Benthic Habitats and the Effects of Fishing

Symposium Abstract: Rapid Build-Up of Fish Biomass, but Still Declining Coral Reefs: Why a Marine Fishery Designation Is Not Enough for the Protection of Reef Epibenthic Communities

E. A. Hernández-Delgado and A. M. Sabat

doi: https://doi.org/10.47886/9781888569605.ch152

Reef fish communities in Culebra Island (27 km off northeastern Puerto Rico) have declined significantly in recent years. In 1999 the government of Puerto Rico established the Luis Pe-a Channel Marine Fishery Reserve (LPCMFR) with the objective of restoring local fisheries. Random stationary visual censuses and permanent line intercept transects have been used since 1996 to document the long-term changes in the coral reef fish and epibenthic communities assemblages before and after designation. A preliminary comparison of data from 1999 and 2002 shows a 38% increase in mean fish species richness/census. A dramatic increase in the abundance (2,539%) and in the biomass 26,618% of the yellowtail snapper, Ocyurus chrysurus , was observed. Also, a significant increase in the abundance (414%) and in the biomass (868%) of the schoolmaster, Lutjanus apodus , was documented. In spite of that, a significant decline of epibenthic communities was observed between 1997 and 2001, including coral species richness (31%), colony abundance (24%), and % coral cover (39%). Also, a 175% mean increase in macroalgal cover was documented. This decline was attributed to a combination of long-term indirect cascade effects of spearfishing, low densities of Diadema antillarum , and to coral disease outbreaks. These results suggest that although a MFR can be an excellent management tool to restore depleted fish stocks, the recovery fish communities alone is not enough to prevent further coral reefs decline associated to acute severe mortality caused by disease. Active restoration, in combination with MFRs, is recommended to recover coral reef epibenthic communities.