Fishing dynamics associated with periodically harvested marine closures

Abstract

Periodically-harvested fisheries closures are emerging as a socially acceptable and locally implementable way to balance concerns about conserving ecosystem function and sustaining livelihoods. Across the Indo-Pacific periodically-harvested closures are commonly employed, yet their contribution towards more sustainable fisheries remains largely untested in the social and ecological context of tropical small-scale fisheries. To address this, we use an interdisciplinary approach to examine harvesting dynamics that would affect sustainability, namely, fishing effort, yield, gear and method use, periodicity of harvesting, controls placed on harvesting and resource owners’ decisions to open and close four fishing grounds in Solomon Islands. We compare these fishing patterns with those on surrounding, continuously open fishing grounds. Our study shows that total effort and total catch from periodically-harvested reef closures are low to moderate compared to reefs open to continuous fishing. When periodically-harvested closures were opened, effort in the closures was relatively intense, however, in most cases yield did not exceed annual benchmarks of sustainability described by previous studies. In some cases, harvesting during openings was restricted to a single taxon and single fishing gear and method, while in others there was unrestricted multi-species and multi-method harvesting. The duration and frequency of openings were highly variable, with open periods ranging from a single night to one month in duration, and occurring between one and 15 times per year. Fishing during openings was permitted for entire fishing communities in some cases, and only for specific rights-holding families in others. Decisions to open periodically-harvested closures tended to be based on immediate social or economic needs, and the openings provided a small boost to fish catch landed in communities. While periodically-harvested closures may alleviate fishing pressure in a small area of fishing grounds by reducing the opportunity to fish, openings of long duration or high frequency, combined with heavy or destructive exploitation, may lead to unsustainable harvesting within the area.