Marine reserves and optimal harvesting

• Published in: Ecology letters Vol. 6; no. 9; pp. 843 - 849
• Main Author: Neubert, Michael G.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01-09-2003
• Subjects: Bioeconomics; fisheries; Marine; marine protected areas; marine reserves; maximum principle; maximum sustainable yield; optimal control theory; source-sink
• ISSN: 1461-023X; 1461-0248
• DOI: 10.1046/j.1461-0248.2003.00493.x

Advocates of no‐take marine reserves emphasize their conservation benefits. Critics counter that reserves would decrease fisheries yield. Analysis of a spatially explicit harvesting model, however, shows that no‐take marine reserves are always part of an optimal harvest designed to maximize yield. The optimal harvest generates a spatial source–sink structure with source populations placed in reserves. The sizes and locations of the optimal reserves depend on a dimensionless length parameter. For small values of this parameter, the maximum yield is obtained by placing a large reserve in the centre of the habitat. For large values of this parameter, the optimal harvesting strategy is a spatial ‘chattering control’ with infinite sequences of reserves alternating with areas of intense fishing. Such a chattering strategy would be impossible to actually implement, but in these cases an approximate yet practicable policy, utilizing a small number of reserves, can be constructed.