Impact of Tournaments on the Largemouth Bass Population at Sam Rayburn Reservoir, Texas

Abstract

There have been concerns regarding tournament-related impacts on black bass Micropterus spp. for 40 years, but few studies have quantified those impacts. About 52% of anglers at Sam Rayburn Reservoir (46,356 ha) participate in tournaments, and the annual number of events probably exceeds 300. In 2003, we tagged and released 6,021 largemouth bass M. salmoides to estimate the annual proportion of the population caught and retained by tournament anglers. Tag returns were obtained via creel sampling to avoid nonreporting uncertainty, adjusted for recruitment and tag loss, and expanded to estimate the total annual tagged fish catch and harvest. We conducted simulations to evaluate the impacts of tournament mortality using rates of 10, 30, and 50% and compared those estimates with nontournament harvest and catch-and-release mortality (simulated at 5, 10, and 15%) to assess the specific contributions to annual angling and total mortality. From 3,447 angler interviews, creel clerks identified 40 largemouth bass caught by anglers during the interview day (27 of which were immediately released, 6 harvested by nontournament anglers, and 7 retained by tournament anglers). Expansion of tag returns resulted in 1,620 fish immediately released (27% of tagged population), 372 harvested by nontournament anglers (6% of tagged population), and 274 retained by tournament anglers (5% of tagged population; 242 were released). Tournament and catch-and-release mortality each comprised a total of 1–6% of the population losses across all simulations. Tournament mortality comprised 6–28% of total angling mortality, whereas catch-and-release mortality was 10–31%. Tournament mortality contributed 1–16% of total annual mortality, compared with 2–17% for catch-and-release mortality and 16–38% for nontournament harvest. We conclude that the tournament-related impacts on the largemouth bass population at Sam Rayburn Reservoir were low.