Nasworthy Reservoir - 2022 Survey Report

Prepared by Lynn D. Wright and Blake Thornton
Inland Fisheries Division - San Angelo District

This is the autho'rs summary from a 42-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations in Nasworthy Reservoir were surveyed in 2020-2022 using electrofishing and trap netting and with gill netting in 2021 and 2023. Anglers were surveyed from June 2021 through May 2022 with a creel survey.  Historical data are presented with the 2020-2023 data for comparison.  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 1,380-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, Channel Catfish, and Hybrid Striped Bass. Red Drum were once an important game species, but the discontinued operation of the power plant on Nasworthy Reservoir in 2003 eliminated the fishery that was dependent on the plant’s heated water effluent. Palmetto Bass (Striped Bass female x White Bass male) were stocked from 1974 to 2007. In 2018 and 2019 Palmetto Bass stockings resumed at a higher stocking density to restructure the Gizzard Shad population. In 2020 and 2022 Sunshine Bass (White Bass female x Striped Bass male) were stocked instead of Palmetto Bass.

Fish Community

• Prey species: Threadfin Shad were present in the reservoir. Electrofishing catch of Gizzard Shad was adequate, however Gizzard Shad IOV was marginal. Electrofishing catch of Bluegill was slightly lower than previous years with most fish being 2 to 6 inches long.
• Catfishes: The Channel Catfish population had good size structure with fish up to 26 inches observed during sampling. Channel Catfish was the most sought-after species in Nasworthy Reservoir.  Blue and Flathead Catfish were present in the reservoir in low abundance. 
• Temperate basses: White Bass were present in the reservoir in low abundance. Hybrid Striped Bass continued to increase in size and abundance from 2018-2020 stockings.
• Largemouth Bass: The Largemouth Bass population continued to be characterized by poor size structure and slow growth. Largemouth Bass below the slot limit tended to be in poor condition, while bass above the slot were in good condition.  Just over 16% of all angler effort at Nasworthy Reservoir targeted  Largemouth Bass.
• White Crappie: White Crappie were highly abundant and showed modest improvements in condition. Growth of crappie also improved, with crappie reaching 10 inches in 2.3 years. The minimum length limit was removed on September 1, 2020 to increase harvest and reduce intraspecific competition.

Management Strategies

• Conduct gill netting in 2025 and 2027.
• Conduct additional electrofishing and trap net surveys in 2023, 2024 and 2025, and general monitoring surveys with trap nets and electrofishing surveys in 2026-2027. Conduct a roving creel survey from June 2026 through May 2027. 
• Access and vegetation surveys will be conducted in 2026.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-5 Inland Fisheries Division Monitoring and Management Program