Georgetown Reservoir - 2009 Survey Report
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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 30-page report. For a copy of the complete report, use the download link in the sidebar.
Fish populations in Georgetown Reservoir were surveyed in 2009 using electrofishing and in 2010 using gill nets. 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 Corp of Engineers (USACE) for purposes of flood control, municipal water supply and recreation. Georgetown Reservoir is the drinking water supply for the cities of Georgetown and Round Rock, and the Brushy Creek Municipal Utility District.
Important sport fish included white bass, largemouth bass, smallmouth bass, catfish species and palmetto bass. Palmetto bass were stocked annually starting in 2003. An angler attitude and opinion survey conducted from 2003 to 2004 indicated anglers supported further stockings of this species. Annual stockings of smallmouth bass were requested in the 2002 and 2006 fisheries management plans. This species was not regularly stocked due to inadequate hatchery production, but annual stockings were made from 2006 through 2008. 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. 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: Gizzard shad and sunfishes were the dominant prey species available. Threadfin shad were also available as forage.
- 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 2010 gill net survey. Natural reproduction of blue catfish was documented in 2010.
- Temperate basses: White bass and palmetto bass were present in the reservoir although abundance of both species has declined since the last survey.
- Largemouth bass: Largemouth bass abundance declined since the last survey. The population was dominated by individuals less than 14 inches in length. Growth and body condition were sub-optimal. According to the last creel survey conducted on the reservoir (2003-2004) anglers seeking largemouth bass and black basses accounted for 44.5% of the directed fishing effort.
- Smallmouth bass: Only one smallmouth bass was collected in the 2009 electrofishing survey despite annual stocking the three previous years.
The reservoir should continue to be managed with existing harvest regulations. Smallmouth and palmetto bass stockings should continue to be requested. Further evidence of natural reproduction of blue catfish and the status of the palmetto bass population should be documented with additional gill net surveys. Smallmouth bass abundance should be documented with additional spring and fall electrofishing surveys.
Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-30-R-35 Statewide Freshwater Fisheries Monitoring and Management Program