Nasworthy Reservoir - 2010 Survey Report

Prepared by Mandy K. Scott and Mukhtar Farooqi
Inland Fisheries Division
District 1-C, San Angelo, 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 in Nasworthy Reservoir were surveyed in 2006, 2008, and 2010 using electrofishing and trap nets, and in 2007, 2009 and 2011 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

Nasworthy Reservoir is a 1,598-acre impoundment located on the southwestern edge of San Angelo, Texas in Tom Green County. It is a shallow, turbid reservoir with stable water levels and extensive emergent vegetation. Access is good with numerous public boat ramps and parks.

Management History

Important sport fish include largemouth bass, white crappie, and channel catfish. Palmetto (hybrid striped) bass were stocked from the 1970s through 2007. Red drum were once an important game species, but the discontinued operation of the power plant on Nasworthy Reservoir beginning in 2003 eliminated this fishery that was dependent on the plant’s heated water effluent.

Fish Community

• Prey species: Gizzard shad were present in good numbers, but few were small enough to be consumed by predators. Few threadfin shad were captured in samples. Bluegill abundance appears to have declined since the 2007 report.
• Catfishes: No blue catfish were sampled. Flathead catfish were present in low numbers. Channel catfish abundance was down slightly from 2007, but still good. Size structure of channel catfish improved since 2007; individuals up to 27 inches were sampled.
• Temperate basses: White bass were present in low abundance. Palmetto bass (hybrid striped bass) abundance declined and size structure increased since stockings were discontinued in 2007.
• Largemouth bass: Largemouth bass abundance was good. Size structure and body condition improved slightly since 2006 but was still poor. Growth rate to 14 inches remained poor since 2006.
• White crappie: White crappie catch rate was about half of the 2006 catch rate; however, more individuals were over 10 inches in the latest survey. Growth to 10 inches was poor, with average 10-inch crappie being 3.5-years old.

Management Strategies

• To improve size structure of largemouth bass population, propose changing the largemouth bass length limit to no-minimum, and only two under 18 inches may be kept.
• Communicate with anglers through public meetings, traditional, and social media to promote the potential benefits of the new regulation.
• Conduct additional electrofishing, trap netting, and gill netting in 2012-2013, additional electrofishing in fall 2011 and 2013, and standard monitoring in 2014-2015.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-1 Statewide Freshwater Fisheries Monitoring and Management Program