Choke Canyon Reservoir - 2021 Survey Report

Prepared by Greg Binion and Dusty McDonald
Inland Fisheries Division – Corpus Christi 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 were surveyed in 2021 using electrofishing and fyke nets and in 2022 using gill netting, spring electrofishing, and multifilament gill netting to assess population trends for important fisheries. Historical data are presented with the 2021-2022 data for comparison. This report summarizes the survey results and contains a management plan for the reservoir based on those findings

Reservoir Description

Choke Canyon is a 25,989-acre reservoir (averaged 16,004 acres in 2021- 2022) located on the Frio River in the Nueces River Basin, approximately 80 miles south of San Antonio. Its main purposes are water supply and recreation. The reservoir has a history of substantial water level fluctuations. The substrate is composed primarily of silt, sand, clay, and gravel/rock. Littoral habitat consisted of native aquatic vegetation, periodically flooded terrestrial vegetation, standing timber, hydrilla, and seasonally abundant water hyacinth.

Management History

Important sport fish species include Largemouth Bass, Blue and Channel Catfishes, White Bass, and crappies. Alligator Gar are also an important component to the overall fishery. Recent management efforts have focused on control of nuisance aquatic vegetation, documenting catch of trophy Largemouth Bass and promoting the ShareLunker Program, enhancing the Largemouth Bass population with stockings, and developing an Alligator Gar monitoring program. Staff annually monitored access areas where invasive vegetation could restrict use. The district has worked with the City of Corpus Christi to develop and implement a water hyacinth control program. District staff conducted herbicide treatments of water hyacinth from 2008 through 2015 (926 total acres). Since 2016, water hyacinth herbicide applications have been conducted through private contractors including treatments in 2016 (132 acres), 2017 (566 acres), 2018 (104 acres), 2019 (5 acres), and 2022 (310 acres). Prior to 2021, angler harvest of all sport fishes had been regulated according to statewide size and bag limits. In September 2021, the regulation for Blue and Channel Catfish changed from the statewide regulation to a 14-inch minimum length, 15-fish daily bag limit.

Fish Community

• Prey species: Gizzard Shad, Threadfin Shad, and Bluegill were present in moderate abundance. Collectively, these species formed the primary forage base. The majority of prey species collected were adequate size for most predator fish.
• Alligator gar: The reservoir continues to support a robust Alligator Gar population and popular fishery. Fifty-six (N = 56) Alligator Gar were reported as harvested through the mandatory reporting system in 2020-2021. Several trophy-sized (≥ 6 ft) Alligator Gar were harvested by anglers.
• Catfish: Blue Catfish abundance remained high and size structure comprised a wide size range of fish. Channel and Flathead Catfish were present in low abundance.
• White bass: Abundance of White Bass was low throughout the survey period. All of the fish collected in 2022 were > 10 inches.
• Largemouth bass: Largemouth Bass abundance was moderate. Size structure indices indicated excellent size composition with abundant preferred size (15 inch) available. Growth was good and mean age at legal length was 1.9 years.
• Crappie: Anecdotally, crappies remained an important component to the overall sport fishery, especially for harvest-oriented anglers.

Management Strategies

• Continue to manage sport fish populations under existing harvest regulations.
• Continue to assist the City of Corpus Christi with the water hyacinth control program.
• Monitor access areas with annual nuisance vegetation surveys where water hyacinth and hydrilla could restrict use.
• Assist Texas State University with annual zebra mussel veliger monitoring.
• Stock Lone Star Bass to maintain high level of trophy production potential and continue to collect data for the Largemouth Bass trophy database.
• Continue to refine the Alligator Gar monitoring program to track population trends and monitor harvest through the mandatory harvest reporting system

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-3 Inland Fisheries Division Monitoring and Management Program