The dead whales appear to be emaciated, a sure sign of starvation, but scientists aren’t sure if the condition has been brought on from a decline of their food supply or overpopulation or even some combination of both.
CBC is reporting today that most recently, of 11 grey whales stranded in Washington state’s Puget Sound, only one survived. Scientists from California, Washington, Alaska, and Canada are all involved in trying to figure out what is happening.
It has been noted that most of the dead grey whales had not reached adulthood yet. Frances Gulland, a research associate at the UC Davis School of Veterinary Medicine, estimates that gray whale deaths could hit 60 or 70 by the end of the spring migration season.
Possible reasons for deaths
Dr. Padraig Duignan is the Marine Mammal Center in Sausalito’s chief pathologist. He says that in a typical year, the center might see two or three dead gray whales, according to the Los Angeles Times.
This year, the center has seen seven and Dr. Duignan performed necropsies on all of them and determined that four had died of malnutrition. “Their skeleton seems to stick out more and more,” he said.
Additionally, members of the American Cetacean Society who annually help with counts of the migrating whales and the calves, have only counted 31 calves since December 1, 2018, said marine biologist Alisa Schulman-Janiger. That number should be much higher, ranging on up to as many as 164 calves.
“Giving birth requires lots of energy and blubber, and thin whales are in no condition to be nurturing pregnancy or a calf,” she said.
“We’re already beyond what we would typically consider high numbers and this is still early in our stranding season,” says Jessie Huggins, stranding coordinator of the Cascadia Research Collective in Olympia, Washington.
Radio Canada International is reporting that Huggins’ Cascadia Research Collective colleague John Calambokidis says the main cause of death appears to be starvation. Calambokidis points out that grey whales feed on sediment along the ocean floor.
“It’s difficult for us to tell at the moment, but we know that, for the last year or two, there have been a number of very skinning whales, ” Huggins told CBC News. He notes that “They didn’t get enough food last summer and, along their normal migration patterns, are just not able to make it all the way to Alaska.”
The whales that wash up on shore are likely not the ones who are dying, he adds. “Many other whales, when they die further off-shore, we never see them,” Huggins said. “Especially skinny ones because they tend to sink first.”
Whatever is behind the whale deaths, we need to find out quickly. “We are concerned because whales are an indicator species for the health of the ocean,” Duignan said. “We use them to tell us what’s happening out there.”
