Comparison of grouper assemblages in northern areas of the wider Caribbean: A preliminary assessment

Groupers (Pisces: Serranidae) are important top-level predators in wider Caribbean, but have experienced significant exploitation, resulting in declines in abundance, size, spawning aggregations, and changes in species composition. Larger groupers are particularly vulnerable to intense fishing because of their longevity, slow growth, delayed reproduction, and aggregate spawning. Marine fishery reserves (MFR), areas permanently closed to consumptive use, offer a viable means to protect grouper resources. This study reports on fishery-independent surveys of groupers in four regions of the tropical western Atlantic during 1995 - 1997: Florida Keys, central Bahamas, southeastern Cuba, and Dominican Republic. The regions surveyed included two national parks and a national marine sanctuay, and were further categorized as: 1) intensively fished with little or no management for groupers (Cuba, Dominican Republic); 2) intensively fished with gear and effort limitations (Florida Keys); 3) lightly fished with some management (N. and S. Exuma Cays, Bahamas); and 4) a. MFR closed to fishing since 1986 (Exuma Cays Land and Sea Park, Bahamas). From 10 - 20 strip transects (20 m x 5 m) were surveyed in shallow-water (l-20 m depth) hard-bottom habitats for grouper species composition, density, and size distribution. Nine grouper species (6 Epinephelus spp., 3 Mycteroperca spp.) were documented among all regions. Areas in which groupers were partially or wholly protected from fishing had greater grouper diversity, density, and biomass, particularly for targeted species such as Nassau grouper (E. striatus). Classification of groupers by three size classes (small, intermediate, large) indicated a distinct gradient from areas with intense fishing to the MFR. In three of the regions affected by intense fishing, one of which has several grouper fishery regulations, grouper abundance and biomass were dominated by non-targeted species such as the graysby (E. cruentatus) and coney (E. fulvus). This second-order effect of fishing probably indicates competitive or predation. MFRs represent a viable means to protect grouper resources, alleviating the complications of enforcement and partially the need to gather fisheries dependent data. The ability of groupers to recover in certain regions may be deterred because of reduced larval recruitment from upstream, heavily fished sources.