OPTOELECTRONIC DEVICE, A USEFUL TOOL TO RECORD SURFACING BEHAVIOR IN AIR-BREATHING FISHES

An optoelectronic digital system was designed to record the frequency of surfacing in Indian catfishes, Clarias batrachus and Heteropneustes fossilis, The system uses a single infrared (IR) beam generated by a transmitter (Tx), The interruption of the beam is recorded by an IR re ceiver (Rx) that relays signals to a 4-digit electronic counter, Thus, the frequency of surfacing over a specified time scale is expressed i n number of interruptions per unit time, The efficiency of the system is tested. This system can be slightly modified to monitor swimming ac tivity, accesses to food, emergence from an artificial burrow, photota ctic behaviour and other behavioural activities of various fish specie s.