A U.N. wildlife conference placed one shark species on a protective list on Tuesday but blocked efforts to do the same for other types hunted to meet mounting Asian demand for shark fin soup.

Conservationists welcomed the new protection for porbeagle sharks, which are about 2.5 meters (8 ft) long and hit by overfishing in the Atlantic and Mediterranean.

But they criticized delegates at the 175-nation Convention on International trade in Endangered Species (CITES) for failing to restrict trade in several other sharks.

“Politics and economics trumped science, especially on marine conservation issues,” said Matt Rand, director of global shark conservation at Pew Environment Group.

The global shark product trade was worth $310 million in 2005, according to Traffic, a wildlife trade monitoring group. Shark populations are dwindling as a result of overfishing.