Model-based localization of deep-diving cetaceans using towed line array acoustic data

Authors

Yvonne M. Barkley, University of Hawai‘i at MānoaFollow
Eva-Marie Nosal, University of Hawaii at Mānoa
Eerin M. Oleson, National Oceanic and Atmospheric Administration, Honolulu

ORCID IDs

Y.M. Barkley 0000-0003-4251-474X.

Date of this Version

7-2021

Citation

J. Acoust. Soc. Am. 150 (2), August 2021

doi:10.1121/10.0005847

Comments

U.S. government work

Abstract

Passive acoustic monitoring using a towed line array of hydrophones is a standard method for localizing cetaceans during line-transect cetacean abundance surveys. Perpendicular distances estimated between localized whales and the trackline are essential for abundance estimation using acoustic data. Uncertainties in the acoustic data from hydrophone movement, sound propagation effects, errors in the time of arrival differences, and whale depth are not accounted for by most two-dimensional localization methods. Consequently, location and distance estimates for deep-diving cetaceans may be biased, creating uncertainty in abundance estimates. Here, a model-based localization approach is applied to towed line array acoustic data that incorporates sound propagation effects, accounts for sources of error, and localizes in three dimensions. The whale’s true distance, ship trajectory, and whale movement greatly affected localization results in simulations. The localization method was applied to real acoustic data from two separate sperm whales, resulting in three-dimensional distance and depth estimates with position bounds for each whale. By incorporating sources of error, this three-dimensional model-based approach provides a method to address and integrate the inherent uncertainties in towed array acoustic data for more robust localization.