North Pacific right whales may be returning to northern parts of the Bering Sea

There are signs the world’s most critically endangered large whale population is expanding north into their former Bering Sea range.

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The North Pacific right whale may be returning to parts of its former range in the Bering Sea. (Brenda K. Rone / NOAA Fisheries)

North Pacific right whales, once numbering in the tens of thousands, swam throughout the Bering Sea until they were nearly wiped out by commercial hunters.

Now the Eastern North Pacific right whale population is estimated to total about 30 individuals, and its habitat is believed to be concentrated in the southeastern corner of the Bering Sea and some nearby areas of the Gulf of Alaska.

But there are signs of resilience in the world’s most critically endangered large whale population, and also signs that the remaining animals are spreading farther into their former Bering Sea range.

“There has been good news in that we have had quite a few sightings in recent years. Anytime we have sightings, that’s a good thing,” said Jessica Crance, a marine biologist and right whale expert with the National Oceanic and Atmospheric Administration’s Alaska Fisheries Science center.

There are now 29 individuals in the population that have been cataloged, and some of those have been seen more than once, “which is great because we know they’re still alive,” Crance said.

NOAA’s National Marine Fisheries Service has just launched its five-year review of the population’s status, as required under the Endangered Species Act. The review is expected to be completed by year’s end.

At the same time, NMFS is considering a new petition from conservation groups to expand the designated critical habitat to include areas farther west in the Bering, along with much more territory in the Gulf of Alaska to the south of the Aleutian Islands. Designated critical habitat requires extra precautions for listed species; an initial response to the March 10 petition should come within a 90-day period, according to federal law.

The existing critical habitat designated in 2008 is not adequate to protect against possible extinction, argues the petition, filed by the Center for Biological Diversity and an organization called Save the North Pacific Right Whale.

It is important to broaden critical habitat designation to include Unimak Pass, the narrow passageway that thousands of vessels use to transit between the Gulf of Alaska and the Bering Sea, the petition argues. “Shipping traffic is dramatically increasing in these areas — funneling through Unimak Pass — which elevates shipping noise and puts the whales at a heightened risk of vessel strikes,” the petition says.

Other threats include climate change, which has increased the risks of marine heatwaves, according to the petition.

Warming conditions may be pushing right whales farther north into the Bering Sea, though information about that is sparse.

The first recorded sighting of overwintering right whales in the Bering Sea came earlier this year when fishermen caught images of whales on video.

That was a significant finding, Crance said. There had been some acoustic detections in past years of the whales in the Bering Sea as late in the winter as January, but until the fishermen saw the whales in February, there were no actual sightings in Bering beyond past December, she said.

“It’s another piece of the puzzle of where these animals are going,” she said. “It broadens our knowledge of their life history,”

The information is also a “beautiful example of collaboration with industry,” Crance said. The fishermen notified the Alaska Department of Fish and Game, which notified the National Marine Fisheries Service, which contacted the U.S. Coast Guard, resulting in a cautionary notice to mariners, she said.

Another important sign came in 2018, when a single male whale was found swimming in the Bering Strait strait region, first in Alaska waters off St. Lawrence Island and then a few weeks later in a Russian fjord.

There are theories about why whales may be pushing farther north into the Bering Sea. There are possibly annual or seasonal variations, as may have been the case in 2018, when even winter ice was scarce and there was virtually no “cold pool” of water serving as an ecological barrier that summer. Or it is possible that the whales are simply re-establishing their past range.

The whales’ use of the busy Bering Sea raises concerns about conflicts with vessel traffic, both fishing vessels and cargo ships.

So far, Crance said, there has been no evidence of right whales killed by Bering Sea vessels or gear entanglements, as happens with the endangered North Atlantic right whale population. Only two have shown evidence of entanglement, and none have snow evidence of ship strikes.

However, with such a tiny population, “It’s been very difficult to quantify any impacts,” she said. Problems may be occurring without biologists’ knowledge, she said. “It’s such a remote area that should a ship strike or entanglement occur, the animal may die before it’s ever noticed,” she said.

In recent years, a few other encouraging signs south of the Bering in the Gulf of Alaska. A juvenile was spotted in 2017, the first since 2005; scientists gave the animal a fitting name: Phoenix. With a 3-to-1 male-to-female ratio, the population faces significant obstacles to reproduction, Crance noted.

Last year, four whales were located, and two of them were newly identified so added to the catalog of known Eastern North Pacific right whales.

Historical experiences of the North Pacific right whales were devastating.

They were known as the “right whale” to hunt because of their slow swimming speed and their high levels of body fat, which caused carcasses to float. Up to 37,000 North Pacific right whales were killed by commercial whalers in the 1800s, according to NOAA. Even after legal commercial whaling ended, the population was targeted in the 20th century by an illegal Soviet hunt that killed an estimated 770 animals, according to NOAA.

Crance, who was on last summer’s cruise that found four right whales, is scheduled to go out again this summer to try to get more information on how many whales remain. The cruise, conducted through the International Whaling Commission’s Pacific Ocean Whale and Ecosystem Research program, will sail along the Aleutian Islands to the western edge of the U.S. exclusive economic zone.