Environmental Conservation


Spillover from marine reserves and the replenishment of fished stocks


a1 National Center for Ecological Analysis and Synthesis, 735 State Street, Santa Barbara CA 93101, USA

a2 Marine Science Institute, University of California, Santa Barbara CA 93106, USA

a3 Department of Environmental Science and Policy, University of California, Davis CA 95616, USA

a4 Biology Department, Woods Hole Oceanographic Institution, MS#34, Woods Hole MA 02543, USA


No-take marine reserves are widely recognized as an effective conservation tool for protecting marine resources. Despite considerable empirical evidence that abundance and biomass of fished species increase within marine reserve boundaries, the potential for reserves to provide fisheries and conservation benefits to adjacent waters remains heavily debated. This paper uses statistical and population models to evaluate published empirical data on adult spillover from marine reserves and shows that spillover is a common phenomenon for species that respond positively to reserve protection, but at relatively small scales, detectable on average up to 800 m from reserve boundaries. At these small scales, local fisheries around reserves were likely unsustainable in 12 of 14 cases without the reserve, and spillover partially or fully offsets losses in catch due to reserve closure in the other two cases. For reserves to play a role in sustaining and replenishing larger-scale fished stocks, networks of reserves may be necessary, but as few exist this is difficult to evaluate. The results suggest reserves can simultaneously meet conservation objectives and benefit local fisheries adjacent to their boundaries.

(Received October 12 2009)

(Accepted December 13 2009)

(Online publication February 24 2010)


c1 Correspondence: Dr Benjamin S. Halpern Tel: +1 805 892 2531 Fax: +1 805 892 2510 e-mail: halpern@nceas.ucsb.edu