Associated community with the zoanthid Palythoa caribaeorum (Duchassaing & Michelotti, 1860) (Cnidaria, Anthozoa) from littoral of Pernambuco, Brazil

The community associated with the zoanthid Palythoa caribaeorum on shores (Porto de Galinhas and Guadalupe) in northeastern Brazil were analysed. Seasonal samples (dry and wet) were made in both beaches throughout one year. This preliminary study identified 28 taxa and recognized two modes of existence, endobionts (three taxa) and hypobionts (25 taxa). Among hypobionts two patterns of ecological relationships were found: those fixed to the rocky substrata or on the base of the zoanthid colony (11 taxa) and the free-living (14 taxa). In some of these relationships, the organisms observed (Carijoa riisei and barnacles), were under the mat as victims of the zoanthid overgrowth (spatial competition). The more abundant taxa were: Mollusca (28%), Crustacea (25%), Nematoda (24%) and Polychaeta (16%). Among all samples species richness, abundance, similarity and diversity were different, especially the dry season of Porto de Galinhas. Porto de Galinhas in the dry season showed the lowest diversity with only one record. After evaluating the different ecological parameters of the P. caribaeorum-associated community, we conclude that the Guadalupe shore maintains annual homogeneity, while Porto de Galinhas shore is notably different during the year. The only environmental difference between them seems to be the effect of human activity from tourism (reef walkers, fishery and diving), that could be directly and indirectly affecting some ecological parameters of this zoanthid-associated community, such as abundance, richness and diversity of species.