Sam Rayburn Reservoir - 2004 Survey Report

For assistance with accessibility on any TPWD documents, please contact accessibility@tpwd.state.tx.us

Prepared by Todd Driscoll
Inland Fisheries Division
District 3-D, Jasper, Texas

This is the authors' summary from a 35-page report. For a copy of the complete report, use the download link in the sidebar.

Sam Rayburn Reservoir was surveyed in 2004-2005 with electrofishing, gill nets, a creel survey, and an aquatic vegetation survey. This report summarizes the results of these surveys and comparisons are made to historical data (1986-2004). Based on this information, a management plan was developed for the reservoir.

Reservoir Description

Sam Rayburn Reservoir is located on the Angelina River in the Neches River basin. The U.S. Army Corps of Engineers (USACE) constructed this reservoir for flood control, generation of hydroelectric power, and for municipal, industrial, agricultural, and recreational uses. At conservation pool, Sam Rayburn Reservoir is 111,422 surface acres, has a shoreline length of 750 miles, and a mean depth of 20 feet. Water level fluctuations average 8 feet annually. Angler and boat access is excellent with 24 boat ramps present. Handicap-accessible facilities are limited to parking spaces at access points. Habitat in the lake consists of aquatic vegetation (primarily American lotus and hydrilla), standing timber, and flooded terrestrial vegetation. Most of the land around the reservoir is used for timber production and agriculture.

Fish Community

• Prey species: Primary prey species include gizzard shad, threadfin shad, bluegill, and redear sunfish. Gizzard shad catch rate in 2004 (136.3/hour) exceeded previous years (2002 – 71.8/hour; 2003 – 103.5/hour) and the historical reservoir average (46.3/hour). The 2004 sample included an increased number of fish available as prey (< 7 inches). Historically, threadfin shad catch rates have been highly variable (mean = 77.0; SD = 139.2) and are probably not reflective of population status. The catch rate in 2004 was 97.5/hour. Bluegill catch rates have increased during the last three survey years (2002 – 238.5/hour; 2003 – 440.8/hour; 2004 – 455.3/hour). Redear sunfish catch rates have ranged from 81.8/hour (2002) to 137.0/hour (2003). Prey species abundance appears to be adequate, as historical growth rates are good and relative weights are within desired ranges. Few anglers target sunfish (< 1% of total fishing effort), but they are frequently harvested by anglers seeking other species.
• Catfishes: Gill net surveys from 2003 – 2005 reflect a decline in blue catfish and channel catfish recruitment rates. Blue catfish catch rates declined from a historical high in 2003 (10.4/net night) to 4.4/net night in 2004 and 5.3/net night in 2005. Most of this decline is attributed to a reduction of fish < 14 inches. Although few blue catfish > 21 inches are collected, anecdotal information indicates passive gear anglers frequently catch fish > 30 pounds. Relative weights indicate fish condition is good (range = 84 – 113). Channel catfish catch rates also declined over the same period (2003 – 8.2/net night; 2004 – 4.5/net night; 2005 – 2.5/net night). Population structure and relative weights have remained relatively similar. Directed rod and reel angler effort, catch, and harvest rates of catfishes were similar in 2002 – 2004. Catfish anglers accounted for 6% of the total fishing effort during all three years. Channel catfish comprised a majority of the harvest in 2003 and 2004. Total estimated harvest of channel catfish increased by 44% in 2004.
• White bass and palmetto bass: Gill net data indicate that the population density of white bass in the reservoir is relatively low, as historical catch rates average 2.6/net night. From 1995 through 2000, palmetto bass fingerlings were stocked annually at low rates (~ 5/acre), but no fish have been stocked since 2000. Gill net catch rates from 2001 – 2003 were relatively low (0.1 – 1.9/net night). Little fishing effort was directed at temperate basses, with most attributed to bank anglers at the reservoir powerhouse.
• Black bass: Electrofishing catch rates of spotted bass have been historically low, averaging 5.2/hour. Catch rates were 2.0, 4.0, and 6.3/hour in 2002, 2003, and 2004, respectively. Few spotted bass > 10 inches were collected. Fall electrofishing catch rates during 2002 – 2004 reflect relatively high and stable largemouth bass recruitment rates (range = 142.3/hour - 170.0/hour). The historical reservoir average is 147.5/hour. Relatively high spring/summer water levels and favorable vegetation coverage during these years likely contributed to high recruitment. Population structure was remarkably similar across years (PSD range = 49 - 55; RSD-14 range = 25 – 27). Relative weights ranged from 89 – 110, indicating largemouth bass were in good condition. Since 2002, total electrofishing effort was increased from two to four hours in an attempt to reduce data variability. However, coefficients of variation from 1999 – 2001 (range = 64 – 101) were similar to 2002 – 2004 (range = 65 – 94). The re-sampling approach developed by Dumont and Schlechte (2004) will be used to determine total effort of future electrofishing surveys. Although the reservoir has been stocked with Florida largemouth bass (FLMB) annually since 1994, overall FLMB influence has remained low and relatively stable. Since 2000, FLMB have been successfully stocked at rates of 100 fish/acre in selected embayments (Caney Creek and Ayish Bayou) to increase stocking influence (i.e., achieve > 20% pure FLMB). Caney Creek received annual FLMB stockings during 2000 – 2002 and electrophoretic analysis in 2002 revealed 32.5% pure FLMB, compared to 5.8% in the reservoir. In 2003 and 2004, Caney Creek maintained levels of pure FLMB without stockings (25.0% and 34.0%, respectively). The Ayish Bayou embayment received stockings in 2003 – 2005 and electrophoretic analysis will begin in Fall 2005. The black bass fishery accounts for the majority of annual fishing effort (66%). Creel surveys indicated that directed effort, catch, and harvest rates were similar in 2002 – 2004. Total harvested numbers of largemouth bass increased by 54% in 2004. Length frequencies of harvested largemouth bass were similar, with the majority of fish ranging from 14 – 18 inches in length. A tournament-monitoring program was implemented in June 2003 to increase information on fish > 14 inches and provide greater insight regarding large (> 20 inches) fish abundance. All monitored tournament variables were relatively similar across 2003 and 2004 survey years, indicating stable population numbers of legal-length fish. Results of Sealy Outdoors McDonald’s Big Bass Splash tournaments reflect an initial decline in large fish catch following the 1998 fish kill attributed to Largemouth Bass Virus (1999–2001). From 2002 – 2005, average fish weights increased to levels observed prior to the fish kill.
• Crappie: Crappie anglers accounted for 20% of the total annual fishing effort. Creel surveys indicate that directed effort, catch, and harvest rates were similar in 2002 – 2004, reflecting stable population abundance and size structure during these years. A majority of the annual harvest is comprised of black crappie, which increased by 91% in 2004.

Management Strategies

• Based on current information, this reservoir should continue to be managed with current regulations. Anderson et al. (2002) found that 47% of Sam Rayburn anglers favor more restrictive largemouth bass length limits. In response to angler opinion, an annual exploitation study was conducted from October 2003 – September 2004 to explore potential pros and cons of alternative length limits. Overall annual largemouth bass exploitation was relatively low (11%) and more restrictive length limits would provide little overall fishery benefit.
• Considering the reservoir’s history of producing trophy largemouth bass (> 10 pounds) and the amount of directed angler effort towards this species, supplemental stocking of FLMB fingerlings should continue until pure FLMB comprise > 20% of the population sample.
• Giant salvinia is present in Toledo Bend Reservoir, making accidental transfer to Sam Rayburn Reservoir a strong possibility. Signs warning anglers of ecological impacts of giant salvinia and high likelihood of transfer have been placed at all main access points on the Texas side of Toledo Bend Reservoir. These signs need to be maintained to prevent introduction into Sam Rayburn Reservoir.

Performance Report as required by Federal Aid in Sport Fish Restoration Act Texas Federal Aid Project F-30-R-30 Statewide Freshwater Fisheries Monitoring and Management Program