The electrophysiological response of fish to hypoxia

Electrophysiological signals, associated with the respiration activity, were recorded from tilapia hybrid (Oreochromis auratus ×Oreochromis niloticus) held individually in electrode chambers. The signals were monitored and processed in real time to yield a set of indices characterizing the energy and frequency of the signal. The fish were exposed to hypoxia and responded by increasing energy parameters, while variations in frequency parameters did not show a clear trend. It seems that tilapia compensates the shortage in oxygen by increasing the tidal volume without varying the ventilation frequency. The technique developed has potential for use as a sensitive monitoring tool for various Stressors, which could assist fish farming management.