Praising several retail chains that have taken the lead in refusing to sell bluefin, WWF said it was time for "retailers around the world to emulate their courageous decision... until this fish is out of danger."
Last November, European Union (EU) fisheries ministers agreed to restrict the fishing of bluefin tuna in the eastern Atlantic and Mediterranean under a 15-year plan to revive dwindling stocks.
The French supermarket giant Auchan, as well as the Italian subsidiaries of Coop and Carrefour, have already stopped selling bluefin.