Coleto Creek Reservoir - 2020 Survey Report

Prepared by Greg Binion and Dusty McDonald
Inland Fisheries Division
Corpus Christi District, Mathis, Texas

This is the authors' summary from a 46-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations in Coleto Creek Reservoir were surveyed in 2018 using fall electrofishing, in 2019 using spring electrofishing, in 2020 using fall electrofishing, low-frequency electrofishing, and baited hoop nets and in 2021 using gill nets to assess population trends for important sport fishes. Anglers were surveyed from January through June 2021 with an access point creel survey. Historical data are presented with the 2017-2021 data for comparison. This report summarizes the survey results and contains a management plan for the reservoir based on those findings.

Reservoir Description

Coleto Creek Reservoir is a 3,100-acre (averaged 2,217 acres in 2020-2021) impoundment located on Coleto Creek in the Guadalupe River Basin, 13 miles southwest of Victoria, Texas. Guadalupe-Blanco River Authority (GBRA) serves as the controlling authority and the reservoir receives water from both the Coleto and Perdido creeks as well as several smaller tributaries. Primary uses include power plant cooling and recreation. Approximately 600 acres are used for cooling ponds and inaccessible to anglers. Water level is typically stable; however, over the survey period water levels fluctuated 5-feet from conservation pool elevation. Substrate was composed primarily of clays, deep loams, and small rock. Littoral habitat consisted primarily of woody debris, native floating-leaved vegetation, and periodically flooded terrestrial vegetation.

Management History

Important sport fish species include Blue and Channel Catfish, Largemouth Bass, and crappies. Palmetto Bass and Red Drum were previously stocked, but these stockings were discontinued due to low directed angling effort. Recent management efforts focused on monitoring and control of nuisance aquatic vegetation, enhancement of structural fish habitat, supplementing the Largemouth Bass population with stocking, compiling catch and harvest statistics on important sport fish populations, and exploratory use and evaluation of low-frequency electrofishing and baited tandem hoop nets to collect population data on catfishes. District staff has also compiled tournament data records to document catches of trophy-size Largemouth Bass. Historically, invasive aquatic vegetation (hydrilla, water milfoil, and water hyacinth) has restricted recreational access. Staff annually monitored access areas where invasive vegetation could restrict use. District staff worked with GBRA staff to manage invasive vegetation and herbicides were utilized for vegetation control, as needed. Angler harvest of all sport fishes has been regulated according to statewide size and bag limits.

Fish Community

• Prey species: Gizzard Shad and various Sunfish species formed the reservoirs forage base. Most prey species collected were adequate size for predator fish. Bluegill abundance substantially decreased over the study period.
• Catfishes: Blue and Channel Catfish were moderately abundant, and the Blue Catfish size structure comprised a wide size range of fish. Legal-size catfish were abundant and available for angler harvest. Catfishes represented a substantial portion of the total directed fishing effort (36.1 %) in 2021. Flathead Catfish were present in low abundance.
• White Bass: Abundance of White Bass was low, and few fish were available for angler harvest. No effort was directed towards White Bass and total harvest was low.
• Largemouth Bass: Largemouth Bass abundance decreased slightly from prior surveys and size structure was primarily comprised of smaller individuals. Largemouth Bass remained the most sought sport fish in the reservoir; however, angling success and directed effort for both tournament and non-tournament anglers were substantially reduced compared to prior years.
• Crappies: Crappies remained an important component to the overall sport fishery, especially for harvest-oriented anglers. Angler catch rate was 1.7/h and total harvest was 1,780 fish.

Management Strategies

• Continue to manage sport fish populations under statewide harvest regulations.
• Conduct creel survey to collect quantitative data on angler use.
• Stock Florida Largemouth Bass to maintain a high level of trophy production potential and continue to collect data for the Largemouth Bass trophy database.
• Work with GBRA and other local partners to continue to develop and implement habitat enhancement projects.
• Monitor coverage and potential expansion of non-native vegetation and continue to work with GBRA on all vegetation control activities.