The discovery of a fast-growing invasive plant will require temporary closure of the Washington County Public Fishing Lake, the Alabama Department of Conservation and Natural Resources said.

Giant salvinia, a free-floating fern native to Brazil, is one of the most aggressive aquatic plants and has the potential to double in size every two to four days, according to the Wildlife and Freshwater Fisheries Division of the ADCNR.

Giant salvinia forms thick mats on the surface of the water that block sunlight and reduce oxygen levels for fish and beneficial aquatic plants. Giant salvinia can overtake aquatic ecosystems and interfere with outdoor recreation, the ADCNR said.

The Washington County Public Fishing Lake will be closed starting Monday.

The Wildlife and Freshwater Fisheries Division will draw down the lake to dry out the giant salvinia around the perimeter. The drawdown will last through the winter to make sure the plants are destroyed. Giant salvinia on the lake’s surface will be treated with aquatic herbicide. The lake will remain closed until the invasive plant is under control.

For alternative fishing locations to Washington County Public Fishing Lake, visit the ADCNR’s Outdoor Alabama or call the WFF Fisheries Section at (334) 242-3471.