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Identification of marine-derived lipids in juvenile coho salmon and aquatic insects through fatty acid analysis.
|Title||Identification of marine-derived lipids in juvenile coho salmon and aquatic insects through fatty acid analysis.|
|Publication Type||Journal Article|
|Year of Publication||2010|
|Authors||Heintz, RA, Wipfli, MS, Hudson, JP|
|Journal||Transactions of the American Fisheries Society|
The energetic benefits enjoyed by consumers in streams with salmon runs depend on how thosebenefits are accrued. Adult Pacific salmon Oncorhynchus spp. deliver significant amounts of nutrients (i.e.,nitrogen and phosphorus) and carbon to streams when they spawn and die; these nutrient additions can havedemonstrable effects on primary production in streams. Consumption of carcass tissues or eggs provides fordirect energy subsidies to consumers and may have significant effects on their condition. In this study,comparisons of juvenile coho salmon O. kisutch and aquatic insects exposed to terrestrial and marine energysources demonstrated that direct consumption of marine-derived lipids had a significant effect on the lipidreserves of consumers. Direct consumption of marine-derived tissues was verified through fatty acid analysis.Selected aquatic insects and juvenile coho salmon were reared for 6 weeks in experimental streams suppliedwith terrestrial or marine energy sources. Chironomid midges, nemourid stoneflies, and juvenile coho salmonexposed to the marine energy source altered their fatty acid compositions by incorporating the long-chainpolyunsaturated fatty acids that are characteristic of marine fish. The fatty acid composition of baetid mayflieswas unaffected. The direct movement of specific fatty markers indicated that direct consumption of marinederivedtissues led to increased energy reserves (triacylglycerols) in consumers. Similar results were obtainedfor juvenile coho salmon sampled from natural streams before and after the arrival of adult salmon runs. Thesedata indicate that marine-derived lipids from anadromous fish runs are an important source of reserve lipidsfor consumers that overwinter in streams.