Where's Whaledo: a software toolkit for array localization of animal vocalizations

Where’s Whaledo is a software toolkit that uses a combination of automated processes and user interfaces to greatly accelerate the process of reconstructing animal tracks from arrays of passive acoustic recording devices. Passive acoustic localization is a non-invasive yet powerful way to contribute to species conservation. By tracking animals through their acoustic signals, important information on diving patterns, movement behavior, habitat use, and feeding dynamics can be obtained. This method is useful for helping to understand habitat use, observe behavioral responses to noise, and develop potential mitigation strategies. Animal tracking using passive acoustic localization requires an acoustic array to detect signals of interest, associate detections on various receivers, and estimate the most likely source location by using the time difference of arrival (TDOA) of sounds on multiple receivers. Where’s Whaledo combines data from two small-aperture volumetric arrays and a variable number of individual receivers. In a case study conducted in the Tanner Basin off Southern California, we demonstrate the effectiveness of Where’s Whaledo in localizing groups of Ziphius cavirostris. We reconstruct the tracks of six individual animals vocalizing concurrently and identify Ziphius cavirostris tracks despite being obscured by a large pod of vocalizing dolphins.

Methods
This dataset was collected during a four-month deployment about 200 km southwest of Los Angeles, California, in the Tanner Basin, known for its Zc presence. Four High-frequency Acoustic Recording Packages, or HARPs were deployed from March 16th to June 11th, 2018. The north and south HARPs each had a single omnidirectional hydrophone with a sampling rate of 200 kHz moored approximately 10 m above the seafloor. The east and west HARPs each had volumetric arrays of four omnidirectional hydrophones in a tetrahedron configuration with ≈ 1 m spacing between hydrophones. The 4-channel arrays had a sampling rate of 100 kHz and sat ≈ 6 m above the seafloor on a rigid mast. The distance between each HARP was between 470 and 1075 m.