Gray Whale Jumping photo by Georg Wolf/Unsplash
Gray whales have a lot to tell us about the health of the ocean and how climate change affects water temperatures and unfortunately, in the last nice days, the Marine Mammal Center, the world’s largest marine mammal hospital, has been investigating four dead gray whales in the San Francisco Bay Area.
A team of scientists from The Marine Mammal Center have already confirmed that one of the whales had been struck by a ship, while the three others cause of death is still under ongoing Investigation.
“Our team hasn’t responded to this number of dead gray whales in such a short span since 2019 when we performed a startling 13 necropsies in the San Francisco Bay Area,” says Dr. Pádraig Duignan, Director of Pathology at The Marine Mammal Center.
The carcass of a 41-foot (12.5meter) adult female gray whale washed ashore San Francisco’s Crissy Field on April 1st. A second adult female gray whale was found April 3rd in Moss Beach in San Mateo county. A third subadult male gray whale was found April 8th floating near the Berkeley Marina and the same day, one adult female gray whale washed up in Marin county’s Muir Beach. A necropsy of this whale attributed cause of death to a ship strike as there was bruising and hemorrhaging to muscle around the whale’s jaw and neck vertebrae due to blunt force trauma.
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, says Dr.Duignan
Gray whales are protected by international law and they are one of the animal kingdom's great migrators. Their migration route takes them close to shore along the west coasts of Mexico, California, Oregon, Washington, or Alaska. They can be seen twice a year in California when they migrate from the southern tip of the West Coast up toward Alaska and back again.
Malnutrition, fishing gear entanglement, and ship strikes have been the most common causes of death in recent years.
The Marine Mammal Center’s researchers are investigating the locations and behaviors of whales in the San Francisco Bay so that decisions can be made to better protect whales, as effective policies are needed to protect them from the life threatening human-caused threats they face in the wild.
Biologists have observed gray whales in bad body condition during their annual migration since 2019, when the National Oceanic and Atmospheric Administration (NOAA) declared an “unusual mortality event”. According to NOAA almost one in four gray whales migrating along the USA west coast has died since the last recorded population assessment in 2015 and 2016.
Members of the public can call the Marine Mammal Center’s rescue hotline at 415-289-SEAL (7325) to report a dead whale or a whale in distress.