Sheldon Reservoir - 2012 Survey Report

Prepared by Michael Homer Jr. and Mark Webb
Inland Fisheries Division
District 3-E, Snook, Texas

This is the authors' summary from a 23-page report. For a copy of the complete report, use the download link in the sidebar.

Fish populations in Sheldon Reservoir were surveyed in 2012 by electrofishing and trap netting and in 2013 by using gill netting. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.

Reservoir Description

Sheldon Reservoir is a 1,229-acre reservoir on Culpepper Bayou in Harris County, Texas, lying within Sheldon State Park. The reservoir has a drainage area of 4.0 square miles and a shoreline length of 13.1 miles. The reservoir has a mean depth of 3 feet and a maximum depth of 20 feet.

Management History

Sheldon Reservoir is a very important asset to Texas Parks and Wildlife and to the people of Houston. To make the most of this resource, Inland Fisheries Division has worked closely with Sheldon Reservoir State Park’s and Infrastructure’s staffs to improve the reservoir in conjunction with the development of the Sheldon Environmental Learning Center. Heavy infestations of hydrilla, giant salvinia, and water hyacinth have greatly impeded recreational use at Sheldon Reservoir. Herbicide treatments over several years have been unsuccessful in maintaining control of noxious vegetation. However, herbicide treatments in 2011 and 2012 have improved the situation.

Fish Community

• Prey species: Greater control of hydrilla, giant salvinia, and water hyacinth from herbicide treatments in 2011 and 2012 improved electrofishing efficiency in fall of 2012. Although Gizzard Shad were not collected in 2004 or 2008 electrofishing samples, 779.0/h were collected in 2012. Most were small, which indicated a young and expanding population. The catch rate of Bluegill in 2012 was 87.0/h, much higher than it was in 2008 (8.0/h) or 2004 (42.0/h). Redear Sunfish are also available as prey. The catch rate in 2012 was 225.0/h, again much higher than it was in 2008 (22.7/h) or 2004 (84.0/h).
• Catfishes: Historically, catfishes have been poorly represented in gill net surveys of the lake. Both Blue Catfish and Channel Catfish were present in Sheldon Reservoir, but catch rates were low. All catfish caught were over 20 inches in length.
• Largemouth bass: Electrofishing catch rate of Largemouth Bass dropped from 249.0/h in 2004 to 21.3/h in 2008 but rebounded to 147.0/h in 2012. Changes in catch rates may be more reflective of increased sampling efficiency by reduced vegetation in the reservoir rather than the actual abundance of the Largemouth Bass population. In 2012, the size distribution of Largemouth Bass was quite good (PSD of 70). The number of stock-sized bass in the survey increased slightly. Relative weight for each inch-class of Largemouth Bass suggested fish were in good condition.
• Crappie: Due to overabundant vegetation, trap net surveys were not conducted for the 2004 and 2008 monitoring years; however, a trap net survey was conducted in the fall of 2012. Black Crappie were more abundant in the fall 2012 trap net survey than White Crappie. Most Crappie were less than harvestable-size and will likely grow to harvestable-size (>10 inches) in the coming years.

Management Strategies

The primary challenge at Sheldon Reservoir is aquatic vegetation management and water level management. An integrated pest management strategy will address the aquatic vegetation problem. Lake Sheldon State Park staff continues to explore ways to supplement water supply to Sheldon Reservoir in low rainfall years. Electrofishing, trap netting, angler access, and gill netting will be conducted every four years. Aquatic vegetation will be surveyed annually.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-221-M-3 Inland Fisheries Division Monitoring and Management Program