MONTEREY >> An unusually high number of humpback and blue whales are gorging on krill this week in the Monterey Bay.
The influx of whales and krill began Saturday, according to Nancy Black, a marine biologist and owner of Monterey Bay Whale Watch. A few miles offshore of Monterey, her crew discovered a mob of dozens of humpbacks, blowing air around the boat.
Thanks to high winds in June, an upwelling of cold water from deep below has drawn large amounts of the tiny shrimp, a favorite food of humpback and blue whales. This is the first significant krill bloom in the Monterey Bay in years, said Black.
“We could see it on the depth sounder, it was down from just below the surface to about 200 feet (deep), was thick with krill patches, and it went on for quite a distance,” Black said.
Sunday, she counted 265 humpback whales, the most she’s seen in nearly 30 years, compared to her average daily humpback count of around 15.
The humpbacks are clumped along a 4-mile stretch where krill accumulate, on the edge of the Monterey Submarine Canyon, she said.
She’s also seen a high number of blue whales this week, around 25 to 30, she said.
Both humpback and blue whales are endangered species, after early 1900s whaling decimated populations. The humpbacks have recovered, from less than 500 in California and Oregon in the 1980s to more than 2,000 today, according to John Calambokidis, researcher at Cascadia Research, a Washington-based marine nonprofit.
However, blue whale counts along North and Central America have remained at roughly 2,000 for 20 years.
Humpback and blue whales typically feed in the Monterey Bay in the summer, and it’s not unusual to see counts fluctuate as they chase prey along the California coast, Calambokidis said.
What is unusual, according to Elliott L. Hazen, research ecologist at NOAA, is recent weather patterns off the California Coast that have disrupted the entire ocean food chain, including whale prey.
In late 2013, researchers noticed an exceptionally warm patch of water, stretching along the West Coast, which was nicknamed “the blob.” Then, this winter, came El Nino, a weather pattern occurring every several years that typically warms the Pacific Ocean. But this time, it had a weaker effect, due to the already warm temperatures from the Blob, Hazen said.
Hazen, also a UC Santa Cruz adjunct professor of ecology and evolutionary biology, recently co-wrote a paper showing how the blob has driven warm water species north. He’s noticed also that whale prey, such as anchovies, are starting to cluster near shore.
“I think there’s probably a similar process at play with the krill,” Hazen said. “There’s good upwelling. There’s good nutrients, but there may be less habitat available to them.”
Humpback whales can communicate over long distances, and blue whales especially — over thousands of miles — via low frequency songs. The whales in Monterey Bay are likely calling their friends in Washington or further north, to let them know there’s plenty of chow here, he said.
Every year, blue whales migrate from Washington to Costa Rica, and humpbacks from Alaska to Hawaii and Mexico.
“While they’re doing these annual migrations, if they find a good buffet along the way, or a good restaurant, they’ll stay much longer,” Hazen said.
At about 100 feet long and more than 200 tons, blue whales are the largest animals ever to have lived on Earth. They eat 4 tons of krill each day.
So when they find a krill patch, they wolf it ferociously, to the point where their bodies “go anaerobic,” like a sprinter at the end of a race, said Hazen.
He made the analogy, “If you’re at a buffet and it’s full of food, you might just keep shoving your face without pausing for breath. You want to get as much food in your mouth as possible, and eventually you’ll start gasping for air.”
