(Colorado City Reservoir - 2004 Survey Report
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Prepared by Mandy K. Scott and Brian E. Van Zee
Inland Fisheries Division
District 1-C,
San Angelo, Texas
This is the authors' summary from a 14-page report. For a copy of the complete report, use the download link in the sidebar.
Colorado City Reservoir was surveyed in 2002 and 2004 using electrofishing and trap nets, and in 2005 using gill nets. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.
Reservoir Description
Colorado City Reservoir is a 1,618-acre reservoir on Morgan Creek west of Colorado City in Mitchell County, Texas. It is a power-plant reservoir with habitat consisting primarily of flooded terrestrial vegetation, native emergent vegetation, boulders, and boat docks. The water level has remained within 15 feet of conservation pool for the last 17 years due to pumping water from Champion Creek and Moss Creek reservoirs to maintain water levels at a sufficient elevation for power generation. The reservoir has been severely impacted by toxic golden alga blooms since 2001 (see Appendix C). Boat and shoreline access are good.
Management History
Important sport fish include largemouth bass, white crappie, and channel catfish. Palmetto (hybrid striped) bass have been stocked since the 1970s, and managed with an 18-inch minimum length limit. Red drum were once an important game species, but the discontinued operation of the power plant on Nasworthy Reservoir beginning in 2003 eliminated this fishery that was dependent on the plant’s heated water effluent.
Fish Community
- Prey species: No bluegills were collected in either the 2002 or 2004 electrofishing surveys. Gizzard shad catch rates (number/hour) declined after the 2001 golden alga bloom from 380/h in 2000 to 100/h in 2002 and 151/h in 2004. These results indicate that recruitment of gizzard shad continues despite the repeated toxic algal blooms.
- Catfishes: No blue catfish or channel catfish have been collected in gill net surveys since 2000.
- White bass: No white bass have been collected in gill net surveys since 2000.
- Largemouth bass: Six individual largemouth bass, ranging from 5 to 7 inches in length, were collected during an electrofishing survey in 2002. No largemouth bass were collected in the 2004 electrofishing survey.
- White crappie: No white crappie have been collected in trap net surveys since 2000.
Management Strategies
Continue monitoring golden alga on a regular basis, and restock the reservoir with prey and sport fish species when water samples indicate low toxicity. The following stockings have been requested for Colorado City in 2005: channel catfish fingerlings (100/acre), bluegill fingerlings (100/acre), and Florida largemouth bass fingerlings (100/acre). The power plant on Colorado City Reservoir is no longer being operated on a continual basis; therefore, the reservoir will no longer support a red drum fishery. We recommend that red drum stockings be discontinued, and that harvest regulations pertaining to red drum be changed to no minimum length limit and no daily bag limit.
Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-30-R-29 Statewide Freshwater Fisheries Monitoring and Management Program