TY - JOUR
T1 - Fatty acid profiles of lake trout reveal the importance of lipid content for interpreting trophic relationships within and across lakes
AU - Happel, Austin
AU - Stafford, Craig P.
AU - Rinchard, Jacques
AU - Czesny, Sergiusz
N1 - Funding Information:
We wish to thank the Illinois Department of Natural Resources, the crew led by Ellen Marsden of the University of Vermont, Montana Fish, Wildlife & Parks, and the Confederated Salish-Kootenai Tribes for supplying fish for this project. We further thank the numerous technicians and undergraduates that helped with sample collection and processing. We extend thanks to two anonymous reviewers who helped improve the manuscript. All work was conducted in accordance to IACUC standards.
PY - 2020/2
Y1 - 2020/2
N2 - Fatty acid profiles increasingly are being used to quantify foraging patterns of consumers, but the associated interpretation may vary with the tissue type and its lipid content. For salmonids, lipid deposits can be found in both dorsal and ventral (“belly flap”) areas of muscle tissues. However, it is uncertain whether belly flap and dorsal muscle fatty acid profiles are similar in natural populations of fish. We examined how fatty acid profiles of belly flap compared to those of dorsal muscle and the consequent impacts on dietary inferences. Fatty acid profiles were derived from lake trout (Salvelinus namaycush) caught in five North American lakes: Champlain, Flathead, Michigan, Ontario, and Swan. Fatty acid profiles were most similar between tissues when lipid content of muscle was > ~10%, the threshold below which similarities decreased and thus increasingly affected dietary inference. Some fatty acids commonly used as trophic indicators preferentially accrued in one tissue over the other depending on lipid content of the tissues. Regardless of tissue type, fatty acid profiles were specific to each lake indicating that food web structures were distinctive over a broad geographic range. Fatty acid profiles of tissues from lakes Michigan and Ontario were highly similar, so were those from Flathead and Swan lakes, whereas those from Lake Champlain were distinct, having comparatively high proportions of 18:1n-9. We conclude that lipid storage areas like belly flaps likely provide a more accurate signal than muscle when using fatty acids to investigate dietary patterns, particularly when muscle lipid levels are low.
AB - Fatty acid profiles increasingly are being used to quantify foraging patterns of consumers, but the associated interpretation may vary with the tissue type and its lipid content. For salmonids, lipid deposits can be found in both dorsal and ventral (“belly flap”) areas of muscle tissues. However, it is uncertain whether belly flap and dorsal muscle fatty acid profiles are similar in natural populations of fish. We examined how fatty acid profiles of belly flap compared to those of dorsal muscle and the consequent impacts on dietary inferences. Fatty acid profiles were derived from lake trout (Salvelinus namaycush) caught in five North American lakes: Champlain, Flathead, Michigan, Ontario, and Swan. Fatty acid profiles were most similar between tissues when lipid content of muscle was > ~10%, the threshold below which similarities decreased and thus increasingly affected dietary inference. Some fatty acids commonly used as trophic indicators preferentially accrued in one tissue over the other depending on lipid content of the tissues. Regardless of tissue type, fatty acid profiles were specific to each lake indicating that food web structures were distinctive over a broad geographic range. Fatty acid profiles of tissues from lakes Michigan and Ontario were highly similar, so were those from Flathead and Swan lakes, whereas those from Lake Champlain were distinct, having comparatively high proportions of 18:1n-9. We conclude that lipid storage areas like belly flaps likely provide a more accurate signal than muscle when using fatty acids to investigate dietary patterns, particularly when muscle lipid levels are low.
KW - Fatty acids
KW - Food webs
KW - Lake trout
KW - Ontogenetic diet shift
KW - Tissue type
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U2 - 10.1016/j.jglr.2019.10.015
DO - 10.1016/j.jglr.2019.10.015
M3 - Article
AN - SCOPUS:85076604536
SN - 0380-1330
VL - 46
SP - 188
EP - 197
JO - Journal of Great Lakes Research
JF - Journal of Great Lakes Research
IS - 1
ER -