Denny Glover refused to believe his fishing buddy at first.
Glover, who was angling with friends on the Sacramento River south of the Rio Vista Bridge last Wednesday, said one of his companions spotted spray from the water. “I honestly, I didn’t believe it. I thought he had mistaken a dolphin or porpoise or whatever,” Glover told KCRA. “I just didn’t believe him.”
A second spout ended all doubt. “Then we saw another spout and there’s no mistaking the size of a whale spout. When it blows when it comes up it’s a big mist of water,” he explained. The creature that breached was longer than their 21-foot boat, Glover added.
The fisherman captured phone video of the massive humpback swimming in the river delta. The Marine Mammal Center has since identified the whale as CRC-11620, an individual known to researchers for more than two decades. The center named the animal Rio.
Rio’s movements have been documented 15 times over the past 24 years along the California and Mexico coasts, with the first recorded sighting in 2002 off California. Earlier this week, the whale appeared in San Francisco Bay before heading east into the Sacramento-San Joaquin River Delta.
Kathi George, Director of Cetacean Conservation Biology at The Marine Mammal Center, addressed the unusual inland appearance. “While it’s unknown whether this whale is just passing through or if there is an underlying, unknown ailment, the best thing people can do is experience this adult whale’s presence from a respectful distance,” she told the California Post.
George added that her team is actively monitoring Rio’s movements. “This whale is in and out of normal habitat area. 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.”
The Sacramento River has drawn lost humpbacks before. In 1985, a whale named Humphrey spent several weeks in the Rio Vista area, captivating national attention before finally returning to the Pacific Ocean. Two decades later, in 2007, mother and calf humpback whales Delta and Dawn held observers’ attention for 20 days in the same region before resuming their normal migration.
Rio’s current detour marks the latest chapter in a pattern of humpback whales straying into this California waterway, though researchers have not indicated whether the animal is in distress or simply exploring.