Echinodermata in the littoral area of Mljet National Park

Background and Purpose: Complete inventarization of the marine flora and fauna inhabiting Mljet National Park and mapping of benthic communities, have still not been made 35 years after the National Park was established. Due to that fact, the goal of this survey was to explore the echinofauna in the coastal area of Mljet National Park and to make a check-list of the species inhabiting it. Materials and Methods: Fifty-nine stations in the littoral area of Mljet Island were explored during the 1995-1998 period. Fifty-five stations were explored by SCUBA-diving, from which thirty-nine stations along the south-western and north-western coast of Mljet National Park and Mljet island and sixteen stations in Mljet Lakes. Samples from one station were collected by the trawl. Samples from old trammel bottom nets were explored at three stations. Results: Fourteen benthic communities were registered in supralittoral, mediolittoral, infralittoral and circalittoral zones. 43 echinoderm species were found, from which 1 Crinoidea, 8 Holothuroidea, 13 Asteroidea, 10 Ophiuroidea and 11 Echinoidea species. Spatial distribution of echinoderms in the area explored depended mostly on the type of the bottom, where certain benthic communities developed. Twenty-eight species were found on rocky bottom while thirty-eight species were found on sandy, detritic and muddy bottoms. The richest communities were Posidonia oceanica meadows (27 species) and community of photophilic algae (24 species). Conclusion: Forty-three species found in the explored area represent about 42% of the Adriatic Sea echinofauna known at present (101 species). Taking into consideration that most of the stations were explored only by SCUBA diving method up to the depth of 40 m, we can consider Mljet National Park as an area rich in echinoderms species.