Dolphins are among the unintended casualties of fishing in Europe's waters.
The World Wide Fund for Nature (WWF) says 1,200 of them died in the Bay of Biscay between December 2018 and March 2019 after getting entangled in fishing gear.
Globally, adds WWF, 720,000 seabirds, 345,000 seals and sea lions, more than 250,000 turtles and tens of millions of sharks die each year as a result of so-called "bycatch", the unintentional capture of marine wildlife by commercial fisheries.
WWF is calling for cameras to be installed on fishing boats.
Dr Antonia Leroy, head of ocean policy at the WWF's Europe office said the installation of cameras would make it possible to identify and measure the degree of accidents. She says this would help find solutions working with fishermen, not against them, "because for everyone right now the situation is not ideal at all".
Cameras would also make it possible to provide additional data on the most dangerous areas and periods for these bycatches.
But fishermen are divided. They argue the use of this tool must be on a voluntary basis.
"It is a very big thing to put cameras on all these vessels, maybe thousands of vessels, just to see how big is the problem," explained Gerard Van Balsfoort, vice-president of Europêche (a body representing thousands of European fishermen).
He says there are easier ways to achieve the same result, such as putting observers on the boats.
For Van Balsfoort putting cameras onboard to prevent dolphin bycatch is "a little bit strange".
Cameras are already in use in Australia, Canada and the USA. For NGOs, this measure would also make it possible to involve fishermen even more in environmental protection.