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In just over a week — nine days — four gray whales have washed ashore in San Francisco Bay Area. On April 9, 2021, experts announced that one had been struck by a ship. They are currently investigating how the other three whales died.
Director of Pathology at The Marine Mammal Center, Dr. Pádraig Duignan, said:
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.
On March 31st, the carcass of a 41-foot — adult female — gray whale washed ashore at San Francisco’s Crissy Field. The following Saturday — April 3rd — a second grey whale landed in Moss Beach in San Mateo County.
A third whale was found floating near the Berkeley Marina on April 7th. The following day a fourth gray whale was found on the shore of Marin County’s Muir Beach.
These mottled gray skin whales — with pigmentation and scarring — are covered with whale lice and barnacles over much of their bodies. Instead of a dorsal fin, they have a small hump and a series of ‘knuckles’ — sharp bumps — two-thirds of the way from their heads.
Gray whales are a type of baleen whale. This means they can filter their food from the water with special prickly structures in their mouths. They are known to migrate between feeding and breeding grounds. Gray whales can swim up to 12,000 miles roundtrip during the migration between grounds.
After they birth their calves off the coast of Baja California, the gray whales will head back towards Arctic waters feeding on sardines, krill, and anchovies.
In 2019, scientists feared the whale’s food supply was dwindling when 13 of them washed ashore in the Bay Area. The scientists thought that due to the lack of sustenance the gray whales were unable to complete their migration.
The legal director of the Center for Biological Diversity’s Oceans program, Kristen Monsell, said:
This many dead whales in a week is shocking, especially because these animals are the tip of the iceberg
Monsell’s organization is suing the federal government to get speed limits in shipping lanes off of California. She added that fishing gear entanglements and ship strikes “kill many whales that we never see.” Experts believe the whales that wash ashore represent around 10 percent of the total number of dead gray whales.
Written by Sheena Robertson
Sources:
NBC: 4 gray whales found dead in San Francisco Bay Area in 9 days
World Wildlife Federation: Gray Whale Facts
Featured Image and Top Image COurtesy of Sam Beebe’s Flickr Page – Creative Commons License