Dunlap Reservoir - 2005 Survey Report

Prepared by John Findeisen and Todd Neahr
Inland Fisheries Division
District 1-E, Mathis, Texas

This is the authors' summary from a 24-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations in Lake Dunlap were surveyed in 2005 using trap nets and electrofishing and 2006 using gill nets. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.

Reservoir Description

Dunlap Reservoir is a 410-acre impoundment located on the Guadalupe River in Guadalupe County and is regulated by the Guadalupe-Blanco River Authority (GBRA). The reservoir, impounded in 1928, is used for water supply, hydroelectric generation, and recreation. The reservoir is mainstream and maintains a fairly constant water level. Substrate in the upper portion is composed primarily of rock and gravel, while the middle and lower portions of the reservoir is composed of clay, sand and silt. Habitat features consisted of boat docks, rocks, and native floating and native emergent vegetation.

Management History

Important sport fish include channel catfish, largemouth bass, and crappie. The management plan from the 2002 survey report focused on nuisance aquatic vegetation and fish habitat improvement. In 1996 Texas Parks and Wildlife Department (TPWD) treated hydrilla with herbicide in conjunction with stocking triploid grass carp. The first objective from the 2002 survey report included monitoring the reservoir for the possible return of hydrilla and water hyacinth, while creating a communication pathway among homeowner groups, the GBRA and the TPWD Inland Fisheries district office. This communication pathway proved helpful in June 2004 when homeowner groups alerted GBRA and TPWD about the presence of Hygrophila sp., another potentially nuisance plant species that is currently present in the Comal River, upstream of Lake Dunlap. The second objective from the 2002 survey report was to enhance fish habitat by installing brushpiles under homeowners’ boat docks. However, due to conflicts between anglers and recreational users this project is still being discussed.

Fish Community

• Prey species: Gizzard shad and bluegill continue to be the dominant prey species for most sportfish. Electrofishing catch of gizzard shad was good and approximately 85% of the gizzard shad collected were available as prey. Electrofishing catch of bluegill was lower than previous years and the majority were less than 6 inches in length.
• Catfishes: Channel, blue, and flathead catfish are present in the reservoir, with channel catfish being the dominant species. Although fewer large channel catfishwere collected in 2006 gill net survey, many were available to anglers.
• Sunfish: Redear and redbreast sunfish reach >8 inches in length in the reservoir. Redbreast sunfish are the most abundant of the two species and have the greatest potential of providing a fishery.
• Black basses: Largemouth, Guadalupe, spotted, and smallmouth bass are present in the reservoir, with largemouth being the dominant species. Largemouth bass exhibited good body condition and growth rates to legal size.
• Crappie: White and black crappie are present in the reservoir, with white crappie being the dominant species. However, trap net catch rates of both crappie species were low compared to other reservoirs in the Guadalupe chain-of-lakes.

Management Strategies

• Continue to work with anglers, recreational users, and the GBRA to enhance fish habitat.
• Stock Florida largemouth bass in 2007.
• Continue to monitor for the return of hydrilla and water hyacinth.
• Obtain funding for a creel survey on this reservoir.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-30-R-31 Statewide Freshwater Fisheries Monitoring and Management Program