«Rapido» trawl fishing in the Northern Adriatic: preliminary observations of the effects on macrobenthic communities

Abstract

       The “rapido", a kind of beam trawl, is used only in the Adriatic Sea. Preliminary results of a study on the impact of the “rapido" gear on macrobenthic communities in the Adriatic Sea (Chioggia-Venice) are presented. Experimental hauls were carried out at two sites (one prohibited to all trawl-fishing activity and one used for commercial fishing) at a distance of 2-3 nautical miles from the coast. With the aim of simulating the action of commercial fishing, either one or several consecutive passages were carried out. Results indicated that trawling produces a furrow about 7 cm deep in the bottom sediment, which disturbs macrobenthic communities. After experimental hauls, the mean abundance values at all stations showed statistically significant differences with respect to controls; no significant statistical differences were found in the commercial fishing area for biomass. Although fished and control areas did not exhibit significant differences two weeks after the experiments, analysis of the diversity indexes revealed that complete recovery had not occurred, since the control areas always had higher values than the fished areas. This study shows that gear such as the “rapido” has a very severe impact on benthic biocoenoses and that its use should, therefore, be better regulated.