Effects of number of largemouth bass per live-well compared to environmental conditions on post release tournament survival

As live release black bass (Micropterus spp.) tournaments increase in popularity, stress associated with live-well confinement may result in increased mortality rates. Variation in number of bass in tournament angler live-wells is common due to a suite of factors (e.g., regulations, number of anglers per boat, angler success), but the effect on delayed tournament mortality relative to other environmental factors is unknown. Largemouth bass Micropterus salmoides were collected and tagged following tournament weigh-ins (n = 80) and monthly electrofishing events (n = 15) in 2018 and 2019 at Brushy Creek Lake, Iowa, USA. A Cormack-Jolly-Seber model in Program MARK was used to evaluate the duration of reduced post-tournament survival (0–7 day) and the effects of number of bass per live-well (1–15 individuals) compared to environmental covariates (air and water temperature) and bass total length on post-tournament survival. Models indicated bass survival was reduced for three days following tournament capture and was negatively related to water temperature, number of bass in live-well, and number of initial tournament mortalities. Largest effects of all covariates on tournament survival occurred at high water temperatures but were reduced at cooler water temperatures. Daily survival probability ranged from 0.9792 (95 % CI: 0.9757, 0.9822) at 5.71 °C to 0.8927 (95 % CI: 0.8720, 0.9103) at 28.79 °C on day of tournament capture. Survival also decreased from 0.9819 (95 % CI: 0.9592, 0.9921) with one bass in the live-well to 0.9632 (95 % CI: 0.4167, 0.9990) with fifteen bass in the live-well. However, the effect number of bass in a live-well has on overall tournament survival is likely minimal due to the infrequency ten or more bass were confined per live-well. Our study provides information on the effect number of bass in a live-well has on post-release tournament survival while providing management insights to improve post-tournament survival for recreational bass fisheries.