Lake Murvaul - 2004 Survey Report
Prepared by Michael W. Brice
Inland Fisheries Division
District 3-A, Marshall, Texas
This is the authors' summary from a 28-page report. For a copy of the complete report, use the download link in the sidebar.
Lake Murvaul was surveyed within the period of June 2004 to May 2005 using electrofishing, gill netting, trap netting, a littoral zone habitat survey, an aquatic vegetation survey, and an angler access survey. Additional electrofishing surveys were conducted during fall 2001, 2002, and 2003. Roving creel surveys were also conducted March through May 2002 (9 days) and June 2003 through May 2004 (36 days). This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.
Lake Murvaul is located on Murvaul Creek in the Sabine River Basin. It was constructed by the Panola County Fresh Water Supply District in 1957 for municipal and industrial water supply and public recreation. The reservoir lies within the East Texas Timberlands Land Resource Area. It has a drainage area of approximately 115 square miles. The reservoir covers 3,820 acres and its shoreline length is 29 miles. Water levels are relatively stable; average annual fluctuation is 2 feet. Boating access is available at four parks; three public and one private. Structural habitat is comprised of inundated timber, brush, riprap, boat docks, and bulkhead. Aquatic macrophytes are present in moderate densities throughout the reservoir. Hydrilla, a non-native aquatic plant once covering approximately 27% of the reservoir surface area, was not found during the 2000 vegetation survey. However, only 2 acres of hydrilla was observed during the 2004 vegetation survey. American lotus is the dominant aquatic macrophyte species covering < 1% (93 acres) of the reservoir. Lake Murvaul received national recognition during the 1960s for its trophy native largemouth bass population. Following the introduction of Florida largemouth bass, Lake Murvaul anglers have continued catch large bass. From 1987 to 1997, six largemouth bass >13 lbs. have been entered into the TPWD ShareLunker Program. The current lake record is 14.87 lbs.
- Prey species: Gizzard shad, threadfin shad, sunfish species, and several species of minnows were present, which indicated good prey fish diversity. Electrofishing catch rates for gizzard shad and threadfin shad in 2004 were 197.0 fish/hour and 502.0 fish/hour, respectively. Index of vulnerability (IOV) for gizzard shad in 2004 indicated 54% of the population was available to existing predators. This was similar to 1997 (50%) but lower than 2000 (84%). Based on these data, moderate densities of clupeids were available as prey. Catch rates for combined sunfish species (redbreast sunfish, warmouth, bluegill, longear sunfish, and redear sunfish) in 2004 was 483.0 fish/hour, which was a substantial decrease compared to both 1997 (1,600 fish/hour) and 2000 (1,551 fish/hour). Size distributions of sunfishes indicated many small fish were available as prey for piscivores. Prey availability was adequate for adult largemouth bass as evidenced by mean relative weights in excess of 90 for most inch groups.
- Catfishes: The relative abundance of channel catfish has increased over the last 14 years from 6.6 fish/net night in 1991 to 21.2 fish/net night in 2005. Stock-size (>11 inches) channel catfish have also shown an increase from 8.4 fish/net night in 1997 to 16.0 fish/net night in 2005. Recruitment of channel catfish has been consistent. Ryan and Brice (2001) reported growth of channel catfish as good; fish reach legal-size (12 inches) during their third growing season. Based on these data, high numbers of legal-size channel catfish are available for harvest. In 2003-20004, angling effort directed towards channel catfish (5.8 hours/acre) accounted for 25.1% of the total angling effort. Anglers targeting channel catfish caught and harvested 3.7 and 2.7 fish/hour, respectively. Only 1.0 flathead catfish/net night was collected during 2005 gill netting. Although present in low densities, flathead catfish contribute to the fishery at Lake Murvaul.
- Sunfishes: Electrofishing surveys indicate sunfishes (redbreast sunfish, bluegill, and redear sunfish) were available for angler harvest. According to Ryan and Brice (2001), redear sunfish and redbreast sunfish attain 6 inches during their third growing season and bluegill reach 6 inches during their fourth growing season. In 2003-20004, angling effort directed towards sunfish species (0.87 hours/acre) accounted for 3.8% of the total angling effort. Anglers targeting sunfish caught and harvested 5.3 and 3.0 fish/hour, respectively.
- Black basses: Prior to 1994, the largemouth bass population at Lake Murvaul could be characterized as low/moderate density with excellent growth. Following the unwarranted introduction and expansion of hydrilla, the population density of largemouth bass increased between 1991 and 1997. Electrofishing catch rates of largemouth bass reached its highest level in 1994 (237.3 fish/hour). However, the majority of these fish were sub stock-size (<8 inches). Therefore, a special 14-21 inch slot length limit was imposed in September 1999 with the objective of increasing the abundance of largemouth bass >14 inches, enhancing fishing quality, and possibly enhancing trophy fishing benefits. Following the decline of hydrilla in 1999-2000, electrofishing catch rates of largemouth bass reached a low of 50.0 fish/hour in 2002. However, recent electrofishing catch rates have increased to 77.0 fish/hour in 2003 and 92.0 fish/hour in 2004. Much of this increase can be attributed to reproductive success and subsequent recruitment of sub-stock fish, but the catch rate of slot-size bass (14-21 inches) has also increased from 16.0 fish/hour in 2001 to 31.0 fish/hour in 2003. Largemouth bass reach 14.0 inches during their second or third growing season indicating average growth compared to other district water bodies. Electrophoretic analysis of largemouth bass collected in 2004 indicated 39.0% Florida alleles, but only 6% of the sample was pure Florida largemouth bass. In 2003-2004, angler effort directed towards largemouth bass (6.3 hours/acre) accounted for 27.4% of the total angling effort. Anglers targeting largemouth bass caught and harvested 0.37 and 0.08 fish/hour, respectively.
- Crappie: White and black crappie are present at Lake Murvaul and provide a popular fishery. In 2003-2004, angler effort towards crappie species (2.18 hours/acre) accounted for 18.7% of the total angling effort. Anglers targeting crappie species caught 2.20 fish/hour and harvested 1.02 fish/hour. The estimated 506,138 crappies harvested by anglers had an RSE of 95, which indicated that the estimate was not very reliable. Catch rates for white and black crappie in trap net collections in 2004 were 5.0 and 3.6 fish/net night, respectively. These catch rates are very similar to the past three surveys conducted over a 10-year period. The catch rate of legal-size (> 10 inches) individuals was 5.0 fish/net night and 2.0 fish/net night for white crappie and black crappie, respectively indicating good numbers of fish are available for harvest. Based on growth estimates, white crappie and black crappie reach legal size during their second and third growing season, respectively.
Based on these findings, the reservoir should be managed under current harvest regulations. The special 14-21 inch slot-length limit for largemouth bass is in its sixth year and will be evaluated following fall electrofishing in 2005. Following this evaluation, fall electrofishing will be conducted every other year beginning in 2008. Because of the trophy potential of this reservoir, Florida largemouth bass will be requested to be stocked in 2006 and 2007 to increase the percentage of pure Florida largemouth bass in the population.
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