Brownwood Reservoir - 2004 Survey Report
Prepared by Spencer Dumont and Mukhtar Farooqi
Inland Fisheries Division
District 1-B, Abilene, Texas
This is the authors' summary from a 20-page report. For a copy of the complete report, use the download link in the sidebar.
Brownwood Reservoir was surveyed in fall of 2004 using electrofishing and trap nets and in spring of 2005 using gill nets. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.
Brownwood Reservoir is a 7,300-acre impoundment located on Pecan Bayou in the Colorado River Basin approximately 70 miles southeast of Abilene. It was constructed in 1933 as a municipal water supply and is controlled by the Brown County Water Control and Irrigation District No. 1. Soil types are sandy or clay-loam soil. Watershed land use is primarily agriculture, residential, and ranching. The reservoir was at or near spillway level at time of sampling. Water level has been within two feet of spillway elevation since 2002.
- Prey species: Electrofishing catch rates of bluegill and sub-stock gizzard shad were 342.0/h and 26.0/h, respectively. Index of vulnerability (IOV) for gizzard shad was poor, indicating that only 38% of gizzard shad were available to existing predators; this was lower than IOV estimates in previous years. Total CPUE of gizzard shad was considerably lower in 2004 (99.0) compared to the 2002 (230.2) survey but similar to the 2000 (99.0) survey. Total CPUE of bluegill in 2004 (342.0) was higher than total CPUE from surveys in 2002 (186.5) and 2000 (196.0), and size structure continued to be dominated by small individuals.
- Catfishes: The gill net catch rate of channel catfish was 2.4/NN in 2005. The channel catfish population continued to have low relative abundance with an apparent increase in the number of smaller fish in 2005 compared to the 2001 and 1997 surveys.
- White bass: The gill net catch rate of white bass was 0.8/NN in 2005, indicating that white bass were present in the reservoir, but in low abundance.
- Palmetto bass: The gill net catch rate of palmetto bass was 0.8/NN in 2005, down from 2.2/NN in 2001 and 3.3/NN in 1997. No fish from the 2002 stocking were collected in 2005. Size structure in 2001 and 2005 was similar; fish ranged in length from 18-24 inches in 2001 and from 19-23 inches in 2005.
- Largemouth bass: The electrofishing catch rate of stock length largemouth bass was 106.0/h in 2004, compared to 62.0/h in 2002. Size structure was not adequate as PSD and RSD-P varied from 30 to 36 and 3 to 12, respectively, since 2000. Age structure in 2004 was similar to the district average as nearly 75% of the 8.0-11.9 inch fish were age 1 or age 0 and over 50% of the 12.0 to 14.9 inch fish were age 2 or less. Age structure of largemouth bass in 2004 showed some improvement since 2000. Body condition in 2004 was poor (relative weight under 90) for nearly all size classes of fish and was similar to body condition observed in previous surveys. Florida largemouth bass influence has remained relatively constant as Florida alleles ranged from 34 to 46% and Florida genotype ranged from 3 to 13% since 1997.
- White crappie: The trap net catch rate of white crappie was 10.4/NN in 2004, higher than in 2000 (5.0/NN) and similar to 1997 (14.0/NN). The PSD was 51 and RSD-P was 22, similar to stock indices from the 2000 survey, while PSD continued to be less than the 66 observed in 1997. Mean relative weight was over 90 for all size classes in 2004 and was similar to values observed in 2000 but generally less than those observed in 1997. Growth of white crappie was adequate; mean age of 9.0 to 10.9 in white crappie was 2.3 in 2005, compared to 2.5 in 2000 and 1.7 in 1997.
- Stock blue catfish to improve poor catfish fishery.
- Discontinue stocking of palmetto bass because of minimal directed fishing effort and declining abundance of palmetto bass.
- Evaluate stratified random sampling design for trap net surveys.
- Conduct trap net survey in 2005, electrofishing survey in 2006, and general monitoring with trap nets, gill nets, and electrofishing surveys in 2008-2009.
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