Six species of tuna are threatened with extinction by overfishing. Data: IUCN. Graphic: AFP

By Marlowe Hood
28 September 2018
(AFP) – Dozens of nations with commercial fisheries in the Atlantic Ocean will grapple next week with a new finding that bigeye tuna, the backbone of a billion dollar business, is severely depleted and overfished.
Unless catch levels are sharply reduced, scientists warned, stocks of the fatty, fast-swimming predator could crash within a decade or two.
Less iconic than Atlantic bluefin but more valuable as an industry, bigeye (Thunnus obesus)—one of several so-called tropical tunas—is prized for sashimi in Japan and canned for supermarket sales worldwide. It is not farmed.
An internal report by 40-odd scientists working under the inter-governmental International Commission for the Conservation of Atlantic Tunas (ICCAT), finalised last week, shows that populations have fallen to less than 20 percent of their historic levels.
Even more critical, the stock is barely half the size needed to support a “maximum sustainable yield”—the largest catch that can be taken without compromising long-term stability of the species.
Current harvests, overwhelmingly legal, are also more than 60 percent above levels that would give bigeye at least a fighting chance of recovering its numbers, the report said.
“The stock is in the red with a very high level of certainty,” said Paulus Tak, a senior officer for the Pew Charitable Trusts, and an official observer at the ICCAT meeting in November that will renew or revise current bigeye quotas.Indeed, 18,000 runs of three distinct computer models returned an unprecedented 99.5 percent degree of certitude.”Bottom line, there are simply too many boats in the water chasing too few fish,” Tak told AFP. [more]

Fisheries nations to decide fate of declining bigeye tuna