Aquatic Plant Management Options for Caddo Lake

Timothy J. BisterTexas Parks and Wildlife Department

Inland Fisheries District 3AMarshall, Texas

Plan Objectives

• Establish long-term management of nuisance aquatic plants in Caddo Lake

• Maintain a healthy lake ecosystem

• Protect native aquatic habitat

• Maintain access for users

Problematic Species

• Waterhyacinth

• Hydrilla

• Giant salvinia

Mechanical Harvesters

• Limited to water >2 feet deep with few stumps

• Past experience has proven ineffective and cost prohibitive

Triploid Grass Carp

• Effective for control of hydrilla• Not effective for waterhyacinth• Not considered a viable control for giant salvinia• Will eat native species• Would require emigration barrier• Would require agreement between TX & LA

Recommendations• Giant salvinia

– Conduct herbicide treatments• Glyphosate/Diquat mixture

– Physical removal/disposal by trained/permitted volunteers

– Increase public awareness through signs, flyers, and news releases

– Release giant salvinia weevils in areas that become uncontrollable with herbicide

– Conduct annual aquatic vegetation surveys to monitor giant salvinia coverage

Recommendations• Waterhyacinth

– Continue herbicide treatments• 2,4-D• WMA, boat ramps, other access• Supplemental efforts from other entities fully

supported

– Conduct annual surveys (Aug/Sep) to monitor coverage of waterhyacinth

Recommendations• Hydrilla

– Maintain critical boat lanes restricted by hydrilla with herbicide

– Not most critical problem at this time

– Assess hydrilla coverage during annual aquatic vegetation surveys

Recommendations• Create on-site vegetation control crew

– May to October– Hire private herbicide applicator

• Pursue additional funding – Support spray crew– Purchase herbicide

• Develop long-term plan