BOISE — An invasive algae with the less-than-appealing nickname of "rock snot" has been confirmed in the South Fork of the Boise River.
Jeff Dillon, regional fisheries biologist for the Idaho Department of Fish and Game, said the single-celled organism with the scientific name didymo was identified in the river this spring.
"It could well be a native (microscopic algae) that's always been there," Dillon said. "But the bottom line is we know it's there, and it's something we need to keep an eye on."
The algae coats rocks. It looks similar to tissue paper and has the feel of wet wool.
Dillon said the algae has been found in other parts of Idaho, but this is the first time it's been confirmed in the South Fork of the Boise River. It's native to North America, he said, and found in other rivers in the Western United States as well.
The South Fork of the Boise is a popular fishing destination, but the slippery algae can make wading a challenge.
Dillon said if it grows abundantly it can reduce plant life in the river as well as the number of fish.
Dave Parrish, Fish and Game state fisheries coordinator, said high spring flows will wash away didymo blooms. He said that won't cause problems downstream, where the river is the source of drinking water for the states most populous river valley.
But Parrish said didymo could be a more serious problem if it got in central Idaho's Silver Creek, which draws anglers from across the nation.
Being spring fed, Parrish said, Silver Creek doesn't have high spring flows to wash away algae blooms.
The algae can be spread by anglers who unwittingly carry it on their wading shoes.
Dave Kumlien, of Trout Unlimited, said the group is trying to educate anglers about the problem and others, such as invasive snails, that can be spread by anglers.
"We're trying to get anglers and others to pay more attention to the whole issue and take proper care of their equipment," Kumlien said.
For example, Trout Unlimited wants anglers to stop using felt-soled wading shoes, which take longer to dry between fishing trips and can carry organisms from river to river.
"Everybody around the country has their own concern (with invasive species), and instead of focusing on one, we should instead look at ways to solve all problems," Kumlien said. "Our goal is really to get people thinking about changing their behavior."