Habitat considerations in optimal fisheries recovery

Fishery managers face an ongoing challenge in managing commercial fisheries in a way which enables the delivery of economic benefits while ensuring those benefits do not compromise the ability of fish stock to deliver future benefits. This challenge is complicated by fishing effort negatively impacting the habitats which support fish stocks and so undermining sustainability of the resource. Depletion of fish stocks and subsequent rebuilding efforts have necessitated the development of strategies which dictate harvest control mechanisms. In this paper, we explore the economically optimal design of these rebuilding strategies for a fishery depleted by overfishing and where the fishing effort results in a negative habitat externality. We assume the harvest control mechanisms include a harvest control rule and a no-take marine reserve and find that the economically optimal recovery of the stock will always incorporate both mechanisms, although the relative weight put on each will change according to biological and economic conditions. We find that the achievement of desired fishery outcomes is generally robust to “approximately optimal” specifications of the rebuilding strategy, except where the fishing habitat is vulnerable. In these conditions, it may be optimal to lead the population to extinction, via depletion of habitat.