CONCEPTUAL ISSUES RELEVANT TO MARINE HARVEST REFUGES - EXAMPLES FROM TEMPERATE REEF FISHES

The size of a refuge needed to sustain a fishery depends on the harves t and on the rate at which both refuge and harvested populations suppl y new recruits to the fishery. Recruitment rates are determined by lar val production, and both intrinsic (e.g., reproductive mode, larval be havior) and extrinsic (e.g., predation, resource availability, current s) factors that influence the geographic range over which a refuge can effectively supply recruits. The size, number, and distribution of re fuges depend on patterns of larval replenishment. Since resource requi rements of fish often change with ontogeny and reproductive condition, refuges may need to include a wide variety of habitats. Larval produc tion by refuges may be enhanced by multispecies management that provid es protection for or allows harvesting of nontarget species. Additiona lly, protection may be needed for resources located outside refuges th at enhance recruitment to harvested populations. Because improperly de signed refuges may endanger a fishery by providing a false sense of pr otection, determining the effectiveness of a refuge is of utmost impor tance. Evaluation criteria should include the ability of a refuge to m aintain high laval production of target species and to contribute to r eplenishment of harvested populations at a level sufficient to sustain a predetermined harvesting rate.