BANGKOK, Thailand -- Conservationists at a global wildlife conference have voted to regulate the trade of shark species that are threatened because their fins are used to make expensive delicacies in Asia.

Delegates at the Convention on International Trade in Endangered Species of Wild Fauna and Flora conference on Monday adopted Colombia's proposal to put the oceanic whitetip and scalloped hammerhead sharks on a list of species whose trade is closely controlled.

Supporters said the species' numbers have declined due to overfishing.

The delegates will also discuss a similar proposal for porbeagle sharks.

Japan and China were among the proposals' opponents. They argue that shark population control is the responsibility not of CITES but of regional fisheries management organizations.