H-4 (Gonzales) Reservoir - 2011 Survey Report
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Prepared by John Findeisen and Greg Binion
Inland Fisheries Division
District 1-E, Mathis, 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.
H-4 Reservoir was surveyed in the fall 2007, 2009, and 2011 and spring 2009 and 2012 using electrofishing, fall 2005, 2007, 2009, 2010, and 2011 using trap nets, and spring 2004, 2008, and 2012 using gill nets. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.
H-4 is a 696-acre reservoir on the Guadalupe River in Gonzales County and is controlled by the Guadalupe-Blanco River Authority (GBRA) The reservoir was impounded in 1931 to provide water for a hydroelectric plant and recreational uses. The substrate is composed primarily of silt, sand, clay, and some gravel and rock. Angler and boat access was limited to only one pay-to-use boat ramp. There were no handicap-specific facilities. At the time of sampling, the habitat was composed of boat docks, stumps, native floating-leaved vegetation, native submersed and emergent vegetation, hydrilla, East Indian hygrophila, and water hyacinth.
Important sport fish species include channel catfish, largemouth bass, and crappie. Anglers have reported catching white, palmetto and striped bass from this reservoir but these species were not collected in gill-net surveys. Palmetto and striped bass migrate downstream from a stocked upstream reservoir (Canyon Lake). Flathead catfish were present in the reservoir, and blue catfish have been stocked in this reservoir but have yet to become the dominant catfish species as seen in other reservoirs throughout Texas. The 2008 management plan focused on working with GBRA on the control of water hyacinth, monitoring water lettuce and East Indian hygrophila, and conducting spring electrofishing surveys to assess perceived spawning and recruitment limitations of largemouth bass. Water hyacinth and water lettuce were chemically treated with herbicides annually and GBRA lowered the water level of the reservoir twice during extended periods of below freezing weather. These management practices were effective in the control of water hyacinth and allowed native aquatic vegetation to flourish. TPWD monitored water lettuce and East Indian hygrophila, yet neither plant became established. Spring electrofishing surveys were conducted and the data showed both spawning and recruitment were no longer a concern, probably a result of more habitat due to the control of water hyacinth and expansion of native vegetation.
- Prey species: Gizzard shad, threadfin shad, and several sunfish species were the primary forage species available to predators. Relative abundance of gizzard and threadfin shad have decreased while sunfish relative abundance has increased.
- Catfishes: Blue, channel, and flathead catfish were present in the reservoir with channel catfish being the predominant species. About half of channel catfish collected were legal-size (≥ 12 inches) with a few fish over 20-inches in total length.
- Black basses: Largemouth, Guadalupe, spotted, and smallmouth bass were present in the reservoir with largemouth bass being the most abundant. Recruitment of largemouth bass increased as a result of the improved habitat, brought about by the control of water hyacinth.
- Crappie: White and black crappie were present in the reservoir with white crappie being the most abundant and robust population.
- Continue managing fish populations under current regulations.
- Continue to work with GBRA on controlling water hyacinth and hydrilla, enhance habitat, and monitor the spread and colonization of East Indian hygrophila.
- Introductions of native aquatic vegetation will be explored and implemented once water hyacinth is controlled.
Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-2 Statewide Freshwater Fisheries Monitoring and Management Program