Fishers' Perception on the Interaction between Dolphins and Fishing Activities in Italian and Croatian Waters

Interactions between fishing and dolphins can be detrimental, since on one hand dolphins can be lethally entangled by nets and trawls, and on the other dolphins can predate fish caught by nets. For dolphins, this interaction can be dangerous as they can be wounded or accidentally killed; for fishers, the predation of their catch results in economic losses due to reduced quantity and/or quality of catches and damage to fishing gear. During July and November 2020, we surveyed the dolphin-fisheries conflict through compiling 209 fisher interviews from nine locations in Italy and Croatia. Fishers mentioned the common bottlenose dolphin (Tursiops truncatus) as the species primarily interacting with fishing, with the major issue being catch damage by predation. The interaction probability varied among gears and seasons, with some fishing activities (e.g., passive nets) more affected than others (e.g., bottom trawls), especially in terms of economic loss (1000-10,000 euro/year on average). More than 70% of the fishers claimed that dolphin populations have increased over the last 10 years, in different degrees and based on different areas. Dolphin bycatch rates are generally low; however, 34.6% of respondents reported having captured at least one dolphin during their career. The fishers' attitude towards acoustic deterrents (pingers) as a mitigation measure revealed that few of them were aware of these devices or were using them.

Automated summary

Interactions between fishing and dolphins can have negative consequences, including dolphins becoming entangled and killed by fishing gear and dolphins predating on fish caught by nets. This interaction poses danger to dolphins and leads to economic losses for fishers. A survey conducted in Italy and Croatia revealed that common bottlenose dolphins are the species most commonly involved in fishing interactions, with catch damage being the main issue. The probability of interaction varied among different fishing gears and seasons, with certain activities experiencing higher economic losses. While dolphin bycatch rates are generally low, a significant percentage of fishers reported capturing dolphins during their career. Awareness and use of acoustic deterrent devices among fishers were found to be limited.