Effects of fishing on reef fish communities at Pedro Bank and Port Royal Cays, Jamaica

Abstract

We examined the results of a natural 'experiment' to determine the effects of fishing on Caribbean reef fish communities. We repeated a trap survey in 1986 of reef fish populations at exposed. offshore sites on southeast (SE) and southwest (SW) Pedro Bank and protected, nearshore sites around the Port Royal Cays (PRC), Jamaica, that had been surveyed in 1969-73. The 'control' area SW Pedro Bank was virtually unexploited in 1969-73 and was lightly-to-moderately exploited in 1986. As 'treatment' areas, exploitation of SE Pedro Bank increased from moderate to heavy between surveys, and from heavy to very heavy around PRC. Overall catch rates declined significantly in heavily exploited areas 82 % over SE Pedro Bank and 33 % around PRC but did not decline over SW Pedro Bank. The largest fishes commonly caught in the traps (lutjanids and large serranids and scarids), f a m ~ e s particularly vulnerable to trap fish~ng (acanthurids and bahstids), and other commerc~ally preferred species groups (small serraruds, haemulids, mullids) dechned most consistently. Increases in catch rate were generally found only in commercially less desirable reef fishes, such as chaetodontids, holocentrids, and tetraodontiformes. The catch (i.e. species) composition changed significantly between surveys in h e a d y exploited areas (SE Pedro Bank and PRC) but not over SW Pedro Bank. Similar changes in 2 different reef environments (SE Pedro Bank and PRC) suggest that quantitative relationships of catch rate and composition with fishing effort may be useful in fishery management.