Eastern Atlantic bluefin tuna's spectacular recovery will be reversed if the region's 51-nation fisheries management body embraces quota recommendations finalised late Friday by its scientific advisory panel, scientists at the meeting warned.

The warm-blooded, fatty fish -- which can grow to the size of a small car, and swim nearly as fast -- underpins a billion-dollar business and is a culinary mainstay of sushi and sashimi in Japan.

The suggested new quota of 36,000 tonnes per year would need to be reduced by nearly a quarter to ensure at least a coin-toss chance of continued growth of the highly prized fish's stocks, currently about half-a-million tonnes.

Inexplicably, both the higher quota recommendation and the evidence of its negative impact were contained in the same report by the International Commission for the Conservation of Atlantic Tunas' (ICCAT) science body, the Standing Committee on Research and Statistics.

The committee "recommended quotas that will lead to the decline of populations that it can't even confirm have recovered", said the Ocean Foundation's Shana Miller, a scientist who participated as an observer at the meeting in Madrid.

"Hopefully, this doesn't return ICCAT to the situation it was in a decade ago, when an international trade ban was being considered," she told AFP.

In 2010, the UN body governing trade in endangered species considered a motion to outlaw international sales of eastern Atlantic tuna, which can fetch tens of thousands of dollars per fish. The motion failed.

But ICCAT did impose stricter quotas on member nations and cracked down on illegal fishing, especially off North Africa's Mediterranean coast.

- 'Political pressure' -

The measures worked better and more quickly than expected, bringing the species to the edge of full recovery.

"We were expecting the scientists to come back after the stock assessment and say, 'eastern bluefin tuna has recovered'," said Rachel Hopkins, an officer for Global Tuna Conservation at the Pew Charitable Trusts, a Philadelphia-based non-profit organisation.

But when scientists ran projections, not all showed continued growth over the next five years.

"Because of that -- and other uncertainties around the science -- they could not declare that the stocks had recovered," Hopkins told AFP.

Nor did ICCAT's science panel estimate the current recovery status, as it normally does.

However, based on the most recent assessment in 2015, it did project population changes over the next five years under different quota scenarios.

The committee concluded that annual quotas must be held to no more than 28,000 tonnes per year to guarantee a 50 percent chance that stocks would continue to expand.

And yet, it advised that the quota be gradually increased to 36,000 tonnes by 2020.

"It is surprising and concerning to us that the scientists made this recommendation despite the uncertainty," said Hopkins.

"It raises the question of whether there is a sufficient firewall in place between the science and political pressure."

Current quotas -- filled in a fishing season that last barely a month -- stand at 23,655 tonnes annually.

Final quotas for the coming three years will be decided in mid-November at an ICCAT meeting in Marrakesh, Morocco.

source: AFP