GULF AND CARIBBEAN RESEARCH Caribbean Marine Protected Areas: PRACTICAL APPROACHES TO ACHIEVE ECONOMIC AND CONSERVATION GOALS

Population density can affect rates of mortality and individual growth. We measured these for the nonexploited bluehead wrasse, Thalassoma bifasciatum, at three sites around St. Croix, US Virgin Islands. Previous work demonstrated that differences in the degree of larval retention in these sites results in very large differences in recruitment intensity. Post-settlement mortality differed among sites and was positively related to recruitment density. Post-settlement growth differences were small. Because of strong mortality effects early in life, adult densities and size/age distributions differed among sites and did not reflect differences in recruitment rate. The site with the highest retention and recruitment (Butler Bay) had many small fish, while the two other sites with lower recruitment rates (Jacks Bay and Green Cay) had proportionally more large fish. These differences resulted in large differences in egg production. Per capita production was highest at the lowest density site (Green Cay). Total egg production at Green Cay was 75% that at Butler Bay, despite only having half the population size, and the highest overall production was at Jacks Bay, with low retention and moderate recruitment. In terms of marine reserve location, sites predicted to have high retention and recruitment may not always be the sites of highest egg production due to density-dependent processes, and it is important to consider the relative values of self-recruitment and larval export in reserve design. types of protection not afforded by other management strategies, including intrinsic protection from overfishing (Dugan and Davis 1993, Allison et al. 1998) and potential enhancement of fisheries (Rakitin and Kramer 1996, Russ and Acala 1996, Allison et al. 1998, Chapman and Kramer 1999). As the number of marine reserves increase, so do the empirical studies comparing these sites to nearby outside areas. It has been well established at this point that both population size and individual sizes tend to be larger inside of reserves relative to nearby fished areas (reviewed in Roberts and Polunin 1991, Dugan and Davis 1993, Halpern in press). This effect of protection occurs despite the fact that virtually all marine reserves to date have been designed and located rather opportunistically (e.g., for social and political reasons) without much consideration of optimal reserve size or the biological, oceanographic, and physical characteristics of the site. However, in recent years, there has been a tremendous upsurge in public interest in reserves and many countries, including the U.S. are moving towards regional and national programs of reserve establishment. Not only is it important that we gain a better understanding of how reserves affect both the areas they are intended to protect and the various stakeholders who use marine resources, but we need to move towards a better “science” of reserve design and siting. Gulf and Caribbean Research Vol 14(2), 107–117, 2003 Manuscript received November 17, 2001; accepted July 15, 2002