DOHA, Qatar - A U.S.-backed proposal to protect the heavily fished hammerhead sharks was narrowly rejected Tuesday over concerns by Asia nations that regulating the booming trade in shark fins could hurt poor nations.

Tom Strickland, the U.S. Assistant Interior Secretary for Fish, Wildlife and Parks, said regional fisheries bodies have done nothing to regulate the trade in endangered scalloped hammerhead, great hammerhead as well as the threatened smooth hammerhead, and their numbers have dropped by as much as 85 percent.

"The greatest threat to the hammerhead is from harvest for the international fin trade and the fin of the species is among highly valued of the trade," Strickland said. Shark fin soup is a much prized delicacy in China.

The measure was only narrowly rejected, failing by five votes to take the necessary two-thirds of the 175-nation Convention on International Trade in Endangered Species to pass.

The tiny Pacific nation of Palau, which last year created the first ever shark sanctuary, joined the Americans in introducing the proposal. It called on countries to protect the species so they can be fished well into the future.

"We must preserve for our children these amazing species," said Palau's Ministry of Natural Resources, Environment & Tourism Harry R. Fritz, adding that his country supports the protection of other shark species as well.

Japan, which successfully campaigned against an export ban on Atlantic bluefin tuna and regulations on the coral trade, led the opposition to the shark proposal. It argued that better enforcement, not trade restrictions was the answer. It also complained it would be difficult to differentiate the hammerheads from other species and would deprive poor fishing nations of much needed income.

They were joined by other countries dependent on the trade, including Singapore and Indonesia which catches the most sharks.

CITES was due to take up similar proposals to protect the oceanic whitetip shark which is also used in the fin trade, the porbeagle shark which is also killed for its meat and the spiny dogfish shark — a chief ingredient of fish and chips and fish sticks.

Conservationist were outrage and disappointed by the ruling, since it came after a string of defeats on marine species including a proposal last week on a shark conservation plan. Japan and China led efforts to kill that proposal, as well.

Hammerheads, more than any other shark species, are killed for their fins and are the most threatened. Fishermen, both industrial and small-scale and many operating illegally, slice off the fins and throw the carcasses back in the ocean and there are as many as 2.7 million hammerheads are caught annually.

Shark fin soup has long played central part in traditional Chinese culture, often being served at weddings and banquets. Demand for the soup has surged as increasing numbers of Chinese middle class family become wealthier.