Granbury Reservoir - 2013 Survey Report

Prepared by John Tibbs and Michael S. Baird
Inland Fisheries Division
District 2-B, Waco, 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 Granbury Reservoir were surveyed in 2013 with electrofishing. Low water levels prevented trap netting surveys in winter 2013 and gill netting surveys in 2014. 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 within the Brazos River system in Hood County, Texas. Near constant water level is maintained by a spillway consisting of 16 tainter gates and 2 sluice gates; retention time has been estimated at 260 days. Primary water uses include storage of flood and storm waters, municipal water supply, power plant cooling, and recreation. Granbury Reservoir has only moderate productivity, yet the fishery has been hampered by golden algae since 2001. Habitat features were dominated by extensive bulk heading, natural shoreline and docks/piers.

Management History

Sport fishes in Granbury Reservoir are currently managed with statewide regulations with the exception of a 16-inch minimum length limit on Largemouth Bass. Important sport fish include Largemouth Bass and Striped Bass. Both have been affected by nearly annual, toxic Golden Algal blooms since 2001. Efforts to mitigate these losses included collecting supplemental fisheries data, stocking Striped Bass annually, and stocking Florida Largemouth Bass. Trap netting became optional in 2009, and because of weak crappie catch rates in prior years, it is no longer a primary objective of scheduled sampling. Most recently, a public relations campaign began within the district to inform and educate constituents about zebra mussels in order to prevent their introduction into Granbury Reservoir. Recent low water levels have made monitoring difficult.

Fish Community

• Prey species: Catch rates of all prey species were well below historical averages.
• Catfishes: Low water levels prevented gill netting in 2014. Blue and Channel Catfish were collected in 2012 at 0.1 and 5.8/nn respectively. Body condition of collected individuals remained high. Flathead Catfish remain present in the reservoir.
• Temperate basses: Low water levels prevented gill netting in 2014. White and Striped Bass were collected in 2012 at 0.8 and 0.1/nn respectively. Body condition of collected individuals remained high.
• Largemouth Bass: The Largemouth Bass catch rate was near the historical average, and body conditions were average.
• White Crappie: Trap netting was last conducted in 2005 and White Crappie were present in the reservoir in low numbers. Low water levels prevented trap netting in 2013.

Management Strategies

• Continue managing Granbury Reservoir with existing regulations, and continue annual stocking requests for Striped Bass pending reservoir water levels.
• Work with the Brazos River Authority to improve ramp usability during low water periods. Conduct standard electrofishing and gill netting in 2017 and 2018 respectively and supplemental electrofishing and gill netting in 2015 and 2016.
• Collect age data from largemouth bass in 2017.
• Collect crappie data from the 2016 and 2018 gill netting surveys.
• Conduct aquatic vegetation and access surveys during summer 2017.
• Continue efforts to educate constituents about zebra mussel issues and protect the reservoir from zebra mussel introductions.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-4 Inland Fisheries Division Monitoring and Management Program