| Summary: | Through the 137Cs mass balance method, annual consumption rates were estimated for juvenile Atlantic salmon parr and precocious males, as well as brook trout from 4 sites within the Ste Marguerite river system, Quebec. With explicit age analysis, feeding rates and growth rates were derived on an individual fish and age class basis. These represent the first consumption estimates for Atlantic salmon in the wild. The individual fish approach provided a range of data for a single site, as opposed to a single estimate per age class, allowing for an evaluation of the relationship between consumption and growth for each species or life-history variant. Subsequently, the concept of field maintenance ration was introduced as the intercept of consumption over growth. Salmonid feeding rates were coupled with density estimates to derive total fish exploitation rates for two streams. The application of age- and site-specific feeding rates derived from the 137Cs mass balance method, solved a long standing paradox in stream ecology as all previously inferred salmonid exploitation rates have been in excess of prey turnover. (Abstract shortened by UMI.)
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