A baby boom of gray whales is apparently under way along Alaska's coast and off Southern California, marine researchers say.

Scientists tracking marine mammals in the Chukchi Sea between Alaska and Russia have recorded an unprecedented number of sightings of gray whale calves in July, the Anchorage Daily News reported Friday.

Fifty-seven cow-calf pairs were recorded between July 1 and July 26, the federal Alaska Fisheries Science Center said.

The biggest number previously counted was 18, reported in 1982 and 2011 for those years' full season, which runs from late June/early July until October.

"There's the potential that some of those are repeat sightings," said Megan Ferguson, project coordinator for the Aerial Surveys of Arctic Marine Mammals Project. "But the fact that we're seeing a five-fold increase makes me think that it is a real increase."

Meanwhile, a researcher at the federal Southwestern Fisheries Science Center in La Jolla, Calif., said California numbers for young gray whales are also high.

"This was a big calf count year," Wayne Perryman told the Daily News in an email, "(with an) estimate of about 1,000 calves, so there should be a lot of them everywhere."

Gary whales make seasonal trips from the Chukchi Sea south to Mexico and are a popular attraction for whale spotters who go out on tour boats from Baja to Alaska when migrations take place.