Dunlap Reservoir - 2009 Survey Report

Prepared by John Findeisen and Greg Binion
Inland Fisheries Division
District 1-E, Mathis, Texas

This is the authors' summary from a 25-page report. For a copy of the complete report, use the download link in the sidebar.

During the 2006-2010 survey period, fish populations in Lake Dunlap were surveyed in fall 2005, 2007, and 2009 using electrofishing and trap nets and spring 2006 and 2010 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

Lake Dunlap 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. Lake Dunlap is classified as a mainstream reservoir and has a fairly constant water level. Substrate in the upper section is composed primarily of rock and gravel, while the middle and lower sections of the reservoir are composed of clay, sand, and silt. Habitat features include boat docks, rocks, and native floating and emergent vegetation.

Management History

Important sport fish include channel catfish, largemouth bass, and crappie species. The management plan from the 2006 survey report focused on fish habitat improvement, largemouth bass genetics, nuisance aquatic vegetation, and implementing a creel survey. The proposed habitat improvement plan was to construct brushpiles under boat docks and piers of cooperating lake-front property owners, however, the plan was not implemented due to concerns of the brushpiles breaking loose and damaging structures downstream and a decline in interest. Largemouth bass were not stocked. Nuisance aquatic vegetation presence/absence was noted on all fisheries and habitat surveys. The proposed creel survey was to be completed by a university; however, funding for this survey was not available.

Fish Community

• Prey species: Electrofishing catch rates of shad and sunfish species increased substantially since the 2006 report. Prey species populations were comprised primarily of small size classes; benefitting most predatory fish species. Redear and redbreast sunfish provided anglers with excellent angling opportunities.
• Catfishes: Blue, channel, and flathead catfish were present in the reservoir, with blue catfish being the predominant species. The relative abundance of flathead catfish appears to be increasing. Proportion of harvestable-sized catfish in the populations was good as the majority of fish sampled were greater than legal length limits.
• Black basses: Smallmouth, spotted, largemouth, and Guadalupe bass were present in the reservoir, with largemouth being the predominant species. Largemouth bass relative abundance increased substantially and they exhibited good body condition and growth to legal size. Several largemouth bass over 20” were collected during the electrofishing survey.
• Crappie: White and black crappie were present in the reservoir, with white crappie being the predominant species. Trap net catches of crappie were again low but, 33 adult crappie were collected in the spring 2010 gill net survey.

Management Strategies

Continue to manage the fisheries under current regulations, refine crappie sampling, continue to monitor the reservoir for nuisance aquatic vegetation, and publicize the sunfish, catfish, and largemouth bass fisheries through media sources local to the reservoir and through the district Facebook page.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-30-R-35 Statewide Freshwater Fisheries Monitoring and Management Program