WWF Cover photo - Soufriere Marine Management Association ...

1. SummaryMarine reserves, areas permanently closed to all fishing, are frequently proposed as a tool for managingfisheries. Fishery benefits claimed for reserves include increases in spawning stock size, animal body size, andreproductive output of exploited species. Reserves are predicted to augment catches through export of offspringto fishing grounds, and spillover of juveniles and adults from reserves to fisheries. Protection of stocks anddevelopment of extended age structures of populations in reserves are argued to offer insurance againstenvironmental variability and management failure. Models also suggest reserves will reduce year-to-yearvariability in catches, and offer greater simplicity of management and enforcement. Reserves are predicted tolead to habitat recovery from fishing disturbance which can also enhance benefits to fisheries.Extensive field research confirms many of these predictions. Reserves worldwide have led to increasesin abundance, body size, biomass and reproductive output of exploited species. Such measures often increasemany times over, sometimes by an order of magnitude or more. Population build up is usually rapid with effectsdetectable within 2-3 years of protection. Increases are often sustained over extended periods, particularly forlonger-lived species and for measures of habitat recovery. Reserves have benefitted species from a widetaxonomic spectrum that covers most economically important taxa, including many species of fish, crustaceans,mollusks and echinoderms.Encouraged by these results, many countries and states have embarked upon initiatives to establishnetworks of marine reserves. However, reserves remain highly controversial among fishers and fishing industrybodies who argue that fishery benefits remain unproven. In the last three years there has been rapid growth in thenumber of cases where fisheries have been shown to benefit from reserves. In this report, we critically analyzethis body of evidence, drawing upon studies of reserves and fishery closures. Fishery managers have long usedfishery closures, areas temporarily closed to fishing for one or more species or to specific fishing gears. They areemployed to help rebuild depleted stocks, reduce gear conflicts, protect vulnerable life stages of exploitedspecies or protect sensitive habitats from damaging gears. Such areas can tell us much about the potential effectsof marine reserves.Fishery benefits from reserves and fishery closures typically develop quickly, in most cases within fiveyears of their creation. Perhaps the most persuasive evidence of fishery effects of reserves comes from changingfishing patterns. In most places where well-respected reserves or fishery closures exist, fishers tend to move theirfishing activities closer to their boundaries. Fishing-the-line, as it is called, allows fishers to benefit fromspillover of animals from reserves to fishing grounds. There are now well-documented cases of spillover frommore than a dozen countries and including a wide range of species. It is more technically demanding to provefishery enhancement through export of offspring on ocean currents. Existing reserves are generally small,making it hard to detect increased recruitment to fisheries at a regional scale. However, there are now severalcases in which export of eggs and larvae have been confirmed, including dramatic enhancement of scallopfisheries in Georges Bank and clam fisheries in Fiji. Small reserves have worked well and repeatedly producelocal benefits. However, regional fisheries enhancement will require more extensive networks of reserves. Someof the most convincing success stories come from places in which between 10 and 35% of fishing grounds havebeen protected. In several cases there is evidence that yields with reserves have risen to higher levels than priorto protection, despite a reduction in the area of fishing grounds. In other cases, smaller reserves have stabilizedcatches from intensively exploited fisheries or slowed existing rates of decline.We describe experiences that prove that success of marine reserves is not contingent on habitat type,geographical location, the kind of fishery involved, or the technological sophistication of management. Reservebenefits are not restricted to habitats like coral reefs, or to artisanal fisheries, as some critics claim. Fisherybenefits have been demonstrated from reserves established in tropical, warm- and cold-temperate waters, and inmany habitats, including coral reefs, rocky reefs, kelp forests, seagrass beds, mangroves, estuaries, softsediments, continental shelves and deep sea. Reserves and fishery closures have worked well for a wide range offisheries, spanning recreational fisheries, artisanal fisheries like those of coral reefs, through small-scalenearshore fisheries for species like lobsters, up to industrial-scale fisheries for animals like flatfish and scallops.They have worked across a similarly broad spectrum of management sophistication, from self-policing bycommitted fishers, through warden patrols to satellite monitoring of distant fishing activities.We now have strong evidence that with the support of local communities, marine reserves offer ahighly effective management tool. However, reserves will only rarely be adequate as a stand-alone managementapproach, although we describe cases where they have worked in the absence of other measures. They will bemost effective when implemented as part of a package of limits on fishing effort, designed to protect exploitedspecies and their habitats.2. IntroductionMarine reserves are areas of the sea that are permanently closed to all fishing. They have been attracting theattention of conservationists and fishery managers since the mid-1980s when the first studies of their effects6