A baseline study of macrofauna from the North Adriatic seaports Raša, Rijeka, Bakar and Omišalj

Seaports are recipients of myriad organic and inorganic pollutants that directly or indirectly released into marine environment. Recently, maritime transport and associated port activities are recognized as increasing source of environmental threats, with ballast water as one of main vectors for initial transport of non-indigenous species (NIS). The goal of this study was to characterize benthic communities associated with hard- and soft-bottom habitats from the four North Adriatic seaports and to check the presence of non-indigenous species. The sampling strategy and methodology followed modified CRIM Protocol (Hewitt and Martin, 2001). Total of 17 higher macrobenthic taxa, and 75 species were identified from the hard substrata, and much less (10 higher taxa, 36 species) from the soft bottom. The results of univariate analyses suggested occurrence of modified and impoverished soft-bottom macrofauna and rather diverse hard bottom fauna. Multivariate analysis indicated significant differences of macrofauna communities among surveyed ports. In total, seven NIS were detected, all belonging to polychaetes. One of them, Platynereis nadiae was recorded for the first time from the Adriatic Sea and it was found in ports of Bakar, Omišalj and Rijeka. Six NIS were reported from the port of Raša: Hydroides dianthus, H. elegans, H. stoichadon, Leiochrides australis, Protolaeospira striata and Pileolaria berkelyana, and the last one was recorded for the first time in the Adriatic Sea.