Empirical Prediction of Fish Biomass and Yield

Abstract

Data taken from the literature were used to develop and compare predictors of fish biomass and yield in lakes. Two new indices, total phosphorus concentration and macrobenthos biomass/mean depth, were the best univariate predictors offish yield (r² = 0.84 and r² = 0.48, respectively) and biomass (r² = 0.75 and r² = 0.83, respectively) for four different data sets. Both new indices were stronger predictors of fish yield when compared to the morphoedaphic index, total dissolved solids, or mean depth for the same data set. The relatively constant relationship between fish biomass and macrobenthos biomass/mean depth implies a near-constant energy transfer from the benthos to the fish regardless of the number of fish species present.Key words: biomass, yield, fish, macrobenthos, phosphorus, depth, dissolved solids, morphoedaphic index, lakes