Using CASS to Estimate Received Levels of Conspecific Beaked Whales
Abstract
Mesoplodon densirostris (Md) are deep-diving marine mammals that use echolocation to forage for prey. Recently, bottom-mounted hydrophones have been used to apply passive acoustic-tracking techniques, allowing a unique view of the group-foraging behaviors of Md. Preliminary analysis of tracks produced for individuals of multiple animal foraging groups revealed animals dive together, separate at depth, and reunite before ascending to the ocean surface. To better understand this observed behavior we utilize the Comprehensive Acoustic System Simulation with Gaussian Ray Bundle eigenray propagation model (CASS/GRAB) to model the known properties of Md echolocation clicks and estimate the received levels that individuals are exposed to from other group members (conspecifics). We hypothesize Md are separating to reduce acoustic masking of echoes. This is expected to be shown in two ways: (1) separation during the dive decreases received levels from conspecifics, and (2) echo levels (EL) from prey should be louder than the noise produced by conspecifics.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2020
- Accession Number
- AD1126872
Entities
People
- Karin Dolan
Organizations
- Naval Postgraduate School