Casa Blanca Reservoir - 2010 Survey Report

Prepared by John Dennis and Randy Myers
Inland Fisheries Division
District 1-D, San Antonio, Texas

This is the authors' summary from a 21-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations in Casa Blanca Reservoir were surveyed in 2004, 2006, and 2010 using electrofishing and in 2005, 2007, and 2011 using gill nets. This report summarizes survey results and contains a management plan for the reservoir based on those findings.

Reservoir Description

Casa Blanca is a 1,055 acre reservoir located near Laredo, Texas, in the Rio Grande River watershed. In 1990, the county park located on the lower end of the reservoir was acquired by Texas Parks and Wildlife and opened in March of 1991 as Lake Casa Blanca International State park. Major uses include recreation and irrigation for a golf course. The reservoir has a history of substantial water level fluctuation. Angler and boat access is adequate. A little less than half of the shoreline is rocky or gravelly, and aquatic plants and flooded terrestrial vegetation typically occupy about 25% of the reservoir. Considerable shoreline access, including a fishing pier, exists for bank angling.

Management History

Important sport fishes include largemouth bass, catfishes, and palmetto bass. Harvest of all sport fish species except largemouth bass has been regulated according to statewide size and daily bag limits. Largemouth bass harvest is currently regulated with an 18-inch minimum size limit (implemented in 1994). Palmetto bass have been stocked regularly with stockings occurring in five years since 2004. Florida largemouth bass fingerlings were last stocked in 2004 and ShareLunker fingerlings were stocked in 2006, 2008, and 2010.

Fish Community

• Prey species: Gizzard and threadfin shad, bluegill and other sunfishes constitute the reservoir’s forage base. Prey species relative abundance and size structure provides an adequate forage base for existing predators.
• Catfishes: Blue and channel catfishes occur in the reservoir. During the study period relative abundance of blue catfish declined, but channel catfish numbers increased. Population size structure declined for blue catfish and remained poor for channel catfish.
• Palmetto bass: Relative abundance of palmetto bass increased over the study period, but population size structure declined.
• Largemouth bass: Since 2004, relative abundance has remained similar and the population has continued to be primarily composed of <14 inch fish. Six largemouth bass from the reservoir have been submitted to the ShareLunker program since 2004.

Management Strategies

Continue to stock palmetto bass annually and evaluate the 18-inch minimum length limit on largemouth bass.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-1 Statewide Freshwater Fisheries Monitoring and Management Program