You are here:
Comparing trophic position of stream fishes using stable isotope and gut contents analyses
Citation:
RYBCZYNSKI, S., DAVID M. WALTERS, K. M. FRITZ, AND B. R. JOHNSON. Comparing trophic position of stream fishes using stable isotope and gut contents analyses. Ecology of Freshwater Fish. Blackwell Publishing, Malden, MA, 17(2):199-206, (2008).
Impact/Purpose:
The objective is to address the risk management LTG for the Contaminated Sites Research Program in the area of contaminated sediments. The contaminated sediments LTGs of “How can we better assess and document the short- and long-term effectiveness of remediation approaches (e.g., dredging vs capping vs monitored natural attenuation (MNA)?” and “How can any short-term negative impacts from the use of one of these options be reduced?” are partially addressed. The research areas include: the miniaturization of sediment toxicity tests & elutriate comparability with whole sediment assays; and bioassays, development and demonstration of ecological tools for sediment monitoring to assess toxicity, gene expression ecological impacts and the use of stable isotope analysis, to develop a mechanistic understanding of energy and material flux within PCB contaminated streams and lakes and their food webs. Stable isotopes techniques will be used to track biomagnification of PCBs and other persistent bioaccumulative contaminants in lake food and stream food webs using a site based approach in collaboration with other ORD labs' contaminanted sediment research.
Description:
Stable isotope analysis (SIA) and gut content analysis (GCA) are commonly used in food web studies, but few studies analyze these data in concert. We used SIA and GCA to identify diets and trophic position (TP) of six stream fishes and to compare TP estimates between methods. Ordination analysis of gut contents identified two trophic groups, omnivores and predators, with one species intermediate. Predators consumed mostly invertebrates, whereas omnivores consumed detritus, aquatic and terrestrial invertebrates, and plants. Omnivores consumed more terrestrial plants in spring than autumn, but predator diets were seasonally invariant.