Preliminary analysis of the Bahaba taipingensis' acoustic spectrum characteristics

We analyzed the acoustic spectrum of Bahaba taipingensis by monitoring its sound with passive acoustic method to provide basic data for the non-destructive investigation method, underwater noise environment analysis and sounding behavior of B. taipingensis. We carried out acoustic monitoring on 96 individuals of B. taipingensis by microMARS acoustic recorder in the indoor aquarrium and the two outdoor pools of Dongguan B. taipingensis Nature Reserve from March to May in 2017 (two periods and each period had 7 days and nights). We had monitored 246 sounds in total, belonging to seven types (drum sound, humming sound, cracking sound, clacking sound, bird sound, cha goo sound and other sounds). No significant difference was observed in the number of sounds between day and night. The drum sound was the main sound of B. taipingensis (175 times). The drum sound was composed of 1−3 pulses, being dominated by a single pulse type of drum (139 times). The drum sound had some sine shaped waveform (energy: 0−1 000 Hz), and its voiceprint was parallel to the timeline. The drum sound's spectral frequency peak ranged from 50 Hz to 140 Hz. The energy distribution of cracking sound was similar to that of drum sound (0−1 000 Hz), while the spectral frequency peak was 180−190 Hz. The energy distribution and frequency of the humming sound, cracking sound, birds sound and cha goo sound were both at low frequency (0−1 000 Hz) and high frequency (3 000−12 500 Hz). The pulse length, width and interval of drum sound were 67−1 333 ms, 35−733 ms and 0−1 130 ms, respectively (the average values were 279 ms, 70 ms and 183 ms, respectively). The length of drum sound and the pulse interval increased with increasing number of pulse of sound signals, while the pulse width decreased.