Many dolphins have been found dead on the Atlantic coast since the beginning of January. These strandings are linked to the fishing nets in which this cetacean is entangled.
"700 dolphins have been stranded on the Atlantic coast since the beginning of the year, including several dozens in the last two days," testifies Olivier Van Canneyt, biologist at the Pelagis Observatory (1). These animals were found on the coasts of Landes, Gironde, Vendée and Charente-Maritime. In fact, mortality is higher, only one in five animals runs aground on the beach. "Winter is a good time for this kind of event, says the researcher. Common dolphins are numerous in the Bay of Biscay to find food and at the same time fishing is in full swing. "
The examination of these animals by scientists shows that the vast majority (more than 80%) of them died as a result of accidental capture by fishing boats. There are traces of net on their bodies or their tails were cut to free them from the mesh. Two types of boat are at the origin of these accidents. The pelagic trawler, towing a huge funnel-shaped net, and the gillneter, a fishing vessel laying its nets on the bottom to pick them up hours later.
France tries to protect its whales
In both cases, the dolphins are trapped, along with the other fish, and die asphyxiated. These boats are fishing bar or hake. Two varieties "friends" of the dolphin because they love like this cetacean small fish: sardines, anchovies, etc. For four years, the number of dolphins found on the coast of the Bay of Biscay has reached high thresholds. "We make assumptions to explain this evolution such as the arrival of foreign boats on this area, the change of shape of the nets or the increase of quotas for the hake fishery", explains Olivier Van Canneyt.
Acoustic repellents to ward off dolphins
To reduce the number of catches, an acoustic repellent (Pinger) has been used by the farmers' organization Les Pecheurs de Bretagne since the beginning of the year. All pelagic trawlers in the Bay of Biscay are equipped with them, as the tests conducted last winter were encouraging. This capsule emits ultrasound repelling dolphins away from the ships. But this device is not suitable for gillnetters: too complicated to equip thousands of kilometers of nets. In addition, this large-scale deployment could generate important cetacean exclusion zones.
A sound repellent developed against predatory fish
The Pelagis Observatory, Ifremer and the National Fisheries Committee are working on a European project for acoustic repellent adapted to all types of fishing and respectful of the environment: Licado (Limitation of incidental catches of dolphins). This new system should be directional and will only trigger in the presence of dolphins.
"We must find solutions quickly because when we observe a decrease in the overall population of dolphins in this area, which is not the case today, it will be too late, warns Olivier Van Canneyt. This animal breeds little, a female gives birth to four or five young throughout her life. " The Bay of Biscay dolphin should not follow the same path as the California porpoise, which has almost disappeared because of fishing.