Cisco Reservoir - 2003 Survey Report

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Prepared by Spencer Dumont
Inland Fisheries Division
District 1-B, Abilene, Texas

This is the authors' summary from a 21-page report. For a copy of the complete report, use the download link in the sidebar.

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

Reservoir Description

Cisco is a 1,050-acre reservoir constructed on Sandy Creek approximately 55 miles east of Abilene, Texas. It is located in the Brazos River Basin, and its primary use is for municipal water supply. Secondary use is recreation. Water level was 21 to 22 feet below conservation level during the sampling period. At time of sampling, littoral habitat was primarily rock and mud flats.

Fish Community

• Prey species: Electrofishing catch rates of bluegill and sub-stock gizzard shad were 64.8/h and 18.4/h, respectively. Index of vulnerability (IOV) for gizzard shad was poor, indicating that only 33% of gizzard shad were available to existing predators; this was lower than IOV estimates in previous years. CPUE of gizzard shad was considerably lower than CPUE from 2001 survey. Bluegill CPUE in 2003 was similar to previous surveys, and size structure continued to be dominated by small individuals.
• Catfishes: The gill net catch rate of blue catfish was 0.8/NN, representing the first time blue catfish have been collected in a gill net survey at Cisco Reservoir. The fish were 12-13 inches long and likely derived from the 2001 stocking. The gill net catch rate of channel catfish was 1.0/NN in 2004. The channel catfish population appears to maintain a small population.
• White bass: The gill net catch rate of white bass was 1.8/NN. This is the first documented appearance of white bass in Cisco Reservoir. The fish were 14 to 17 inches long and were 3 to 5 years old.
• Largemouth bass: The electrofishing catch rate of stock length largemouth bass was 63.2/h in 2003, dropping from 87/h in 2001 and 112/h in 1999. Size structure was poor as PSD and RSD-P varied from 16 to 25 and 1 to 4, respectively, since 1999. Growth of largemouth bass was poor in 2003, progressively declining from previous surveys. With average growth, nearly 75% of 8.0- to 11.9-inch fish should be age 1 or less; the 2003 survey indicated that only 39% were age 1 or less. For 12.0- to 14.9-inch largemouth bass, about 50% of these fish should be age 2 or less with average growth; in the 2003 survey, these fish ranged from age 3 to age 7. Body condition was poor (relative weight under 85) for all fish collected.
• White crappie: The trap net catch rate of white crappie was 22.6/NN in 2003. Trap net catch rates of white crappie have steadily increased since 1996. The PSD was 43 and RSD-P was 18, similar to stock indices from the 1999 survey. Mean relative weight was under 90 for all size classes. Growth of white crappie was slow as the mean length at age 4 was 10.7 inches.

Management Strategies

Problems at Cisco Reservoir are primarily fertility based. A large influx of water would greatly improve the fish populations. Encourage anglers, through press releases and individual contacts, to harvest legal white bass.

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