Use of stable isotopes to distinguish farmed from wild Atlantic salmon, Salmo salar |
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Authors: | J. B. Dempson M. Power |
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Affiliation: | Fisheries and Oceans Canada, Science, Oceans and Environment Branch, St John's, Newfoundland, Canada;, Department of Biology, University of Waterloo, Waterloo, Ontario, Canada |
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Abstract: | Abstract – Stable isotopes of carbon and nitrogen ( δ 13C and δ 15N) were examined in wild and aquaculture origin Atlantic salmon, Salmo salar , to evaluate their utility to identify escaped farmed fish. Samples of muscle tissue obtained from wild Conne River, Newfoundland, salmon were significantly more enriched in nitrogen ( δ 15N: mean = 12.75; SD ± 0.38‰) but depleted in lipid corrected carbon ( δ 13C': mean = −20.51; SD ± 0.23‰) by comparison with aquaculture specimens obtained from Bay d'Espoir, Newfoundland ( δ 15N = 10.96 ± 0.19‰; δ 13C' = −19.25 ± 0.17‰) resulting in a complete separation of the two groups. Aquaculture specimens differed in δ 13C' from analyses of commercial salmon diet by 0.24‰, within the enrichment range associated with trophic transfers, while the δ 15N values in salmon muscle were enriched by 5.01‰. Although differences occurred in direct comparisons of white muscle and adipose tissue ( N = 49), the average δ 13C' and δ 15N signatures varied in absolute amounts by only 0.5‰, supporting the use of adipose tissue as a nonlethal means to determine isotopic signatures of Atlantic salmon. |
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Keywords: | Atlantic salmon Salmo salar escapees farmed salmon stable isotopes Conne River Newfoundland |
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