Four rapidly dwindling shark species prized in Asia for fins and in Europe for meat will be swimming against the current at a UN wildlife trade meet days after an attempt to protect tuna was crushed.Starting Sunday, the 175-nation Convention on the International Trade in Endangered Species (CITES), will consider separate proposals that would require cross-border trade in these open-water predators be tracked and reported.The small island nation of Palau, dependent on scuba tourism, along with Sweden and the United States, have sponsored the measures, with backing from Egypt and Rwanda.Japan, which led the successful drive to keep Atlantic bluefin in its sushi bars, has said they should be voted down.Tokyo points to a lack of data, and argues that CITES, meeting in Doha through Thursday, is not the right tool to oversee high-value commercial fauna.Scientists acknowledge a paucity of data.At the top of the marine food chain, most of these fearsome predators roam the open seas, and there is no global system in place to monitor population levels.Of the 139 nations that have reported shark catches to the Food and Agriculture Organisation (FAO) since 2000, less than half list species, "making it difficult to assess the impacts of fisheries," said Laurence Fauconnet, a shark expert at Scripps Institution of Oceanography in La Jolla, California.But the studies that have been done paint a grim picture, indicating that each year some 70 million sharks of all types are harvested.Sharks are especially vulnerable to overfishing because most species take many years to mature and have relatively few young.The scalloped hammerhead, once common in coastal tropical waters, has declined by 75 to 90 percent in the Indian and Pacific Oceans over two decades, said Demian Chapman at the Institute for Ocean Conservation at Stonybrook University in New York.Listed as "endangered" by the International Union for the Conservation of Nature (IUCN), the fish is the top choice of gourmets for shark fin soup, a prestige food consumed by Chinese communities around the globe.Four other "look-alike" species are covered in the proposal to prevent the scalloped hammerhead from being harvested by mistake.Also sought for its fins is the oceanic white tip, listed by the IUCN as "critically endangered" in most of the Atlantic and "vulnerable" globally.Its meat can sell for 100 dollars (74 euros) a kilo, making it one of the most expensive seafoods by weight.The other two proposals would regulate international trade of the porbeagle, also fished for fins and meat, and the spiny dogfish, a staple of generic "fish fingers" and other prepared foods.At the last CITES meeting in 2007, spiny dog and porbeagle failed to gain protection.But delegates and conservationists in Doha point to two factors that could help one or more of the measures pass the CITES threshold of a two-thirds majority this time around. Unlike the Atlantic bluefin bid for a so-called Appendix I ban on all international commerce, the shark proposals are seeking Appendix II status, which only requires tracking of exports and scientific assessments. "The problem today is not there is serious mismanagement of trade in sharks, but that there is not management at all," said Sue Lieberman, policy director for the Pew Environment Group in Washington. Also, the debate over bluefin pitted commercial interests against conservationists, and the result suggests it was a mismatched fight. In the case of sharks, there is business on both sides of the issue: dozens small island nations, and some bigger ones, reap serious revenue from scuba-related tourism. "It has been calculated that a live shark is worth 100 times more than dead one," said Ibrahim Didi, environment minister from the Maldives, in Doha as an observer. Lieberman said: "If hammerheads are gone, people are not going to come to swim with the jellyfish." All told, a third of the world's 64 species of pelagic, or open water, sharks face extinction, according to report issued last June by the IUCN's Shark Specialist Group.