Washington - A US government agency declared a cluster of beluga whales off Alaska's Cook Inlet to be endangered by extinction, in a statement issued Friday.

The National Oceanic and Atmospheric Administration's Fisheries Services announced the decision. Anchorage, Alaska's largest city, sits at the end of Cook Inlet, which opens onto the Gulf of Alaska, Kodiak Island and the Pacific Ocean.

The beluga population in Cook Inlet has failed to recover "in spite of protections already in place," said James Balsiger, the Fisheries Service acting assistant administrator.

The endangered designation means that any federal government agency involved in activities that could impact the beluga population in and around Cook Inlet must first consult with the Fisheries Service, to make sure that the whales would not be threatened.

The Fisheries Service declared the Cook Inlet belugas depleted in 2000.

According to the agency, the beluga population declined by nearly half from 1994-98. The latest estimates put the Cook Inlet belugas at 375 whales, down from 653 in 1994.

Alaskan native peoples have been restricted in hunting belugas in Cook Inlet since 1999, harvesting only five whales since then.

The recovery of the local beluga population from a 2005 low of 278 could be caused by a combination of stranded whales, disease and killer whale predation, as well as the growing Anchorage-area human population, oil and gas exploration and other industrial activity.