Cooling Largemouth Bass during simulated live-well holding increases physiological change and prolongs recovery
Joelle L Busby, Shasta R Kamara, Cory D SuskiAbstract
Objective
This study aimed to quantify the physiological and behavioral responses of Largemouth Bass Micropterus nigricans to reductions in temperature during simulated live-well holding following exercise.
Methods
We first acclimated Largemouth Bass to three temperatures (15°C, oscillating between 10°C and 20°C, and 25°C) that represent seasonal conditions in the Midwestern United States and then subjected them to exhaustive exercise and brief air exposure (angling simulation). Following this angling simulation, one group of fish was placed in a dynamic shuttle box system to identify the temperature they preferred while recovering from exercise. A second group of fish was placed into intermittent flow respirometry to quantify the metabolic consequences of an acute cooling event during recovery after exercise and then experienced an increase in temperature that simulated release at the conclusion of a tournament into a warmer water body.
Results
After a simulated angling event, Largemouth Bass preferred to recover at temperatures above their acclimation temperature. In addition, Largemouth Bass that experienced a reduction in water temperature after exercise had prolonged recovery times and a reduced aerobic scope compared with fish that recovered at acclimation temperature. Largemouth Bass that were cooled during recovery and then warmed, simulating a return to an epilimnion after being in a cool live well, experienced a metabolic shift.
Conclusions
Largemouth Bass prefer to recover in water slightly warmer (2–4°C) than their acclimation temperature, likely to facilitate recovery from physiological alterations after exercise. Cooling of live wells in angling tournaments delays the recovery of fish, and returning cool fish to a warmer ambient water body results in a thermal challenge that prolongs recovery time. Anglers should refrain from cooling their live wells and should focus on maintaining live-well temperatures near that of the epilimnion where Largemouth Bass are captured.