Dozens of gray whales are dancing around in shallow, nearshore waters north of Sitka this spring, raising their tails to the sky as they feed from the seafloor.
In recent years, mariners have noticed more and more gray whales visiting waters near Sitka. Researchers say roughly 150 to 200 gray whales appeared in the Sound last spring, soon after the returning Sitka herring population began to spawn.
Gray whales are arriving again this spring to feed along their annual, 12,000-mile-plus migration route from the coast of Baja California, where they breed each winter, to their northern foraging grounds in the Bering and Chukchi Seas.
On Wednesday, scientists with the Alaska Whale Foundation, a nonprofit organization based in Baranof Warm Springs, counted about 60 to 70 gray whales in the Sound.
Compared with this time last year, fewer gray whales have arrived, says Dr. Lauren Eckert, AWF's board president who is visiting Sitka with a team of researchers until mid-May.
Eckert said that team members saw about five gray whales during their first weekly, systematic survey on March 26, and about 45 gray whales the next week, on April 2.
The team of AWF researchers is following the gray whales in local waters this spring to track their numbers and study their feeding habits, which appear to center on herring eggs.
Last spring, the whales keyed in on herring spawning grounds about two weeks after the fish laid their eggs.
In a presentation co-hosted by the Sitka Maritime Heritage Society last month, foundation Executive Director Dr. Andy Szabo said that last year the gray whales’ distribution seemed to be overlaid almost exactly with areas where herring spawned in Sitka Sound.
Whale-watchers have “been seeing them behaving in ways that suggested that they're eating herring eggs. … and have even seen herring eggs coming out of the months,” Szabo said.
Szabo said that AWF, which typically focuses on humpback whale research, decided to study the gray whales’ feeding habits in Sitka Sound given the “extreme importance of herring to ecological communities, commercially, and culturally” to people in the area.
“If you have 150 or 200 or so gray whales coming in during that very critical herring spawning moment, and they're consuming herring eggs, that could potentially have an impact on that population of herring,” Szabo said. “So there’s a lot of interest in understanding what might be the impact of all these whales on the herring.”
AWF is working to quantify “what people suggested was already going on, and hopefully get to a point where maybe we could actually estimate how much (herring eggs) these animals are eating …and what their impact might be in terms of biomass removal,” Szabo explained.
“Hopefully next year, or at least in the next ten years, we’ll be able to answer this question for you,” Szabo said.
The ongoing foundation project got started in 2024 in collaboration with the University of Alaska Southeast Sitka Campus and Dr. Lauren Wild, after local researchers noticed an increased presence of gray whales in Sitka Sound beginning in about 2019.
The increased presence in Sitka Sound coincided with gray whale population declines. The National Oceanic and Atmospheric Administration determined that the species experienced an “unusual mortality event" from late 2019 through late 2023, when about 700 of the whales were found dead in the eastern North Pacific.
The Whale Research Program at UAS-Sitka has been keeping track of the gray whales as their population changes. Jan Straley at UAS-Sitka has been monitoring gray whales near Sitka since the early 1990s, beginning with assistance from Mt. Edgecumbe High School students.
Wild and Straley started noticing the increases near Sitka in 2020, and UAS started an official gray whale monitoring and research project in 2023.
UAS and AWF worked in partnership in 2024 to monitor and study the feeding habits of the whales. UAS is continuing to monitor the gray whales this year, Wild said.
The foundation is now conducting standalone research to try to find out the impact that gray whales are having on the local herring population. The nonprofit is devoting about three months to research this year.
AWF team members began their stay in Sitka this spring by hosting a week-long drone workshop with the Sitka Sound Science Center, which SSSC celebrated with a custom whale cake by the Backdoor Cafe's Dan Gunn.
Eckert and Szabo have attended meetings with Sitka Tribe of Alaska leaders to share updates about their team’s project.
Eleven people comprise the AWF team that’s visiting Sitka, and are often seen bustling around Eliason Harbor, where the foundation keeps two boats, the 28-foot Hewescraft Paula T. and the 17-foot Zodiac Barbara Bell.
Since mid-March, the crew has gone out to study the whales each day that the weather allows.
Liah McPherson, an AWF fellow and doctoral student at the University of Hawaii at Manoa, described during an interview this month how the team is conducting “weekly systematic surveys of the whole Sound, including areas where herring are spawning and whale foraging habitat … to estimate the abundance of whales in the Sound.”
The team is taking drone photos of the whales to identify them, and to make judgments on the health of the whales, many of which appear to be younger males.
In another part of the study, the team is tagging the whales with suction cup video cameras that pop back up to the surface after riding along on the whales to film their habits. AWF is licensed by the National Marine Fisheries Service to deploy the tags.
McPherson said the tags capture “video, audio and movement under the water,” showing the whale’s “foraging behavior under the water, what they’re feeding on, and how often."
While feeding on herring eggs in Sitka Sound, the baleen whales also filter tiny creatures from sediment on the seafloor, and eat other small species like krill.
Eckert said that AWF researchers also are referencing the Alaska Department of Fish and Game’s public spawn deposition data, created each year from float planes and SCUBA diver surveys, to identify the areas where most herring spawn occurred this year.
Dr. Martin Van Aswegen, a postdoctoral fellow at the University of Hawaii at Manoa and AWF team member, will take all of this data, and apply a model he’s used with humpback whales to try to estimate the number of herring eggs consumed by the gray whales in Sitka Sound.
Van Aswegen said during the interview this month that the process begins with 2D drone images that provide accurate measurements of the gray whales. He said his model can convert those measurements “into volume, 3D volume, and then volume across the tissue types.”
By studying the whales with this method throughout the spring, the team hopes to track “how much lipids, or fats, they are gaining,” he said.
The team will estimate how much of that weight gain is a result of herring egg consumption, and use measures of the “energy density of blubber, the energy density of herring eggs, and the rough cost of digestive efficiency … to estimate the number of herring eggs consumed.”
All of these metrics will help the team try to find out the impact of the whales on local herring, as well as the “value of Sitka Sound and herring to these gray whales," McPherson said.
Meanwhile, the team is rounding out their studies by speaking with as many mariners and other knowledgeable local residents as possible.
“Other whale watchers are radioing in to tell us what they’re seeing out there in the sound,” McPherson said. “We’ve had some pretty cool conversations the past couple of weeks.”
Eckert said that, even when the team departs from Sitka, researchers will be looking to learn more from these peoples' experiences.
"We continue to be interested in chatting with anyone who wants to talk to us about this," Eckert said. "If anyone would like to reach out with information or ideas, we'd be happy to talk to people."
Contact information for Alaska Whale Foundation personnel is available on their website at www.alaskawhalefoundation.org.
