Polychaete assemblages of rocky shore along the South Adriatic coast (Mediterranean Sea).

The present study deals with the distribution of hard substratum polychaete assemblages under different environmental conditions. Samples were collected along a stretch of coast from Torre Guaceto to Otranto (Southern Adriatic Sea, Italy), in three transects perpendicular to the coast from 5 to 25 m in July 2000, by scraping off 400 cm(2). A total of 3188 specimens, belonging to 118 taxa were collected. Multivariate analysis showed that polychaete assemblages differed among depths with a clear difference between the shallowest sites (5 m) and the deeper ones (15-25 m). A variation among sites was also observed, with highest differences among sites within samples collected at 5 in depth, and with a sharp separation of some samples relative to Torre Guaceto from the remaining ones. Some potential causes for the observed differences both within and among sites were hypothesized and discussed, as well as the usefulness of polychaete assemblage analysis as descriptor of different environmental situations