The major goal of marine reserves is to protect biological diversity and ecosystem functions. Marine reserves should be integrated into stock assessments, catch limits, bycatch reduction policies, and habitat protection measures. One can define this integration to mean the adjustment of marine reserve design and fishery management policies to maximize the benefits of both fisheries and reserves, while minimizing the costs. The potential benefits of marine reserves to fisheries are: insurance against management errors; reference conditions for stock assessments; some measure of bycatch reduction; insurance against extinction of unassessed yet vulnerable species; and some measure of habitat protection. Marine reserves may enhance catch-per-unit-effort and total catches. While displacement of fishing effort and attendant congestion and localized depletion in other areas does not appear to be a problem with small reserves, these issues could become significant if very large reserves are created. Fishing capacity reduction measures and limited entry programs can help to prevent these problems, as well as address one of the fundamental drivers of overfishing and lack of profitability.