Cetacean sensitivity and threats analysis to assess effectiveness of protection measures: an example of integrated approach for cetacean conservation in the Bonifacio Bouches

The conservation of the highly mobile marine mammals species is challenging. One of the primary tools for conservation of marine species and the maintenance of ecosystem processes is the establishment of marine protected areas which is based on the identification of areas of high ecological value, or the identification of effective mitigation measures for the main threats. Bonifacio Bouches is mainly a coastal area which encompasses several Natura 2000 sites and is included in the Pelagos Sanctuary for the protection of marine mammals. Numerous regulations are applied here targeting shipping and related activities for environmental protection and navigation safety. Integrated data on cetacean species, maritime traffic and marine litter were collected from systematic surveys performed on board ferries crossing the Bonifacio Strait (2013–2019). Data were seasonally investigated considering spring/summer and autumn/winter as potentially different for ecological and anthropogenic conditions. Seasonal models of preferred habitat for fin whale, striped dolphin and bottlenose dolphin were compared with the existing protected areas, evidencing gaps of spatial protection measures for the species. A species sensitivity score was integrated with threats analyses highlighting the priority areas/seasons requiring enhanced conservation efforts. Despite the existing regulations, results showed that the intense anthropogenic pressure represents a risk for the ecological richness in many areas lacking of protection. Outcomes provide us indication on candidate areas where an extension of spatial protection measures could favour the priority bottlenose dolphin species, and the areas/seasons that need improved mitigation of the main threats. The application of similar approach in wider areas can be useful to verify protection measures for highly mobile species.