ANCHORAGE, Alaska (Reuters) - The depleted population of beluga whales that swim off the coast of Alaska’s largest city was listed as endangered on Friday by the federal government.

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Alaska Gov. Sarah Palin, the Republican vice-presidential candidate, called the listing “premature” after she had pressed for more time to make beluga population counts.

Environmentalists hailed the listing decision, but criticized the time it took to materialize.

“Hopefully the State of Alaska will now work toward protecting the beluga rather than, as with the polar bear, denying the science and suing to overturn the listing,” Brendan Cummings, oceans program director for the Center for Biological Diversity said in a statement.

The National Oceanic and Atmospheric Administration said it has determined that belugas in Cook Inlet, the channel that flows from Anchorage to the Gulf of Alaska, are at risk of extinction and deserving of strict protections under the Endangered Species Act.

The population, which fell to a low of 278 in 2005 from 653 in 1994, has yet to rebound from a period of over-harvesting by the region’s Native hunters, officials said.

Hunting of Cook Inlet belugas largely ceased in 1999, but the population continues to struggle, officials said.

“In spite of protections already in place, Cook Inlet beluga whales are not recovering,” James Balsinger, acting assistant administrator for NOAA’s Fisheries Service, said in a statement.

Conservation groups said they had initially filed a petition to list the population as endangered under the Endangered Species Act in March 1999.

“The science was clear — and it has been for a very long time,” said marine mammal scientist Craig Matkin of the North Gulf Oceanic Society. “The population is critically endangered.”

At the urging of the Palin administration, NOAA delayed a listing decision that had been expected in April this year so that it could conduct one additional summer population survey.

“The State of Alaska has had serious concerns about the low population of belugas in Cook Inlet for many years,” Palin said in a statement after the NOAA decision. “However, we believe that this endangered listing is premature.”

Denby Lloyd, commissioner of the Alaska Department of Fish and Game, said they had urged NOAA to delay the listing “for a few years to get more population counts.”

“Of course, whenever you have a population of marine mammals that is this low, it is a cause for serious concern,” Lloyd said. “We just aren’t sure that an endangered listing, and all the legal requirements it brings with it, is necessary to assure the health of this population at this time.”

Various industry groups have also fought the listing, which they fear will hamper Cook Inlet oil and gas development, cargo shipping, commercial fishing and major construction projects.

The beluga population of Cook Inlet is among five beluga populations in Alaska waters.