H-4 (Gonzales) Reservoir - 2015 Survey Report

Prepared by Greg Binion
Inland Fisheries Division – Corpus Christi District

This is the authors' summary from a 31-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations in H-4 Reservoir were surveyed in 2016 with spring electrofishing, trap netting, and gill netting. Historical data are presented with the 2016 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

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 generation and recreation. The substrate is composed primarily of silt, sand, clay, and some gravel and rock. Angler and boat access was limited to one pay-to-use boat ramp. There were no handicap-specific facilities. Primary habitat was composed of boat docks and piers, timber, native floating-leaved and submersed vegetation, hydrilla, and water hyacinth.

Management History

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 have not been collected in any survey. Palmetto and Striped Bass migrate downstream from a stocked upstream reservoir (Canyon Lake). Flathead Catfish were present in the reservoir in low abundance. Blue Catfish have been stocked, but relative abundance remains low. The 2012 management plan focused on working with GBRA on the control of water hyacinth, monitoring water lettuce and East Indian hygrophila, and publicizing fishing opportunities. Over the current study period, water hyacinth control was achieved with herbicides and temporary drawdowns during winter months. Hydrilla spread throughout the reservoir in 2014 and was controlled with an herbicide application. Sport fisheries were publicized through local media outlets.

Fish Community

• Prey species: Gizzard Shad and Bluegill formed the reservoirs forage base. Gizzard Shad abundance remained consistent while Bluegill abundance decreased from 2011.
• Catfishes: Channel Catfish abundance was substantially reduced over the survey period yet size composition was dominated by larger individuals. Blue and Flathead Catfish were present in low abundance.
• Largemouth Bass: Largemouth Bass abundance decreased slightly over the study period. Size composition was balanced and comprised both juvenile and adult fish. Mean age at legal length was 3.0 years.
• Crappie: White Crappie was the predominant crappie species in the reservoir. Size structure was balanced and roughly half of the fish collected were available to anglers. Growth was average and mean age at legal length was 2.1 years.

Management Strategies

• Continue managing fish populations under current regulations.
• Continue to work with GBRA on controlling water hyacinth and hydrilla.
• Monitor the spread and expansion of water lettuce and East Indian hygrophila.
• Conduct additional electrofishing and trap netting to monitor declines in Largemouth Bass and crappie abundance.
• Conduct exploratory tandem baited hoop net and low frequency electrofishing surveys as alternative means to collect population level data on catfishes.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-6 Inland Fisheries Division Monitoring and Management Program