Fishing activities overlap with bottlenose dolphin core habitats of Ischia and Procida islands

Tursiops truncatus – the common bottlenose dolphin – is a species of conservation interest, listed in Annex II and IV of Habitat Directive (92/43/CEE) that requires strict protection and the creation of specially protected areas for conservation, managed according to the ecological requirements of the species, within the “Nature 2000” network. A local population of bottlenose dolphins has been monitored over fifteen years in the sea waters around Ischia and Procida Islands in the frame of the Ischia Dolphin Project, an ongoing long-term research program on Tyrrhenian cetaceans. The study area lies partially within the boundaries of "Regno di Nettuno" Marine Protected Area (MPA), which is classified by IUCN as an Important Marine Mammal Area (IMMA), where pods of cetacean key species such as common dolphin (Delphinus Delphis), bottlenose dolphin, and fin whale (Balaenoptera physalus) live. Investigating habitat exploitation by bottlenose dolphins is crucial for conserving this protected species. Between 2004 and 2018, 1186 surveys were performed, resulting in 91 encounters with the species. To investigate bottlenose dolphins' habitat exploitation, we combined both behavioral observations and spatial analysis. Kernel Density Estimation and Hotspot analysis allowed to delineate fine-scale areas of higher concentration of critical activities (feeding, socializing/mating, resting) and interactions with fisheries (gillnets and trawlers). Results show a vital region for feeding, resting, social cohesion, and mating, i.e. essential habitat for bottlenose dolphins. Unfortunately, these critical habitats are only partially protected by the zonation of the MPA, because it overlaps with human activities, especially fishing. Although the influence of fisheries on dolphins' behavior and movements needs further investigation, the results thus far collected suggest that effective management measures should take into account the human-animal conflict that can arise in these critical areas.