Combined threats keep Cook Inlet beluga numbers perilously low, scientists say

The dire state of the endangered Cook Inlet beluga population, which is now below 300 animals and has continued to decline, is blamed on a variety of factors. They include industrial noise, urban pollution, vessel traffic, oil and gas activities, food stress and climate change.

What about all of the above?

And for scientists working on how the beluga population can recover, the sheer range of problems can make it hard to come up with answers.

Scientists are studying several of these threats, and their research was a major focus of the Alaska Marine Science Symposium held last week in Anchorage.

One project maps numerous combined stressors in the endangered belugas’ habitat. The map was created by independent scientist and consultant Mandy Migura for Defenders of Wildlife and  in collaboration with other organizations.

The map shows the locations of: 

• Cook Inlet vessel traffic routes, 
• oil and gas operations,
• urban runoff,
• permitted pollution discharge areas,
• noise-creating industrial operations, 
• zones where industrial operators have permits allowing them to disturb belugas and
• other human activities in the animals’ range. 

The only safe space for belugas, according to the map, is a strip of water in the northernmost part of the belugas’ range, within Knik Arm.

“It’s kind of like death by 1,000 cuts or the straw that broke the camel’s back,” Migura said.

The National Oceanic and Atmospheric Administration produced a plan in 2016 to aid the beluga population’s recovery. The plan found that cumulative impacts were among the top three threats to the population’s continued existence, along with underwater noise and the possibility of some catastrophic event.

This poses a conundrum, Migura said. If no individual factor is responsible for the belugas’ continued decline, how can any individual human activity be curtailed through regulation?

Migura said the regulatory system is not designed to manage that in a comprehensive or holistic way. That has meant no meaningful limits, even after the endangered listing that’s supposed to protect the belugas was applied, on all the activities that contribute to the problem.

“It’s really hard to actually look at the entire environment as a whole,” she said. 

The result is continued decline and no meaningful curbs on development. “There hasn’t been an obvious change in how they’re managed or how their prey is managed or how their habitat is being managed,” she said.

Migura would know. She is a veteran of NOAA Fisheries and was one of the agency’s leaders in creating the recovery plan.

The Cook Inlet beluga population plunged from about 1,300 in the 1970s to fewer than 300 now. Though it was designated an endangered species in 2008, it continued to drop at a rate of 2.3% a year from then until 2018.

The last official population estimate, based on a 2018 aerial survey, was 279. Though biannual surveying was interrupted by the COVID-19 pandemic, a new population estimate is expected this year. An updated population status review released last September, something required every five years under the Endangered Species Act, gave a pessimistic prognosis. “Given that the Cook Inlet beluga whale population is extremely small and the cause of the population’s decline in numbers remains unknown at this time, recovery is not anticipated in the foreseeable future,” the status review said.

Despite all of the data depicted on Migura’s map – intended to present the belugas’ plight in visual form – it remains incomplete. It does not include, for example, all “mixing zones,” the areas where wastewater discharge is allowed to create pollution concentrations above legal limits, with the assumption that dilution will occur. It does not include the locations of the fish that belugas eat, food sources that are known to have suffered some declines. And it does not include climate change impacts, which range broadly.

Plans are to update the map as additional information comes in, Migura said.

The map is just one perspective of the Cook Inlet beluga population dilemma highlighted at the symposium. In other research findings, individual risk factors were examined.

Noise is considered a threat because it potentially interferes with the whales’ ability to communicate with each other through their varied calls. Sonia Kumar, a graduate student at the University of Alaska Fairbanks, presented findings from her acoustic study that showed how belugas are largely absent from the mouth of the Kenai River when the site is buzzing with summer commercial and sport fishing and other activity, but that the whales use the area after that activity ceases and the waters are quieter.

Another issue is food availability. Research presented by independent scientist William Bechtol concluded that there are major gaps in knowledge about salmon, oil-rich eulachon and other fish that Cook Inlet belugas eat. Eulachon stocks are known to have fallen in recent years, but monitoring salmon escapement in northern Cook Inlet, for example, has been pared back because of state budget cuts, according to Bechtol.

Beluga strandings, which occur occasionally, pose another threat to the population, especially given its small size. A NOAA Fisheries-led analysis described the 27 known stranding events that occurred from 2020 to 2022. Some of those events involved multiple whales. All three of the stranding events in which beluga survived happened in 2020, and one involved 17 animals of different ages. In all, there were nine dead belugas found stranded in 2020, 10 dead belugas found in 2021 and five in 2022, the report said. More than half of the dead were calves or fetuses, the report said.

From 2015 to 2022, 67 dead Cook Inlet belugas were found stranded, according to NOAA Fisheries.

Other research painting a picture of reproductive failures – in the form of absent beluga calves — is emerging of the Cook Inlet population.

A study published in December used photographic evidence to track the demographic mix of the belugas over 13 years. It found fewer calves than would be typical. Calculations are that maternal belugas in the Cook Inlet population are having babies once every four years, on average, That compares to the usual reproduction schedule for belugas elsewhere: once every two or three years.

Exactly how that is happening – whether adult females are not getting pregnant or unable to bring pregnancies to term or newborns are failing to survive – is unknown, said Gina Himes Boor of Montana State University, the study’s lead author. Also unknown is exactly what’s causing the reproductive problems. “Nothing was really a red flag,” she said.

The study used thousands of photographs taken from vessels between 2005 and 2017 that enabled scientists to see distinctive markings on the beluga skins that identify individuals. That photographic work is being done through the cooperative Cook Inlet Beluga Whale Photo-ID Project; Tamara McGuire, the principal investigator on that project, is also a coauthor of the new study on low reproduction.

A separate but related study found that the largest groups of Cook Inlet belugas seen in the ice-free seasons, which in past years numbered in the hundreds, were only 80 and 50 in 2021 and 2022. It is too early to conclude that there is a trend, said Himes Boor, who is a coauithor of that study. But there are some ideas about why the large congregations have become smaller. “It might indicate that food resources are low and they’re having to disperse more,” she said.

As research into the dwindling population continues, there is little to celebrate, Himes Boor said.

Still, “the good news is that we’re getting more and better information about what’s going on with them,” she said.

Other positive signs might come from the work of a group called the Cook Inlet Beluga Whale Recovery Implementation Task Force. The task force, comprising federal and state agency officials and other experts, reviewed its recent work at its annual meeting, held Friday in Anchorage.

A lot of the work is aimed at helping the fish that Cook Inlet belugas eat, by protecting or enhancing their habitat. That includes buying easements to protect estuaries – the tidal mouths of rivers – and killing invasive species that inhibit salmon spawning or survival.

Other work is focused on public education and enhancing science done by regular citizens. That includes adding signs along Cook Inlet advising users about the belugas’ vulnerabilities; programs to teach boaters to avoid conflicts with the whales; public awareness about steps to take if stranded whales are spotted; and public engagement projects like the annual Belugas Count! event in September, which encourages citizen scientists to help gather information about the population size and the whale locations.

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