J. B. Thomas Reservoir - 2007 Survey Report

Prepared by Charles Munger
Inland Fisheries Division
District 1-A, Canyon, Texas

This is the authors' summary from a 29-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations in J.B. Thomas Reservoir were surveyed in 2007 using electrofishing and trap nets and in 2008 using gill nets. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.

Reservoir Description

J.B. Thomas Reservoir is a 7,820-acre impoundment (constructed in 1952) on the main stream of the Colorado River. The dam is located 16 miles southwest of Snyder and west of State Highway 208, in Scurry County, Texas. The reservoir is owned by the Colorado River Municipal Water District and provides water to three member cities. The reservoir has a drainage area of 3,950 square miles, however, it experiences frequent water level fluctuations. Capacity during 2007 was approximately 6% of capacity or 1,000 acres. The reservoir has been at under 20% capacity from 1994 to 2004. Angler access is good and there is one boat ramp. There are limited handicap-specific facilities. Habitat consisted primarily of nondescript mud bank and flooded terrestrial vegetation.

Management History

Important sport fish include largemouth bass, white crappie, and catfish. The sport fish populations have only been managed with statewide regulations.

Fish Community

• Prey species: Gizzard shad were abundant in the reservoir and had an IOV of 97 indicating most were available to existing predators. Electrofishing catch of bluegills was average for the reservoir, but the population was dominated by small individuals.
• Catfishes: Blue catfish were relatively abundant in the reservoir, but growth was poor. Channel catfish had low relative abundance and poor growth. Flathead catfish were present in the reservoir.
• White bass:White bass were present in the reservoir in low numbers with relatively few legal fish. Growth rates were good with fish reaching legal size by age 1.
• Largemouth bass: Stock-length largemouth bass were relatively abundant compared to previous samples. Size structure was good. Largemouth bass had adequate growth rates and legal-size fish were in good condition.
• White crappie: White crappies were very abundant but few fish were of legal size. Growth was poor as no fish reached legal size before age 4.

Management Strategies

Conduct general monitoring with trap nets, gill nets, and electrofishing in 2011-2012. Investigate possible regulation changes on blue catfish and white crappie to alleviate a growth bottlenecks.

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