Study On Auditory Sensitivity In Carassius Auratus Linnaeus

In order to achieve effective action of using sound to control fish stocks.Fishermen have been using sound in water since a long time ago,which can be used to attract or drive fish.Gradually,this approach has become an important strategy for fisheries resource management.Controlling a school of fish by sound requires a thorough understanding of the auditory characteristics of the species to be studied.The auditory characteristics of fish include five indicators: the threshold of hearing,the shielding effect of environmental noise on fish hearing,the ability of audio frequency discrimination,the ability of sound source location,the memory of learning sound.At present,fish population is not only threatened by habitat degradation,chemical pollution,fishery development and so on which are hard to avoid,but also threatened by various kinds of noise.The influence of noise on fish is paid more and more attention,but the accurate experimental data are very scarce.So few people really understand the effect of noise on fish.In this paper,the auditory characteristics of Carassius auratus Linnaeus,one of the main freshwater economic fishes in China,are studied.The research includes three parts: first,the auditory threshold of Carassius auratus Linnaeus was measured by electrocardiogram(ECG)method;second,the auditory threshold of Carassius auratus Linnaeus was determined by auditory brainstem response(ABR)method;thirdly,the listening images of the two methods are drawn,and the data and methods are compared and analyzed.The aim is to understand the auditory characteristics of Carassius auratus Linnaeus and to provide reference and data support for the development of fresh water acoustical domesticated pasture.Forty Carassius auratus Linnaeus samples were collected from Dalian fresh water fish farm in November 2017.Each of the two methods selected 20 test fish with better vitality were used to study by ECG(electrocardiogram)method and ABR(auditory brainstem response)method respectively.In the course of ECG test,the test fish were domesticated by the combination of sound and electricity.The auditory threshold of Carassius auratus gibelio is measured by sinusoidal continuant at the frequency of 100,200,300,400,500,600,700,800,900,1000,1500,2000 Hz.The results showed when the frequency range was 100~200 Hz,the auditory threshold of Carassius auratus Linnaeus was 98 dB~115 dB,when the frequency range was300~800 Hz,the auditory threshold presented a fluctuating downward trend and gradually decreased with the increase of the sound frequency of stimulation.The minimum threshold is 71±0.51 dB,and the most sensitive frequency is 800 Hz,and the auditory threshold corresponding to this frequency is 70±0.55 dB,then,in the frequency range above 800 Hz,the auditory threshold of Carassius auratus Linnaeus increased with the increase of frequency.In the course of ABR test,the auditory threshold of Carassius auratus Linnaeus was measured with pulse intermittent when the frequency was 100,200,300,500,800,1 1000,1500,2000 Hz by using the SigGenRZ software to make sound respectively,the results showed that the auditory threshold of the ABR method was basically similar to that of the ECG method,andthe most sensitive frequency was 800 Hz,with auditory threshold 75 ±0.55 dB.The results show that the auditory threshold measured by ECG method was slightly lower than that by ABR method,but there was no statistical difference between them(P > 0.05).ECG method is commonly used to determine the auditory threshold of fish,and ABR method is adopted in recent years.Both methods have their own characteristics,but ABR method has certain advantages in terms of signal acquisition and experimental operation.In terms of signal collection,ECG method requires surgical implantation of electrodes accurately into the outer membrane of the thoracic cavity of fish,while ABR method is to insert electrodes into the auditory nerve through the middle of the skull of fish.For Carassius auratus Linnaeus,ABR method is relatively simple to collect signals.In terms of experimental operation,ECG method needs to domesticate the test fish with electric shock,so that it can generate memory for stimulating sound.Electric shock may cause damage to the fish,thus affecting the accuracy of measurement results.The ABR method does not require any form of domestication,but can directly determine the fish's response to the stimulation sound through the electroencephalogram signal.