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(202) Approaches to evaluating effects of metal-contaminated sediments on rainbow trout. Hansen, J.1, Welsh, P.1, Neptun, K.1, Lipton, J.1, 1 ABSTRACT- Effects of metal-contaminated sediments on fish may occur through dietary toxicity of ingested metals accumulated in invertebrates or through metal-induced changes in invertebrate communities. Experimental evaluation of the dietary toxicity of metals to fish has largely involved feeding studies with food spiked with inorganic metal salts which may not simulate the bioavailability and toxicity of organically incorporated metals. Limited experimentation has been performed in which metal-contaminated invertebrates collected from contaminated site have been fed to trout. However, these experiments potentially have been confounded by differences in dietary quality (e.g., fat, carbohydrate) between metal exposure treatments. We discuss results from a series of controlled experiments to assess the dietary effects of metals on trout using laboratory-reared invertebrates. We describe alternative experimental approaches and practical limitations to testing dietary toxicity of metals. Finally, we report on field investigations assessing sediment-invertebrate-nutrition interactions. Key words: dietary toxicity, metals, rainbow trout, growth |
