Jacques Cousteau never, as rumor has it, investigated the waters of Lake Tahoe. The story probably evolved out of a visit his grandson made to Tahoe in the 1980s to attend a fund-raiser.

Charles Goldman, founder of the UC Davis Tahoe Research Group, recently confirmed that the Cousteau rumor is not true. What he couldn’t dispute is the possibility that the lake could be home to a giant sturgeon, the largest freshwater fish in North America. It can live up to 100 years and grow to 900 pounds.

Sturgeon are bottom feeders and Tahoe is deep, more than 1,600 feet. During the more than 30 years Goldman has studied the lake, people have told him repeatedly they’ve spotted something large and hard to identify in the lake. This fall, Goldman is planning to be part of a project, Tahoe Deep Blue, that will explore the bottom of Tahoe with a remote operated vehicle.

“There’s a possibility there might be a giant sturgeon … that was introduced accidentally to the lake,” said Goldman in a recent phone conversation. “We’ve had so many sightings of an enormous something over the years.”

Goldman said he is by no means sold on the idea. He said he suspects such sightings can be attributed to wave movements and light fragmentation.

Dennis Murphy, an ecologist at the University of Nevada, Reno, who has spent his summers at Tahoe for the last 50 years, said he doesn’t dismiss the idea of sturgeon in the lake, but he wouldn’t bet on it.

“I’m not going to poo-poo it,” Murphy said. “It’s not impossible but it would be very surprising.

“I will say there have been a number of folks who have done relatively deep scuba diving … and it’s highly likely it would have been seen by now.”

When Murphy stumbled upon a jellyfish at Echo Lake about 10 years ago he thought he had made a discovery.

“I flipped. I had no idea,” Murphy said. “Turns out there are freshwater jellyfish across the United States. As a biologist I knew nothing about it. Once I looked it up, I found out it was not a rare occurrence.”

The jellyfish are about the size of a human fist and have been spotted at Fallen Leaf Lake and Echo Lake in late summer and early fall, according to Murphy.

Sport fishermen who dock at Tahoe Keys Marina and have a combined 52 years experience fishing Tahoe said they’ve never seen any fish bigger than the 20-pound range.

“I’ve heard stories that people have seen a 5-foot-long fish,” said Kombiz Farokhpour, who owns The Tahoe Fisherman. “It could be a sturgeon or a lake trout. It might look like big fish depending on how many beers a guy’s had.”

“Or it could just be people talking,” said Chris Ziegler, owner of First Strike Sportfishing.

Dennis Mitchell, owner of Eagle Point Fishing Charters, has been fishing Tahoe since 1973.

“I haven’t ever seen one,” Mitchell said. “Heard a lot of stories. We normally don’t fish past 300 feet.”

— Gregory Crofton can be reached at (530) 542-8045 or by e-mail at gcrofton@tahoedailytribune.com