Species-specific impacts of a small marine reserve on reef fish production and fishing productivity in the Turks and Caicos Islands

Abstract

Marine reserves are widely considered to potentially benefit reef fisheries through emigration, yet the empirical basis for predicting the extent of this for small reserves is weak. The effects of fishing pressure and habitat on biomass and catch per unit effort (CPUE) of three species of exploited reef fish were studied at South Caicos, Turks and Caicos Islands. Distribution and abundance of hogfish (Lachnolaimus maximus) and white margate (Haemulon album) were inversely correlated with cover of fleshy macroalgae. Nassau grouper (Epinephelus striatus) were positively associated with vertical relief, but were unaffected by algal cover. Mean size, density, and biomass of hogfish were higher in a small (4 km²) marine reserve than on fished reefs, as was biomass of white margate. CPUE of hogfish was inversely related to distance from the centre of the reserve, suggesting that spillover of this species from the reserve to adjacent reefs may enhance local yields, possibly providing economic incentives for fishers to comply with reserve regulations. Fishing pressure, however, had no apparent effect on Nassau grouper. Larger fishes and those that migrate to spawn, such as economically valuable Nassau grouper, may move over too large a range to be effectively protected by small marine reserves. Small reserves may not protect all fish, but they can increase the biomass of smaller or more sedentary reef fishes and may be a useful tool for the conservation or management of species such as hogfish. Other policy options, such as seasonal spawning closures or total allowable catches, need to be considered for larger, more mobile fishes in the Turks and Caicos Islands.