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Current Projects

Estimating capture probabilities of common stream fishes in the Eastern Corn Belt Plain

Jason C. Doll and Thomas E. Lauer

Imperfect detection of fish can lead to biased estimates of abundance and assemblage level descriptors such as the Index of Biotic Integrity. Accentuating this bias are two items. First the schooling behavior of fish confounds the efficacy of traditional models in estimating abundance and capture probability. Second, we know habitat influences fish distribution and catchability. Although multi-pass depletion sampling of fish can be used to estimate some of the bias, assuming fish behave independently, quantifying both schooling and habitat bias effects is required to fully understand fish abundance. Thus, our objective in this study is to determine how imperfect detection of common stream fishes is influenced by schooling behavior and a suite (15) of physicochemical variables. To meet this objective, we will conduct multi-pass depletion surveys at 25 randomly selected sites in the Eastern Corn Belt Plain ecoregion in Indiana. We will use these data and extend an existing model to estimate abundance and capture probability of schooling and non-schooling species. These estimated capture probabilities can then be applied to standard electrofishing surveys to improve the accuracy of abundance estimates and can be applied to biological monitoring tools to create multimetric indices that are more sensitive to perturbation.

This project is funded by a grant through the Indiana Water Resources Research Center and Ball State University.