Georgetown Reservoir - 2005 Survey Report
Prepared by Stephan J. Magnelia and Marcos J. De Jesus
Inland Fisheries Division
District 2-C, San Marcos, Texas
This is the authors' summary from a 41-page report. For a copy of the complete report, use the download link in the sidebar.
Fish populations in Georgetown Reservoir were surveyed in 2005 using electrofishing and in 2006 using gill nets. Anglers were surveyed from March 2003 to February 2004 with a creel, attitude/opinion and expenditure survey. This report summarizes the results of the surveys and contains a fisheries management plan for the reservoir based on those findings.
Georgetown Reservoir is a 1,297 acre impoundment of the North San Gabriel River located in Williamson County, Texas. The dam was constructed in 1980 by the U.S. Army Corps of Engineers (USACOE) for purposes of flood control, municipal water supply and recreation.
Important sport fish included white bass, largemouth bass, smallmouth bass, catfish species and palmetto bass. Palmetto bass were stocked in 2003, 2004 and 2005. Anglers supported further stockings of this species. Annual stockings of smallmouth bass were requested in a 2001 fisheries management plan. This species was not stocked due to inadequate hatchery production. Stockings of blue catfish were made in 2000 and 2001 in an attempt to establish a fishery for this species. A prior stocking in 1989 appeared to be unsuccessful in establishing a population.
Largemouth bass have been managed since 1993 with a 14-to 18-inch slot-length limit. An analysis of that length limit change suggested it had been successful in increasing density and angler catch rate of bass greater than 14 inches in length. Angler harvest of sub-slot bass was not sufficient to improve growth under the slot length limit. Bass anglers surveyed who had been fishing the reservoir prior to implementation of this length limit indicated fishing quality had improved under the slot length limit. White bass were managed until September 2004 under a 12-inch minimum length limit. This regulation was rescinded after an analysis suggested reservoir inflow during spawning periods, not angler harvest, were probably more influential in determining white bass population density. Trap netting for white crappie was not performed due to historically low catch rates and the high cost/benefit ratio associated with collecting these data.
- Prey species: Sunfishes and gizzard shad were the dominant prey species available. Threadfin shad were available in low density.
- Catfishes: Channel catfish were present in low density, but were still the dominant catfish species present. Blue catfish stocked in 2000 and 2001 were collected in the 2006 gill net survey.
- Temperate basses: White bass and palmetto bass were present in the reservoir. White bass were a popular sport fish. Keeper size (> 18 inches) palmetto bass were present.
- Largemouth bass: Largemouth bass were abundant, but the population was dominated by individuals less than 14 inches in length. Growth and body condition were sub-optimal. Anglers seeking largemouth bass and black basses accounted for 44.5% of the directed fishing effort.
- Smallmouth bass: No smallmouth bass were collected in 2005. It appears regular stockings are necessary to sustain a population of this species in Georgetown Reservoir.
The reservoir should continue to be managed with existing harvest regulations. Smallmouth and palmetto bass stockings should continue to be requested. Natural reproduction of blue catfish should be documented with routine gill net surveys.
Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-30-R-31 Statewide Freshwater Fisheries Monitoring and Management Program