Farmed cod escapees and net-pen spawning left no clear genetic footprint in the local wild cod population

Varne, Rebekka; Kunz, Kristina; Johansen, Torild; Westgaard, Jon‐Ivar; Uglem, Ingebrigt; Mork, Jarle

doi:10.3354/aei00153

Cited by 5 publications

(6 citation statements)

References 73 publications

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“…The last decade has seen both a rise in concern regarding the direct genetic impacts of farmed escapees and a large number of new studies bearing on this issue, and there is an urgent need to review current understanding. This is amplified by the development of aquaculture production of other species, which also involves potential genetic interactions with wild conspecifics (Glover, Dahle, & Jorstad, 2011;Somarakis, Pavlidis, Saapoglou, Tsigenopoulos, & Dempster, 2013;Varne et al, 2015).…”

mentioning

confidence: 99%

Half a century of genetic interaction between farmed and wild Atlantic salmon: Status of knowledge and unanswered questions

et al. 2017

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Atlantic salmon (Salmo salar) is one of the best researched fishes, and its aquaculture plays a global role in the blue revolution. However, since the 1970s, tens of millions of farmed salmon have escaped into the wild. We review current knowledge of genetic interactions and identify the unanswered questions. Native salmon populations are typically genetically distinct from each other and potentially locally adapted. Outside Norway, introgression remains unquantified, and in all regions, biological changes and the mechanisms driving population-specific impacts remain poorly documented. Nevertheless, existing knowledge shows that the long-term consequences of introgression is expected to lead to changes in life-history traits, reduced population productivity and decreased resilience to future challenges. Only a major reduction in the number of escapees and/or sterility of farmed salmon can eliminate further impacts. K E Y W O R D Saquaculture, evolution, fish farming, fitness, genetic, hybrid

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mentioning

confidence: 99%

Half a century of genetic interaction between farmed and wild Atlantic salmon: Status of knowledge and unanswered questions

et al. 2017

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“…Although the cod farming industry is currently experiencing low productivity, the potential for genetic interactions between escapees and wild conspecifics is high, given that cod have the ability to escape into the wild via spawning within cages (Jørstad et al 2008), as well as escape into the wild itself (Uglem et al 2008, Jensen et al 2010. In Norway where this has been studied, interactions between farmed escaped cod and wild populations have already been reported (Glover et al 2010, 2011, Varne et al 2015. While the present study did not investigate potential fitness differences between partly domesticated and wild cod, we did investigate growth differences as a proxy for domestication status.…”

Section: Discussionmentioning

confidence: 99%

Growth of wild and domesticated Atlantic cod Gadus morhua reared under semi-commercial conditions

Otterå¹,

Heino²,

Sørvik³

et al. 2018

Aquacult. Environ. Interact.

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Genetic interactions between farmed escapees and wild fish represent a challenge to environmentally sustainable aquaculture. Breeding programs for Atlantic cod Gadus morhua have been initiated; however, the genetic response to selection, and therefore the degree of domestication, has not been evaluated. We compared growth of 2 wild and 2 partly domesticated strains that had been under selection for 2 generations. Offspring of 54 synchronously produced families were reared in 2 common-garden experiments, each consisting of Phase I: parallel rearing in mesocosms and tanks 0−8 mo post-hatch, and Phase II: rearing in tanks or sea-cages 8−18 and 8−34 mo post-hatch, respectively. One of the domesticated strains displayed significantly higher growth compared to the wild Northeast Arctic cod population (48−67% higher weight), while the other domesticated strain had a similar growth rate to the Northeast Arctic cod population. The wild population from southern Norway displayed a significantly higher growth rate compared to the wild Northeast Arctic cod population. These results represent the first experimental estimation of domestication-driven changes in farmed cod, and demonstrate that the first breeding programs for this species have been partially successful, resulting in improved growth rates of cod in 2 generations.

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“…While the possibilities of such reproductive interaction cannot be ruled out, the expression of secondary sexual characteristics in farmed cod has been modified compared to the wild counterparts 217 . Varne et al 218 studied potential genetic introgression of farmed cod escapees and net pen spawning in Trondheimsfjord, Norway, and found no clear genetic footprint in the local wild population. They could not find any larvae of farmed origin in plankton samples and related the lack of genetic footprint to fitness and survival of net pen spawned larvae and adult escapees.…”

Section: Cage Productionmentioning

confidence: 99%

“…75,216 While the possibilities of such reproductive interaction cannot be ruled out, the expression of secondary sexual characteristics in farmed cod has been modified compared to the wild counterparts. 217 Varne et al 218 gence in farmed cod is rapid which could affect their competitiveness in terms of reproduction and survival capabilities. 206 Further, there are clear differences in morphology, physiology and behaviour between farmed and wild cod in terms of anti-predator behaviour and feeding strategies.…”

Section: Escapesmentioning

confidence: 99%

Development of cod farming in Norway: Past and current biological and market status and future prospects and directions

Puvanendran

Mortensen

Johansen

et al. 2021

Reviews in Aquaculture

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Atlantic cod is a historically abundant species in the North Atlantic region and has contributed to the prosperity of many nations. But a decline in stocks in the last century has prompted to initiate commercial farming of cod in captive conditions. Several approaches have been employed ranging from stock enhancement, capture‐based aquaculture and intensive cod farming. However, except for the enhancement efforts which were carried out for almost a century, efforts on other methods were intermittent coinciding with lower quotas. Intensive farming was attempted in Norway, Scotland, Ireland, Canada, Iceland and Faroe Islands in the 2000s. But it was carried out hastily to cash in the demand for cod in the market even though there were many biological knowledge gaps that are required for a successful aquaculture venture. The reasons for the failure of commercial farming in Norway during the 2000s were not only because of limited knowledge of the biology of cod but also the economic meltdown in Europe in 2008. Cod farming came to a halt; however, the Norwegian National Cod Breeding Program (NCBP) initiated in 2003 continued to operate and produced a fifth generation of a domesticated cod in 2019. Efforts to fill the gaps and the selective breeding for better growth and disease resistance within NCBP have improved the quality of the juveniles produced. We will discuss the past efforts and reasons for failure in farming of cod, how the current situation looks and the future direction in terms of cod biology, political atmosphere and market.

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Farmed cod escapees and net-pen spawning left no clear genetic footprint in the local wild cod population

Cited by 5 publications

References 73 publications

Half a century of genetic interaction between farmed and wild Atlantic salmon: Status of knowledge and unanswered questions

Half a century of genetic interaction between farmed and wild Atlantic salmon: Status of knowledge and unanswered questions

Growth of wild and domesticated Atlantic cod Gadus morhua reared under semi-commercial conditions

Development of cod farming in Norway: Past and current biological and market status and future prospects and directions

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