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Using stable isotopes to confirm the trophic ecology of Arctic charr morphotypes from Lake Hazen, Nunavut, Canada
Author(s) -
Guiguer K. R. R. A.,
Reist J. D.,
Power M.,
Babaluk J. A.
Publication year - 2002
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2002.tb00285.x
Subject(s) - arctic , biology , trophic level , ecology , δ15n , isotope analysis , habitat , isotopes of nitrogen , sympatric speciation , stable isotope ratio , δ13c , physics , quantum mechanics
Stable isotopes of carbon and nitrogen were used to examine differences in the feeding ecology of sympatric morphotypes of Arctic charr Sahelinus alpinus from Lake Hazen, Ellesmere Island, in the Canadian High Arctic. Large and small morphotypes possessed significantly different carbon and nitrogen signatures with large‐form Arctic charr being more depleted in 13 C and more enriched in 15 N than the small‐form. Isotope and stomach content analyses yielded consistent results and indicated short‐ and long‐term reliance on fish as a food for large Arctic charr. Large‐form individuals predate on juveniles but do not predate on small‐form individuals ≥ 250 mm. The observed cannibalism by large‐form individuals, therefore, does not act to maintain the bimodal length‐frequency distribution in Lake Hazen. Bimodality is argued to arise for ecological reasons connected with differing habitat use by the morphotypes and the associated differences in resource consumption opportunities.