic salmon grow much faster than wild salmon when reared together in fish tanks under farming conditions (size ratios typically 1:2-3). In contrast, domesticated salmon only display marginally higher growth than wild salmon when reared together in rivers (size ratios typically 1:1-1.2). This begs the question why? Is this a difference in the plastic response driven by divergent energy budgets between the two environments, or is it a result of selection, whereby domesticated salmon that display the greatest growth-potential are those at greatest risk of mortality in the wild? We reared domesticated, hybrid and wild salmon in a river until they smoltified at age 2 or 4, and thereafter in fish tanks for a further 2 years. In the river, there was no difference in the mean size between the groups. In contrast, after being transferred from the river to fish tanks, the domesticated salmon significantly outgrew the wild salmon (maximum size ratio of ~1:1.8). This demonstrates that selection alone cannot be responsible for the lack of growth differences observed between domesticated and wild salmon in rivers. Nevertheless, the final size ratios observed after rearing in tanks were lower than expected in that environment, thus suggesting that plasticity, as for selection, cannot be the sole mechanism. We therefore conclude that a combination of energy-budget plasticity, and selection via growth-potential mortality, cause the differences in growth reaction norms between domesticated and wild salmon across these contrasting environments. Our results imply that if phenotypic changes are not observed in wild populations following introgression of domesticated conspecifics, it does not mean that functional genetic changes have not occurred in the admixed population. Clearly, under the right environmental conditions, the underlying genetic changes will manifest themselves in the phenotype.
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Affiliation(s)
- Kevin A Glover
- Institute of Marine Research, P.O. Box 1870, N-5817, Bergen, Norway. .,University of Bergen, Department of Biology, P.O. Box 7803, N-5020, Bergen, Norway.
| | - Monica F Solberg
- Institute of Marine Research, P.O. Box 1870, N-5817, Bergen, Norway
| | - Francois Besnier
- Institute of Marine Research, P.O. Box 1870, N-5817, Bergen, Norway
| | - Øystein Skaala
- Institute of Marine Research, P.O. Box 1870, N-5817, Bergen, Norway
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12
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Castellani M, Heino M, Gilbey J, Araki H, Svåsand T, Glover KA. Modeling fitness changes in wild Atlantic salmon populations faced by spawning intrusion of domesticated escapees. Evol Appl 2018; 11:1010-1025. [PMID: 29928306 PMCID: PMC5999203 DOI: 10.1111/eva.12615] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 02/11/2018] [Indexed: 12/17/2022] Open
Abstract
Genetic interaction between domesticated escapees and wild conspecifics represents a persistent challenge to an environmentally sustainable Atlantic salmon aquaculture industry. We used a recently developed eco-genetic model (IBSEM) to investigate potential changes in a wild salmon population subject to spawning intrusion from domesticated escapees. At low intrusion levels (5%-10% escapees), phenotypic and demographic characteristics of the recipient wild population only displayed weak changes over 50 years and only at high intrusion levels (30%-50% escapees) were clear changes visible in this period. Our modeling also revealed that genetic changes in phenotypic and demographic characteristics were greater in situations where strayers originating from a neighboring wild population were domestication-admixed and changed in parallel with the focal wild population, as opposed to nonadmixed. While recovery in the phenotypic and demographic characteristics was observed in many instances after domesticated salmon intrusion was halted, in the most extreme intrusion scenario, the population went extinct. Based upon results from these simulations, together with existing knowledge, we suggest that a combination of reduced spawning success of domesticated escapees, natural selection purging maladapted phenotypes/genotypes from the wild population, and phenotypic plasticity, buffer the rate and magnitude of change in phenotypic and demographic characteristics of wild populations subject to spawning intrusion of domesticated escapees. The results of our simulations also suggest that under specific conditions, natural straying among wild populations may buffer genetic changes in phenotypic and demographic characteristics resulting from introgression of domesticated escapees and that variation in straying in time and space may contribute to observed differences in domestication-driven introgression among native populations.
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Affiliation(s)
| | - Mikko Heino
- Department of Biological SciencesUniversity of BergenBergenNorway
- Institute of Marine ResearchBergenNorway
- International Institute for Applied Systems Analysis (IIASA)LaxenburgAustria
| | - John Gilbey
- Freshwater Fisheries LaboratoryMarine ScotlandPitlochryUK
| | - Hitoshi Araki
- Research Faculty of AgricultureHokkaido UniversitySapporoJapan
| | | | - Kevin A. Glover
- Department of Biological SciencesUniversity of BergenBergenNorway
- Institute of Marine ResearchBergenNorway
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13
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Judging a salmon by its spots: environmental variation is the primary determinant of spot patterns in Salmo salar. BMC Ecol 2018; 18:14. [PMID: 29650003 PMCID: PMC5897946 DOI: 10.1186/s12898-018-0170-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Accepted: 03/27/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In fish, morphological colour changes occur from variations in pigment concentrations and in the morphology, density, and distribution of chromatophores in the skin. However, the underlying mechanisms remain unresolved in most species. Here, we describe the first investigation into the genetic and environmental basis of spot pattern development in one of the world's most studied fishes, the Atlantic salmon. We reared 920 salmon from 64 families of domesticated, F1-hybrid and wild origin in two contrasting environments (Hatchery; tanks for the freshwater stage and sea cages for the marine stage, and River; a natural river for the freshwater stage and tanks for the marine stage). Fish were measured, photographed and spot patterns evaluated. RESULTS In the Hatchery experiment, significant but modest differences in spot density were observed among domesticated, F1-hybrid (1.4-fold spottier than domesticated) and wild salmon (1.7-fold spottier than domesticated). A heritability of 6% was calculated for spot density, and a significant QTL on linkage group SSA014 was detected. In the River experiment, significant but modest differences in spot density were also observed among domesticated, F1-hybrid (1.2-fold spottier than domesticated) and wild salmon (1.8-fold spottier than domesticated). Domesticated salmon were sevenfold spottier in the Hatchery vs. River experiment. While different wild populations were used for the two experiments, on average, these were 6.2-fold spottier in the Hatchery vs. River experiment. Fish in the Hatchery experiment displayed scattered to random spot patterns while fish in the River experiment displayed clustered spot patterns. CONCLUSIONS These data demonstrate that while genetics plays an underlying role, environmental variation represents the primary determinant of spot pattern development in Atlantic salmon.
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14
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Harkat S, Laoun A, Belabdi I, Benali R, Outayeb D, Payet-Duprat N, Blanquet V, Lafri M, Da Silva A. Assessing patterns of genetic admixture between sheep breeds: Case study in Algeria. Ecol Evol 2017; 7:6404-6412. [PMID: 28861243 PMCID: PMC5574784 DOI: 10.1002/ece3.3069] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 04/02/2017] [Accepted: 04/02/2017] [Indexed: 11/06/2022] Open
Abstract
In developing countries, cross-breeding between local breeds and indigene or exotic breeds represents one of the main threats to the livestock diversity, leading to genetic dilution and loss of unique allelic combination underlying essential local adaptive traits. In this study, two Algerian sheep breeds, known to be highly admixed, were considered as a case study, to demonstrate how combination of different methodologies coupled with the use of specific softwares can be efficient to assess the spatial structuration of a hybrid zone, even in a case of extreme admixture. A fine sampling covering distribution areas of both breeds was implemented in order to study the admixture area and adjacent zones from a phenotypic (i.e., 19 quantitative traits were considered) and a genetic point of view (i.e., 21 microsatellites markers were used). Both approaches gave concordant patterns, highlighting areas with sheep most differentiated (or less admixed) for each breed. In detail, the region of Biskra appeared as the most preserved for the Ouled-Djellal breed and the northwest of Laghouat was identified as the most preserved area for the Rembi breed. The approach proposed in the study offers a low-cost solution to identify the most representative flocks of a breed, allowing the implementation of efficient conservation plans.
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Affiliation(s)
- Sahraoui Harkat
- Laboratoire des biotechnologies liées à la reproduction animale Université de Blida Blida Algeria
| | - Abbes Laoun
- Université de Djelfa Djelfa Algeria.,Ecole nationale supérieure vétérinaire d'El-Harrach Alger Algeria
| | - Ibrahim Belabdi
- Laboratoire des biotechnologies liées à la reproduction animale Université de Blida Blida Algeria
| | - Rédha Benali
- Laboratoire des biotechnologies liées à la reproduction animale Université de Blida Blida Algeria
| | - Djouhar Outayeb
- Laboratoire des biotechnologies liées à la reproduction animale Université de Blida Blida Algeria
| | - Nathalie Payet-Duprat
- INRA UMR 1061 Génétique Moléculaire Animale Limoges France.,Université de Limoges UMR 1061 Génétique Moléculaire Animale Limoges France
| | - Véronique Blanquet
- INRA UMR 1061 Génétique Moléculaire Animale Limoges France.,Université de Limoges UMR 1061 Génétique Moléculaire Animale Limoges France
| | - Mohamed Lafri
- Laboratoire des biotechnologies liées à la reproduction animale Université de Blida Blida Algeria
| | - Anne Da Silva
- INRA UMR 1061 Génétique Moléculaire Animale Limoges France.,Université de Limoges UMR 1061 Génétique Moléculaire Animale Limoges France
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15
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Burgerhout E, Mommens M, Johnsen H, Aunsmo A, Santi N, Andersen Ø. Genetic background and embryonic temperature affect DNA methylation and expression of myogenin and muscle development in Atlantic salmon (Salmo salar). PLoS One 2017; 12:e0179918. [PMID: 28662198 PMCID: PMC5491062 DOI: 10.1371/journal.pone.0179918] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 06/06/2017] [Indexed: 12/13/2022] Open
Abstract
The development of ectothermic embryos is strongly affected by incubation temperature, and thermal imprinting of body growth and muscle phenotype has been reported in various teleost fishes. The complex epigenetic regulation of muscle development in vertebrates involves DNA methylation of the myogenin promoter. Body growth is a heritable and highly variable trait among fish populations that allows for local adaptations, but also for selective breeding. Here we studied the epigenetic effects of embryonic temperature and genetic background on body growth, muscle cellularity and myogenin expression in farmed Atlantic salmon (Salmo salar). Eggs from salmon families with either high or low estimated breeding values for body growth, referred to as Fast and Slow genotypes, were incubated at 8°C or 4°C until the embryonic 'eyed-stage' followed by rearing at the production temperature of 8°C. Rearing temperature strongly affected the growth rates, and the 8°C fish were about twice as heavy as the 4°C fish in the order Fast8>Slow8>Fast4>Slow4 prior to seawater transfer. Fast8 was the largest fish also at harvest despite strong growth compensation in the low temperature groups. Larval myogenin expression was approximately 4-6 fold higher in the Fast8 group than in the other groups and was associated with relative low DNA methylation levels, but was positively correlated with the expression levels of the DNA methyltransferase genes dnmt1, dnmt3a and dnmt3b. Juvenile Fast8 fish displayed thicker white muscle fibres than Fast4 fish, while Slow 8 and Slow 4 showed no difference in muscle cellularity. The impact of genetic background on the thermal imprinting of body growth and muscle development in Atlantic salmon suggests that epigenetic variation might play a significant role in the local adaptation to fluctuating temperatures over short evolutionary time.
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Affiliation(s)
| | | | | | | | | | - Øivind Andersen
- Nofima AS, Ås, Norway
- Department of Animal and Aquaculture Sciences, Norwegian University of Life Sciences, Ås, Norway
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16
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Harvey AC, Fjelldal PG, Solberg MF, Hansen T, Glover KA. Ploidy elicits a whole-genome dosage effect: growth of triploid Atlantic salmon is linked to the genetic origin of the second maternal chromosome set. BMC Genet 2017; 18:34. [PMID: 28399816 PMCID: PMC5387229 DOI: 10.1186/s12863-017-0502-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 04/06/2017] [Indexed: 12/30/2022] Open
Abstract
Background The Atlantic salmon aquaculture industry is investigating the feasibility of using sterile triploids to mitigate genetic interactions with wild conspecifics, however, studies investigating diploid and triploid performance often show contrasting results. Studies have identified dosage and dosage-compensation effects for gene expression between triploid and diploid salmonids, but no study has investigated how ploidy and parent-origin effects interact on a polygenic trait in divergent lines of Atlantic salmon (i.e. slow growing wild versus fast growing domesticated phenotype). This study utilised two experiments relating to the freshwater growth of diploid and triploid groups of pure wild (0% domesticated genome), pure domesticated (100% domesticated genome), and F1 reciprocal hybrid (33%, 50% or 66% domesticated genome) salmon where triploidy was either artificially induced (experiment 1) or naturally developed/spontaneous (experiment 2). Results In both experiments, reciprocal hybrid growth was influenced by the dosage effect of the second maternal chromosome, with growth increasing as ploidy level increased in individuals with a domesticated dam (from 50% to 66% domesticated genome), and the inverse in individuals with a wild dam (from 50% to 33% domesticated genome). Conclusions We demonstrate that the combined effect of ploidy and parent-origin on growth, a polygenic trait, is regulated in an additive pattern. Therefore, in order to maximise growth potential, the aquaculture industry should consider placing more emphasis on the breeding value of the dam than the sire when producing triploid families for commercial production. Electronic supplementary material The online version of this article (doi:10.1186/s12863-017-0502-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- A C Harvey
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway.
| | - P G Fjelldal
- Institute of Marine Research (IMR), Matre Research Station, NO-5984, Matredal, Norway
| | - M F Solberg
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - T Hansen
- Institute of Marine Research (IMR), Matre Research Station, NO-5984, Matredal, Norway
| | - K A Glover
- Institute of Marine Research, P. O. Box 1870, Nordnes, NO-5817, Bergen, Norway.,Department of Biology, University of Bergen, P. O. Box 7803, N-5020, Bergen, Norway
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17
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Harvey AC, Solberg MF, Troianou E, Carvalho GR, Taylor MI, Creer S, Dyrhovden L, Matre IH, Glover KA. Plasticity in growth of farmed and wild Atlantic salmon: is the increased growth rate of farmed salmon caused by evolutionary adaptations to the commercial diet? BMC Evol Biol 2016; 16:264. [PMID: 27905882 PMCID: PMC5134087 DOI: 10.1186/s12862-016-0841-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 11/25/2016] [Indexed: 11/10/2022] Open
Abstract
Background Domestication of Atlantic salmon for commercial aquaculture has resulted in farmed salmon displaying substantially higher growth rates than wild salmon under farming conditions. In contrast, growth differences between farmed and wild salmon are much smaller when compared in the wild. The mechanisms underlying this contrast between environments remain largely unknown. It is possible that farmed salmon have adapted to the high-energy pellets developed specifically for aquaculture, contributing to inflated growth differences when fed on this diet. We studied growth and survival of 15 families of farmed, wild and F1 hybrid salmon fed three contrasting diets under hatchery conditions; a commercial salmon pellet diet, a commercial carp pellet diet, and a mixed natural diet consisting of preserved invertebrates commonly found in Norwegian rivers. Results For all groups, despite equal numbers of calories presented by all diets, overall growth reductions as high 68 and 83%, relative to the salmon diet was observed in the carp and natural diet treatments, respectively. Farmed salmon outgrew hybrid (intermediate) and wild salmon in all treatments. The relative growth difference between wild and farmed fish was highest in the carp diet (1: 2.1), intermediate in the salmon diet (1:1.9) and lowest in the natural diet (1:1.6). However, this trend was non-significant, and all groups displayed similar growth reaction norms and plasticity towards differing diets across the treatments. Conclusions No indication of genetic-based adaptation to the form or nutritional content of commercial salmon diets was detected in the farmed salmon. Therefore, we conclude that diet alone, at least in the absence of other environmental stressors, is not the primary cause for the large contrast in growth differences between farmed and wild salmon in the hatchery and wild. Additionally, we conclude that genetically-increased appetite is likely to be the primary reason why farmed salmon display higher growth rates than wild salmon when fed ad lib rations under hatchery conditions. Our results contribute towards an understanding of the potential genetic changes that have occurred in farmed salmon in response to domestication, and the potential mechanisms underpinning genetic and ecological interactions between farmed escapees and wild salmonids. Electronic supplementary material The online version of this article (doi:10.1186/s12862-016-0841-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alison Catherine Harvey
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Deiniol Road, Bangor University, Bangor, LL57 2UW, UK
| | | | - Eva Troianou
- Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - Gary Robert Carvalho
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Deiniol Road, Bangor University, Bangor, LL57 2UW, UK
| | - Martin Ian Taylor
- School of Biological Sciences, University of East Anglia, NR4 7TJ, Norwich, UK
| | - Simon Creer
- Molecular Ecology and Fisheries Genetics Laboratory, School of Biological Sciences, Deiniol Road, Bangor University, Bangor, LL57 2UW, UK
| | - Lise Dyrhovden
- Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - Ivar Helge Matre
- Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway
| | - Kevin Alan Glover
- Institute of Marine Research, P.O. Box 1870, Nordnes, NO-5817, Bergen, Norway.,Sea Lice Research Centre, Department of Biology, University of Bergen, Bergen, Norway
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