A catch per unit effort - soak time model for the Bristol Bay red king crab fishery, 1991-1997

Abstract

Postseason commercial fisheries data are used to estimate a catch per unit effort (CPUE) – soak time relationship for the 1991–1993 and 1996–1997 Bristol Bay red king crab (Paralithodes camtschaticus) fishery in order to gain regulatory and in-season management insight. Use of commercial fishery data allows our model to capture the influence of biological and environmental effects as well as behavioral responses of crabbers to changing natural and regulatory conditions on CPUE. However, data deficiencies present a variety of estimation challenges, especially when the data are derived from neither a contemporaneous nor a scientifically designed sample of the fleet. A statistical framework for dealing with such challenges is illustrated in this paper. This research uncovered three major results. First, data pooling guided by recursive estimation/hypothesis testing is shown to be essential. Second, the analysis provides insight into CPUE response to changing conditions, whether biological, ecological, or policy induced. Third, it is apparent that more complete and contemporaneous collection of commercial fisheries data is critical to refine the estimation of CPUE - soak time relationships. Then, it may be possible to isolate the inter- and intra-seasonal influence of biological and environmental effects as well as behavioral responses of crabbers to changing natural and regulatory conditions.