Death of rare whale investigated
Scientists at the Marine Mammal Center in Sausalito are working to find out what killed a rare pygmy sperm whale that washed ashore in Sonoma County over the weekend.
The approximately 8footlong adult female whale was discovered Sunday morning at North Salmon Creek Beach, the center said. Scientists found out the whale was pregnant upon further examination.
A team from the center was sent to the beach to perform a necropsy — an autopsy on an animal — in an effort to find out whether the whale was killed by human causes, such as a boat strike or a fishing net entanglement, or from other causes like disease or malnutrition.
Since pygmy whales are a deepdiving species that don’t frequently breach the ocean’s surface, they rarely wash ashore and can be difficult to track. The Marine Mammal Center has responded to only three other cases of pygmy sperm
whales in its 45year history, said Barbie Halaska, the center’s necropsy manager.
“The opportunity to examine a pygmy sperm whale along the California coast is invaluable because it allows us to build important baseline data on this littleknown species,” Halaska said in a statement.
The necropsy team, working at about onethird of its normal personnel due to the pandemic, collected a variety of bone, organ and tissue samples. The final necropsy report is expected to take several weeks to complete.
The whale was found with several scrapes and “sluffing” — or areas of missing skin — when it washed ashore, the center said. It’s unclear what caused the scrapes: While the scientists described the carcass as “relatively fresh,” it’s not known how long the dead whale was drifting in the ocean before it washed up on the beach.
Pygmy whales can weigh between 700 and 1,000 pounds, grow up to 11.5 feet and live up to 23 years, according to NOAA Fisheries. A unique trait among the species is a sac filled with dark liquid in its intestines, which the whale can release like a squid if threatened by a predator.
They can dive at least 1,000 feet. Their diets include squid, octopus, crab, shrimp and fish, according to NOAA.
Since the whales avoid planes and boats, which scientists use to determine population size, it’s difficult to assess how many are in the wild.
Primary threats to the
whales include entanglement, hunting, vessel strikes and marine debris, according to NOAA.
The whale will be left on North Salmon Creek beach to decompose natu
rally, the Marine Mammal Center said. That process can take a few weeks for smaller whales, but the majority of the decomposition process occurs quickly after a necropsy,
according to the center.