Lake Fork: Anatomy of a Trophy Fishery
January 29, 2018
It started as another water-supply reservoir for Dallas' mushrooming population that would also provide a 28,000-acre fishery for bass-happy Texans. But Bob Kemp, the Texas Parks and Wildlife Department (TPWD) fish chief at the time, saw more, much more. He had a vision of making the Lone Star State the trophy bass capital of North America.
Seeing the success of Florida bass in California, Kemp imported them. (Note: biologists now recognize what was formerly the Florida subspecies of largemouth bass as a separate species officially named Florida bass. The fish formerly recognized as the northern subspecies is now named largemouth bass.) After several years of study, Kemp had Florida bass stocked into farm ponds dotting the landscape of what was soon to be Lake Fork.
Since shortly after it opened in 1980, Lake Fork has been the icon for trophy bass fishing and management. It demonstrated the benefits of Florida bass stocking outside Florida and became a model for trophy bass management via novel harvest regulations, a progression of protected-slot length limits. Slot limits are used to protect mid-size bass from harvest while reducing the number of smaller bass, thereby reducing competition for food and stimulating growth of protected-size fish to trophy size. When applied wisely, they not only keep numbers of quality-size bass in the fishery, but also to shift the size structure to larger fish.
While the vision of Bob Kemp and his dedicated staff of fishery and hatchery biologists are responsible for creating and maintaining Lake Fork, the overnight celebrity status of Lake Fork is largely due to a bass named Ethel caught in 1986. Ethel was no ordinary bass. She was a 17.67-pound state record kept alive by her captor, Guide Mark Stevenson. And she was the fish that spawned the Operation Share a Lone Star Lunker program, subsequently renamed the ShareLunker Program, that has collected huge Texas bass for selective breeding.
Ethel was moved from the TPWD Athens hatchery to a far more stately and visible home — the huge center-stage aquarium at the Springfield, Missouri, Bass Pro ShopsÂ store. If people were unaware of Lake Fork before Ethel's debut at Bass Pro, they knew about it after she arrived. By the late 1980s, fishery managers throughout the southern bass belt were implementing and evaluating slot limits and planning introductions of Florida bass.
Lake Fork wasn't the first reservoir in Texas stocked with Florida bass. The state record was reset almost annually after Florida bass were stocked into select reservoirs beginning in the 1970s. But Lake Fork made the trophy-bass benefits of Florida bass stocking and slot limits visible to anglers and fishery managers, further highlighted by another record from Fork in 1992, 18.18 pounds.
But from my perspective as a fishery scientist, the most notable accomplishment is the sustained production of giant bass. For 30 years, Lake Fork has continued to produce trophy bass, and this single lake is the source of almost half of the 565 13-pound and larger bass entered into the ShareLunker Program. It's produced many more 13-plus pound bass than that total because ShareLunker entries are accepted only from October to April and some eligible fish aren't entered. Lake Fork has also produced 13 of the top 20 heaviest bass recorded in Texas.
What makes Lake Fork unique? It's built on fertile ground and has a good forage base of gizzard and threadfin shad as well as crappies, bluegill, yellow bass, and white bass that are sized for big bass. The bass population has good genetics. While these desirable characteristics are shared by other great bass fisheries, no lake has matched Fork's sustained output of trophy bass.
Seeking an explanation for what makes Fork so wonderfully unique led me to Kevin Storey, TPWD's management biologist in charge of the resevoir for the past 17 years. "No doubt Florida bass stocking has a lot to do with the trophy bass production in Fork," Storey says. "The Florida bass allele frequency (a measure of the proportion of genes from Florida bass) is a relatively high 52 percent, indicating the growth potential is well established in the population. Annual stockings of Florida bass — a total of 13.7 million fingerlings from 1995 to 2016, an average of 621,000 per year — have helped ensure the continued strong influence of Florida bass genetics. And an average of 10,500 ShareLunker progeny have been stocked in most years since 2006.
"The high angler release rate likely also contributes to the large numbers of giants," he says. "Our creel surveys indicate 93 to 99 percent of legal-sized bass caught by non-tournament anglers are released. The size regulation, a 16- to 24-inch protected slot limit that allows harvest of five fish per day, with only one 24 inches or larger, helps, too.
We've used several different slot limits throughout Fork's history, and changed the daily bag limit from five to three fish, then back to five. The present regulation, which appears to be working well, protects quality-size bass while encouraging the harvest of smaller bass needed to keep the 16-to-24 inchers growing fast."
But here I had to interrupt Storey. Bass managers throughout the southeastern U.S. lament that slot limits are no longer working to restructure bass populations because anglers won't harvest sub-slot fish. The high release rate suggests the same malady should afflict Fork. Bass fishing effort at Fork is a high 22.7 angler hours per acre per year and catch rate is relatively high at 0.3 to 0.4 fish per hour. Although mortality of caught-and-released bass is assumed to be low (less than 10 percent), the combination of high effort and catch rate may expose enough bass to this low fishing mortality that enough fish are removed from the population to keep remaining ones growing fast.
"The effectiveness of the high slot limit in protecting quality-size fish is due to not granting exemptions to tournaments," Storey reports. "Tournaments are big business here and benefit local economies. We try to work with tournament organizations and bass clubs where we can. The no-exemption decision was based on a scientific study of mortality of tournament-caught bass on Lake Fork that found mortality rates would jeopardize trophy-bass production. Tournament organizations have the option to hold catch-measure-release events, but few do."
Habitat is always fundamental to productive bass fisheries. When Fork filled, a lot of timber was left in the lake. Deep-water wood remains, but most of the shallow wood and shoreline brush is gone. Submerged vegetation fluctuates but seldom exceeds 20 percent areal coverage, and recent coverage has been significantly lower. Like other Texas reservoirs, lake levels fluctuate with multi-year wet and drought cycles. But water-level fluctuations in Fork historically have been moderate compared to many other reservoirs and this has limited the spread of terrestrial and wetland plants onto exposed shorelines. Recent drought, though, has encouraged establishment of these plants that become prime fish (and fishing) habitat when lake levels return to normal. Nevertheless, habitat doesn't seem so special at Lake Fork.
Review of Storey's annual reports and a lengthy Q&A session with him failed to reveal biological reasons why Lake Fork is the unique trophy bass fishery that it has been and continues to be. Storey, too, has not identified the secret ingredients but, whenÂ pressed for an answer he humbly offers, "The right things happened at the right time."
Lake Fork, like all reservoirs, is aging. While not a factor in what Lake Fork has been, habitat enhancement efforts, such as placing fish attractors in deeper water and establishing buttonbush in the water fluctuation zone, will benefit the lake in the future. Important to present and future habitat enhancement efforts are the cooperative and productive relationships that TPWD maintains with the Lake Fork Sportsman Association (a group of fishing guides, riparian landowners, and local and fishing-relatedÂ businesses), and the reservoir controlling authority (Sabine River Authority). Cooperation occurs when people are willing to work together for a common goal. In the case of Lake Fork, that common goal includes an economic component. The annual total economic impact of Lake Fork's fishery is estimated at more than $38 million.
Lake Fork has made memories for anglers and millions of dollars for local businesses. It's also served as a training ground for upcoming bass pros and as a laboratory for lure designers. One can only guess how long it will continue to produce trophy bass, but it's a sure bet that every possible effort will be made to sustain this unique fishery.
*Dr. Hal Schramm, Counce, Tennessee, is an avid angler, fishery biologist, and freelance writer. He often contributes to In-Fisherman publications.