Several government agencies are evaluating policy options for addressing global climate change. These include planning for anticipated effects and developing mitigation options where feasible if climate does change as predicted. For fisheries resources, policy questions address effects on international, national, and regional scales. Climate change variables expected to affect inland and offshore fisheries include temperature rise, changes in the hydrologic cycle, alterations in nutrient fluxes, and reduction and relocation of spawning and nursery habitat. These variables will affect resources at all levels of biological organization, including the genetic, organism, population, and ecosystem levels. In this context, changes in primary productivity, species composition in the food-web, migration, invasions, synchrony in biological cycles, shifts in utilization of niches, and problems of larvae entrainment in estuaries have been identified. Maintaining ecosystem robustness (i.e., high biodiversity) is another component of the problem. Action requires establishing priorities for information needs, determining appropriate temporal and spatial scales at which to model effects, and accounting for interactive changes in physical and biological cycles. A policy response can be derived when these results are integrated with social needs and human population constraints.