CONICET | Buscador de Institutos y Recursos Humanos

The objective of this study is to provide information about a harbor fouling community dominated by Metridium senile in Southern Patagonia. Several steel tubes of the wharf of Puerto San Julián were extracted to perform repair tasks, allowing study the attached benthic community. Sampling was conducted at three levels: lower intertidal; 3-4 m depth subtidal and 6-7 m depth subtidal. In the lower intertidal, M. senile provided a relative abundance of 43%, being accompanied by Perumytilus purpuratus, Mytilus edulis platensis and Aulacomya atra atra, among the most abundant species. In subtidal levels the anemone presented abundances of 64 and 65%, being accompanied by Monocorophium insidiosum in the 3-4 m depth level and by Sabellidae and Syllidae at the deepest level. In the lower intertidal, epibiosis was more frequently on P. purpuratus, A. atra atra and M. edulis platensis. In subtidal levels the substrate-organisms diversity increased significantly and the anemone was fixed to A. atra atra, M. edulis platensis, Paramolgula gregaria, Crepipatella dilatata, Austromegabalanus psittacus, Hiatella arctica, Polyzoa opuntia, Pyura sp. and Sabellidae tubes. The great plasticity of M. senile to settle on different organisms, along with other strategies, makes it a colonizer able to displace other species that could compete by substrate. Given the cosmopolitan nature of M. senile; that this species has not been previously reported in the region; and taking into account our results, we discuss the possibility of consider this sea anemone as invasive alien species in Argentina.