ANCHORAGE — The beluga whales that swim in Cook Inlet are continuing to struggle and appear headed for extinction if nothing changes, a government official said Friday.

A survey done in June found the whales “are not recovering,” said Julie Speegle, a spokeswoman for the National Oceanic and Atmospheric Administration. “We don’t know why.”

Cook Inlet belugas, considered genetically distinct, have been struggling and in decline for years.

The white whales have been listed as endangered under the federal Endangered Species Act since 2008, when the count was higher than the most recent population estimates.

The survey estimated the number of belugas in Cook Inlet at 312. The previous year’s estimate was 284 whales. The increase is not enough to be scientifically significant, NOAA officials said. The aerial survey is conducted from a small plane with bubble windows, behind which scientists count the whales and make video recordings to come up with yearly estimates.

NOAA says estimates have been as low as 278 whales and as high as 366 in the past decade. The annual survey has been done since the early 1990s.

Speegle said NOAA is developing a recovery plan, which is expected to be completed by late spring. Recovery plan team members include scientists, citizens groups, Alaska Natives, and conservation and oil and gas development groups.

The recovery plan will set out management actions with the goal being the survival of Cook Inlet’s belugas, Speegle said.

The Cook Inlet population has declined steadily since the 1980s from a high of about 1,300. The loss was accelerated between 1994 and 1998, when Alaska Natives harvested nearly half of the remaining 650 whales. Belugas have not bounced back despite a hunting ban.

Scientists said there was one new and interesting finding from last summer’s survey. A group of belugas was observed in a location where they had not been spotted in more than a decade. A group of 12 to 21 whales was first observed swimming north into upper Cook Inlet. They then moved into Trading Bay, where they remained.

“Beluga whales have not been observed in this area during our surveys since 2001,” said Kim Shelden, chief scientist of the survey.

The state of Alaska fought the endangered species listing, saying it would hurt economic development at the Port of Anchorage, as well as oil and natural gas development in nearby waters. A federal judge last year affirmed the listing.