Gray whales are dying along the West Coast, and scientists are trying to figure out why

As gray whales embark on their 10,000-mile-long migration from Baja California north toward Alaska, experts have noticed an increase in whale deaths.

“We’re certainly concerned with the numbers we’re seeing,” Justin Greenman, assistant stranding coordinator for the National Oceanic and Atmospheric Administration’s Stranding Network, told ABC 7.

Of the 31 whales found dead along the West Coast in 2019, 21 of those have been found along the California coast, ABC 7 reported.

The peak of stranding season, when experts tend to find more dead whales washing up, is late April through June, according to the Mercury News. But already, 2019 marks “the third-largest gray whale mortality total on record,” the newspaper said.

Authorities have been able to study about half of the total dead whales, and have mostly found that the whales have “empty stomachs and low muscle content,” Greenman told the Mercury News.

In the San Francisco Bay, seven migrating gray whales have been found dead so far in 2019. Three of those collided with ships, but the others reportedly died of starvation, according to the Santa Cruz Sentinel.

Michael Pierson, a naturalist with San Francisco Whale Tours, told the Sentinel that he noticed evidence of whales feeding in the Bay Area, which is unusual. Gray whales usually wait to eat until the summer, when they’re in their Arctic feeding grounds, and often fast the rest of the time.

Officials said that gray whales are moving closer to shore to look for food, since they can’t find it in deeper waters, according to ABC 7. A similar problem occurred about 20 years ago; 2000 was the worst whale mortality years on record, according to the Mercury News.

Greenman told ABC 7 that the increase in emaciated whales they’re seeing could mean that there isn’t enough food to sustain the gray whale population.

The whales tend to pass through California waters in the springtime, when they’re making their way from breeding grounds in Baja California.

Things weren’t looking good there, either. Researchers in Mexico found that 60 percent of the whales showed up skinny, and calf counts were down to about a third of what they were just a year earlier, according to the Mercury News.

“This is alarming,” Steven Swartz, a marine biologist who’s studied the whales in Mexico for more than 40 years, told the Sentinel. “What might be happening now is that the skinny whales we saw in Mexico this past winter ... are basically running out of gas.”

Related stories from San Luis Obispo Tribune