Gray Whale West Coast Woes – An Evolving Mystery
A young gray whale who briefly enjoyed the moniker “Willapa Willy” for swimming about 20 miles up the Willapa River of Washington state died April 4, igniting global coverage in outlets such as the BBC. Speaking as someone who lives near this river, I can assure you that it is not a normal waterway in which to find a whale. The Cascadia Research Collective (CRC) and other observers noted that the whale appeared thin and malnourished, but uninjured.
This one strange, sad story of Willapa Willy would remain a curious anecdote if not for the nearby discovery of two more dead gray whales at Ocean Shores, a town about 20 miles north of the entrance to the Willapa River, on the same day. As reported on OregonLive, both whales were in a starved condition not unlike Willapa Willy according to John Calambokidis of the CRC. These two were a male and female that measured around 42 feet long each. Both were older than the juvenile that swam up the river. The male had a “significant head trauma” that differentiated it from the other two.
The mystery of the three dead gray whales deepens and becomes even more concerning when one looks at the macrolevel picture of the East Pacific gray whale population. As one of our contributors, Brianna Bowman, reported in the March/April issue of Nautical Northwest magazine, the gray whale population has endured an alarming population decrease ever since around 2017.
“A large number of gray whales died, to the extent that scientists labeled this time period an Unusual Mortality Event, or UME,” reported Bowman. While the event ended in 2023 with some population stabilization, the numbers have continued to decline to about 13,000 whales—the lowest population estimate since the 1970s when fear of the species’ extinction was very real.
As Bowman reports, there is speculation that the warming oceans may be playing a primary role in the current gray whale woes. These whales migrate to the Arctic to feed on amphipods that live on algae that grow under the sea ice. With less sea ice, less algae grows and thereby fewer amphipods spawn to feed upon. This mechanism could explain the malnourished state of these gray whales.
One question I have for this theory is that during this time of year, spring, the gray whales are migrating northward to the Arctic feeding grounds from the warm calving waters of Mexico. Wouldn’t this malnourishment from a barren Arctic feeding season happen on the other side of the summer, during the fall migration back south? These whales would presumably be dying from malnourishment set in motion last year. Notably too is the fact that gray whales are specialized mud feeders with many of them filtering shrimp from the mucky seafloors between Mexico and the Arctic. Has something happening to this mud-based food source as well?
Another curious element to all this is that the gray whale population was actually at its historic population high right before the UME kicked in. According to NOAA, the estimated gray whale population enjoyed an all-time high between 2014 – 2016 with over 25,000 individuals (Fig. 1). This is about double the estimated gray whales that we have today a mere decade later.
Now this is just me speculating, but when a significant die off among a species after a population boom occurs, the culprits are often factors like natural food scarcity, predation, or disease. This is not to discount other theories like the Arctic sea ice theory, but other possible mechanisms should be examined as well. They are also not mutually exclusive, as a combination of two or more of these threats could be creating some kind of perfect storm.
Something curious jumps out to me when I look at the NOAA population chart (Fig. 1). The last population boom of gray whales before 2014 was around 1986 – 1988. Note too that a large population decrease—from over 25,000 down to about 15,000 in 1992 – 1994—occurred that looks quite a bit like what is occurring now. Another UME is noted too in 1999 – 2000.
What caused these other mortality phases? How did the gray whales recover from those previous events? Answering these questions might help us better understand what is going on with the gray whales now. In the meanwhile, the sudden deaths of so many beloved gray whales is alarming. Hopefully we can collectively find the cause and reverse the trend before the situation worsens. If a gray whale ever swims up the Willapa River again, ideally he or she will be a healthy individual who gets back to sea after an unusual inland side adventure.
