A stable isotope analysis of trophic polymorphism among Arctic charr from Loch Ericht, Scotland

• Published in: Journal of Fish Biology
• Main Authors: McCarthy, I. D., Fraser, D., Waldron, S., Adams, C. E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2004
• Subjects: Arctic; Arctic charr; Salvelinus alpinus
• Online Access: http://dx.doi.org/10.1111/j.0022-1112.2004.00526.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.0022-1112.2004.00526.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.0022-1112.2004.00526.x

Analysis of nitrogen stable isotope ratios (δ 15 N) in white muscle and liver shows temporal stability in the trophic levels at which the two sympatric morphs of Arctic charr Salvelinus alpinus from Loch Ericht feed. The results confirm an ontogenetic dietary switch to a more piscivorous diet, occurred in all individuals of one of the morphs, above a size threshold of 16·5 cm fork length, indicating that this occurs at a high frequency in this population and that once made, the return to feeding to a lower trophic level is infrequent.