Lake Balmorhea - 2009 Survey Report
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Prepared by Mandy Scott and Mukhtar Farooqi
Inland Fisheries Division
District 1-C, San Angelo, Texas
This is the authors' summary from a 17-page report. For a copy of the complete report, use the download link in the sidebar.
Fish populations in Balmorhea Reservoir were surveyed in 2009 using electrofishing, and in 2010 using gill nets. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.
Balmorhea Reservoir is a 573-acre impoundment located in the Pecos River Basin approximately 5 miles southwest of Balmorhea. Due to heavy irrigation demand, the reservoir water level usually drops severely each summer, reaching a low point in the fall, and then refills from spring inflows during the winter. Balmorhea Reservoir experienced a mild golden alga (Prymnesium parvum) bloom and subsequent fish kill in winter 2004. A more severe bloom and fish kill occurred in winter 2006, and perennial blooms have occurred since. Habitat was mostly nondescript (natural) shoreline or flooded dead terrestrial vegetation, with a small amount of native emergent vegetation.
Important sport fish have included largemouth bass, redear sunfish, white crappie, and catfish. Fish populations were mostly eradicated in August 1998 in an effort to eliminate the introduced sheepshead minnow and improve the sportfish population that had been overtaken by carp, large gizzard shad, and small sportfish. Texas Parks and Wildlife Department (TPWD) re-stocked the reservoir with channel and blue catfish, northern largemouth bass, sunfish, and white crappie during 1998-2001. A special research project included the introduction of triploid Florida largemouth bass from 1999 through 2003. Genetic analyses demonstrated that some cross-breeding was occurring between northern and Florida largemouth bass, indicating that not all of the stocked Florida largemouth bass were sterile. After the fish kill of 2004, TPWD restocked the reservoir with fingerling blue and channel catfish, bluegill, Florida and northern largemouth bass, and adult white crappie.
- Prey species: Gizzard shad and bluegill have declined to very low numbers due to golden alga blooms. Redear sunfish were not encountered in recent samples.
- Catfishes: Channel catfish were present in extremely low numbers.
- Largemouth bass: Abundance appears to have declined significantly, but the 2009 sample indicated some bass were able to survive over-winter despite toxic golden alga blooms.
- White crappie: This species apparently is no longer present in the reservoir.
- Suspend stocking and other management activities until conditions improve.
- Conduct at least annual water quality tests to detect changes in golden alga presence and toxicity.
- Conduct mandatory monitoring in 2013/2014, and determine whether largemouth bass are reproducing.
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