Optimization of scuba diving activities in a Mediterranean marine protected area based on benthic vulnerability assessment

Scuba diving has become an increasingly popular recreational activity, involving approximately 6 million active divers worldwide.The high frequency of diving can impact the benthic communities of marine protected areas (MPAs), possibly jeopardizing the beneficial effects of protection.The Portofino MPA, in the Ligurian Sea, is one of the main scuba diving destinations in Europe, with up to 40,000 dives per year concentrated along 6.5 km of coast.The vulnerability of megabenthic (i.e. animals larger than 5 cm) communities to scuba diving impacts was evaluated at four different depths at all MPA diving spots with close attention to the fragility of all observed species, their frequency in the transects and the inclination and type of substrates.The most vulnerable spots lie below 30-m depth and are characterized by complex coralligenous biocoenoses rich in erect, fragile carbonatic species.The results allowed scuba diving management within the MPA to be optimized. Two main responses have already been put in place: (i) the promotion of a mandatory course for 'Underwater Environmental Supervisors' directed at local divemasters, instructors and owners of diving centres; and (ii) the proposal for the application of conservation measures to scuba diving activities.