Estimating Recycling of Fish in Catch-and-Release Fisheries

The prevalence of catch-and-release angling for many species has increased over the past several decades. A potential benefit of catch-and-release fisheries is higher catches for anglers due to multiple captures of individual fish within a season. We term the measure of this benefit "recycling rate," defined as the total catch in a fishing season divided by the number of individuals caught at least once. Multiple-capture studies are common in the literature, but our recycling rate is a new metric that could be helpful in evaluating recreational fisheries. Estimates of recycling rate will be dependent on several factors, especially the distribution of angling selectivities among individual fish, which is generally unknown. We compared several models that estimated recycling rate based on different assumptions about angling selectivity. Application of the models to Smallmouth Bass Micropterus dolomieu data from Lake Mille Lacs, Minnesota, demonstrated that estimates of recycling rate were robust to assumptions about the distribution of angling selectivity.