Study On Underwater Vocalizations And The Effect Of Underwater Noise On Yellow Drums(Nibea Albiflora)

In recent years,with the increasing of offshore human activities,the man-made noise level is increasing,and its influence on marine fish has attracted more and more attention.Man-made noise has different degrees of influence on fish from behavior to death.The drums are widely distributed along the coast of China,and have characteristics of making sound and relatively high hearing sensitivity.Therefore,it is more vulnerable to man-made noise.The vast majority of drums is delicious and has high economic value.It is the one of most important fishes for traditional fishing and mariculture.Therefore,it is very important to study the sound characteristics of drums and the effect of noise on drums.Yellow drums(Nibea albiflora)are the most common sciaenid fish along the coast of China.In this paper,yellow drums were used as the research object.Firstly,Voluntary vocalizations of the cage-cultured yellow drums in Dongshan Island,Fujian were recorded by using the passive acoustic monitoring technique.Secondly,the effect of fishing boat noise and underwater air pump noise on the yellow drums were evaluated.Finally,the vocalization characteristics of the yellow drums under hand-held disturbance were analyzed.This study supplemented the vocal database of yellow drums and provided a theoretical basis for the protection of its wild resources.The main contents and results of this paper are as follows:1.Recorded the voluntary vocalizations of cage-cultured yellow drums,and analyzed the parameters of the time domain,frequency domain,bandwidth,energy and Q value of the vocalizations,and the relationships between the parameters were also analyzed.Besides,the source levels of the voluntary vocalizations of yellow drums were evaluated.The results showed that there was diel periodicity in the vocalizations of yellow drums.The chorus was taken during the period from 19:00 to 02:00.The vocalizations during this period were mostly multiple-pulses(more than two pulses).Besides this period,the yellow drums had very little vocalizations and were mainly single-pulses.The vocalizations had short pulse duration,low dominate frequency and lower Q value.The mean pulse duration of single-pulses and multiple-pulses were 4.69±0.86 and 5.35±0.95 ms,respectively.The mean dominate frequency of single-pulses and multiple-pulses were 536.79 ± 93.21 and 598.89 ±58.24 Hz,respectively.The mean Q value of single-pulses and multiple-pulses were 1.61±0.63 and 1.67±0.43,respectively.The mean-3 dB bandwidth of single-pulses and multiple-pulses were 368.78±133.65 and 413.40±270.24 Hz,respectively.The mean-10 dB bandwidth of single-pulses and multiple-pulses were 721.3 8±254.71 and 924.99±415.43 Hz,respectively.There was a certain correlation between the parameters of time domain,frequency domain,bandwidth and Q value of the voluntary vocalizations of the yellow drums.The time parameter showed a positive relationship with the dominate frequency,but negative with the-3dB bandwidth.The source level estimation results of yellow drums showed that the average peak and effective sound source level were 155.73±2.00 and 146.6611.70,respectively.The sound source level estimation results showed that the average peak and effective sound source levels were 155.73±2.00 and 146.66±1.70 dB,respectively.2.The effect of small fishing boat noise on yellow drums was evaluated by comparing the 1/3 octave band sound pressure level of vocalizations emitted by yellow drums with the small fishing boat noise,and the influence range was also evaluated.The critical signal-to-noise ratio(ie,the 1/3 octave band sound pressure level difference between the signal and noise when the fish can just detect the signal)was setted as 10 dB,which was the same as the Holt's study in the noise masking effect on fish.The results showed that the noise of small fishing boat may cover the vocalizations of yellow drums with a distance of approximately 12 m.3.Since air pump equipment was commonly used in the laboratory aquaculture environment,the noise generated by air pump was used as the underwater disturbance noise to study its impact on the vocal behavior of the yellow drums.The results showed that in the presence of air pump noise,there were two types of vocalizations with different time domain characteristics:typel and type2,and both of them were mainly single-pulse.Under air pump noise interference,the frequency parameters(average dominant frequency and center frequency),bandwidth parameters(-3 dB bandwidth and-10 dB bandwidth),and Q value of typel were all lager than those under the freedom state.While type2 has a larger-10 dB bandwidth than the freedom state,the rest of the bandwidth parameters,frequency parameters,and Q values were smaller than those under the freedom state.There was a peak at around 5 kHz for the type 1 vocalization signals and air pump noise.The results showed that air pump noise may have an impact on the vocal behavior of yellow drums.4.In order to study the vocalizations of yellow drums under disturbance state,the vocalizations of yellow drums under hand-held disturbance were recorded and analyzed.The vocalizations of the yellow drums under hand-held were mostly multi-pulses.There were mainly three call categories with distinct time domain characteristics:type1,type2 and type3.Compared with the freedom state,the duration of the average interpulse interval under hand-held disturbance was shorter.The dominant frequency,center frequency,-10 dB bandwidth,and Q value of type 1 were lager than those under the freedom state;the dominant frequency,center frequency and bandwidth parameters of type 2 were smaller than the freedom state.While the average dominant frequency,center frequency and Q value of type3 were all smaller than the freedom state,the bandwidth parameters were lager than the freedom state.