Abstract

Jamaica's commercial fishery has long shown signs of overexploitationexpressed as reduced CPUE and the disappearance oflarge-sized fish. Heavy fishing pressure often results in reduced abundance, a change in size structure, and shifts in community structure. We assessed the reefs along ˜305 km of Jamaica's northern shelf and performed visual fish censuses at sixty sites according to the AGRRA protocol. Jamaica's fish community was characterized relative to AGRRA results from other Caribbean regions. Although variable, densities of most fish species were only slightly lower in Jamaica than other regions. Fish size was consistently small along the north coast. Total lengths of commercially valuable fishes (Serranidae, Lutjanidae, Haemulidae; n = 1,191) ranged from 5-10 cm smaller in Jamaica than other regions we sampled. As valuable species become increasingly scarce due to overfishing, lower trophic levels (e.g., herbivorous scarids and acanthurids) are targeted by the fishing community. Herbivores play an importantrole inmaintaining coral reefs by keeping macroalgae from becoming competitively dominant. An inadequate abundance of herbivores on Jamaica's reefs has resulted in a shift from a coral-dominllted to an algal-dominated community structure. Scaridae and Acanthuridae are smaller (by 4 - 15 cm and 5 - 8 cm, respectively) on Jamaica's reefs than conspecifics from other regions. Mean total length for all scarid species was 12 cm (n = 6158) and acanthurid species averaged 10 cm total length (n = 1950). Terminal phase scarids were not commonly encountered and large individuals (> 30 cm) of any fish species were rarely sited during our assessment. The fish population of Jamaica's north coast may be undergoing a late stage of exploitation, displaying signs of recruitment overfishing and indications of reduced genetic variation for size. Lower potential for reproductive output associated with small-sized individuals puts Jamaica's fish population at risk and the potential loss of herbivorous fishes threatens the recovery and sustainability of Jamaica's reefs.

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