Falcon Reservoir - 2005 Survey Report
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Prepared by Randy Myers and John Dennis
Inland Fisheries Division
District 1-D, San Antonio, Texas
This is the authors' summary from a 27-page report. For a copy of the complete report, use the download link in the sidebar.
Fish populations in Falcon Reservoir were surveyed in 2005 using electrofishing and trap nets and in 2006 using gill nets. Creel sampling was used to survey anglers from January 2006 to June 2006. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.
Falcon Reservoir is a 83,654-acre water supply and hydroelectric impoundment located in south Texas on the Rio Grande River bordering Mexico. Water levels began declining in 1992 due to drought, then increased in 2003, reaching to within 11 feet of conservation pool in 2005. Habitat in 2005 was primarily flooded terrestrial vegetation. Commercial gill netting is legal on the Mexican side of the reservoir and conducted illegally on the Texas side.
Important sport fishes historically include largemouth bass, catfishes, crappie, white bass, and striped bass. White bass and crappie currently do not provide fisheries in the reservoir because of low population abundance due to the extended period of low water and commercial gill netting. Stockings of TPWD-reared temperate basses and white crappie have been terminated because of gill netting in the reservoir. Concurrent with the increasing water level, Florida largemouth bass (FLMB) and northern largemouth bass were stocked in 2003 and 2004. Largemouth bass harvest was managed with a 10-inch minimum length limit (MLL) and a 10-fish daily bag limit (DBL) until 1985 when the regulation was changed to a 14-inch MLL and 5-fish DBL. Harvest of all other species has been according to statewide regulations.
- Prey species: Gizzard shad, threadfin shad, and bluegill form the reservoir’s forage base. Other sunfishes and tilapia also exist in the reservoir and contribute to the forage base. Relative abundance of bluegill has increased and relative abundance of gizzard shad has decreased over the last three sample years.
- Catfishes: Since 2002, blue catfish relative abundance remained consistent and population size structure improved. Channel catfish relative abundance increased since 2002. Sixteen percent of the total angling effort was directed at catfishes during the 6-month creel period in 2006 with anglers harvesting 3,035 blue catfish and 8,786 channel catfish.
- Temperate basses: No white bass were collected in 2002, 2004, and 2006. Striped bass stocking has not been conducted since 2002, therefore relative abundance is low. No angler catches of either species were reported during the 6-month creel period in 2006.
- Largemouth bass: Relative abundance of largemouth bass increased since 2002 and size structure of the population improved in 2005 compared to in 2003. Anglers caught, on average, 1.40 fish/h and harvested 15,557 fish during the 6-month creel period.
- White crappie: Relative abundance of white crappie remained very low. One white crappie was collected in 2005, three in 2001 and zero in 1998. No white crappie were reported caught by anglers during the 6-month creel period.
Promote the reservoir and its high quality largemouth bass fishery and work with TPWD law enforcement to better understand the impact of commercial gill netting on the reservoir’s fish community.
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