AEI 1:11-19 (2010)  -  DOI: https://doi.org/10.3354/aei00003

Spatiotemporal distribution of coastal and oceanic Atlantic cod Gadus morhua sub-groups after escape from a farm

Ingebrigt Uglem1,*, Pål Arne Bjørn2, Hiromichi Mitamura3, Rune Nilsen2

1Norwegian Institute of Nature Research, Tungasletta 2, 7485 Trondheim, Norway
2Nofima Marin, Muninbakken 9-13, PO Box 6122, 9291 Tromsø, Norway
3Graduate School of Informatics, Kyoto University, Kyoto 606-8501, Japan

ABSTRACT: Little is known about how escaped farmed Atlantic cod Gadus morhua L. affect the environment, but the potential for negative ecological consequences might be significant. In this study, the movements of adult farmed north-east Arctic cod (NEAC) and Norwegian coastal cod (NCC) were mapped after a simulated escape from an aquaculture farm to evaluate if post-escape movements and potential for recapture differs between these 2 genotypes. There was no major difference between NEAC and NCC equipped with acoustic transmitters with respect to spatiotemporal distribution or swimming depth during a 10 wk period after simulated escape incidents. The tagged cod immediately descended to average depths <20 m, and subsequently were most frequently observed along the shore. A substantial proportion of the farmed cod released at the cod farm left within the first week, while cod released at a nearby mussel farm were attracted to the cod farm. Beyond Week 2, the fish detected at the cod farm consisted of approximately similar proportions of fish released at either the mussel or cod farm. One third of the tagged cod was recaptured in local small-scale commercial and recreational fisheries during the first 3 wk after release. Thus, our results indicate that organised recapture fishery is a realistic option for reducing possible ecological and genetic impacts of escaped farmed cod. Such fishery must, however, be initiated as soon as possible after an escape incident and there is a need for development of a methodology for rapid detection and efficient recapture of escapees.


KEY WORDS: Atlantic cod · Gadus morhua · Aquaculture · Fish escape · Recapture


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Cite this article as: Uglem I, Bjørn PA, Mitamura H, Nilsen R (2010) Spatiotemporal distribution of coastal and oceanic Atlantic cod Gadus morhua sub-groups after escape from a farm. Aquacult Environ Interact 1:11-19. https://doi.org/10.3354/aei00003

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