Assessment of hypoxia avoidance behaviours in a eurythermal fish at two temperatures using a modified shuttlebox system

Behavioural avoidance responses of red drum (Sciaenops ocellatus) to aquatic hypoxia were investigated at 22 and 30 degrees C using a modified shuttlebox system. Fish movement between a control side maintained at normoxia and a hypoxic side with stepwise decreasing water oxygen tension was analysed for entries into the hypoxic side, residence time per entry into the hypoxic side and total time in the hypoxic side. Acclimation to 30 degrees C increased the oxygen threshold for the onset of hypoxia avoidance behaviours for entries and total time, while residence time per entry was unchanged.

Automated summary

The study showed that at 30°C, red drum exhibit avoidance behaviors towards hypoxia, with the oxygen threshold affecting the frequency and total time of entries into the hypoxic side. However, the residence time per entry remains unchanged.