The Northern Adriatic Sea coralligenous: habitat in peculiar environmental conditions?

The Gulf of Venice is scattered with several hundreds of rocky outcrops, locally named in different manner, formed by a base rock (local sediments cemented by seeping methane) hosting the growth of stunning coralligenous and other calcareous bio-concretions, where filter feeders and calcareous algae represent most of the epibiota . They represented for a long time naturally protected areas in a sea over-exploited by fishery, sometimes using illegal methods and techniques. Up to a few years ago the northern Adriatic coralligenous was able to withstand much different and harder environmental conditions (highest water movement, or occasional environmental “disasters” as the oxygen crisis in 1977 and several “mucilaginous”), than the other coralligenous found in the Mediterranean. Now the vitality and the abundance of benthic assemblages seem to have decreased in the last few years along the Adriatic coasts – from Trieste to Chioggia – possibly due to the scarce plankton local availability At the same time even the primary production decreased together with the “blue fish” availability. In the last few years only, the beauties of the tegnùe have been discovered by the media, but luckily at least two areas (off Caorle and Chioggia) were declared “marine protected zones”. Today underwater tourism is strongly fostered in the Chioggia area; but rumours among divers start to indicate the beginning of an overall environmental possible crisis, more evident in the epibiota