Bluefin Fishing Quota Will Rise Only Slightly PARIS - The international commission responsible for the conservation of the Atlantic and Mediterranean bluefin tuna agreed Monday to hold the 2013 fishing quota close to this year's number despite modest signs of an improvement in stocks of the bluefin, the world's most valuable fish. Delegates of the International Commission for the Conservation of Atlantic Tunas, or Iccat, recommended a total bluefin catch of up to 13,500 tons next year in the Eastern Atlantic and Mediterranean, up marginally from 12,900 tons this year. A Canadian proposal to raise the quota for the Western Atlantic stock, which is managed separately, went nowhere, and it will remain at the current 1,750 tons. Iccat's bluefin discussions, held in Agadir, Morocco, differed markedly from some held in the recent past in which conservationists fought for quota reductions amid signs that the stock might be on the verge of collapse. This year, a stock assessment by Iccat scientists suggested that the Mediterranean bluefin population had recovered a bit, with fish mortality declining and stock biomass showing "a clear increase." The scientists warned that the data on which they based their models remains sketchy, partly because of illegal, unreported and unregulated fishing in the Mediterranean, and they called for a conservative approach. The biomass of the Eastern Atlantic and Mediterranean bluefin has declined by about 30 percent over the last two decades, particularly since the onset of tuna "ranching" for the sushi trade, and the fish is listed as endangered by the International Union for Conservation of Nature. Conservationists generally welcomed indications that Iccat member states are following the scientific recommendations. "They listened to the scientists this time," said Susan Lieberman, director of international policy at the Pew Environment Group. This is an organization that has had a long history of ignoring the science. But the conservation community was disappointed by Iccat's refusal to extend protections to endangered sharks. The organization had been considering such proposals, including a ban on the fishing of porbeagles and a cap on the shortfin mako catch. Those measures failed to gain any traction. In a statement, María José Cornax, fisheries campaign manager for Oceana Europe, said the shark results revealed "a baffling, contradictory approach within Iccat," with the organization moving in a positive direction on bluefin but apparently less concerned about other species within its mandate. "Iccat must remove its blinders and look beyond this one fish to the many other stocks for which it is responsible," she said. Ms. Lieberman said she was "optimistic" that shark protections would gain acceptance in a meeting next year of the Convention on International Trade in Endangered Species of Wild Fauna and Flora, the United Nations treaty organization, as the momentum for such measures has been gaining momentum. She praised Iccat delegates for agreeing to reopen the commission's treaty to discuss how its mandate might need to be changed to address the management of shark fisheries. "That's important," she said. On the high seas, no one's in charge of sharks. No one's taken responsibility. In an earlier version of this post, a reference to the director of international policy at the Pew Environment Group misspelled her surname. As correctly noted elsewhere in the post, she is Susan Lieberman, not Liebeman.