Aquatic Plant Management Options for Caddo Lake Timothy J. Bister Texas Parks and Wildlife...

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