The elimination of radiocaesium from fish

1. A general model for fish to predict the elimination rate of radiocaesium from a regression of water temperature, weight and a categorical variable for exposure (steady state, nonsteady state), was developed from published data. 2. The generality of the new model for the elimination of radiocaesium from fish provides aquatic ecologists with the means to simplify greatly and improve existing methods for estimating ration for fish through the use of Cs-137 based bioenergetics models. 3. Comparisons of the general model with other less complete data suggests that the model is applicable to many of the common taxa of north temperate fish. 4. Fish whose tissue pools are equilibrated to ambient concentrations (steady state) appear to eliminate radiocaesium at a rate much slower than those in non-steady state. Application of previous laboratory models to steady state field situations would overestimate the elimination rate of radiocaesium by 1.4-fold.