Lyndon B. Johnson Reservoir - 2020 Survey Report

Prepared by Mukhtar Farooqi and Patrick Ireland
Inland Fisheries Division
San Marcos/Austin District

This is the authors' summary from a 35-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations in Lyndon B. Johnson (LBJ) Reservoir were surveyed in 2020 using electrofishing, and in 2021 using gill netting. Historical data are presented with the 2017-2021 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

Lyndon B. Johnson Reservoir is a stable-level 6,502-acre impoundment of the Colorado and Llano Rivers in Burnet and Llano counties, Texas. It was constructed in 1951 by the Lower Colorado River Authority (LCRA) for purposes of hydro-electric and steam-electric power, flood control, and water conservation. The reservoir has a drainage area of approximately 36,290 square miles and a shoreline length of about 270 miles. Residential and commercial properties border most of the shoreline area.

Management History

Important sport fish include Largemouth Bass, Channel Catfish, and White Bass. Management activities included Florida Largemouth Bass stockings from 2011 to 2016 to improve the potential for trophy Largemouth Bass, and conducting annual aquatic vegetation surveys to monitor exotic invasive species. The reservoir is managed under statewide regulations. Lyndon B. Johnson Reservoir had little vegetative coverage prior to 2012.

Fish Community

• Prey species: Bluegill, Gizzard Shad, and Redbreast Sunfish were the predominant prey species in 2020. Threadfin Shad and Redear Sunfish were also available as forage. The forage base was sufficient to support sportfish.
• Catfishes: Blue Catfish relative abundance was low, as was the case in previous surveys. Channel Catfish was the predominant catfish species in the reservoir; catch rate had increased since the previous two surveys. Flathead Catfish were present in low numbers.
• White Bass: This reservoir continued to support a low-abundance White Bass population. Most individuals sampled were of harvestable size.
• Largemouth Bass: Largemouth Bass abundance was moderate; population size structure was good, and overall body condition for most fish was close to optimal.

Management Strategies

• Based on current information, the reservoir should continue to be managed with existing regulations.
• Aquatic vegetation surveys should continue to be conducted annually to monitor coverage of non-native water hyacinth, Eurasian watermilfoil, and hydrilla.
• Standard gill netting and electrofishing surveys will be conducted in 2024 – 2025, and an additional electrofishing survey in 2022.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-2 Inland Fisheries Division Monitoring and Management Program