An unintended experiment in fisheries science: a marine area protected by war results in Mexican waves in fish numbers-at-age

Marine protected areas (MPAs) have become a major focus in fisheries management and marine ecology (1-3). The European Union is a signatory of the Johannesburg Declaration on sustainable development which calls for a network of MPAs to be established by 2012 (4). Of those MPAs that have been scientifically monitored, and shown to be effective, most are in the (sub-) tropics (mainly coral and rocky reefs) or in kelp forests: i.e. they are almost exclusively inshore. One reason often cited for the success of MPAs in lower latitudes is that their fish populations tend to live out their lives in more clearly defined habitats. In open, temperate marine regions where dispersal potential and gene flow in fish are higher, however, there remains much debate over whether MPAs will be effective measures for conservation at all (5-9). Moreover, there is very little quantitative information on how fish populations in temperate seas actually respond to the instigation of MPAs.JRC.G.4-Maritime affair