Reprinted with permission from The Planet magazine, June 8, 2022
Camano Island is known for its sprawling beaches, lush forests and ample whale-watching. One thing its tourism website doesn’t advertise is the sight and smell recently occupying a portion of the island’s western shore: the rotting carcass of a 12-meter long gray whale. Like the hundreds of other gray whales that have washed ashore all along the Pacific Coast since 2019, this whale was found emaciated, likely having starved to death.
Since 2016, Eastern North Pacific gray whale populations have declined from around 27,000 to less than 21,000. In the past three years, 500 of these whales have been stranded across Canada, the U.S. and Mexico in what is known to scientists as an Unusual Mortality Event (UME). As scientists investigate the second such trend in 20 years, the question arises: Are these strandings part of an isolated event or are they a sign of struggles to come?
Sarah Colosimo, a wildlife biologist for the Washington Department of Fish and Wildlife (WDFW) who specializes in marine mammals, was the first scientist on-site to investigate the Camano Island stranding. On a cloudy Thursday afternoon in late March, Colosimo raced over from her regular surveys on the Stillaguamish River to find the stranded whale. She arrived with nothing more than an approximate location and what little information she had gathered from a few photos taken by the locals. Despite this ambiguity, Colosimo had no problem finding the carcass.
“A dead whale on the beach is pretty hard to mistake,” Colosimo said. “I could definitely see it from a ways away.”
The carcass was about the same length as a full-size school bus and its tongue alone weighed roughly the same as a fully-grown giraffe.
Colosimo’s most recent work with WDFW revolves around the predation of birds and pinnipeds — seals, walruses and sea lions — on salmon in the Stillaguamish River. Although Colosimo had previously investigated marine mammal strandings, this was the first time she had to respond on her own. Other than a few WDFW enforcement officers who showed up later, the private beach was occupied only by Colosimo, an enormous whale carcass and the occasional seagull.
‘CSI for marine mammals’
Upon her arrival, Colosimo saw several dead parasites on the animal’s carcass, indicating it had died before washing ashore. After taking measurements, she noticed fresh blood in several places across the body, including around the blowhole. The blood provided no obvious cause of death, but hinted at possible internal disease or the whale having scraped against something sharp.
“A lot of the work that we do in wildlife biology is trying to unravel the mysteries of what’s going on with these other animals around us,” Colosimo said. “It’s like a CSI for marine mammals.”
Although once an endangered species, Eastern North Pacific gray whales eventually recovered and were removed from the Endangered Species List in 1994. Since that year, they have been the victims of not one but two UMEs, the first of which occurred from 1999-2000. It resulted in a population decline of around 23% or the equivalent of thousands of whales. While the cause of the current die-off is not entirely understood, gray whales face constant threats: habitat degradation, ocean noise, vessel strikes, fishing-gear entanglement and disturbance from whale watching activities.
Two days after Colosimo’s initial inspection, she returned to the stranding. This time, she was not alone. In addition to Colosimo, a team of researchers and biologists had assembled, including a stranding coordinator from Cascadia Research Collective, a WDFW marine mammal research scientist, a veterinarian from World Vets and a handful of volunteers from various environmental organizations.
“A whale necropsy is a pretty big job,” Colosimo said. “So you definitely need a lot of people. You need muscle.”
To confirm the cause of death, they first needed to examine its internal organs. After reviewing Colosimo’s measurements and notes from two days prior, the team began using knives, meat hooks and brute force to peel back the whale’s layers of blubber.
“We could tell that it was malnourished,” said Jessie Huggins, the team’s stranding coordinator and co-leader. “It had no subcutaneous fat and had severe atrophy of the muscle and the blubber tissues. There was no oil left in the blubber.”
With the cause of death determined, the researchers turned to their next question: Where did this mystery whale come from?
Gray whales generally fall under one of two subspecies: Eastern North Pacific gray whales live along the west coast of North America and Western North Pacific gray whales reside along the coast of eastern Asia. Two hundred of the Eastern North Pacific whales are known to scientists as the Pacific Coast Feeding Group because they spend most of their time in the Pacific Northwest rather than migrating all the way to the Arctic in search of food. A dozen of these whales within this feeding group are called the Sounders. They have remained in the Salish Sea year-round and have affectionately been given names like Earhart and Patch by the scientists who study them.
Sad, smelly … and depressing
For better or worse, the whale on Camano Island didn’t match any of the Cascadia Research Collective’s 2,000 cataloged gray whales, so it wasn’t a Sounder or a member of the Pacific Coast Feeding Group, said John Calambokidis, a senior research biologist at collective. Unlike the other 99% of Eastern North Pacific gray whales, the Sounders and the Pacific Coast Feeding Group appear to be unaffected by the current UME. This whale, like so many other strandings, was an unknown individual from an unknown subgroup. Even with its identity still undetermined, Colosimo and her fellow researchers are working to understand these whale deaths and the role humans play in them.
“Whales feed on something, whether it’s the ghost shrimp around the northern Puget Sound or small arthropods in the arctic or bison shrimp along the Washington coast,” Calambokidis said. “If we want to have whales, we have to protect those things because that’s what allows gray whales to survive.”
The effects of climate change are considered a significant threat to the species, particularly at high latitudes like the Arctic, where gray whales typically feed in the summer. As the timing and distribution of sea ice fluctuates with rising temperatures, so do the patterns of the whale’s prey. Without regular access to their prey, the whales are subject to nutritional stress, lower reproductive rates and evolving migration routes, all of which could contribute to future UMEs. Additionally, changing water temperatures and currents could have repercussions on gray whales’ migration and navigational patterns.
While it may be too soon to know if the current spate of deaths is just a temporary setback or a troubling sign of what’s to come, the overall sentiment shared among the scientists is surprisingly optimistic.
“The gray whales are a success story,” Calambokidis said.“With success comes new challenges.”
The Sounders’ risky survival strategies, which include navigating dangerously within abrupt tidal shifts in the Salish Sea, are far from perfect, but they have survived not one but two UMEs. These whales are proof of the resilience and perseverance this species is capable of, Huggins said.
“Yes, it’s sad and it’s smelly and it’s kind of depressing, but what we do matters,” Huggins said. “It will contribute to the whales that remain and that’s probably the best part.”
— Reported by Cooper Castelle
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