The effects of temperature on food consumption, growth rate, and somatic indices in the winter-dormant cunner (Tautogolabrus adspersus)
University of New Brunswick
As fish are ectotherms, temperature is an important environmental factor, making the cold and poor food availability of winter a critical constraint. Winter dormancy (sheltering, inactive state involving reduced or no feeding) can be a strategy utilized to survive winter. I investigated a winter-dormant fish, the cunner (Tautogolabrus adspersus), to test the hypothesis that fasting is an obligate behavior of dormancy. I predicted that cunner exposed to temperatures below the dormancy threshold (~7.3°C) will have a higher thermal sensitivity to food consumption than those held above the threshold. I recorded the daily food consumption and growth rate in cunner over 28 days at several seasonal temperatures (15°C, 12°C, 9°C, 6°C, and 3°C). Even when food was available below the dormancy threshold, cunner did not feed or fed at an extremely low level, which constrained growth at approximately 9°C. Thus, appetite and growth are greatly, or even completely, suppressed during dormancy.