Story 2: France (Fisheries and conservation)

Story 2: Negative interactions between dolphins and fishing in Corsica (France)

Bottlenose dolphins (Tursiops truncatus) have a very large distribution range and are found all around Europe. They exploit a large variety of coastal habitats up to 200 meters in depth and are generally encountered in groups of about ten, rarely more than 20. Bottlenose dolphins like interface zones between two marine environments, which are zones with greater diversity and abundance of fish. This puts them into direct competition with fishers, especially in Corsica where the coastal strip is particularly narrow. In 2000, within the context of its «Cap Ligures» programme for the conservation of Mediterranean marine mammals, WWF-France did an inventory of bottlenose dolphins in Corsica. They found dolphin communities all around the island but fewer on the eastern side. They also encountered the anger of fishers, which had reached a critical point in the face of increased attacks by bottlenose dolphins on their nets. 

In this particular case, the dolphins had learned to take advantage of fishing nets for their own benefit. They sometimes eat directly from them, tearing the nets and angering the fishers as nets are difficult or even impossible to repair. Aggression towards dolphins and accidental captures were the consequences.

At the same time, the bottlenose dolphin plays an essential part in the marine ecosystem as a major predator. Disturbing its biology could cause an imbalance in ecosystem functioning, potentially directly impacting the fishing industry.

The international marine sanctuary PELAGOS (comprising Bonifacio and Scandola and the Agriates) holds half of the total Corsican bottlenose population, estimated at between 198 to 242 individuals. The conflict is also due to overfishing and the reduction of fish stocks, leading to the accentuation of competition between dolphins and fishers.

The EU-funded LINDA project helped to quantify the extent of the conflict between the dolphins and the fishers. It determined the impact of the attacks on fishing and suggested alternative practices which may limit them. It studied 1075 nets during 386 sea trips in 2004, involving 27 fishing boats of which 13% had been attacked by dolphins. The project revealed that fishing nets were attacked by dolphins every 4 or 5 fishing days. Certain variables were found to influence the frequency of attacks: high production nets, small mesh sizes (mesh > 9, 9 is the number of knots per 25 cm), and nets set between 25 and 50 metres deep. Analysis showed an interesting fact, namely that the commercially valuable species targeted by fishers are not part of the bottlenose dolphins’ usual diet.

The LINDA project worked on implementing measures to reduce the conflict: working with fishers to devise strategies for avoiding bottlenose dolphins, testing alternative fishing techniques, producing economic assessments of the cost of modifying fishing techniques etc. As a result, the relationship between fishers and dolphins has improved over time. The involvement of fishers, regular information on the progress of results, consideration of their suggestions and finally, the attention paid to the difficulties faced by their profession, largely contributed to calm the tensions which were palpable at the start of the study.

As shown in this example, the conflict between fishers and environmental protection has many faces, and the implementation of spatial measures, zonation systems or a fishery ban is not always the right solution. While many countries do not deal with this conflict as part of the MSP process, this example shows that a more integrated approach to management and decision making is crucial in order to consider the perspectives of multiple sectors. Active engagement with fishers and improved awareness of the importance of safeguarding a balanced ecosystem is also important.

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