Environmentalists called for a global ban on the trade in Atlantic bluefin tuna, after the body responsible for managing stocks cut quotas but did not suspend fishing of the threatened species.
The International Commission for the Conservation of Atlantic Tunas (ICCAT) reduced the 2010 quota for eastern Atlantic bluefin tuna to 13,500 tonnes - a cut from 22,000 tonnes in 2009.
The 30% cut in quotas, along with a shorter fishing season, reductions in the size of the fleet and provisions for suspending the fishery next year if scientists found there was a serious risk of stock collapse, were welcomed by the European Commission.
Commissioner for Maritime Affairs and Fisheries Joe Borg said he was confident that "this unprecedented set of concrete and ambitious steps will mark decisive progress in managing and conserving this migrating stock in the Mediterranean and the Atlantic".
"Our goal is to ensure the return to a healthy bluefin tuna stock and a viable and sustainable fishery for our fleet.
"Admittedly, ICCAT had a very tough task this year, but it has certainly risen to challenge," he said.
But green groups said the measures would not be enough to help dwindling stocks of the fish recover, with only a complete suspension of the industry delivering the turnaround in declines caused by overfishing.
Susan Lieberman, director of international policy for the Pew Environment Group, said: "Since its inception, the International Commission for the Conservation of Atlantic Tunas has been driven by short-term commercial fishing interests, not the conservation ethic implied by its name.
"Only a zero catch limit could have maximised the chances that Atlantic bluefin tuna could recover to the point where the fishery could exist in the future."
And WWF UK's marine programme manager Sally Bailey said: "Now, more than ever, WWF sees a global trade ban as the only hope for Atlantic bluefin.
"ICCAT's reduction in quota is not based on scientific advice, and is entirely unacceptable."
The conservation charity said a study by ICCAT had shown only a total halt to fishing the species would yield significant chances of the bluefin population recovering enough to not need trade restrictions by 2019.
It also said illegal fishing, rule breaking and over-capacity of the fishing fleet in the Mediterranean were hampering efforts to protect Atlantic bluefin tuna.
WWF said it was now vital to secure global trade restrictions on the fish.
Under proposals put forward by Monaco in July at ICCAT the fish would be listed as an endangered species in the Convention on International Trade in Endangered Species (Cites), temporarily suspending trade in the species, which fetches high sums in its main market Japan.
The move has been backed by a number of governments including the UK.
Today Fisheries Minister Huw Irranca-Davies said: "Our position has always been that full protection for bluefin tuna is urgent and necessary and so we are pleased to see that there will be substantial reductions - in the region of 30% - in the quantity of bluefin tuna which can be fished.
"ICCAT has taken significant steps to protect this species from the threat of extinction by further reducing fleet capacity, reducing the fishing season for purse seiners by three months to one month and has put in place measures that mean that fishing of bluefin tuna could be stopped altogether should their preservation require it.
"In the UK we will continue to argue robustly for the preservation of this iconic species."