Climate Fluctuation and Revenue Maximization in the Eastern Bering Sea Fishery for Walleye Pollock

Abstract

The eastern Bering Sea fishery for walleye pollock Theragra chalcogramma yields gross exvessel revenues on the order of US$300 million. Small variations in exvessel prices, total allowable catches, or allocation of catches between seasons and among industry sectors can lead to large changes to exvessel revenues. Our estimated bioeconomic model suggests that oceanographic conditions associated with lagged temperature anomalies exert a significant influence on recruitment and have a persistent effect on total biomass. Exvessel revenues increase or decrease as a function of increased biomass, depending on market relationships and harvest policies. When harvest limits are based on constant exploitation rates, temperature anomalies affect harvester revenues with a 3–4-year lag. We used the integrated model for stochastic simulations of −3°C to +5°C temperature anomalies and 10–30% annual exploitation rates. Median recruitment increased in the simulations as a function of temperature and exploitation rate. Median spawning biomass was positively related to temperature but inversely related to exploitation rate. The frequency of recruitment failure and stock failure increased at high exploitation rates across the range of temperature anomalies examined. Although median catch was positively related to temperature and exploitation rate, so was its variance. Expected exvessel revenues were maximized along a ridge that extended from a 26–30% exploitation rate at low temperatures to a 13–16% exploitation rate at high temperatures.