WWF Cover photo - Soufriere Marine Management Association ...

and Barrett 1999, Shears and Babcock 2002). Similar effects have been observed in Californian reserves(Lafferty and Kushner 2000). Aggregate measures of change in biomass conceal such effects. Species with highpopulation turnover rates will tend to respond to protection quickly, but their populations may fall as those oflarger bodied predator species begin to recover (Pinnegar et al. 2000). A classic example is the transformation ofrocky shores in Chile following protection. As the exploited predatory gastropod Concholepas concholepasrecovered, it reduced densities of mussels and herbivorous gastropods turning bare rocky shores into beds ofseaweed (Castilla 1999). We are only just beginning to see evidence of such changes in dominance of species inthe longest established reserves.5. Which species benefit from reserve protection?For a species to benefit from protection in a reserve, it is necessary for some fraction of the population to spend asignificant part of their lives there. This pre-condition has led to a widespread misconception that reserves willonly benefit sedentary species, and the corollary that they will not benefit migratory species. A recent reportproduced for the FishAmerica Foundation, a recreational fishing industry lobby group, takes this as the startingpoint for a cursory analysis asking which species of fish will benefit from reserves (Shipp 2002). Shipp (2002)considered a series of species in US waters and then made subjective judgments on whether or not he believedthey would benefit from marine reserves. In the great majority of cases he concluded reserves would offer nofishery benefit, but offered very little empirical evidence in support of his conclusions, citing only two papersthat report studies of real marine reserves.Certainly, some of the species that benefit most quickly from reserves are relatively sedentary, such asscallops (Murawski et al. 2000), abalones (Wallace 1999), and some fish (Russ and Alcala 1998, Murawski et al.2000, Roberts et al. 2001a). However, populations of many species with greater mobility do build up in reserves.Indeed we are learning much about the behavioural complexities of exploited species by studying protectedpopulations. For example, twenty years ago, few people thought that small reserves could protect populations oflobsters because in many species there are seasonal inshore-offshore movements that would take lobsters intofishing grounds. However, there is now compelling evidence from several different species in widely separatedparts of the world that lobster stocks do build-up in reserves: from the Mediterranean (Goñi et al. 2001a,b), NewZealand (Kelly et al. 2000, Davidson et al. 2002), Australia (Edgar and Barrett 1999), Bahamas (Lipcius et al.2001a) and Canada (Rowe 2001, 2002), to name a few. It is now evident that a proportion of the lobsterpopulation shows high levels of site fidelity in each place studied (Kelly 2001, Rowe 2001).The New Zealand sparid fish, Pagrus auratus, was another species not expected to benefit much fromsmall, nearshore reserves because individuals seasonally move between inshore and offshore locations. Yet theyshowed swift responses to reserve protection, again because a fraction of the population demonstrated strong sitefidelity, while others moved (Willis et al. 2001).South African research shows a similar pattern of differential propensity to move within a species. In atag and recapture study, Griffiths and Wilke (2002) found that 7.4% of recaptured Petrus rupestris had moveddistances between 200km and 1000km. The remainder of the population had much more limited movements,with 95% of recaptures occurring within a radius of 14km. Attwood (2002) reports similar behaviour in theGaljoen, Dichistius capensis, in which the furthest displacement of a tagged fish was 1300km, corresponding toalmost the entire geographic range of the species. Nonetheless, many individuals have more limited ranges ofmovement and there have been marked increases in abundance and size of this fish in South African reserves(Buxton and Smale 1989, Attwood 2002). For four other shorefish species tagged by Griffiths and Wilke (2002),95% of recaptures were within radii of 7km, 13km, 15km and 49km and they conclude that a minimum reservelength of 45km would be effective at protecting this multispecies complex. For reserves to work well, they mustbe scaled to the movements of the species protected or must be sited in places where they can offer transientprotection to them. The latter effect is described below.Fixed location marine reserves can also protect migratory species. Fishery managers already use closedareas to protect juvenile nursery areas of species that undergo ontogenetic migrations (i.e. move from one habitatto another as they grow). Such areas are a simple way to increase yields by preventing premature capture ofyoung animals (Horwood et al. 1998). For example, juvenile lobsters are protected in Florida Bay until they arelarge enough to migrate to reefs in the Florida Keys where they can be captured (Davis and Dodrill 1980). Thereare large areas closed to trawling in Alaska and Kamchatka to protect juvenile Red King Crab (Armstrong et al.1993).The above examples point to ways in which reserves can benefit species that undergo annualmigrations. The key is offering protection at places and times when the species are particularly vulnerable tocapture. Roberts and Sargant (2002) point out that many migratory species aggregate or pass through migrationbottlenecks where they can become highly vulnerable to targeted fisheries. For example, cod, Gadus morhua,populations in Newfoundland were intensively fished in nearshore spawning aggregation sites prior to the stockcollapse in 1992 (Kulka et al. 1995). Spawning aggregations of Nassau groupers, Epinephelus striatus, and other10