The bottlenose dolphin is the second most sighted species in Mediterranean waters and the only one that finds its preferred habitat on the continental shelf, where it is by far the most abundant species, with over 88 % of sightings (Gnone et al., 2021).
The bottlenose dolphin is therefore, of all the species present in the Mediterranean basin, the one that most often interacts with humans and the anthropic activities that take place within the coastal strip.
The bottlenose dolphin is known for its behavioural plasticity and its ability to opportunistically exploit fishing gear to supplement its diet. Such behaviour may involve interaction with gillnets (small-scale fishing), bottom trawling, fish cages and others.
In the case of artisanal fishing, the action of the bottlenose dolphin may cause not only depredation of the net, but also damage to the net itself, exacerbating the conflict with the fishermen.
The depredation activity also entails risks for the bottlenose dolphins. It may happen that dolphins get entangled in the same net they are plundering, with immediate effects (acute mortality) and long-term effects (chronic entanglement, ingestion of net shreds).
There is also the possibility that fishermen, in an attempt to remove bottlenose dolphins from nets, use potentially dangerous solutions, such as throwing firecrackers or, in the most extreme cases, deliberate killing or mutilation (Silvani et al., 1999).

In an attempt to reduce depredation and mitigate the conflict between bottlenose dolphins and fishermen, the use of acoustic deterrents has been proposed, i.e. devices attached to the net that are activated in the presence of the animals (by acoustic sensors) and emit deterrent sounds in an attempt to draw the animals away from the fishing gear. However, bottlenose dolphins have shown the ability to become accustomed to the emitted sounds in a relatively short time and thus bypass the deterrent. Modern devices emit a variety of sounds to delay the learning process, but it appears that bottlenose dolphins are able to ‘generalise’ the signal emitted by the device and the effectiveness of acoustic deterrents over the long term remains uncertain. Acoustic deterrents also contribute to noise pollution, potentially conflicting with descriptor 11 of the Marine Strategy Framework Directive (Introduction of energy, including underwater noise, is at levels that do not adversely affect the marine environment).
Regarding the impact on bottlenose dolphin demographic units, data collected through the diagnostic activity carried out by C.Re.Di.Ma. on cetacean carcasses stranded in Liguria since 2015 (Reports Spiaggiamenti C.Re.Di.Ma. 2015-2016-20172018-2019) have revealed a non-negligible role, certainly underestimated, for impacting anthropic activities, related to the interaction with fishing activities and vessel impacts as a cause of death hypothesis in the area, and, in particular, a significant increase in bycatch injuries (bycatch, or capture of species that are not the target of a fishing activity) from 2020 to date.