The role of marine reserves in achieving sustainable fisheries

TLDR

Many fishery management tools aim to keep commercially important stocks above target levels, but their conservation value is limited and they cannot fully prevent global fish stock declines. The authors argue that extensive marine reserves, which are off‑limits to fishing, must be integrated into modern fishery management to reverse declines, safeguard marine life, and sustain ecosystem processes. Complete, permanent protection from fishing in marine reserves preserves sensitive habitats, allows natural age structures to develop, maintains genetic variability, and prevents evolutionary changes caused by fishing. Marine reserves can sustain higher reproduction rates, greater resilience to environmental variability, and provide insurance against management failures, thereby mitigating the continuing global decline in fish stocks.

Abstract

Many fishery management tools currently in use have conservation value. They are designed to maintain stocks of commercially important species above target levels. However, their limitations are evident from continuing declines in fish stocks throughout the world. We make the case that to reverse fishery declines, safeguard marine life and sustain ecosystem processes, extensive marine reserves that are off limits to fishing must become part of the management strategy. Marine reserves should be incorporated into modern fishery management because they can achieve many things that conventional tools cannot. Only complete and permanent protection from fishing can protect the most sensitive habitats and vulnerable species. Only reserves will allow the development of natural, extended age structures of target species, maintain their genetic variability and prevent deleterious evolutionary change from the effects of fishing. Species with natural age structures will sustain higher rates of reproduction and will be more resilient to environmental variability. Higher stock levels maintained by reserves will provide insurance against management failure, including risk-prone quota setting, provided the broader conservation role of reserves is firmly established and legislatively protected. Fishery management measures outside protected areas are necessary to complement the protection offered by marine reserves, but cannot substitute for it.