The quiet winter brought fewer bodies than previous years. However, the Pelagic Institute is not out of business: this week, the body of a young dolphin was autopsied, the marks on his body of which indicate that he was caught in a net.
In a large open room on the outside of the University of La Rochelle, Willy Dabin and his colleagues are busy around the animal on Vendee’s Saint-Hilaire-de-Riez Beach in February. Cetaceans were kept in the cold, their body had been slightly degraded by birds, but at first glance, the study engineer, responsible for the stranding part of Pelagis, a scientific institute that has been monitoring chains since the 1970s, discovered marks on his skin.
A new project has been launched to better understand the capturing of occasional dolphins
parallel strips on the abdomen, ‘A very straight grid’. “Squeeze while the animal is alive”he comes out.
During the autopsy, the results will remain neutral. No one interprets the signs. Everything is recorded in writing, and photographed, so that vets can make a diagnosis. But external pests immediately lead to a hypothesis: fishing in fishing nets. In this case, the dolphin remains stuck under the water and dies of suffocation.
Same results on the long beak (rostrum) of marine mammals: we can see the encirclement on the upper and lower lips continuously, the teeth moving in alignment with these lines, some even broken.
On internal examination, under the thick skin of the dolphin, the flesh under these pressed strips had changed color: it had taken on a purple complexion, while it should have been white.
Several sets of clues make it possible to establish a diagnosis of shock-related death: a healthy animal, with certain external lesions, death by asphyxiation, a full stomach (the dolphin approaches the nets to feed), and the absence of major co-morbidity, or congestion of multiple organs, says Sarah Wend. A veterinarian, presenting her own report in parallel, for a double slate of examinations during an autopsy. Depending on the results, a degree of certainty is associated with the diagnosis.
Dolphins chase prey the same fish species targeted by fishermen. Explains Elodie Martinie-Cousty, leader of the NGO France Nature Environnement (FNE)’s Oceans, Seas and Coasts Network, which is assisting with the process.
3,000 to 11,000 dolphins are captured annually
“In France, we lost two years with a new minister (The Sea, Annick Girardin) and a government that does not want to listen to scholars and ask for studies.” Additional, she regrets. “In the meantime we don’t underestimate the catch.”
In 2016-2017, the first peak of the strands on the Atlantic coast sounded the alarm. Since then, their number indicates hunting levels “unbearable” For the common dolphin groups, a protected species, in the Bay of Biscay, Pelagias tirelessly reminds us. A network of more than 400 reporters helps him monitor the coast.
⋙ Thousands of dead fish were thrown into the Bay of Biscay
In this area, the annual catch is estimated “Between 3000 and 11000” The dolphins, to Europe’s population of 680,000 individuals, confirmed to Ifremer in early April to mark the launch of the Delmoges Project, which aims to better understand the increase in bycatch by fishing vessels since 2016 and suggest different ways to reduce it.
Autopsy techniques, which are increasingly advanced, should allow for better knowledge of the causes of death. Bycatch, mainly by trawls and gillnets, is the leading cause of death among stranded dolphins.
⋙ Threatened, bottlenose dolphin under close watch in the Mediterranean
France is in the sights of the European Commission, which accuses it of not taking enough measures to curb by-catch “In her waters and by her fleet”. If she does nothing, she risks financial fines.
The measures taken in response to this warning – the installation of underwater pulse transmitters (pingers) on fishing vessels and the improvement of monitoring (onboard cameras, on-board monitors, aerial surveillance) or the obligation to record by-catch – are evaluated to the commission source.
“We have the possibility of closing (temporary fisheries, editor’s note), we don’t, and dolphins are paying the price,” Storm, Representative Caroline Rose (the Greens), who attended the autopsy that day, as did Senator Arnaud Bazin (Les Republic). As a reminder, the European Fund for Maritime Affairs (FEAMPA), can be used to fund other fishing technologies or offset in the event of a shutdown.
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