Fish Biology Fish Biology Impact of Tournaments on the Largemouth Bass Population at Sam Rayburn Reservoir
Impact of Tournaments on the Largemouth Bass Population at Sam Rayburn Reservoir
Hopefully, many of you recall catching tagged largemouth bass two years ago at Sam Rayburn. In addition, during October 2003 – October 2004 TPWD creel clerks interviewed a lot of you while fishing. Although we conduct these creel surveys throughout the year as part of our routine fishery monitoring efforts, the frequency of these surveys was increased during this period. These events were part of a research project to determine impacts of tournaments on the largemouth bass population.
Concerns associated with bass tournaments have existed since the inception of tournament fishing over 30 years ago. Issues most commonly discussed are fish relocation and potential concentration of fish at tournament weigh-in sites, and increased fish mortality due to stressors associated with livewell confinement and handling during the weigh-in.
Tournament fishing is popular at Sam Rayburn Reservoir. For example, 52% of Sam Rayburn anglers participate in at least one bass tournament per year, compared to 14% of Texas anglers overall. We also know that there are over 300 bass tournaments per year at Sam Rayburn, comprising 19% of the total annual fishing effort. Therefore, we know that tournaments result in annual largemouth bass deaths, but estimating the specific proportion of the entire bass population affected by tournaments is key to understanding overall impacts. Since management of the largemouth bass fishery at Sam Rayburn is a very high priority of TPWD, we tagged and released a known number of fish to 1) estimate the annual proportion of the largemouth bass population > 14 inches killed by tournament anglers and 2) compare fish deaths from tournaments to angler harvest and catch-and-release mortality associated with fish immediately released.
During a week in October 2003, we organized a work crew of nearly 50 TPWD employees and tagged 6,021 largemouth bass throughout the entire reservoir at 362 different release sites. Fish ranged in size from 1 – 11 pounds. To obtain tagged fish returns from anglers, we conducted 72 creel surveys during the one-year period, obtained 3,447 angler interviews, and observed a total of 40 tagged bass (27 were immediately released, 6 were harvested, and 7 were caught and weighed in by tournament anglers). These observations were expanded by a detailed computer program to reflect all bass angling effort over the one-year period. After crunching the numbers, in one year we estimated 2,266 tagged bass were caught (38% of population), 1,620 fish were immediately released (27% of population), 372 fish were harvested (6% of population), and 274 (5% of population) were taken to weigh-ins by tournament anglers.
To determine how many fish actually died from tournament-related mortality and catch and release mortality, we applied a range of mortality rates obtained from previous studies (10 – 50% for tournament mortality; 5 – 15% for catch and release mortality). We are 95% confident that annual tournament mortality kills 1 – 7% of the largemouth bass population at Sam Rayburn, but our actual estimate is only 2%. Although the proportion of the bass population harvested by anglers was also low (6%), three times more bass end up in the frying pan than die from tournament mortality. In fact, because bass fishing effort is high and catch-and-release fishing is popular (anglers immediately release 42% of catch > 14 inches), we estimated hooking mortality associated with catch-and-release kills the same proportion of the bass population as tournaments (2%). We make this comparison to illustrate the low impact of tournament mortality, not to suggest catch-and-release fishing is negative. Without question, voluntary angler release of bass has helped sustain and enhance the bass fishery at Sam Rayburn.We did conclude that short-term fish concentration associated with release at weigh-in sites is a valid concern. In one year, we estimated 31,050 bass are transported to weigh-in sites, with the majority released at just two places in the lower end of the reservoir. However, we also estimate 31,050 bass represents just 5% of total bass numbers in the reservoir, so this potential concentration affects only a small proportion of the entire population.
We thank the many anglers that voluntary called us with reports of tagged fish and cooperated while we conducted our creel surveys. During the study, we interviewed some anglers over 10 different times. Contact us with questions or concerns about this study by phone (409-384-9572) or email ( This e-mail address is being protected from spambots. You need JavaScript enabled to view it ). Good luck and good fishing!
Todd Driscoll is a district fisheries management biologist for Texas Parks and Wildlife Department where he has worked for 10 years. He received a B.S. in Fisheries Biology from Kansas State University and a M.S. in Fisheries Management from Mississippi State University. His primary responsibilities include fisheries management of Sam Rayburn and Toledo Bend reservoirs in Southeast Texas. Todd is an avid bass angler and participates in approximately 25-30 local and regional bass tournaments per year. He also represents Lowrance Electronics as a Technical Pro Staffer, working tournament support and service at BASS, FLW, and owner’s tournaments across the country.