Seasonal thermal plasticity of cardiac function in temperate and Arctic fishes with different overwintering strategies
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Date
2024-12
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University of New Brunswick
Abstract
Fishes can experience large thermal variation over rapid and prolonged time scales, which challenges critical physiological functions. I investigated the seasonal thermal plasticity of acute temperature responses of heart rate and cardiac adrenaline regulation in temperate and Arctic fishes with different overwintering strategies. Though their distinct overwintering strategies impose different cardiac demands, the winter-dormant cunner and winter-active brook char showed a relatively similar ability to acclimate heart rate and adrenergic sensitivity to three seasonally relevant temperatures in the laboratory. In contrast, wild winter-active lake trout from the central Canadian Arctic showed largely consistent thermal performance of heart rates between seasons; however, seasonal changes in the cardiac cycle were apparent in winter. Overall, my studies indicate the potential influence of overwintering strategy on the thermal limits of cardiac function and highlights the wide diversity of cardiac thermal plasticity among fishes along with the importance of conducting physiological research in the field.