Granbury Reservoir - 2017 Survey Report

Prepared by Michael S. Baird and John Tibbs
Inland Fisheries Division
Waco District

This is the authors' summary from a 32-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations in Granbury Reservoir were surveyed in 2017 using electrofishing and trap netting, and in 2018 using trap netting and gill netting. Historical data are presented with the 2017-2018 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

Granbury Reservoir is an 8,700-acre impoundment located near the City of Granbury, Hood County, Texas and is operated by the Brazos River Authority (BRA). Primary water uses include storage of flood and storm waters, municipal water supply, power plant cooling, and recreation. Bank and boat access are adequate. Habitat features consisted mainly of bulk heading, natural shoreline, boat docks and piers and emergent aquatic vegetation. Water level has been near conservation pool since June 2015.

Management History

Important sport fish include Largemouth Bass, Channel Catfish, White Bass and Striped Bass. Sport fishes are currently managed with statewide regulations with the exception of a 16-inch minimum length limit on Largemouth Bass. Sport fishes were affected by frequent, toxic Golden Alga (GA) blooms from 2001 through 2012. Efforts to mitigate these losses included increasing sampling effort, stocking Striped Bass annually, and stocking Florida Largemouth Bass to supplement the population. Golden alga blooms have not caused any major fish kills in recent years. Trap netting became optional in 2009. In 2013, management efforts began focusing on supporting the statewide public relations campaign “Clean. Drain. Dry”, and posting appropriate aquatic invasive species (AIS) signage at access points to try and prevent the spread of zebra mussels into the reservoir. In 2016, the BRA funded a cooperative effort (including several local partners) to build and deploy fish attracting structures (i.e., 28 crappie condos and 16 Mossback Safe Haven structures) near mid-reservoir, to begin to enhance fish habitat reservoir-wide. Recent management efforts include aquatic vegetation and boater access surveys conducted during summer 2017, a tier III Largemouth Bass age and growth sample during fall 2017, trap netting in winter 2017, and additional trap netting and standard gill netting during spring 2018.

Fish Community

• Prey species: Threadfin Shad were present in the reservoir in low abundance. Gizzard Shad were abundant while most sunfishes were only collected in fair numbers.
• Catfishes: Channel Catfish were abundant and body condition improved with increasing size; most were of legal-length. Blue and Flathead Catfish were present in low numbers.
• Temperate basses: White and Striped Bass were collected in fair to good quantities. Most of the White Bass were of legal-length. Striped Bass recruitment (from recent stockings) appeared to be good, and about one-third of the sampled fish were of legal-length for anglers.
• Largemouth Bass: Largemouth Bass were abundant and the catch rate was the highest observed since 2003. Legal-length fish comprised over 40% of the sample. Body condition was very good across all size classes.
• White Crappie:White Crappie were observed during winter and spring trap netting, and during spring gill netting. Fifty-four to 79% of sampled fish were of legal length for anglers, while body condition was good to excellent across seasons and gear types.

Management Strategies

• The sport fishes in Granbury Reservoir will continue to be managed with existing regulations, except the Largemouth Bass regulation will soon revert to the statewide length and bag limit as part of a statewide effort to simplify regulations for this species. We will continue to maintain Aquatic Invasive Species signage at access points and inform the public about the negative impacts of invasives. Access and vegetation surveys will be conducted in summer 2021, and electrofishing and gill netting surveys will be conducted in 2021 and 2022.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-3 Inland Fisheries Division Monitoring and Management Program