Physiological significance of the weigh-in during live-release angling tournaments for largemouth bass

In the current study, we simulated different components of a live-release angling tournament (angling, live-well confinement, and weigh-in) to determine the relative physiological significance of these tournament components for largemouth bass Micropterus salmoides. Our results indicated that depletions of white muscle energy stores and accumulations of muscle lactate (i.e., a large metabolic disturbance) are the most important consequences of live-release angling tournaments for largemouth bass. This study also showed that there are two distinct components of a live-release tournament that cause a metabolic disturbance in largemouth bass: angling and the weigh-in. While the physiological consequences of angling are already well understood, this is the first study to show that the weigh-in portion of a live-release tournament also causes a large anaerobic disturbance in largemouth bass. In our simulation, the weigh-in resulted in a 75% decrease in white muscle phosphocreatine, a 46% decrease in ATP, and a 62% decrease in glycogen relative to control largemouth bass. The weigh-in simulation also caused the lactate concentration in white muscle to increase by about sevenfold relative to control fish and resulted in significant changes to cardiac function. Based on these results, subsequent experiments were performed to determine the main factor(s) responsible for the metabolic disturbance that results from the weigh-in. These experiments demonstrated that the period of air exposure during the weigh-in was a major cause of this disturbance. We recommend that tournament organizers minimize the air exposure that largemouth bass receive during the weigh-in to improve the physiological condition of released tournament-caught fish.