Didymo found in Mad River

Didymo found in Mad River

July 18, 2008

The presence of the invasive algae didymo in the Mad River was confirmed by the Agency of Natural Resources (ANR) on July 10, 2008. In a follow up on a sample submitted by a concerned citizen, Leslie Matthews, ANR invasive aquatics expert, found an extensive bloom near Riverwatch Lane in Warren. The algae covers 75-100 percent of the stream bottom at the site, and extends hundreds of meters upstream from that location. In addition, Caitrin Noel, Watershed Coordinator for Friends of the Mad River, has observed didymo in several locations including near the Park and Ride in Warren Village, at Riverside Park, and at Lareau swimhole.

The discovery of didymo in the Mad River – a watershed neighboring the White River – emphasizes the need for all river users to help prevent the spread of didymo to new locations both within and also outside of the White River watershed. At present, didymo is blooming on the main stem of the White River, between the mouth of Locust Creek and Cleveland Brook in Bethel. It is also blooming in Locust Creek, from the mouth upstream to the first bridge on Old Route 12, as well as at the mouth of Stony Brook in Stockbridge.

Because didymo cells are microscopic, they may be present anywhere in the White River watershed without being visible to the naked eye. For this reason, we encourage all river users to CHECK, CLEAN and DRY their gear after each use in the White River. For more information about the CHECK, CLEAN, and DRY protocols, visit our Didymo Resources page.

Volunteer opportunity

To identify where didymo cells are present within the White River watershed, we will be conducting plankton net surveys throughout the watershed this fall. Plankton nets capture didymo cells that are present in the water column. By using plankton nets to test areas of the White River watershed that do not have didymo blooms (upstream of Stockbridge on the main stem, major tributaries), we will be able to determine the extent of didymo’s spread within the watershed. State biologists are using this technique to identify the presence of didymo in Vermont watersheds where didymo blooms have not been confirmed.

To learn more about plankton net surveys or to volunteer, contact us at (802) 763-7733 or info@whiteriverpartnership.org.