‘It’s alarming’: 4 gray whales found dead in Bay Area

Four dead gray whales have washed up on beaches in the San Francisco Bay Area in the last nine days.

Experts said Friday that one whale was struck by a ship; they were trying to determine how the others died.

“It’s alarming to respond to four dead gray whales in just over a week, because it really puts into perspective the current challenges faced by this species,” said Dr. Padraig Duignan, director of pathology at the Marine Mammal Center.

The carcass of a 41-foot adult female gray whale landed March 31 at San Francisco’s Crissy Field. A second adult female was found April 3 at Moss Beach in San Mateo County. A third was found Wednesday floating near the Berkeley Marina, and one washed up Thursday at Marin County’s Muir Beach.

The whales migrate 10,000 miles to spend the winter off Mexico, where they mate and birth calves near the coast of Baja California.

They head back north and stay off the coast of California in spring and summer to feed on anchovies, sardines and krill before continuing on their northerly migration to food-rich Arctic waters.

In 2019, at least 13 dead whales washed ashore in the Bay Area, and scientists said they feared it was because the animals were starving and couldn’t complete their annual migration from Mexico to Alaska.

Biologists have observed gray whales in poor condition during their annual migration since 2019, when an “unusual mortality event” was declared by the

National Oceanic and Atmospheric Administration.

Malnutrition, entanglement in fishing gear and trauma from ship strikes have been the most common causes of death found by the Marine Mammal Center’s research team in recent years.

A necropsy of the whale found at Muir Beach revealed significant bruising and hemorrhaging to muscle around the jaw and neck vertebrae, consistent with blunt force trauma due to a ship strike.

The whale was otherwise in good body condition based on the blubber layer and internal fat levels, the center said.

Nearly one in four gray whales migrating along the U.S. West Coast have died since the last recorded population assessment in 2015 and 2016, according to NOAA.

“This many dead whales in a week is shocking, especially because these animals are the tip of the iceberg,” said Kristen Monsell, legal director of the Center for Biological Diversity’s oceans program.

Experts estimate that the washed-up whales represent just 10% of the total number of dead, with the rest sinking into the sea, unnoticed by humans.

Monsell said that California lawmakers should require fishing gear that doesn’t use rope, and that federal regulators should set mandatory speed limits for ships.

“Ship strikes and fishinggear entanglements kill many whales that we never see,” she said.

Monsell’s organization is suing the federal government to set speed limits in shipping lanes off California, she added.