The dolphins' bodies were horribly mutilated, the fins cut off.
But what shocked French marine researchers wasn't just the brutality of the deaths of these highly intelligent mammals, but also the numbers involved — a record 1,100 have washed up on France's Atlantic coast since January.
The mass deaths, widely blamed on aggressive industrial fishing, has alarmed animal welfare groups and prompted France's ecology minister to launch a national plan to protect them.
"There's never been a number this high," said Willy Daubin, a member of La Rochelle University's National Center for Scientific Research. "Already in three months, we have beaten last year's record, which was up from 2017 and even that was the highest in 40 years."
Though Daubin said 90 percent of the fatalities resulted from accidental capture in industrial nets, the reason behind the spike this year is a mystery.
"What fishing machinery or equipment is behind all these deaths?" he asked.
Autopsies carried out on the dolphins this year by La Rochelle University's National Center for Scientific Research show extreme levels of mutilation.
Activists say a common practice is for fishermen to 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. He's under pressure not least because of French President Emmanuel Macron's 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."
It claims many of the trawlers they watch in the region don't activate the repellent devices owing to fears they will scare off valuable fish as well, and operators only turn them on if they are checked by an "onboard observer."
It also said that increasing the number of devices is no long-term solution for the underwater mammals as the move would make the ocean an uninhabitable drum of noise pollution.
"The government needs to take responsibility and act — especially Macron, who said he wanted to protect ecology," Lamya Essemlali, President of Sea Shepherd France, told The Associated Press.
She pointed to scientists who predict the current rates of fishing will likely drive the dolphin population to extinction.
"The spotlight has been put on the trawlers that fish for sea bass ..., which is a scandal. But they were not the only ones responsible."
She suggested that aggressive hake fishing, which was given the green light three years ago after long ban, was a major factor. The spike in dolphin deaths also began three years ago.
Sea Shepherd explained the ecological crisis as stemming from unprecedented demand for low-cost fish.
"Right now, the sea bass that is being caught by the trawlers that kill dolphins, you can find on the French market for eight euros-per-kilo ($9)," she said.
Global seafood consumption has more than doubled in the past 50 years, according to European Commission, a rate that rights groups have branded unsustainable.