Whale surveys planned for eastern Bering Sea this summer

Two surveys this summer will crisscross the region’s seas by air and ship to check on the populations of various whale species.
Beginning in June, the latest aerial survey of beluga whales will take place over Norton Sound and the Yukon River Delta. Then, in August, the International Whaling Commission plans a baleen whale survey, using a Japanese vessel which will sail across the eastern Bering Sea into the Chukchi Sea as part of an international effort to monitor large baleen whale populations.
Information about the upcoming surveys was shared in a Strait Science talk last week by Jessica Crance and Kim Shelden, research biologists with NOAA’s Cetacean Assessment and Ecology Program, which is responsible for studying the status of whales in Alaskan waters. Both researchers operate out of the Alaska Fisheries Science Center in Seattle.

Belugas
The beluga survey is an effort by NOAA scientists working with the Alaska Beluga Whale Committee, or ABWC, which includes subsistence hunters and formed in 1988 to conserve and manage beluga populations.
“They are one of the only whales present in really large numbers in the Norton Sound and Yukon area during the ice-free months,” Shelden said. “And the more we understand about these belugas, the better we understand the ecosystems where they live and how these ecosystems are changing.”
ABWC and NOAA coordinated two previous aerial surveys of belugas in the eastern Bering Sea—in 2017 and 2022.
“To conserve and manage belugas requires knowledge about the past, the present, and the future and this means trying to find answers to a number of questions,” Shelden said.
The aerial surveys should help researchers and managers better understand how abundant belugas are and which habitats are important to them.
Shelden explained that during these surveys, the team flies in predetermined lines called transects at an altitude of just over a thousand feet and at a speed of about 115 knots. The aircraft will have five people on board: two pilots, one observer that looks out the left window, one that looks out the right window, and one scientist who records data into a computer.
For the 2024 survey, the team is adding a camera to mount on the belly of the plane to help detect whales that may surface directly under the aircraft. The camera may also help document presence of calves, juveniles, and adults based on body color.
The team also expanded the area of the survey further south.
“Based on the recommendations from the ABWC, we’ve added even more lines south to Hooper Bay since we were encountering whales south of the 2017 study area during our 2022 surveys,” Shelden said.
Additionally, they’ve tacked on extra days to the survey after the weather in the summer of 2022 prevented them from flying as much as they planned. They only flew about 2,200 miles of track line, compared to 5,400 miles in 2017.
The team only counted 821 belugas in 2022, though they observed much larger group sizes than those seen in 2017. The researchers used models to account for the gaps in data, and they ultimately estimated that there were a little over 20,000 belugas in 2022, compared to the 12,269 counted in 2017, Shelden said. She added that those results should be published in a scientific journal later this year.
The team hopes to have its latest abundance estimate by fall of 2025, Shelden said, but, come next month, the group plans “to get out daily reports of where we’re flying and what we’re seeing.”

Large baleens
The other survey will focus on large baleen whales and is run by the International Whaling Commission.
Called the Pacific Ocean Whale and Ecosystem Research Survey, or POWER Survey for short, this annual effort began in 2010 to understand the abundance and density of large whales in remote areas.
Each year, the survey covers a large chunk of the North Pacific. This year and next year, the researchers will survey a small portion of the southern Chukchi Sea. They’ll also survey the eastern Bering Sea in this summer, and then the central Bering Sea next summer.
They’ll begin this year’s journey in Dutch Harbor in mid-August and return there by the end of September.
Japan will provide the vessel, the Yushin Maru #2, and crew.
Though this vessel has been used for Japanese whaling, Crance confirmed that the researchers won’t be killing any whales.
“There will be no harvesting of any marine mammal species at all,” said Crance, who will be on board the ship as NOAA’s representative. “This is strictly just a visual and passive acoustic survey.”
The team will follow set paths across the ocean and count every marine mammal they see, including walruses and seals, though their focus is on large whales.
“In the southern Chukchi, we’ll be looking primarily for gray whales to help us better understand stock structure,” Crance said. “In the southern Bering Sea, we’re hoping to find humpback whales to try and better understand the different stocks that are meeting in those areas. And then, of course, North Pacific right whales are always the highest priority species.”
If the animal they see is considered a high-priority species, such as a right whale, they’ll break from their track line to get a photo ID and take a biopsy sample of the animal’s skin and blubber to get more information about its sex, reproductive status and diet.
Right whales were once widely distributed throughout the entire North Pacific and Bering Sea before they became the target of commercial whaling in the 19th century. Crance said there are only estimated to be about 50 North Pacific right whales in the eastern population.
The 2017 survey passed through the habitat of right whales in the eastern Bering Sea. Crance explained that the team added passive acoustics to their methods that year to try to locate the species since they are rarely sighted.
“By adding passive acoustics, and these instruments to our surveys, we have been able to sight at least 18 confirmed unique right whales,” she said. “Since the POWER Survey’s inception, we’ve sighted even more that we just weren’t able to photograph. We’ve been able to get six different biopsy samples. So this has really been a phenomenal opportunity for us to increase our knowledge about this critically endangered population.”
Crance said she will be sending out daily emails to all the villages’ tribal offices when the ship is in their area.
“I’ll be including information such as position, course, speed, weather conditions, planned activities for the day, any species seen, or anything else that that might be of interest or of note,” she said.
If there is a need to get in touch with the Yushin Maru #2, Crance said anyone can call it over VHF systems. “Their AIS will be turned on for the entirety of the survey,” she said.