Studies of the acoustic activity of white whales (in captive conditions and the possibility of their signals using to control behavior of fish in fishing process

Abstract

The purpose of the work: identification of acoustic activity of belugas in conditions of aviary keeping and justification of the possibility of using their signals in fishing.The material of research was digital audio recordings of hydroacoustic signals of belugas collected from 2016 to 2018.Methods used: analysis of hydroacoustic data, visualization of the daily acoustic activity of belugas in different seasons, identification of stereotypes of acoustic behavior and characteristic signals in captive conditions and during fish hunting. Novelty: for the first time a substantiation for the possibility of using signals of one of the species of toothed whales — belugas registered in the captive conditions, to influence on the behavior of hydrobionts and solve practical problems of fishing and fish protection is given.Results: the highest acoustic activity of white whales is observed during the day and noticeably decreases at night with increase and decrease in the morning and evening hours. Maximum acoustic activity precedes the feeding of dolphins.The most common tones are those containing the fundamental frequency and harmonics. Characteristic features of the sounds are high variability of duration from 0.25 to 2.5 s, pronounced frequency components in the 500–2500 Hz spectrum zones, amplitude and frequency modulation, sound pressure levels of the signal up to 500 Pa /1 m.Acoustic activity of belugas during fish hunting and in the period preceding feeding in captive conditions, stereotypical. Typical are low-frequency frequency-modulated calls and whistles in the hearing range of fish, as well as a curtain of air bubbles and body and tail slaps. Possible ways of using beluga whale signals to increase the efficiency of fishing are proposed.Practical significance: the results of the study open up the possibility of using the signals of belugas to remotely control the movement of fish, create artificial concentrations and deterrent of hydrobionts in the intended areas.