A Multivariate Approach to Assessing Harvest Regulations

In inland waters fishery managers often have to evaluate management actions with imperfect monitoring data consisting of fish catch rates, lengths, and weights.  Metrics derived from these type of data are often imprecise and frustrate the effectiveness of evaluations. We applied a multivariate approach to a set of metrics descriptive of fish catch, size, and condition to evaluate the effects of length limits on a game fish population. By combining multiple metrics, each with limited discriminating capacity, the multivariate approach improved the robustness of the assessment and our ability to discern effects. We suggest that in many situations fishery managers may be able to improve their ability to detect the effects of management actions by considering multiple metrics concurrently through multivariate analyses.