Dunlap Reservoir - 2013 Survey Report

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

This is the authors' summary from a 27-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations in Lake Dunlap were surveyed in 2013 using electrofishing and trap netting and in 2014 using gill netting. Historical data are presented with the 2013-2014 data for comparison. 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 included boat docks, rocks, flooded timber, and both native and exotic vegetation species.

Management History

Important sport fish include Blue and Channel catfish, Largemouth Bass, and White Crappie. The management plan from the 2010 survey report focused on spring trap net sampling for White Crappie, exotic species, especially exotic vegetation, and publicizing the Largemouth Bass and Blue Catfish populations. Fall trap net catch rates of White Crappie were historically less than 1.0/nn using both standard and non-standard surveys. Spring trap nets using both random and biologist-selected stations were conducted with mixed results. Exotic species were monitored via vegetation and routine fisheries surveys. Water hyacinth was found and mechanically removed from the reservoir since the last report. Several press releases were prepared and distributed regarding the excellent Largemouth Bass and Blue Catfish angling opportunities. An unsanctioned cutting of submerged timber occurred since the last report.

Fish Community

• Prey species: Electrofishing catch rates of shad and sunfish species decreased since the 2010 report but did not negatively impact predatory species. 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 Channel Catfish being the predominant species. The majority of catfish sampled were greater than Legal length limits and both Blue and Flathead catfish reached a large size.
• Black basses: Smallmouth, Spotted, Largemouth, and Guadalupe bass were present in the reservoir, with Largemouth Bass being the predominant species. Largemouth Bass relative abundance decreased since the 2010 report, however, they continued to exhibit good body condition and growth to legal size. Several Largemouth Bass over 20” were collected during the electrofishing survey and numerous fish >10 pounds, including a ShareLunker in 2012 were reported by anglers.
• Crappie: White Crappie were present in the reservoir. Spring trap nets surveys at both random and biologist-selected stations did not result in consistent catch rates of White Crappie. Further refining of spring trap net surveys should be examined.

Management Strategies

Continue to manage the fisheries under current regulations. Continue to refine White Crappie sampling, to monitor the reservoir for nuisance aquatic vegetation, and to work with the local Friends of Reservoirs (FOR) group on enhancing habitat in the reservoir.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-4 Inland Fisheries Division Monitoring and Management Program