Grey whales are ocean sentinels due to their adaptability and foraging habits, meaning they have a lot to tell us about the health of the ocean.
Starvation, fishing nets, and collisions with vessels are the most common causes of grey whales’ death. This species is often used as a barometer to gauge the state of the ocean due to their adaptability and eating habits.
Four grey whales have been found dead in the San Francisco Bay Area in the past nine days, according to the Marine Mammal Centre, the world’s largest marine mammal hospital. Concerned with the number of dead animals, a team of scientists from the centre is now working to determine the causes of their deaths.
The first dead female grey whale was found on 31 March in San Francisco’s Crissy Field. The second washed ashore at Moss Beach in San Mateo County on 3 April. The third was reported near the Berkeley Marina, and the last one in Marin County’s Muir Beach.
“It’s alarming to respond to four dead grey whales in just over a week because it really puts into perspective the current challenges faced by this species”, said Padraig Duignan, director of pathology at the centre.
An autopsy on one of the dead whales showed that it was hit by a ship, while examinations of the other carcasses didn’t reveal any signs of trauma or inflectional disease.
“Grey whales are ocean sentinels due to their adaptability and foraging habits, meaning they have a lot to tell us about the health of the ocean, so to see the species continue to suffer with the added threats of human interaction is a major cause for concern”, Duignan said.
He added that the team had not faced “this number of dead grey whales in such a short span” since 2019. At the time, scientists observed grey whales during their annual migration, reporting their poor condition, after 13 dead whales had been found. Experts said it could have happened due to starvation as the animals couldn’t accomplish their migration from Mexico to Alaska.