Sacramento -- Scientists say they don't know why a "yucky" kind of algae is fouling a stretch of a California river to the displeasure of swimmers and fishermen.
About 10 miles of the Bear River northeast of Sacramento is clogged with a strange algae called "didymo," short for its scientific name, Didymosphenia geminata, The Sacramento Bee reported Monday.
People's dislike of the algae has earned it the nickname "rock snot."
"No doubt, it is pretty yucky, and that's the complaint from a lot of recreationists," Leah Elwell at the Center for Aquatic Nuisance Species in Livingston, Mont., said. "If you're kayaking, you don't want to get a mouthful of that. It does kind of foul up your day."