PREDATION EFFECT ON THE EARLY DEVELOPMENT OF THE FOULING COMMUNITY AT URCA REGION, GUANABARA BAY, RIO DE JANEIRO

Abstract

The influence of fish predation on the early fouling community development was evaluated by exclusion experiments. Plywood panels were vertically fixed to different types of exclusion cages to distinguish the effects of predation (cage and control treatments) and common caging artifacts (light and current treatments). The experiment design consisted of 4 random blocks submitted to 4 different treatments, that were submerged at 1 m deep by a floating device, from Sept/92 to Jan/93 (4 months). The percent cover of sessile species was recorded twice a month. The initial settlement of fouling community was very similar in all treatments. The dominance of hydrozoans on initial panels was followed by serpulids. Two patterns of community development could be observed after 75 days: the dominance of balanids on panels exposed to predation and dominance of bryozoans on protected ones. The effect of fish predation was observed from the 3 rd month on, indicating that community development can change with successional stage.