Overview
- The whale was first reported in San Francisco Bay on Sept. 15 and was filmed near the Rio Vista Bridge on Wednesday about 60 miles from the Pacific Ocean.
- Researchers identified the animal as CRC-11620 from regional photo-ID catalogs and say it has been documented roughly 15 times since 2002 with a last known sighting in Baja California in February 2026.
- The Marine Mammal Center and the U.S. Coast Guard are tracking the whale and coordinated monitoring was in place through Thursday evening with no confirmed new sightings after the Rio Vista report.
- Scientists say it is unclear whether the whale is transiting normally or is affected by an underlying health issue and they point to past upriver cases such as Humphrey in 1985 and Delta and Dawn in 2007 that ultimately returned to the ocean.
- A fisherman’s video of the sighting has drawn public attention and officials warn that untrained attempts to rescue or redirect a large whale are dangerous, so they ask people to give the animal space and report sightings to The Marine Mammal Center or apps like WhaleAlert.