Acoustic control of feeding in Tilapia culture

Abstract:

The technique of measuring fish appetite is the key to accurate automatic feeding. As light attenuates quickly in the water, visual observation is not an effective method to measure the fish appetite in the turbid water body of fish farms. Recent studies have shown that the feeding activity of fish can be measured directly by monitoring sounds emitted by the fish during a feeding period. In our study, we used an acoustic monitoring platform that was composed of a programmable filter and a standard measuring hydrophone, with bandwidth from 1 Hz to 470 kHz and with free field voltage sensitivity of -217 dB (reference level 1 V/μPa) under 40 kHz. Tilapias in the laboratory pond were fed by hand, while the feeding sound of Tilapia was recorded for the analysis of its feeding activity. The feeding sound with the frequency ranging from 0 to 6 kHz could be distinguished from background noises. The appetite of Tilapias faded after a period of feeding, resulting in the decrease in feeding activity and the subsequent change in the acoustic power. The acoustic power had a significant positive correlation with the feeding activity. Therefore efficient feeding strategies can be established, based on the appetite feedback (generated by the moving average of acoustic power) together with growth models and feeding models.