ABSTRACT

Objective

Live-well confinement can place multiple sublethal stressors on captured fish that can prolong the time for recovery and contribute to the likelihood of tournament-related mortality. The goal of this study was to quantify water temperatures in live-release tournaments across multiple seasons and then use this information to quantify the impacts of thermal conditions on Largemouth Bass Micropterus nigricans during live-well holding.

Methods

To define thermal conditions during live-well holding and the influence of these thermal conditions on Largemouth Bass, a series of complementary field and laboratory studies were conducted. The field study quantified the temperature of live wells in several live-release angling tournaments. The laboratory study used the temperature data from the field to inform holding condition treatments and subsequently quantify the physiological changes in Largemouth Bass induced by thermal conditions in live wells.

Results

Results from the field showed that thermal conditions in live wells were highly variable, both within and across anglers and tournaments. Several trends in thermal patterns were observed. Laboratory simulations of these patterns showed that cyclical cooling of 4–5°C simulating multiple additions of ice during holding resulted in considerable physiological disturbance and impaired recovery for Largemouth Bass. Disturbances also increased in simulations that increased live-well temperature. Reflex impairment indices were not influenced by any treatment.

Conclusions

Thermally dynamic recovery environments induce physiological disturbances and prolong recovery from exercise and should be avoided. Given the intense tournament pressure in this system and throughout North America, our results identify key practices that could mitigate tournament practices that would inhibit Largemouth Bass recovery from tournament activities.

Lay Summary

Tournament-caught Largemouth Bass experience variable live-well temperature regimes; our findings indicate that reducing thermal variation in live wells can result in less stressful holding conditions that may reduce release mortality.

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