Scientists with the Marine Mammal Center have responded to three more dead gray whales reported in San Francisco Bay recently, center officials said Friday.
The three whales washed ashore between April 27 and May 4 in Tiburon, the Port of Oakland and at Angel Island State Park.
Since early last month, the Marin Headlands-based center and partners such as the California Academy of Sciences in San Francisco's Golden Gate Park have investigated the deaths of four other gray whales and one fin whale all found in the Bay Area, with three of those determined to have died due to a ship strike.
The most recent whales won't have their causes of death determined because of inaccessible or unsafe locations, and the Marine Mammal Center is in talks with the National Oceanic and Atmospheric Administration about possibly safely towing the whale carcasses into the open ocean so they can naturally decompose there.
"Over the last few years, our experts have observed gray whales frequenting San Francisco Bay in greater numbers and for longer periods of time. These whales are at increased risk from human activity, which is why we are committed to better understanding the ongoing challenges and threats these animals face," Kathi George, the center's director of field operations and response, said in a statement.
Increased strandings of gray whales since early 2019 along their entire migratory range prompted the NOAA to declare an Unusual Mortality Event that remains ongoing for the species.
Malnutrition, entanglement and ship strikes have been the most common causes of death in whales studied locally in the Bay Area.
Here's a detailed list of the nine dead whales found in or near the bay so far this year, provided by the Marine Mammal Center:
- Feb. 20: Adult female pygmy sperm whale; North Salmon Creek Beach (Point Reyes National Seashore); cause of death: undetermined
- April 1: Adult female gray whale; Angel Island State Park via San Francisco Bay (Crissy Field); cause of death: undetermined
- April 3: Adult female gray whale; Fitzgerald Marine Reserve, San Mateo County; cause of death: suspected ship strike
- April 8: Subadult male gray whale; Angel Island State Park via San Francisco Bay (Berkeley Marina); cause of death: undetermined
- April 8: Adult female gray whale; Muir Beach; cause of death: ship strike
- April 24: Juvenile male fin whale; Fort Funston (San Francisco) now at Thornton Beach in Daly City; cause of death: suspected ship strike
- April 27: Gray whale; Keil Cove (Tiburon) now currently at Kirby Cove/Lime Point (Sausalito); cause of death: undermined (no necropsy performed, only samples taken)
- May 3: Gray whale; Port of Oakland; cause of death: undetermined (no necropsy performed, only samples taken)
- May 4: Gray whale; Angel Island State Park; cause of death: undetermined (no necropsy performed, only samples taken)
In 2019, from March through May, scientists investigated 13 dead gray whales in the Bay Area. In 2020, the center responded to five dead gray whales in the same time period, center officials said.
Marine Mammal Center researchers have seen increased numbers of the whales in the Bay this spring as they continue their migration north to food-rich Arctic waters and are urging boaters and anyone else on the water to keep a safe distance from the whales and to report any sightings to 415-289-7325.