Abstract

Our objective was to provide a baseline data bank of the ecological conditions of the proposed Culebra Island’s Marine Fishery Reserve (MFR). Aerial photographs were analyzed using dot grids to determine the percent coverage of bottom communities. We used line intercept transects to quantitatively describe coral reef epibenthic communities and stationary visual censuses to quantitatively describe fish communities. With these data we calculated the following community parameters: species richness, abundance, Shannon-Weaver Index (H’n), evenness (J’n), % of coral cover, total biomass and standing stock biomass. Bootstrapping analysis was used to test for significant differences in the average values of these parameters between sampling stations and years. Seagrass beds were the most abundant community type (35%), followed by coral reefs (34%), sandy bottoms (11%) and hard grounds (10%). A total of 69 coral species were identified, including 4 hydrocorals, 25 octocorals and 40 scleractinians. Epibenthic surveys showed that there were no significant changes in species richness, H’n, and J’n between 1997 and 1998 in sampling stations CR1 and CR2. There was a non-significant increase in colony abundance between 1997 and 1998 mostly due to partial coral tissue mortality and its consequent colony fragmentation. Only 29% of the hard corals were considered to be healthy. 46% were overgrown by filamentous algae, 37% by macroalgae and 20% were bioeroded. Coral mortality was estimated to be 32.9 +- 5.6% at CR1 and 28.3 +- 9.8% in CR2 for the 1998 data. A total of 221 fish species were identified, including 1 13 genera and 59 families. Fish surveys demonstrated no significant changes in the fish community of the Carlos Rosario Beach between 19% and 1998. But, there were significant differences between Carlos Rosario Beach and Cayo de Luis Peña. The latter showed significantly higher average values in tish abundance, total biomass, standing stock biomass, and biomass and density of fishery target species. Our data indicate that the proposed MFR has a high coverage of critical habitats, high diversity of corals and fishes, and that fish populations are very healthy in parts of the proposed reserve. Cayo de Luis Peña is less accessible to spearfishermen ta Carlos Rosario Beach, which suggest that there is a severe overfishing problem in the latter locality. We recommend to the government of Puerto Rico to take action as soon as possible and establish a " no take” MFR in Culebra Island to prevent further depletion of fish stocks.

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