Rate of bioerosion by parrotfish in Barbados reef environments

Six species of parrotfish (Scaridae) in reef environments on the west coast of Barbados show a variety of feeding behaviours. They were observed to spend 80% of their time feeding on surfaces covered with filamentous algae and 20% on sand. Only Sparisoma viride consistently leaves well-defined scars on live coral. The biomass of all parrotfish species in the three environments studied ranges from 20 to 58 kg/ha (2 to 5.8 g.m (super -2) ). The gut turnover rate of these parrotfish is estimated at 8 times per day. The composition of the sediments in the reef environments was compared to that in the guts of the various parrotfish species to determine the amount of sediment produced from the rocky substrate and the amount of sediment recycled by parrotfish feeding. Sparisoma viride is the only species that causes significant bioerosion and new sediment production; the other parrotfish recycle old sediment. The rate of bioerosion on the fringing reef is 61 g.m (super -2) .a (super -1) , on the bank reef it is 40 g.m (super -2) .a (super -1) , and the Moorings study area 168 g.m (super -2) .a (super -1) .