Choke Canyon Reservoir - 2015 Survey Report

Prepared by Greg Binion
Inland Fisheries Division – Corpus Christi District

This is the authors' summary from a 42-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations were surveyed in 2015 using electrofishing and baited tandem hoop netting, and in 2016 using gill netting to assess population trends for important sport fishes. Anglers were surveyed from 1 June 2015 to 31 May 2016. Historical data are presented with the 2015-2016 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 13,744 acres in 2015-2016) 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 some gravel/rock. Littoral habitat consisted of native aquatic vegetation, periodically flooded terrestrial vegetation, standing timber, and seasonally abundant water hyacinth and hydrilla.

Management History

Important sport fish species include Largemouth Bass, Blue and Channel catfishes, White Bass, and crappie. Recent management efforts have focused on control of nuisance aquatic vegetation, compiling catch and harvest statistics on important sport fish species, documenting catch of trophy Largemouth Bass, and supplementing the Largemouth Bass population through stockings in 2009-2011, 2013, and 2016. The district has worked with the City of Corpus Christi to develop and implement a water hyacinth control program. District staff conducted herbicide treatments on water hyacinth in 2008 (195 acres), 2009 (80 acres), 2010 (525 acres), 2011 (45 acres), 2012 (51 acres), and 2015 (30 acres). Staff annually monitored access areas where hydrilla could restrict use. Angler harvest of all sport fishes has been regulated according to statewide size and bag limits.

Fish Community

• Prey species: Gizzard and Threadfin Shad, Bluegill, and Redear sunfish formed the reservoirs forage base. Population size structure of prey species was suitable to support sport fish populations.
• Alligator Gar: Anglers harvested an estimated 337 Alligator Gar in 2015/2016 and angler catch rate 0.3/fish per hour of effort.
• Catfishes: Blue Catfish abundance remained high and size structure comprised a wide size-range of fish. Angler success for Blue Catfish was high and anglers harvested an estimated 106,283 fish. Channel Catfish were also present, but in low numbers.
• White bass: Abundance of White Bass was low throughout the survey period; however, the majority of fish collected in 2016 were > 10 inches and thus available for angler harvest. Anglers harvested an estimated 14,504 fish in 2015/2016 and angling catch rate averaged 1.9/fish per hour.
• Largemouth bass: Largemouth Bass abundance increased in 2015 relative to prior years; however, size structure was dominated by smaller individuals. Mean age at legal length was 2.7 years. Largemouth Bass continued to be the most sought individual sport fish species in the reservoir.
• Crappie: White Crappie was the fourth most sought sport fish species in the reservoir and was an important component to the overall sport fishery.

Management Strategies

• Continue to manage sport fish populations under existing harvest regulations.
• Conduct a creel survey to collect quantitative data on angler use.
• Continue to assist the City of Corpus Christi with the water hyacinth control program.
• Monitor access areas where hydrilla could restrict use.
• Stock Florida Largemouth Bass when water level increases.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-6 Inland Fisheries Division Monitoring and Management Program