UW Aquatic & Fishery Sciences Quantitative Seminar

Steve Martell

UBC Fisheries Centre

Stock Assessment from a Fisheries Management Perspective

Abstract

The majority of fisheries management systems rely on output controls; for example how much fish should the fishery remove in the upcoming fishing season (i.e., Total Allowable Catch, TAC). The statistical tools for determining appropriate TACs are well developed; however, historical data often lack sufficient information to resolve structural confounding in the statistical models. It is often necessary to use prior information about key population parameters in order to provide management advice. Informative priors for biological parameters influence management variables in a not so transparent way. Traditional assessment models estimate population parameters and then translate these parameters to management variables (e.g., MSY and F MSY or other proxies). This seminar will demonstrate how age-structured assessment models can be re-parameterized directly in terms of management variables, from which biological parameters are then derived. The motivation for this change is to improve communication between stock assessment scientists and fisheries managers, improve statistical properties of the models, and allow for the use of informative priors on the management variables themselves.