The increased attention on the Atlantic bluefin tuna and other marine life by the 175-nation Convention on International Trade in Endangered Species, or CITES, tops an ambitious agenda for nearly two weeks of meetings beginning Saturday in Doha.
The conference also is expected to take up issues ranging from combating elephant poaching for ivory in Africa to proposals to ban trade in polar bear skins and parts. And less-known species such as the spiny-tailed iguanas of Mexico and Central America and the spectacular Dynastes satanas beetle of Latin America - both prized by collectors - will be discussed.
Susan Lieberman, director of international policy with the Pew Environment Group in Washington, said the focus on marine habitats reflects the belief that current conservation tools are inadequate to protect plummeting stocks of many commercial fish.
According to U.N. Food and Agriculture Organization, more than half of all marine fish stocks are under threat.
"If these measures pass, then it says the global community, the governments of the world, recognize that there is something wrong out there with the oceans and we have to regulate what we are taking out of sea," said Lieberman, who previously headed the U.S. delegation to CITES.
"I see this as a conservation moment," she added. "If it doesn't pass, it says fisheries interest which overexploit oceans species in our sea will continue and that the world community is not willing to look at the long-term health of planet."
Both the shark and tuna proposals are likely to be among the most contentious. They pit the Europeans and Americans against fishing nations in North Africa and Asia - especially Japan, which has already vowed to ignore any bluefin ban.
A bid to regulate the trade in red and pink corals - harvested to make expensive jewelry - could also divide the delegates.
Monaco - the sponsor of the proposed banning the export of Atlantic bluefin tuna - says numbers have fallen by nearly 75 percent since 1957. But most of the decline has occurred in the past decade with demand driven by sushi lovers in Japan and elsewhere for its succulent red and pink meat.
The World Wildlife Fund and other environmental groups said the steep decline has been fueled by a surge in what are called purse seine fleets, which essentially surround the schools of tuna and scoop them up with a massive net. The efficient operations use GPS systems and helicopters to spot schools of Atlantic bluefin.
The United States backed the ban proposal last week while many European countries also expressed support - though France and the European Commission have endorsed a compromise to delay the ban until 2011.
U.S. Assistant Secretary of the Interior for Fish and Wildlife and Parks Tom Strickland said it's clear that the present international oversight of tuna fishing has failed to "take the steps necessary to protect the declining populations."
The International Commission for the Conservation of Atlantic Tunas, or ICCAT, currently regulates tuna fishing.
"The (tuna) fishery is at risk of collapse," Strickland told The Associated Press. "If we don't take dramatic action, we are afraid it will be too late and we won't be able to recover the species."
60 Minutes: King of Sushi in trouble Over Tuna:
Watch CBS News Videos Online
Japan, which consumes 80 percent of Atlantic bluefin, has said it will ignore the ban. The more critical issue is whether other key fishing countries will join Japan's rebuff - which would allow them to sell tuna to Japan.
Japan believes the management of Atlantic bluefin should remain solely under ICCAT, which conservationists contend has failed to enact appropriate fishing quotas and done little to crackdown on illegal fishing. It has an economic incentive to do so. The Atlantic bluefin business nets about $7.2 billion a year, according to the environmental group Sierra Club.
Japan also argues that concerns about the extinction of Atlantic bluefin are overblown.
"ICAAT has set up solid catch rules, and if we follow these the numbers should recover," said Hisashi Endo, director of ecosystem conservation office in the Fisheries Ministry in Tokyo. "We don't think there's any need to bring this to CITES."
The threat of ban has some Japanese warning their culture is under siege. Sushi is an iconic dish in Japan with fatty bluefin - called "o-toro" in Japan - going for as much as 2,000 yen ($20) a piece in high-end Tokyo restaurants.
Hisao Masuko, director of international division of Japan Tuna Fisheries Cooperative Association, said he fears a ban could open the door to tighter regulations on other tuna species.
"This time it might be Atlantic bluefin, but next time it'll be southern bluefin, and then the bigeye tuna," Masuko said. "So we need to really fight this."
Many Asian countries - along with some in Latin America and Africa - are expected to oppose proposals to regulate the trade of at least four shark species including scalloped hammerhead and whitetip.
These shark species have seen their numbers drop dramatically since the 1980s, due to rising demand for shark fin soup especially among China's nouveau rich and their use as an alternative for traditional fish and chips in Europe.
"All four of these sharks are overexploited because their fins or meat are particularly valuable," said Amanda Nickson, head of species program for WWF International. "They are slow growing and take a long time to mature which makes it difficult for a species like this to recover from over-exploitation."