Humpback whale swims 60 miles inland after losing way from SF Bay

A wayward humpback whale found itself 60 miles away from the entrance of San Francisco Bay earlier this week. It’s not clear if the whale, named Rio, is still in the Delta, or if it managed to escape back toward freedom.

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The humpback was first seen in SF Bay on Tuesday, the Marine Mammal Center said in a news release. Although its sex is unknown, it is a “well-known” whale in the area, the Marine Mammal Center said. The whale has been documented many times before, with 15 recorded sightings between California and Mexico over the last 24 years. Using photos from the Cascadia Research Collective, the whale headed past Benicia, Suisun Bay and into the Sacramento-San Joaquin River Delta was identified as Rio.

The whale made its way into the Sacramento River, where it was spotted by the U.S. Coast Guard on Wednesday. One witness told ABC10 that the whale surfaced about a block from Rio Vista City Hall, which sits along the river near the Rio Vista Bridge.

Rio’s wrong turn could be the result of illness, injury or simply bad navigational skills, experts said. 

“This whale is in an out-of-normal habitat area,” said Kathi George, Director of Cetacean Conservation Biology at the Marine Mammal Center. “Our team is actively monitoring the situation, and we kindly ask the public to please avoid changing the whale’s course and let the animal decide where it wants to go.”

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As of Sunday morning, it’s not clear if Rio made it back to deeper waters or if it is still stuck in the Delta. 

Whales entering the Delta are rare but not unheard of. The most famous cetacean in Bay Area history is Humphrey, a humpback who got trapped for 24 days in and around the sloughs of Rio Vista. Whales are not evolved for life in fresh water, so any time they stray from the salty sea, their lives are in danger. Humphrey’s detour was nearly a deadly one, and his roughly 24 days inland were the longest ever recorded by a whale. 

If you go in search of Rio, officials ask that you keep your distance. People on kayaks and boats should maintain at least 100 feet between themselves and the whale.