Fishing boats in UK waters should have cameras on board to help prevent thousands of endangered marine animals being killed accidentally every year, experts say.

That includes at least 720,000 sea birds, 300,000 cetaceans (whales, dolphins, and porpoises), 345,000 seals and sea lions and more than 250,000 turtles.

Tens of millions of sharks are also killed needlessly by the fishing industry, the new report by the conservation giant WWF says.  

They are among the many species of marine wildlife that are endangered or on the brink of extinction that are victims of fishing gear from commercial fisheries — so-called by-catch.

The study, called What’s in the Net, drawn up jointly with Sky Ocean Rescue, calls for the UK government to make “remote electronic monitoring” (REM) with cameras mandatory by law to monitor catches and improve accountability.  The cameras should be phased in, rolling out on bigger, more high-risk vessels first, the group said.

In 2018, research found that simply attaching bright LED lights to fishing nets has the power to ward off turtles and seabirds that would otherwise become trapped in them and die. 

A report around the same time identified some of the world’s biggest seafood firms as contributing to the deaths of more than 100,000 whales, dolphins, seals, turtles and seabirds that are killed in agony every year by discarded fishing equipment.

Many of the creatures are drowned, strangled or mutilated by plastic gear lost or abandoned at sea, while others suffer “a prolonged and painful death, usually suffocating or starving” either because they cannot fish or their stomachs are full of plastic.

The researchers said “ghost gear” had become a huge, but overlooked, threat to marine life, and 640,000 tons of it are added to the oceans each year — a rate of more than a ton every minute. 

WWF conservationists have previously estimated up to a million tonnes of fishing gear are left in the sea each year. 

The Living Planet Report 2020 by the charity showed that nature is in freefall, with a 68 per cent decline in species’ population sizes since 1970, including a heavy toll on marine biodiversity caused by unsustainable fishing.  

Last month, the government launched a call for evidence on whether technology could be used more widely on fishing boats in English waters to prevent overfishing, with a consultation due next year.

Fishing is the biggest threat to marine wildlife, because of the use of unselective fishing gear such as gillnets, purse seine, trawl nets and longlines, the new report says, and currently there is very little independent monitoring of most fishing at sea.  

A study by University of Exeter has previously said the suffering caused by entanglement in lost or discarded fishing gear causes is a major animal welfare concern. 

Cameras would also allow human observers at sea to operate more safely, the authors argue.  

Helen McLachlan, a fisheries expert at WWF-UK, said: “WWF is calling on the UK to demonstrate global leadership by adopting full monitoring with cameras across vessels fishing in our waters, including those fisheries known to be at high risk of wildlife by-catch.

“Nature is in freefall and we need urgent action to turn this around both on land and at sea.”  

WWF is urging governments worldwide to adopt REM cameras.  A spokesman for the Department for Environment, Food and Rural Affairs said: “We have a beautiful and diverse marine ecosystem, which is why we are working closely with fishermen to reduce accidental by-catch. 

“We recently launched a call for evidence to examine whether monitoring technology could be used more widely on fishing boats operating in English waters, and our Fisheries Bill will soon set out policies to minimise by-catch and, where possible, eliminate it.”

The government says it is due to publish an action plan to tackle cetacean by-catch in UK waters next year.