Proposals to ban the trade in Atlantic bluefin tuna and to impose restrictions on the shark trade top the agenda as the UN Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) opens this weekend in Qatar. Many of the nearly 40 proposals slated for discussion at the 12-day meeting relate to marine species, which negotiators and conservationists say reflects increased awareness of the hazards faced by the world’s oceans. Among the most controversial will be a recommendation that the bluefin tuna trade be banned until populations of the fish can recover from decades of overfishing. U.S. officials say they will support a ban, as will the European Union, albeit with conditions; Japan, which represents more than half of the world market for tuna, opposes a ban. Governments from 175 nations are participating in the CITES meeting, which will also deal with proposals relating to hammerhead sharks, red coral, and polar bears, as well as a proposal by Tanzania and Zambia to resume trade in their stocks of elephant ivory.