Comparing Minimum-Size and Slot Limits for Brook Trout Management

Consideration of reproductive, growth, and natural mortality characteristics in the design of fisheries management strategies requires adequate data and a comprehensive understanding of the influence of each factor in determining population responses to management. A review of previous management literature indicated a range of responses have been observed when size limit regulations for different species were imposed or changed. This suggests that selecting appropriate management strategies for a given set of conditions is difficult. Accordingly, strategies should be tested for efficacy before implementation. An individual-based model incorporating specific consideration of density-dependent mortality and life history characteristics was calibrated for use against available field data and used to compare random harvest and size limit management strategies for a lotic population of brook trout Salvelinus fontinalis. Results compared favorably with field-based studies of trout management strategies. With combinations of low exploitation rates and minimal degrees of protection, minimum-size-limit strategies maximize postharvest abundance levels, but slot limits are most effective at inducing favorable shifts in population size structure. For combinations of high exploitation and protection, slot limits dominate minimum-size limits in terms of abundance, harvest, and population size structure. Although neither strategy can be considered universally superior, slot limits minimize the risks of a collapse in the fishery resulting from overharvest.