A nasty algae that can suffocate habitat and food sources for fish has been found in a creek in one of Wyoming's premier watersheds, according to a river group.

Didymo, an algae commonly called "rock snot," was found in Lake Creek, a tributary of the Snake River, by the U.S. Geological Survey, the Snake River Fund reported Friday.

"It's a pretty big deal," said Lexey Wauters, executive director of the group. "If didymo takes off in our area, it has the potential to completely decimate a stream. That's what's happened in New Zealand, and the New Zealand government has actually closed some watersheds to human travel because of didymo and trying to contain it."

The algae, Didymosphenia geminate, has a texture like wet wool and can look like wet toilet paper. It can form "mats" on stream beds, suffocating aquatic vegetation so fish have nothing to eat.

While it has been found in streams in Montana, Colorado, South Dakota and Idaho, it previously had been found in only one stream in Wyoming - the middle fork of the Popo Agie near Lander.

Baker Salsbury, owner of Westbank Anglers in Jackson, has his shop just 200 yards from Lake Creek. He hadn't heard about the confirmation of didymo and said there is other algae in the stream that looks like the dangerous algae.

"If that's the case, we need to close wade fishing on Lake Creek," he said. "This is a huge deal."

He said didymo grows "exponentially fast," and the mats of algae can cover the entire river bottom. He said it is nearly impossible to get rid of, and in New Zealand, river managers are poisoning entire streams to get rid of didymo.

The algae is widely thought to be human borne and spread by water recreationists not cleaning boats, kayaks, whitewater rafts, waders and other supplies before entering new waterways.

Salsbury said aquatic hitchhikers of all types are the biggest threat to waterways in Wyoming and elsewhere.

"The biggest threat is obviously people fishing in other places here and abroad get it on their equipment," including waders, boots, boats and even felt on their boots. "If people don't wash their equipment properly, the threat is great. The whole invasive species beyond didymo is the biggest threat we have to our boating community."

Sue Consolo-Murphy, chief of science and resource management with Grand Teton National Park, said more information is needed about this algae to know what the implications are for waterways in the area.

She said a park technician was preparing to do a survey of various waterways, but high flows prevented the study. Still, the technician looked into Lake Creek from the road, saw the algae and took a sample.

That sample was confirmed to be didymo by the U.S. Geological Survey, but its exact implications are not yet known, Consolo-Murphy said.

The Wyoming Game and Fish Department's Jackson fisheries supervisor and U.S. Geological Survey representatives were not available for comment Friday.