All fisheries-management models incorporate simplifying assumptions about ecological and oceanographic mechanisms that are fundamentally uncertain or stochastic, but exploited fisheries are also subject to equally important uncertainties associated with fisherman behavior. Fishermen make decisions ranging from long-term entry/exit decisions to daily or even hourly decisions about where and how to fish. These decisions are influenced by regulations, technology, weather, and expectations about prices, costs, and abundance. They ultimately determine the spatial and temporal pattern of mortality in an exploited fishery. Although biologists have tried to incorporate fisherman behavior into management models, much of the work is ad hoc, whereas economics has a rich tradition of both conceptual and empirical behavioral modeling. This paper is an attempt to demonstrate the potential usefulness of economics-based behavioral modeling, with data collected for biological management. A model of participation and spatial choice is constructed, and the economic model is linked to a biological model of metapopulation dynamics and used to forecast the implications of management measures that might be applied to the red sea urchin fishery in California. The results show that modeling spatial behavior strongly affects the predicted outcomes of management policies even if the policies are not spatial in character.