Stream ambient noise, spectrum and propagation of sounds in the goby Padogobius martensii: Sound pressure and particle velocity

Abstract

The most sensitive hearing and peak frequencies of courtship calls of the stream goby, Padogobius martensii, fall within a quiet window at around 100Hz in the ambient noise spectrum. Acoustic pressure was previously measured although Padogobius likely responds to particle motion. In this study a combination pressure (p) and particle velocity (u) detector was utilized to describe ambient noise of the habitat, the characteristics of the goby’s sounds and their attenuation with distance. The ambient noise (AN) spectrum is generally similar for p and u (including the quiet window at noisy locations), although the energy distribution of uspectrum is shifted up by 50–100Hz. The energy distribution of the goby’s sounds is similar for p and uspectra of the Tonal sound, whereas the pulse-train sound exhibits larger p–u differences. Transmission loss was high for sound p and u: energy decays 6–10dB∕10cm, and sound p∕u ratio does not change with distance from the source in the nearfield. The measurement of particle velocity of stream AN and P. martensiisounds indicates that this species is well adapted to communicate acoustically in a complex noisy shallow-water environment