Marine mammal tracks from two-hydrophone acoustic recordings made with a glider

A multinational oceanographic and acoustic sea experiment was carried out in the summer of 2014 off the western coast of the island of Sardinia, Mediterranean Sea. During this experiment, an underwater glider fitted with two hydrophones was evaluated as a potential tool for marine mammal population...

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Bibliographic Details
Published in:Ocean Science
Main Authors: E. T. Küsel, T. Munoz, M. Siderius, D. K. Mellinger, S. Heimlich
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2017
Subjects:
G
Online Access:https://doi.org/10.5194/os-13-273-2017
https://doaj.org/article/83c5b87e85924c89b3e62b82cc719b11
Description
Summary:A multinational oceanographic and acoustic sea experiment was carried out in the summer of 2014 off the western coast of the island of Sardinia, Mediterranean Sea. During this experiment, an underwater glider fitted with two hydrophones was evaluated as a potential tool for marine mammal population density estimation studies. An acoustic recording system was also tested, comprising an inexpensive, off-the-shelf digital recorder installed inside the glider. Detection and classification of sounds produced by whales and dolphins, and sometimes tracking and localization, are inherent components of population density estimation from passive acoustics recordings. In this work we discuss the equipment used as well as analysis of the data obtained, including detection and estimation of bearing angles. A human analyst identified the presence of sperm whale ( Physeter macrocephalus ) regular clicks as well as dolphin clicks and whistles. Cross-correlating clicks recorded on both data channels allowed for the estimation of the direction (bearing) of clicks, and realization of animal tracks. Insights from this bearing tracking analysis can aid in population density estimation studies by providing further information (bearings), which can improve estimates.