HONG KONG — A major international meeting on wildlife trade ended on Thursday with final decisions to extend protections for dozens of animal and plant species — including five types of sharks — that have come under severe pressure from soaring demand and overfishing.

Conservationists welcomed the decisions by the Convention on International Trade in Endangered Species, or Cites, to regulate trade in the threatened species, including for the first time trade in mantas and five shark species: the oceanic whitetip, the porbeagle and three types of hammerhead sharks. Shark populations have fallen sharply in recent years as demand for their fins, predominantly from China, has risen.

The group reached a preliminary agreement on Monday to add those species to the protected list, but there was concern that it might be overturned at the conference’s final plenary session. South American and West African countries rallied to block efforts by Japan to reopen the debate; Japan, like China, has long opposed restrictions on fishing.

“Today was the most significant day for the ocean in the 40-year history of Cites,” said Susan Lieberman, the deputy director of international policy at the Pew Charitable Trusts, in a statement. “This victory indicates that the global community will collaborate to address the plight” of threatened ocean species, she added.