Up to 1,100 dolphins with badly mutilated bodies have washed up along the coast of France in just three months – the highest number in 40 years.
Examinations of the animals found many with their fins cuts off and other extreme injuries, thought to have occurred as the dolphins tried to free themselves from fishing nets.
The deaths have alarmed environmental activists and Frances ecology ministry has launched a national plan to protect the animals after campaigners warned it could lead to them becoming extinct.
Willy Daubin, of La Rochelle Universitys National Center for Scientific Research, said: Theres never been a number this high.
Already in three months, we have beaten last years record, which was up from 2017 and even that was the highest in 40 years.
Though Daubin said 90 per cent of the fatalities resulted from accidental capture in industrial nets, the reason behind the spike this year is a mystery.
He admitted he did not know what fishing machinery or equipment was behind the deaths.
It is thought trawlers using massive nets to catch sea bass are responsible for a great percentage, as dolphins become hoovered up in the nets in the process.
Lamya Essemlali, President of Sea Shepherd France, said that dolphins suffocate after becoming trapped because they cannot get to the surface for air.
These fishing vessels have nets that are not selective at all so when they put their net in the water and the water is full of dolphins they get in the net, she explained.
Dolphins are not fish, they are mammals, and they need to get to the surface to get air.
So what happens is they suffocate and they also injure themselves, when they try to get away from the nets and thats the reason why we find all these marks on their bodies.
Daubin and his team carried out autopsies on the dolphins this year and found mutilations that were more extreme than in previous years.
Activists say they are due to fisherman who often cut body parts off the suffocated dolphins after they are pulled up on the nets, to save the net itself.
French Ecology Minister Francois de Rugy rushed last Friday to La Rochelle in an attempt to lower the number dying as a result of human action.
Hes under pressure not least because of French President Emmanuel Macrons pro-ecology stance and oft-quoted slogan to Make the Planet Great Again.
Rugy has come up with some plans, including bolstering research into existing acoustic repellent devices in place in some 26 two-vessel trawlers off the Bay of Biscay, an industrial fishing hub in the Atlantic Ocean.
When activated, the devices send unpleasant signals to nearby dolphins that cause them to swim away.
But animal rights group Sea Shepherd said they do not go far enough, and has already decried such measures as useless.