Invasive Algae Confirmed in Elk River


Mar 11, 2001
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Invasive Algae Confirmed in Elk River


The invasive algae known as Didymo have been found in the Elk River in the Webster Springs area, according to Bret Preston, Assistant Chief, West Virginia Division of Natural Resources Wildlife Resources Section. Following reports from anglers that heavy algal mats were seen in the Elk River, DNR staff collected samples from three locations near Webster Springs. The samples were sent to the Maryland Department of Natural Resources for confirmation. All three samples contained Didymo.

Didymo is a common name for Didymosphenia geminata, a freshwater diatom species that can form extensive mats on stream beds. The thick mats can cover native algae and aquatic insects, and make fishing very difficult. These thick mats appear slimy, but feel more like cotton or wool fabric. The algal mats are also called "rock snot" and can be white, yellow or brown in color. The algae form stalks that attach to rocks. While the algae eventually die and break off, the stalks persist and may impact stream habitats and aquatic organisms for weeks or months.

Didymo is native to the northern latitudes of North America, Europe and Asia. Its range has expanded and it now can be found in rivers in the western United States and more recently in Maryland, New York, New Hampshire, Pennsylvania and Vermont. It has also been found in three western Virginia rivers (Jackson, Pound and Smith). "In West Virginia, the DNR will work with other state and federal agencies, and anglers to monitor Didymo in the Elk River and other locations," said Preston.

This range expansion is largely attributed to anglers and boaters. Didymo can be attached to waders, paddles and boats. Felt-soled boots and waders are likely the worst culprit in the spread of these algae. The porous material stays damp and the algae cells can remain alive in the damp felt bottoms. "We encourage anglers to take precautions against moving Didymo and other potential invasive species from one waterbody to another," said Preston. While anglers and boaters may be responsible for the introduction of some unwanted species, they also are the most important line of defense in minimizing the spread of aquatic invasive species by following a few simple steps.

· Before leaving a stream, scrub mud and debris off of boots and fishing gear.

· Disinfect boots and equipment by scrubbing or soaking in 5 percent salt solution (2 cups of salt in 2.5 gallons of water) for one minute and then let dry completely. You may also scrub equipment with dishwashing detergent and rinse well.

· Allowing equipment to completely dry for at least 48 hours will also kill Didymo, but realize that felt bottoms of boots may require longer drying times.

· Soak items in very hot water (140° F).

Anglers are encouraged to report unusual algal mats that may be Didymo to DNR district offices and the Elkins and Charleston offices.

Media Contact:
Bret Preston, Wildlife Resources Section (304) 558-2771

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