Evaluating effects of total and partial restrictions to fishing on Mediterranean rocky-reef fish assemblages

Fish assemblages were assessed by visual census in sublittoral rocky reefs at the Tavolara-Punta Coda Cavallo Marine Protected Area (TMPA; Mediterranean Sea) and compared among locations characterised by different protection levels: no-take/no-access zones, two types of partial protected areas (PPAs, where professional and recreational fishing are regulated in a different way) and locations outside the TMPA. Fish assemblage structures evaluated on abundance data did not differ among different protection levels, while no-take/no-access zones clearly differed from the rest when data were expressed as biomass. Biomass of many target species was higher in no-take/no-access zones mostly due to greater fish size rather than density. For some fish (e.g. the dusky grouper Epinephelus marginatus), however, both greater density and larger size contributed to the greater biomass in no-take/no-access zones. No differences were found between the two types of PPAs, and between PPAs and the locations outside the TMPA, in terms of assemblage structures, and in density, size and biomass of target species. These results suggest the need to 1) improve management in PPAs or re-think of their role, and 2) quantitatively assess pressure of both professional and recreational fishing operating within and adjacent to MPAs, in order to allow MPAs to set up proper regulations (e.g. limiting professional or recreational fishermen, number and type of gears), and 2) achieve the best balance between ecological targets and reduction of conflicts among different categories of marine resource users.