Pacific white-sided dolphins are seen in Chimelong Ocean Kingdom in Zhuhai, south China's Guangdong Province, July 2, 2019. Three pacific white-sided dolphin cubs made their first public appearance on Tuesday in Zhuhai. The three cubs, born in May of 2019, are all male.(Photo: Xinhua)

Three knocks on the cabin door: "Half past midnight!"

It's time for the team from Sea Shepherd, a group dedicated to protecting the world's marine life, to start their nightly patrol.

Six volunteers set out in a semi-rigid boat to monitor and film the operations of a nearby fishing fleet.

They already know that increasing numbers of dead dolphins are washing up on France's Atlantic beaches.

Their mission is to document the damage these vessels are doing to the dolphin population.

Since December 22, Sea Shepherd's Sam Simon, a converted meteorological observation vessel, has been the base for these nightly patrols in the Bay of Biscay off the southwest coast of France.

The volunteers can spend hours waiting as the trawlers winch up their enormous nets.

But their presence is not welcome.

"Bunch of scavengers!" shouts one crew member from a trawler just a few yards away.

Although the trawlers are fishing for sea bass, Sea Shepherd wants to record whether dolphins - or other cetaceans - have also been caught in their nets.

Earlier in their campaign, they posted a video of two dolphins being hauled aboard a fishing trawler: One had apparently already drowned, but the other, still alive, was struggling to escape the netting.

Operation Dolphin By-Catch aims to warn the public about the issue - and pressure the authorities to take action.

They argue that industrial trawling is devastating the dolphin population, with hundreds washing up dead on the west coast of France every year.

"The problem has been going on for 30 years, but there is a kind of omerta," says Lamya Essemlali, president of Sea Shepherd France.

And according to the experts, the numbers are rising.

"2019 was the year of all the records," says marine biologist Helene Peltier of the University of La Rochelle.

Between January and April, when the toll is highest, 1,200 small cetaceans washed up dead on the beaches of France's west coast - 880 of them common dolphins.

Of those they autopsied, 80 percent showed signs of collisions with fishing boats: cuts, broken teeth, battered heads, asphyxia.

And because most dead dolphins sink or are carried off to sea, they estimate that in all, 11,300 dolphins died in 2019.

AFP