Use of acoustic stimulus to recognize abnormal zebrafish behavior in water quality warning systems

Fish behavioral responses have impeded the development of water quality warning technology due to high false alarm rates. The causes of abnormal behavior in fish such as zebrafish (Danio rerio), are often unknown. In this study, acoustic stimuli were tested in recognizing abnormal zebrafish behavior under cadmium exposure. Acoustic startle response sensitivity curves were obtained and analyzed to determine the loudness and frequencies at which the zebrafish responded to the stimuli. The standard stimulus duration was 30 s, and the interval between two stimulations was 20 min. It was found that Cd exposure can weaken zebrafish acoustic startle responses, particularly at 100 Hz and 97 dB, and was significantly correlated with the reduction of the response. After 30 min, the average rate of swimming activity decreased to 24% in 0.25 TU and to 17.6% in 2 TU exposure. This indicates that the acoustic stimulation elicits a response that could help determine a false alarm. Based on this data, we designed a model for testing the abnormal behavior. This study can offer insights for improving the accuracy and stability of water quality warning systems, and is beneficial to the development and application of early-warning systems with biological monitoring of water quality.