Ecological Systems and Devices Annotation << Back METHOD OF OPERATIONAL PASSIVE ACOUSTIC MONITORING OF GRAY WHALES IN THE AREA OF OFFSHORE OIL AND GAS FACILITIES L.E. Karachun, E.S. Kondrashova, A.E. Malashenko The evaluation of the effectiveness of the method of simultaneous operational observation of several whales (a pack of whales) at any time of the day and in conditions of limited visibility (fog, rain) using several special hydro acoustic stations integrated into a system with the transmission of information to observers via a radio channel through an anchored radio beacon is investigated. The method is based on the direction finding of sound signals produced by gray whales. An adult whale uses sound signals only for communication, perceives and reproduces sounds in the frequency range from 7 to 9000 Hz. The level of sounds produced by the whale is sufficient for bearing by specialized sonar antennas at long distances. Keywords: hydroacoustic complexes; noise direction finding; spectral characteristic; radiation pattern; signalto-noise ratio. DOI: 10.25791/esip.11.2021.1268 Pp. 086-096.