Calaveras Reservoir - 2015 Survey Report

Prepared by John Dennis and Randy Myers
Inland Fisheries Division – San Antonio District

This is the authors' summary from a 37-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations were surveyed using electrofishing and gill nets during the 2012-2016 monitoring period. A vegetation survey was conducted during the study period. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.

Reservoir Description

Calaveras Reservoir is a 3,110-acre power plant cooling reservoir located in Bexar County inside Loop 1604 southeast of San Antonio. A near-constant water level was maintained by pumping from the San Antonio River. Thousand Trails Management Services regulates access to public facilities at the site. Boat angler access was excellent. Aquatic plant coverage in the reservoir was primarily bulrush. Exotic Blue Tilapia and armored catfish populations have become established in the reservoir.

Management History

Important sport fishes included Red Drum, hybrid Striped Bass, and Blue and Channel Catfishes. The Red Drum and Hybrid Striped Bass populations were maintained by frequent fingerling stockings (by TPWD). Sunshine bass (4-6 inch total length), purchased by City Public Service Energy, were stocked in 2014 and 2015. Northern Largemouth Bass (NLMB) were stocked to increase genetic diversity; however stocking success was short-lived. Angler harvest of all sport fishes, except Red Drum, were regulated according to statewide size and daily bag limits. The Largemouth Bass regulation was changed from a minimum size limit of 18 inches to statewide regulations September 1, 2015. Harvest of Red Drum is restricted to a 3-fish daily bag and 20-inch minimum size limit.

Fish Community

• Prey species: Gizzard Shad, Threadfin Shad, and Bluegill were the primary prey species and were present in sufficient numbers and sizes for utilization by predators.
• Catfishes: The reservoir contained abundant populations of Blue and Channel Catfish which supported a popular fishery. Since 2006, Blue Catfish relative abundance has increased and Channel Catfish relative abundance has decreased.
• Hybrid Striped Bass: Relative abundance varied somewhat from year to year during the survey period, but have declined since 2000. However, the stockings have provided a consistently popular fishery for this species.
• Largemouth Bass: Relative abundance remained low and only a negligible fishery exists.
• Red Drum: This introduced species has supported a popular fishery and abundance has increased since 2007.

Management Strategies

Continue to stock hybrid Striped Bass and Red Drum to support these popular fisheries. Assess growth and survival of Red Drum via otoliths collected from angler-caught fish. Conduct biennial gill net surveys, a habitat survey and fall daytime electrofishing survey in 2019, and a 6-month creel survey in 2017.

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