Binational Management of Pacific Hake (Merluccius productus): A Stochastic Modeling Approach

Abstract

We use an age-structured stochastic recruitment model to examine a stock managed by two nations: the Pacific Hake (Merluccius productus) fishery. The model computes the mean and variance in stock and yield and the probability (risk) that the stock falls into a critically low condition. An optimization algorithm finds effort quotas that maximize expected yield over a short-term planning horizon while constraining the risk of critically low stock conditions. Yields produced exceed those of constant effort alternatives, but with year-to-year fluctuations in fishing effort including fishery closures. These occur in different years for the United States and Canadian fisheries depending on the condition of the stock and the incoming year class. Binational management of fishing effort is also presented as a two-person game with a weighted difference between fishery catch and effort as payoff. Nash (rational players), maxi–min (self-protecting), and Pareto (cooperative optimizing) strategies are examined. There are striking shifts in relative effort between United States and Canadian fisheries as the cost of effort changes relative to catch. This approach shows potential benefits to both players in playing a long-term cooperative strategy.