Lake Fork - 2003 Survey Report

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Prepared by Kevin W. Storey and Randall A. Myers
Inland Fisheries Division
District 3-B, Tyler, Texas

This is the authors' summary from a 48-page report. For a copy of the complete report, use the download link in the sidebar.

Lake Fork was surveyed from June 2003 to May 2004 using electrofishing, trap netting, gill netting, an access point creel survey, and an aquatic vegetation survey. This report summarizes the results of the surveys and contains a management plan for the reservoir based on those findings.

Reservoir Description

Lake Fork is located in Wood, Hopkins, and Rains counties, Texas on Lake Fork Creek, a tributary of the Sabine River. It was constructed by the Sabine River Authority to provide water for municipal, industrial, and recreational uses. Angler access is good with four public boat ramps and numerous private boat ramps and marinas. Limited bank access is available at public boat ramps, a day-use area operated by the controlling authority, and through a number of marinas. Littoral zone aquatic habitat is diverse with timber, native emergent plants, and native floating plants occurring along 50%, 46%, and 22% of the lake shoreline, respectively (Storey and Myers 2002). Bulkhead, concrete, and rip-rap are present along less than 6% of the shoreline, and boat docks in combination with other habitat types occupy 9% of the shoreline (Storey and Myers 2002). Total coverage of aquatic plants accounted for 10% of the reservoir surface area, with hydrilla (Hydrilla verticillata) being the most abundant plant (6.6%). The distribution and abundance of hydrilla has continued to increase during the last three years providing additional cover beneficial to centrarchids. During the last year, lake elevation declined to its lowest level since February 2000, but at its lowest (January 2004) was only 2.5 feet below conservation pool elevation. By the end of May 2004, the water level returned to conservation pool elevation. Water hyacinth coverage has declined following herbicide treatment in spring/summer 2003, but surveys and treatments will continue on an annual basis.

Fish Community

• Prey species: Lake Fork contains abundant and diverse prey fish populations supporting abundant predators. The size structure of the gizzard shad population has remained similar since 2000. Threadfin shad are also present and serve as important prey due to their small size. Catch rates of bluegill and redear sunfish in 2003 were higher than in 2002, but were similar to other years. Moderate sized individuals (4-5 inches) dominated in both populations. Yellow bass are abundant in Lake Fork and likely provide an important prey item for largemouth bass. Prey fish populations in Lake Fork are adequate judged by the excellent body condition of largemouth bass. Sunfish (redear sunfish, bluegill, and longear sunfish) provide a limited recreational fishery. Angling effort directed at sunfish accounted for less than 0.5% of the total angling effort expended in 2003–2004.
• Channel catfish: Lake Fork provides an excellent quality channel catfish fishery. Catch rate of channel catfish in gill nets in 2004 (12.9 fish/net night) was the highest on record. Relative weights of legal-length catfish (> 12 inches) exceeded 85. In 2003-2004, angling effort directed towards catfish (1.47 hours/acre) accounted for 6.3% of the total angling effort which was higher than in 2002-2003 (1.25 hours/acre). In 2003-2004, angler catch rate (1.44 fish/hour) and harvest rate (0.82 fish/hour) were greater than in the previous three years. Total catch of catfish amounted to 2.87 fish/acre during 2003-2004 and 63% of these fish were harvested (1.82 fish/acre). Compared to previous years, more fish were harvested in 2003-2004, although proportionally fewer individuals over 20 inches were documented caught. Other catfish species, including blue catfish, flathead catfish, and yellow bullhead are present, but they contribute little to the total fishery.
• Temperate basses: There is a limited fishery for yellow bass in Lake Fork accounting for less than 1% of total angling effort. Most of the yellow bass harvested by anglers in 2003-2004 ranged from 7 to 10 inches total length. A small population of white bass also exists in Lake Fork as evidenced by the establishment of a lake record in May 2001 (3.1 lbs) and the first time capture of a single specimen during 2004 gill net surveys. This 17 inch fish was aged and was found to be 3-years old. There are also a number of white bass x yellow bass hybrids caught each year. The current lake record white bass x yellow bass hybrid, weighing 4.01 lbs, was caught in March 2003. Another large hybrid, caught in May 2003, was found to be 5-years old. It is unlikely that the presence of white bass, or their hybrids, is having any kind of negative effect on Lake Fork’s largemouth bass population since their numbers are low and prey fish populations remain abundant.
• Black bass: Electrofishing surveys conducted during the spring and fall show the presence of a stable, high-quality largemouth bass population. Statistical testing of catch rate data (analysis of variance) revealed no significant difference (P <0.05) among years in electrofishing catch rate of largemouth bass during the past four years (Appendix 5). Population size structure also remained stable with PSD ranging from 31-46 during the past five years. Largemouth bass in Lake Fork exhibit rapid growth, low mortality, and above-average condition. They grow to 16 inches during their fourth year. Total annual mortality estimates ranged from a low of 0.20 in 2002 to a high of 0.66 in 1995 (Appendix 11). Since 1999, total annual mortality has remained low and relatively constant (0.20-0.30). Mean relative weight of fish in the slot was above 90 in both spring and fall. Annual stockings of Florida strain largemouth bass (FLMB) have maintained the FLMB allele frequency above 30%. In 2003, FLMB allele frequency of age-0 fish was 41.0%, within the range observed since 1989 (32–58%, Appendix 2). Pure Florida bass accounted for 6% of the age-0 fish sampled in 2003. Approximately 500,000 FLMB fingerlings have been stocked annually since 2000 in Caney Creek, north of Highway 154 at an effective stocking rate of 100/acre. Genotype frequency of the population from the stocked area was compared to that in the rest of the lake. Results in 2003 show no significant difference between the two areas (x2; P = 0.12). It is likely that insufficient time has elapsed since the initial stocking for these differences to become apparent. The reservoir continues to receive high directed angler effort for largemouth bass. In 2003-2004, largemouth bass angling effort accounted for 72% of the total effort. Angling effort in 2003-2004 (16.9 hours/acre) was higher than in 2001-2002 (15.1 hours/acre), but lower than in 2002-2003 (20.5 hours/acre) Angler catch rate during 2003-2004 (0.36 fish/hour) was similar to that in 2002–2003 (0.34/hour) and 2001-2002 (0.39 fish/hour). The estimated number of largemouth bass caught in 2003-2004 (7.40 fish/acre) was lower than in 2002-2003 (8.25 fish/acre), but higher than in 2001-2002 (6.72/acre). In the last three creel years, (2003-2004, 2002-2003 and 2001-2002) the majority of released fish (67%, 55%, and 62%, respectively) were below the protected slot limit (16-24 inches). In 2003-2004, largemouth bass harvest rate remained low (0.01 fish/hr). These estimates include fish actually harvested as well as those temporarily retained by tournament anglers. During the first 12 months of the Lake Fork Trophy Bass Survey (Appendix 10), anglers from 33 states reported catching a total of 1,889 bass over 7 pounds. The top 5 states of reporting-angler origin were Texas (64.3%), Oklahoma (6.3%), Louisiana (5.3%), Missouri (4.6%) and Arkansas (4.2%). As expected, most trophy fish catches occurred during spring. During the first 3 months of the survey (March – May), 67% of the year’s entries were reported. The monthly number of entries was greatest in March (685) accounting for 36% of the total entries for the first year. In December 2003, anglers reported the lowest number of trophy catches (12). By far, the vast majority of entries were 7 pounders (40.1%) and 8 pounders (31.2%). Anglers weighed 78% of their entries, and of these fish, 15.7% were 10 pounds or heavier. These large fish also included 9 ShareLunkers from spring 2003 and 2004. By contrast the trophy bass survey of 1998/1999 recorded 42.6% of 7 pounders, 28.0% of 8 pounders, and 10.9% fish 10 pounds and heavier. Anglers measured 59% of their entries, and 30.4% of these were 24 inches or longer. Fish in the 22 and 23 inch classes were most abundant of the measured entries, representing 29.2% and 27.0% of the total respectively.
• Crappie: Trap nets have historically been ineffective in Lake Fork at collecting enough crappie to assess population trends. Nonetheless, the trap net catch rate in fall 2003 was the highest observed during the review period for white crappie (3.5 fish/net night). The majority of the fish collected (67%) were smaller than the minimum length limit (10 inches) with most being age-0 individuals. White crappie growth rates were good with fish reaching legal size in their third year. Black crappie catch rate in 2003 (0.8 fish/net night) was lower than in 1999 (3.3 fish/net night), but similar to other years. Growth assessments were not made for black crappie due to low sample size. Lake Fork supports a quality crappie fishery that is monitored by an ongoing annual creel survey. Results indicated that crappie were Lake Fork’s second most popular species with annual directed angling effort (4.90 hours/acre) representing 20.9% of the total effort in 2003-2004. Angler catch rate of crappie (black and white combined) has declined slightly over the last four years. The estimated number of crappie caught during this time period has also declined. Angler harvest rate of crappie in 2003-2004 was 0.93 fish/hour and this rate has remained consistent over the last four years (range 0.81 - 1.07 fish/hour). Total crappie harvested has declined from 7.51fish/acre in 2000-2001 to 4.84 fish/acre in 2003-2004. The majority of harvested fish (79%) were black crappie. The most common size class of harvested crappie (black and white combined) was the 10 inch class which accounted for 39% of total harvest. Angler compliance with the minimum length limit, in effect from March through November, was high with illegal harvest accounting for only 1.1% of all crappie harvested. In the winter quarter, when there was no minimum length limit, 41% of harvested crappies were less than 10 inches. A similar proportion was found in 2002-2003 (37.5%) and 2001-2002 (40%). Harvest of fish <10 inches accounted for 19% of crappie harvested in 2003-2004 which was higher than the contribution of this size in the previous year (7.5%). The size distribution of crappie harvested for the last three years was similar, but the contribution of fish harvested during the winter quarter (44%) was approximately twice that observed in the previous two years.

Management Strategies

Largemouth bass are vital to Lake Fork and the local economy (Hunt et al. 1996), so management strategies are geared to maintain and enhance this prestigious fishery. The harvest regulation for largemouth bass changed on September 1, 2000 to the current 16-24 inch slot length limit with a 5-fish daily bag limit of which only one fish can be >24 inches total length. Data from the Lake Fork Trophy Bass Survey will be used to document the catch of trophy bass and fish above the upper end of the slot-length limit. Since 2001, Florida largemouth bass have been stocked annually in a 5,000-acre embayment of Caney Creek, north of the Highway 154 bridge at an effective rate of 100 fish/acre to increase the frequency of FLMB in the largemouth bass population. In fall, 2004, age-1 largemouth bass will be tested to determine if differences exist in the proportion of FLMB and pure Florida bass between the stocked area and the remainder of the lake. Monitoring of water hyacinth distribution and coverage will continue and recommendations will be made for further treatment as needed.

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