© David Merron / WWF-US
Co-producing knowledge
Listening for belugas in Alaska’s Yukon River
Beluga conservation efforts depend on an accurate understanding of whales. Indigenous hunters also need to know how these whales are faring in order to determine a sustainable harvest level. As ELISABETH KRUGER explains, that’s why WWF–US is bringing together western science and Indigenous Knowledge to answer questions that are important to all who care about belugas, such as: How many belugas are there, and how are they adapting to changes in their ecosystem?
It is estimated that the eastern Bering Sea off the coast of Alaska is home to more than 12,000 beluga whales. But this number includes only those whales that are spotted in the ocean. It doesn’t take into account the belugas that might be swimming in the Yukon or Kuskokwim rivers.
Indigenous hunters in the region have long known that beluga whales often migrate upstream in search of food. But tracking the whales in rivers is often challenging. First, belugas are notoriously elusive—and finding a non-invasive method to detect belugas that spend time in rivers is difficult. Often, scientists depend on aerial surveys to come up with beluga estimates. But this entails planes flying over waterways, which many community members worry will scare away birds and animals that Indigenous communities depend on for subsistence hunting.
That’s how the idea of using hydrophones to “listen” for belugas came about.
© Elisabeth Kruger / WWF-US
Searching for belugas in the Yukon’s muddy waters
In summer 2023, we began supporting a beluga monitoring pilot project—at the request of a representative from the Alaska Beluga Whale Committee (ABWC)—to try to determine whether belugas were using the river at the same time that scientists were counting them in their ocean habitat. To do this, we partnered with Manuel Castellote at the University of Washington and NOAA Fisheries. Castellote worked with ABWC representative and Yup’ik hunter Marvin Okitkun to choose two sites on each side of the Lower Yukon River. The team then set up two stations at each site with underwater microphones, or hydrophones, placing them on the bottom of the river to continuously record the sounds of the river.
From June to September, Okitkun, along with another Indigenous hunter, Brandon Kameroff, periodically checked on the equipment at the two sites, removing debris and entangled plant material from the lines anchoring the hydrophones. They also collected the memory cards from the hydrophones at the end of the season. These were sent to Castellote to see if any beluga sounds had been detected and analyze the data.
Although a similar technique has been used before to monitor belugas in the Eklutna River in Cook Inlet, one of the unknowns when we launched the project was whether this type of equipment would even work in the Yukon River. The Yukon is a shallow, wide, fast-flowing river with an extremely silty bottom. One of the big questions was whether beluga sounds could be detected once the hydrophones were sitting on the river’s muddy bottom.
© Elisabeth Kruger / WWF-US
The pilot project clearly demonstrated that using hydrophones to detect belugas in the Yukon River works—and it’s an approach that is both cost-effective and non-invasive.
– Elisabeth Kruger, Arctic wildlife manager, WWF-US
© Elisabeth Kruger / WWF-US
Using lesson learned to support conservation
Over the four-month period, the pilot project clearly demonstrated that using hydrophones to detect belugas in the Yukon River works—and it’s an approach that is both cost-effective and non-invasive. That’s good news for scientists and hunters trying to ensure that belugas continue to thrive in the future.
But this pilot project is just the beginning. As in the rest of the Arctic, climate change is altering the ecosystem in this region, and we hope that the lessons learned from this pilot will inform the ongoing monitoring of beluga habitat use in the Yukon Delta.
The data collected by the hydrophones could provide vital information to help answer critical questions about the beluga population in the region, such as: How are belugas responding as the ecosystem changes? Is their habitat use shifting? Are they spending more time in the Yukon or travelling further upriver?
Ultimately, combining acoustic monitoring in the Yukon River with aerial surveys will result in a better understanding of belugas—and will support better management and conservation of this population. Although belugas were once abundant throughout Alaska’s waters, the Cook Inlet beluga stock has dwindled to a fraction of its historic estimated size of about 1,300 despite decades of conservation efforts. The goal of WWF-supported projects like this one is to make sure Alaska’s other beluga stocks don’t suffer the same decline.
© Elisabeth Kruger / WWF-US
ELISABETH KRUGER is the WWF-US manager for Arctic wildlife. She works at the forefront of Arctic conservation, mitigating threats to the wildlife of coastal Alaska.
