Rio Vista, California — A group of fishermen got an extraordinary surprise on the Sacramento River this week when a massive humpback whale surfaced near their boat, creating a rare wildlife encounter deep inside California’s river delta.
Denny Glover and his friends were fishing south of the Rio Vista Bridge on Wednesday when one of the men suddenly noticed a spray rising from the water.
At first, Glover wasn’t convinced they had seen a whale.
“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.”
But when the spray appeared again, there was little room for doubt.
Fishermen Realize a Massive Whale Is Nearby
Glover said the second appearance made it immediately clear that the animal was far larger than anything they had expected to encounter on the river.
“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 whale’s enormous size became even more apparent when it surfaced near the fishing boat.
“Just the part of the whale that breached was longer than our 21-foot boat.”
The fishermen quickly pulled out a phone and managed to record video of the humpback swimming through the river delta, capturing a remarkable moment that few people would expect to see so far inland.
Whale Named Rio Has a Long History in California Waters
The animal isn’t completely unknown to researchers.
The Marine Mammal Center identified the humpback as CRC-11620, a whale that has been given the name Rio. Researchers have been tracking its movements for more than two decades, documenting repeated appearances along the California and Mexico coasts.
According to the center, CRC-11620 has been documented 15 times over the past 24 years.
The whale was first spotted in 2002 off the California coast. Since then, researchers have continued documenting its movements as it travels through waters along California and Mexico.
Earlier this week, Rio was spotted in San Francisco Bay before apparently continuing east into the Sacramento-San Joaquin River Delta.
That latest movement brought the whale into an environment where encounters with a humpback of this size are highly unusual.
Marine Mammal Experts Urge People To Keep Their Distance
The Marine Mammal Center confirmed the recent sighting and urged members of the public to avoid getting too close to the animal.
Researchers don’t currently know whether Rio is simply exploring an unusual area or whether there could be an underlying reason for the whale’s movement.
“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,” Kathi George, Director of Cetacean Conservation Biology at The Marine Mammal Center, told.
George also emphasized that people should avoid interfering with the whale’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.”
That guidance is especially important in a busy river and delta environment, where boats and other human activity could potentially alter the whale’s movements.
California Has Seen Other Famous River Whales
Rio’s unusual appearance is not the first time a humpback whale has ventured into the Rio Vista area.
In 1985, a humpback named Humphrey spent several weeks near Rio Vista, attracting widespread attention before eventually finding his way back toward the ocean.
More than two decades later, another memorable encounter occurred.
In 2007, mother-and-calf humpbacks named Delta and Dawn remained in the area for about 20 days, captivating people who watched their movements before the whales eventually returned toward more typical habitat.
Rio’s latest appearance is now adding another chapter to the area’s unusual history of visiting humpback whales.
Would you have believed your friends if they told you a massive humpback whale was swimming beside your fishing boat? Share your reaction in the comments.
