ASYNCHRONOUS FOOD AVAILABILITY ON NEIGHBORING CARIBBEAN CORAL-REEFS DETERMINES SEASONAL PATTERNS OF GROWTH AND REPRODUCTION FOR THE HERBIVOROUS PARROTFISH SCARUS-ISERTI

Little is currently known about the temporal linkage between naturally occurring food levels and patterns of growth, reproduction, and feeding behavior by fishes on coral reefs. This study examines seasonal changes in these variables for populations of the herbivorous striped parrotfish Scarus iserti on 2 reefs in the San Bias region of Panama. Although less than 3 km apart, these populations experience notably different environmental conditions during Panama's annual cycle of rainfall and drought. In response to lower rainfall and higher dry-season winds and wave action, the renewal rate and standing crop of the striped parrotfish's algal food fell on a semi-exposed reef while rising on a more protected reef. Opposite trends occurred when wind and waves abated with the return of the wet season. In response, parrotfish on the 2 reefs showed opposite patterns of seasonal growth and reproduction, indicating that reef-associated environmental conditions determine seasonal peaks of reproduction for these fish. This result challenges the notion that planktonic conditions encountered during early life-history stages generally drive seasonal reproduction by coral reef fishes.