Effects of marine reserves on coral reef fish communities from five islands in New Caledonia

The effect of marine reserve protection on coral reef fish communities was studied on five islands located in the southwest lagoon of New Caledonia. Commercial fish communities and Chaetodontidae, sampled before fishing prohibition and after five years of protection, were compared. Reference stations were also sampled to assess variability in unprotected communities on the same time scale. The hypothesis that marine reserves protect and develop fish stocks was confirmed. Species richness, density and biomass of fish on the protected reefs increased respectively by 67%, 160% and 246%. This increase was statistically significant, whereas the reference stations showed only a small increase in density. There were significant increases in the species richness, density and biomass of the major exploited fish families (Serranidae, Lutjanidae, Lethrinidae, Mullidae, Labridae, Scaridae, Siganidae and Acanthuridae) and also of the Chaetodontidae. No significant increase in the mean lengths of fishes was noted among the main species, with the exception of one species of Siganid. Size structure changed for most of the main species, as the proportion of small individuals increased after five years of protection. Detrended correspondance analysis indicated that marine reserve protection was the most important determinant of the fish community structure. The second determinant was the position along an inshore-offshore gradient. Marine reserve protection resulted in an increase in the relative abundance and species richness of large edible species within the assemblages.