Lewisville Reservoir - 2003 Survey Report

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Prepared by Raphael Brock and Thomas Hungerford
Inland Fisheries Division
District 2-D, Fort Worth, 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.

Lewisville Reservoir was surveyed using trap netting and electrofishing in 2003 and gill netting in 2002 and 2004. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.

Reservoir Description

Lewisville Reservoir, Denton County, is a 29,592-acre impoundment constructed by the U.S. Army Corps of Engineers in 1954 on Elm Fork of the Trinity River. It was built to provide flood control, water for municipal and industrial purposes, and recreation. Other principal tributaries are Hickory Creek and Little Elm Creek. In 1989 the conservation pool level of the reservoir was raised from 514 ft. mean-sea-level (msl) to 522 ft. msl. Lewisville Reservoir has a drainage area of approximately 968 square miles. Rainfall in the watershed averages 33.5 inches per year. Angler and boat access is adequate. There is one handicap accessible facility. A native aquatic plant habitat restoration project was initiated on Lewisville Reservoir in 1998 in cooperation with Lewisville Aquatic Ecosystem Research Facility (LAERF). Partial work on the project began, but drought conditions resulted in no vegetation being planted in 1998. In 1999 the drought continued as water levels declined to 14 feet below conservation pool. Limited plantings have occurred since with little or no success. Striped bass were stocked each year from 1991 until 1999. Stockings were discontinued because of low catch rates and because several summer fish kills of striped bass occurred.

Fish Community

• Prey species: The electrofishing catch rate of gizzard shad was 552.5/hour in 2003, which was higher than the two previous surveys and the district average of 274.0/hour. The 2003 threadfin shad electrofishing catch rate was 245.0/hour, which is higher than the district average of 205.0/hour. Electrofishing catch rates of bluegill and longear sunfish, the two principal sunfishes in Lewisville Reservoir, in 2003 were 111.5/hour and 90.5/hour, respectively. Catch rates for both these species are higher than the previous sample. Catch rates for bluegill are lower than the district average of 158.0/hour while catch rates of longear sunfish are near the district average of 88.0/hour.
• Catfishes: The gill netting catch rate of blue catfish was 4.9/net night in 2004, which is similar to the 2002 catch rate of 5.1/net night and is higher than the district average of 1.6/net night. Relative weight values for sizes of fish 16 to 18 inches is beginning to decrease. The gill netting catch rate of channel catfish in 2004 was 1.9/net night which is similar to previous samples, but lower than the district average of 5.7/net night.
• Temperate basses: The white bass gill netting catch rate was 5.3/net night in 2004 and 3.7/net night in 2002 which were lower than the district average of 8.2/net night. Palmetto bass were stocked in Lewisville Reservoir in 1999, 2000, 2002, and in 2003. The palmetto bass gill netting catch rate was 0.3/net night and 0.7/net night in 2002 and 2004 respectively. In the spring of 2004, a palmetto bass was caught by an angler in excess of 15 pounds. Growth rates of palmetto are above district averages and harvestable size occurs by age 3.
• Black basses: The 2003 electrofishing catch rate for spotted bass of 30.5/hour is higher than the 1999 sample and higher than the district average of 24.0/hour. The electrofishing catch rate of largemouth bass for 2003 (76.5/hour) was much lower than the district average of 129.0/hour but higher than the previous catch rate in 1999 (40.0/hour). Largemouth bass catch rates have been below the district average for the past several samples and can probably be attributed to low water levels which have resulted in poor sampling conditions. Largemouth bass continue to grow at the district average and reach harvestable size by age 2. Florida largemouth bass (FLMB) alleles increased slightly from the previous sample (22%) to 26%. This increase occurred despite no FLMB stockings since 1998.
• White crappie: The trap netting catch rate for white crappie in 2003 was 29.5/net night, and 40.5/net in 2001. These catch rates are very high when compared to the district average of 16.1/net night. Crappie reached harvestable size by age 2.

Management Strategies

• Based on current information, existing regulations should be maintained on Lewisville Reservoir. Palmetto bass will be requested for stocking annually at a rate of 10/acre as long as forage is not limited.
• Lewisville Reservoir is heavily utilized for recreational activities. The negative effect of these activities on angling needs to be investigated to determine future management activities.
• Lewisville Reservoir continues to support an abundant catfish population. Research on the fishery needs to be conducted to develop management activities which can improve the catfish population.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-30-R-29 Statewide Freshwater Fisheries Monitoring and Management Program