The mutilated corpses of hundreds of dolphins have been found piled up on a French beach.

They were some of the thousands accidentally killed by the fishing industry each year that wash up on the country’s coast, observers say.

The animals had suffered fractures, snapped tails, broken flippers and deep wounds from nets cutting into their flesh.

And experts fear the toll of “bycatch” victims is threatening the survival of French dolphin populations.

The grim find was made by volunteers from Sea Shepherd France in Les Sables d’Olonne, on France’s Atlantic coast near La Rochelle.

Tragic photos show beached whales Show all 15 1 /15 Tragic photos show beached whales Tragic photos show beached whales A dead sperm whale lies on Hunstanton beach in Norfolk on 5 February 2016 AFP/Getty Tragic photos show beached whales Volunteers pour buckets of water over the 80 remaining live pilot whales found stranded on remote Ocean Beach on New Zealand's southern-most Stewart island, 8 January 2003 AFP/Getty Tragic photos show beached whales Contractors clear away the body of one of the dead 48ft sperm whales that were washed-up on a beach near Gibraltar Point in Skegness, Lincolnshire in 2016 PA Tragic photos show beached whales People pass by a beached whale at the Pointe de la Torche, near Brest in France on 29 November 2011 AFP/Getty Tragic photos show beached whales A woman touches the tail of a large whale carcass on Wattamola Beach at the Royal National Park in Sydney on 25 September 2018 AFP/Getty Tragic photos show beached whales Beached humpback whale in California, 2015 AFP/Getty Tragic photos show beached whales Dead long fin pilot whales at Hamelin Bay on Australia's west coast on 23 March 2009 AFP/Getty Tragic photos show beached whales A 36ft sperm whale lies dead on the beach at Sutton Bridge, in The Wash, off the Lincolnshire coast, where it became stranded in 2004 PA Tragic photos show beached whales A female fin whale opens its mouth as it lies stranded and alive on the beach at Carlyon Bay, Cornwall on 13 August 2012 Getty Tragic photos show beached whales The lower jaw of a dead sperm whale that stranded itself on a beach in Hunstanton, Norfolk on 5 February 2016 Getty Tragic photos show beached whales One of the five sperm whales that were found washed ashore on beaches near Skegness, Lincolnshire over the weekend on 25 January 2016 Getty Tragic photos show beached whales Employees at work to skin the remains of a beached 60ft whale on 25 January 2013 AFP/Getty Tragic photos show beached whales Two long-finned pilot whales are stranded on a beach in the northern French city of Calais on 2 November 2015 AFP/Getty Tragic photos show beached whales A sperm whale lies dead after becoming stranded on a beach in Hunstanton, Norfolk on 5 February 2016 Getty Tragic photos show beached whales Crowds gather as a sperm whale lies dead after becoming stranded on a beach in Hunstanton, Norfolk on 5 February 2016 Getty

Local authorities gather up the corpses of dolphins washed up along stretches of beaches before once a week sending them to a rendering plant.

Each year trawlers fishing for sea bass kill up to 10,000 dolphins, according to Sea Shepherd – more than those slaughtered in the combined annual catches of the Faroe Islands and Taiji, Japan, which both cause mass public outrage.

French authorities pile up the hundreds of bodies and once a week send them away (Sea Shepherd Global)

The mammals are caught in fishing nets that capture everything in their path, suffering an “agonising” death by drowning. Any pulled up alive usually die from wounds inflicted by fishermen on the vessels, monitors say.

Trawlermen cut the dolphins open in an attempt to make them sink and disappear.

Catches happen every night, all year round along the French coast, peaking between January and March.

It is estimated only a fifth of the total killed are found on shore, with 990 dead dolphins washed up since December.

In 2016 scientists from the Pélagis Observatory in La Rochelle and university academics warned that death tolls from fishing risked driving populations to extinction.

“Dolphins are a sensitive species which are slow to reproduce their few offspring. By the time the decline in their population is visible, it’s usually too late,” said a spokesperson for activist group Sea Shepherd. “If we still want to see dolphins in France tomorrow, it’s urgent to take immediate measures to protect them.

“However, the French state is turning a deaf ear to all the scientists’ warnings, and the fishermen involved are taking advantage of the general public’s ignorance.”

The organisation wants a ban on fishing in sea bass spawning grounds and on the sale of juvenile fish.

French fishermen consider dolphins to be accidental catches even though they are protected by international conservation law, a spokesman for its French arm said.

The Loire fisheries committee says trawlers have pingers – sound repellents – but last month monitors said they observed two trawlers that had caught dolphins and did not have pingers.

The Independent has asked the French agriculture ministry to comment.