More than 50 fishing nations meet this week in Majorca to try and agree quotas for the under-pressure bigeye tuna
More than 50 fishing nations meet this week in Majorca to try and agree quotas for the under-pressure bigeye tuna AFP / JOHN WESSELS

The fate of big-eye tuna, over-fished and in decline, could be decided this week when fishing nations meet to set quotas after failing last year to agree on safeguard measures for the valuable food resource.

Scientists warn that unless the catch is reduced, stocks of Thunnus obesus -- prized for sashimi in Japan and canned worldwide -- could collapse within years.

A scientific report prepared for last year's meeting of the International Commission for the Conservation of Atlantic Tunas (ICCAT) showed that numbers had plummeted to less than 20 percent of historic levels.

This was only about half what is needed to support a "maximum sustainable yield" -- the largest catch that can be taken without compromising the long-term stability of a species.

ICCAT, which groups more than 50 parties including the European Union, convenes in Majorca, Spain, on Monday for another review of the situation in the Atlantic and the Mediterranean, having failed last year to agree quotas or how to include all members in the system.

Previously, ICCAT has a headline quota of 65,000 tonnes, but in practice the catch was nearer to 80,000 tonnes, well into the danger zone, according to NGOs.

The EU on Monday proposed a quota of 62,500 tonnes through to 2022 which would include 17 countries currently catching more than 1,250 tonnes a year.

Ivory Coast, Gabon, Ghana and Guinea Bissau, meanwhile, back a quota of 57,500 to 60,000 tonnes, while the Latin American states of Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama and Mexico are pressing for no change.

For the Pew Charitable Trusts, "a quota of 60,000 tonnes would be too high," fisheries expert Grantly Galland told AFP, suggesting 50,000 tonnes instead.

A quota of 60,000 tonnes would make the stock recovery period "too long," Galland said.

Some experts have calculated that cutting the total catch to 50,000 tonnes per year would give bigeye tuna a 70 percent chance of recovery by 2028.

ICCAT will also be looking at other species at risk -- albacore tuna and sharks.

For albacore, it suggests a quota of 110,000 tonnes from 2020.

For its part, the World Wide Fund for Nature recommends that no-go zones be established for certain periods so as to reduce the number of juvenile tuna caught.

The International Pole and Line Foundation (IPNLF), which promotes artisanal line fishing for tuna, wants the meeting to take on board the special concerns of developing coastal countries.

As for sharks, which have suffered massive human predation, Senegal is pushing for all shortfin mako sharks caught to be released, dead or alive.

The shortfin mako, also known as the blue pointer or bonito shark, is among the most at risk and is already protected under international trade by the wild fauna and flora CITES convention aimed at controlling trafficking in endangered species.