Concern grows over non-native algae

CASSVILLE, Mo. -- Missouri conservationists and anglers are guarding the state's streams against a nonnative invasive type of algae that has earned the nickname "rock snot" because of its slick nature.

Until last year when the state Department of Conservation launched a public awareness program, longtime fly fisherman Paul Niegsch of Kansas had never heard of the single-celled algae didymo, which blooms in freshwater rivers and streams with consistently cold temperatures and the right pH level.

Didymo, short for its scientific name Didymosphenia geminata, forms large mats that blanket river and stream beds, critically altering habitats and cutting off food sources for fish, The Joplin Globe reported.

"It can also make fishing impossible -- or nearly impossible," said Paul Spurgeon, who manages the Missouri Department of Conservation trout hatchery at Roaring River State Park, south of Cassville.

Didymo has expanded in recent years to 18 states, including a 13-mile stretch of the White River in neighboring Arkansas where it was found in 2005. Beaver Lake in Arkansas and Table Rock and Taneycomo lakes in Missouri are part of the White River basin, all upstream from where the algae was found just south of the state line.

"That's very, very close, and a lot of anglers who fish there (White River) also come to Missouri rivers and streams to fish," Spurgeon said.

Didymo mats easily can detach from a stream bed and float downstream on their own, and the algae can be transferred between bodies of water on an angler's porous, felt-soled waders or fishing gear. That prompted a ban of felt-soled waders in Missouri in 2012.

Felt-soled waders are popular among anglers because they provide better traction on slippery river surfaces than some other options, such as rubber.

"It has never been found in Missouri. We're being preventative. We're trying to stay ahead of the game," Spurgeon said.

The conservation department started letting the public know about the dangers of didymo in 2012 and continues working to get the word out.

"We've held public forums to help educate the anglers and the retailers and outfitters, too -- they're the ones selling the equipment," Spurgeon said. "We've handed out buttons and brochures, and we have signs up."

Niegsch, the fly fisherman, spotted some of those signs while fishing in Missouri. Trout parks also built boot- and gear-cleaning stations near wade-in fly fishing zones so anglers can disinfect their equipment.

The conservation department also directed the state's hatcheries to conduct testing in their rivers and streams. Roaring River Hatchery had planned its test for early August, but that was postponed after a flood caused the river to rise a couple feet overnight. Spurgeon said the testing will be conducted in the spring.

"We'll do algae scrapings on rocks. We want to find out: Is it already here? Do we need to ramp up our efforts? If it's not, we stay with prevention," Spurgeon said. "Meanwhile, we're just making sure everyone knows to check. Clean and dry -- that's our motto."

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Information from: The Joplin (Mo.) Globe, http://www.joplinglobe.com