Epifaunal inventory of two shipwrecks from the Belgian Continental Shelf

Issue Title: Theme Marine Biodiversity: Patterns and Processes, Assessment,Threats, Management and Conservation Shipwrecks are almost the only subtidal substrata available for epifaunal colonization along the Belgian coastal waters and have never been scientifically prospected up to now. Two shipwrecks have been investigated during the summers of 2001 and 2002. De-visu observations and examination of 14 scraped surfaces of 0.0625 m^sup 2^allowed the identification of a total of 121 macrofauna species. Species richness cumulative curves provide an estimated number of 150-280 species. Both shipwrecks are dominated by Cnidarians. The tube-dwelling amphipod Jassa herdmani was also particularly abundant. Striking differences were observed between shipwrecks. Different faunal assemblages were observed on vertical and horizontal surfaces. Species richness could not been correlated with diversity indices. Samples with high species diversity were observed when the Hydrozoan Tubularia indivisa was dominant. On the contrary, when the Anthozoan Metridium senile was dominant, samples showed a very low species richness. Finally, the Poriferan Dysidea fragilis has to be considered as a new species for the Belgian fauna.[PUBLICATION ABSTRACT]