Ban on fishing bluefin tuna should not be lifted after Brexit, warn scientists

The ban on fishing bluefin tuna should not be lifted after Brexit, scientists have said, despite growing pressure from anglers.

It is currently illegal to catch the enormous variety of tuna that can grow to 2,000lbs and which largely vanished from British waters in the 1990s because of overfishing.

However in the past few years large schools of the bluefins have been spotted off the south coast of England and in the Irish sea, leading to calls for the ban to be lifted.

Anglers claim Brexit presents a ‘unique opportunity’ to relax fishing laws, but scientists say the resurgence of the fish is down to a natural phenomenon of sea warming rather than the recovery of the species.

A new study by British marine biologist Dr Richard Kirby, formerly of Plymouth University, and the University of Lille, found the fish are coming further northward because of the Atlantic Multidecadal Oscillation (AMO) which increases sea temperatures in a 60 - 120 year cycle.

"Bluefin tuna have been extensively overfished and the recent changes in distribution are most likely environmentally driven rather than due to fisheries management and stock recovery,” said Dr Kirby.

"Before we further exploit bluefin tuna either commercially or recreationally for sportfishing, we should consider whether it would be better to protect them by making the UK's seas a safe space for one of the ocean's most endangered top fish.”

Dr Robin Faillettaz, from the University of Lille, added: “When water temperature increases during a positive AMO, bluefin tuna move further north.

“However, the most positive phases of the AMO also have a detrimental effect upon recruitment in the Mediterranean Sea, which is currently the most important spawning ground, and that will affect adult abundance a few years later.”

The EU currently has a fishing quota of 16,000 tonnes of bluefin tuna, with around 98 per cent of that designated to commercial fishing off the coasts of Spain and France. The UK has no quota at all, making it illegal to catch the fish.

After Brexit the government will be allowed to apply for its own quota and anglers have described it as 'a once in a generation opportunity'.

David Mitchell, head of marine at The Angling Trust, said: “The return of giant bluefin tuna to our shores provides the UK with a once in a generation opportunity to establish a sustainable, economically optimal, scientifically important fishery for them right here in Britain.”

Bluefin tuna are globally classified as 'endangered', with restaurants in Japan especially willing to pay sky-high prices.

In 2013 a sushi restaurant in Tokyo paid over £1m for a single fish, which weighed close to 500lbs.

The new study was published in Science Advances.