Emaciated gray whales have been washing up on the West Coast at a rate that's alarming scientists.
At least 64 gray whales have turned up dead along the coasts of California, Oregon and Washington this year — the highest number since 2000.
Just in the last two months, nine of these massive marine mammals have been found deceased in the San Francisco Bay area, which The Marine Mammal Center called “a cause for serious concern.”
John Calambokidis, biologist and founder of nonprofit Cascadia Research in Olympia, Washington, says this year, his team's most common finding when responding to a perished whale has been poor body conditions due to starvation.
"They'll have a visible blubber layer but there will be almost no oil at all — no fat left in that blubber layer," he tells Here & Now's Peter O'Dowd.
Calambokidis explains that gray whales typically feed for months before they migrate south to their breeding grounds in Mexico. During the whale's migration, they typically don't eat, meaning they fast for about 4 months, he says.
So many of the whales that have died, he says, "didn't quite have enough of a reserve" to make it through the fasting period.
He gives two reasons for this lack of fat reserve in some of their bodies: an increasing gray whale population — their population is now estimated at 27,000 — and an inadequate food supply.
Before migration begins, most gray whales feed on tiny, bottom-dwelling crustaceans called amphipods in Arctic waters near Alaska — but scientists believe there might not be enough prey to get them fat enough for their long journey south.
"Gray whales have this unique adaptation of being able to feed right on the bottom, sucking up a slurry of sediment and organisms," Calambokidis says. "So [scientists] think, because that's where most of the gray whales go and the main prey they feed on, that's where the issue is."
But there's more to the phenomenon than just the decrease in their prey, he says.
Not only are the whales battling for food, they're also faced with a warming Arctic. The Marine Mammal Center recognizes climate change as a factor in gray whale's feeding patterns.
"Climate change affects water temperatures and prey availability, leading to shifting food sources for marine mammal populations and other marine species," the center says.
When desperate gray whales can’t access the food they need to survive, they'll begin appearing in unusual areas where they aren't normally found — making themselves vulnerable to human activities.
Some of their recent deaths along the West Coast — from Puget Sound, Washington, to Long Beach, California — have resulted from blunt force trauma injuries, usually from boats. When gray whales try feeding near these coastal areas, they are faced with human-made obstacles, such as shipping, fishing and netting.
As for mortality rates for the rest of 2019, Calambokidis says that in Washington state, the numbers may exceed previous records.
"We're still early in the year and typically we see peak gray whale strandings in April, May, June and sometimes into July," he says. "So we're still early in this peak period and it has not shown signs of abating yet."
This segment aired on May 27, 2019.