Calaveras Reservoir - 2007 Survey Report

Prepared by Randy Myers and John Dennis
Inland Fisheries Division
District 1-D, San Antonio, Texas

This is the authors' summary from a 23-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations were surveyed using electrofishing in fall 2002, 2003, and 2007, bass only electrofishing in fall 2005, gill nets in spring each year from 2006 to 2008, and trap nets in 2004. 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 within the San Antonio city limits. A near-constant water level was
maintained by pumping from the San Antonio River during periods of low rainfall and
runoff. Angler access and recreational facilities, maintained by the San Antonio River
Authority, remained excellent. Both boat ramps were renovated in 2007. Aquatic
plant coverage in the reservoir was <1%. Blue tilapia (Oreochromis aureus) and
sailfin catfish (Pterygoplichthys multiradiatus) populations have become well
established in the reservoir.

Management History

Important sport fishes included red drum, palmetto bass, and channel catfish. The red drum and palmetto bass populations were maintained by stocking, with palmetto bass stockings occurring in 8 of the last 10 years and red drum stockings in 9 of the last 10 years. Northern largemouth bass (NLMB) have been stocked to increase genetic diversity; however stocking success was short-lived. Hybrid and sub-adult white crappies were stocked to re-introduce the species to the reservoir; however a self-sustaining white population did not result. Orangemouth corvina and Orangemouth corvina/speckled trout hybrids were stocked to provide an additional sport fish; however these stockings were also terminated because of low success. Angler harvest of all sport fishes, except largemouth bass and red drum, was regulated according to statewide size and daily bag limits. A minimum size limit of 18 inches and a 3-fish daily bag limit were implemented in 1990 for largemouth bass and harvest of red drum was restricted by a 3-fish daily bag and 20-inch minimum size limits.

Fish Community

• Prey species: Gizzard shad, threadfin shad, and bluegill were the primary prey species and present in sufficient numbers and sizes for utilization by predators.
• Catfishes: The reservoir contained an abundant population of channel catfish which supported a popular fishery. Blue catfish were also present, but were not as abundant as channel catfish.
• Palmetto bass: Population abundance varied somewhat from year to year. However, the stockings provided a consistently popular palmetto bass fishery.
• Largemouth bass: Population abundance for this species has increased since 2002, but remained low overall. This species provided a limited fishery.
• Red drum: This species supported a popular fishery; however standard fisheries sampling gears were ineffective at collecting sufficient individuals to monitor trends in abundance and population size structure.

Management Strategies

• Continue to stock palmetto bass and red drum to support these popular fisheries. Also, continue to monitor the largemouth bass population response to the current special harvest regulation.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-30-R-33 Statewide Freshwater Fisheries Monitoring and Management Program