This story was originally published on YachatsNews.com and is used with permission.
The first few springtime sightings of gray whales in the Atlantic Ocean between 2010 and 2021 left many marine researchers scratching their heads.
They wondered why whales known almost exclusively to populate the waters off the West Coast of the United States, Mexico and Canada suddenly were swimming an ocean away in the Atlantic?
A fourth sighting off the coast of Miami in late December by a fishing charter only deepened the mystery.
Now, an Oregon State University whale researcher based in Newport is wondering if something much more profound is going on.
“While these reports always inspire some awe for the ability of a whale to travel such an incredible distance,” doctoral candidate Clara Bird wrote in a recent blog post, “they also inspire questions as to why and how these whales end up so far from home.”
Bird works in OSU’s Geospatial Ecology of Marine Megafauna Laboratory, which focuses on the ecology, behavior, health and conservation of species including baleen whales, seals, sea lions, seabirds and sharks.
Some corollary research efforts have already argued that climate change, diminishing sea ice levels and disappearing food sources may be pushing gray whales far beyond the northern Bering and Chukchi seas, where they normally spend the spring and summer months.
It’s possible, researchers suggest, that a few individual whales, whether purposefully or because they got lost, swam through the relatively ice-free Arctic and into the Atlantic and even Mediterranean oceans.
The swarm of news stories that followed each successive sighting emphasized the rarity of formally named eastern North Pacific gray whales turning up anywhere other than the Pacific Ocean.
Pacific Coast Feeding Group
It’s right here where Bird wonders if her own specialized area of research – studying a subgroup of the Eastern North Pacific gray whale population known as the Pacific Coast Feeding Group – may hold some answers.
Most of the roughly 16,000 gray whales in the far larger Eastern North Pacific population travel right on past Oregon’s coast during their southern migration to their winter breeding grounds in Mexico. They then make a northward return journey in summer to feeding grounds in the Bering and Chukchi seas between Alaska and Russia.
By contrast, the Pacific Coast Feeding Group, which numbers just over 212 individuals, spends summer months feeding in near-coast waters off Oregon, Washington, southern Canada and northern California.
For reasons still not fully understood, the smaller group split off from its longer-commuting cousins at some point in the past.
What’s certain, however, is that both males and female gray whales in the subgroup differ from those in the larger group.
They are measurably shorter and weigh less than their offshore counterparts. They tend to employ their own, uniquely developed feeding strategies, with subgroup members having perfected ways to feed on bottom-lying food in the shallower waters directly off the coast. And, at some point, for reasons not yet known, they peel off from the larger contingent to feed in the shallow and rocky kelp beds off the coasts of Oregon, Washington, northern California and British Columbia.
Larger questions
Potential answers to the larger question of why the subgroup split from the main population of Pacific gray whales rest on topics such as, maybe the subgroup doesn’t grow as big because the more limited range it has adopted doesn’t require it to; and, have limits on near-shore nutrients caused the subgroup to remain smaller in size?
But what has Bird particularly intrigued is the idea that gray whales now starting to show up in the Atlantic Ocean may be early efforts to establish the same sort of separate population that the Pacific Coast Feeding Group has successfully accomplished closer to home.
“At this point, there’s really nothing conclusive that can be said,” Bird told YachatsNews. “But it’s all very interesting in the context of the weird little whales we have here.”
Bird said she is confident that none of the first three modern sightings of gray whales in the Atlantic involved members of the subgroup, since they aren’t known to travel far enough north for spring foraging to then move into the Arctic and then on into the Atlantic.
The fourth sighting, in December, “indicates that this whale ‘got lost’ on its way to the wintering grounds after a foraging season,” Bird wrote in her recent blog post. Unlike the first three, this whale was healthy, looking more like an explorer than a wandering straggler.
“The possibility that we are observing the very early stages of a new population or group forming is particular interesting to me in the context of how we think about the Pacific Coast Feeding Group of gray whales.”
Researchers know that gray whales have moved between the Atlantic and Pacific several times in the past 1,000 years, “when sea level and climate conditions (including ice cover) allowed them to,” Bird wrote. “Meaning, that we could be seeing a pattern of mixing of whale populations between the two oceans repeating itself.”
Definitive answers about whether a new population of gray whales is, indeed, forming in the Atlantic could be years away, Bird said, but she and a growing number of researchers are intrigued.
“If we are, indeed, seeing the beginning of something, it’s in the very, very early stages,” Bird said. “But it will be extremely interesting to see what happens in the next few decades.”