Marine Parks Need Sharks?

Abstract

In their report “Fishing, trophic cascades, and the process of grazing on coral reefs” (6 Jan., p. 98), P. J. Mumby et al. showed that increased grouper biomass within the Exuma Cays Land and Sea Park (ECLSP) did not acutely impair the grazing capacity of parrotfish populations (a major prey item), alleviating concerns that marine reserves may cause trophic cascades that will impede the recovery of imperiled Caribbean coral reefs. Although Mumby et al. suggest that this finding was primarily due to coincident beneficial reserve effects for parrotfish, we suggest that the abundance of sharks in the ECLSP, due to limited shark fisheries in the Bahamas (1), may have been an important contributing factor.