A 30-foot gray whale that washed ashore north of Cannon Beach makes a total of four dead whales that have landed on the Oregon coast in less than two weeks.
Researchers caution that recent stormy weather has increased the likelihood of beachings — including of a sperm whale and three gray whales discovered since mid-January.
But the deaths of the gray whales are also part of a much larger trend causing the gray whale population on the West Coast and Alaska to plummet 38% since 2016.
National Oceanic and Atmospheric Administration spokesperson Michael Milstein said the preliminary investigation into the “unusual mortality event” indicates many of the cetaceans aren’t finding enough food when they travel to the Arctic each summer.
“Gray whales have one of the longest migrations known. They go up and down the West Coast twice a year, which is pretty phenomenal. And they’ve got to pack on a lot of energy to be able to do that,” he said. “They’re not getting enough to eat.”
The first whale found this month, a sub-adult male gray whale, was recovered Jan. 11 in Winchester Bay and was slain by killer whales, according to Milstein.
Then on Jan. 14, the beaching of a 40,000-pound sperm whale at Fort Stevens State Park on the tip of Oregon’s coastline drew significant media attention. That whale was struck and killed by a propeller gash.
Scientists determined that a 12-foot-long newborn female gray whale, found Jan. 18 also at Fort Stevens, had just begun to nurse when it died.
The gray whale discovered Saturday near Cannon Beach had been dead for at least a month when it washed ashore, according to the staff at the Seaside Aquarium. A sizable shark bite came after the whale had died, the staff said.
The Cannon Beach and Winchester Bay whales were too decomposed to conduct a necropsy, but numerous samples were taken from the calf for further study, according to Milstein.
Only about 10% of deceased whales end up on dry land, he added. While the population of 2,000 sperm whales has remained roughly stable, the number of gray whales living off the West Coast has dropped to 16,650 at last count.
“They’re basically not replacing themselves at the same rate,” Milstein said. “So what’s really important is to find very recent strandings … so we can get samples that help us understand why they might have died.”
All four beached whales will be left to decompose in place to provide nutrients to seabirds, according to a spokesperson for Oregon’s state Parks & Recreation Department.