Influence of sponge morphology on the composition of the polychaete associated fauna from Rocas Atoll,northeast Brazil

The relationships between the morphology of sponges and variables describing their harbored polychaete fauna were analyzed along Rocas, the only known South Atlantic Atoll, together with the location on host and feeding habits. The identification and quantification of all the associated organisms highlighted the dominance of polychaetes. The adults of the symbiotic species Haplosyllis spongicola were the most dominant sponge endobionts. However, both juveniles and epitokes (reproductive individuals) of H. spongicola were also found, suggesting that this species completes its life cycle inside the host. Polychaete density was significantly greater in lobate sponges than in massive and encrusting forms. Conversely, the highly specific symbiotic mode of life of H. spongicola species seems to play a major role in structuring the composition of the polychaete fauna in relation to sponge morphotypes along Rocas Atoll.