Mermet Lake Curly Pondweed Eradication Program


The Illinois Department of Natural Resources, with partial funding from the National Fish and Wildlife Foundation and assistance from the River to River CWMA, is working to eradicate curly pondweed (Potamogeton crispus) from Mermet Lake.

Curly pondweed is an aggressive aquatic plant that infests still or slow-moving waters throughout the United States. Curly pondweed can dominate the near-surface and sediment layers of shallow (under 15 feet) water systems. It can spread via plant fragments or turions (tubers).

Curly pondweed goes dormant in the summer, and this dieback often creates low dissolved oxygen conditions that can lead to fish kills. Since curly pondweed was first discovered in Mermet Lake in 2003, the lake has experienced large fish kills and a significant decline in the fisheries resource and subsequent loss of recreational use.

In 2007, the DNR developed an eradication plan, which involves water column treatments, sediment treatments, spread prevention measures, education, and research. (click here to see the executive summary of the eradication plan) Through the activities outlined in the eradication plan, Mermet Lake is starting to see a reduction in curly pondweed abundance.