Quantification of beaked whale echolocation click parameters to inform passive acoustic monitoring and facilitate sonar mitigation
Abstract
Repeated incidents of mass strandings of beaked whales concurrent with the use of mid-frequency navy sonar have prompted the pressing need to minimize beaked whale sonar exposure. Specifically, we need to know the distribution and abundance of beaked whales in marine areas slated for sonar exposure, and passive acoustic monitoring (PAM) is, due to the deep-diving behavior of beaked whales, effectively the only useful tool for doing so. Here I propose to measure critically missing information about beaked whale echolocation clicks that is required for PAM surveys to estimate the density and abundance of beaked whales in naval ranges and planned operational training areas. I will do that by developing and deploying a 200 m long, autonomous deep-water vertical hydrophone array with 11 SoundTraps (https://www.oceaninstruments.co.nz/) at 800 meters depth. With this deep water array, the source levels and beam patterns of clicks from Sowerby#s Blainville#s and Cuvier#s beaked whales can be quantified to estimate detection ranges in different ambient noise levels to inform glider efforts and static PAM recorder spacings. Additionally, the array allows for parameterization of the numerous beaked whale clicks recorded off the main beam axis, enabling us to speak to what clicks from the same species look like in varying degrees off-axis. These on- and off-axis parameters will greatly benefit advances in automated classification methods used to identify beaked whale echolocation clicks to species level and hence greatly enhance effective g0 by allowing for the inclusion of many more clicks in analysis of PAM data. These data will hence critically aid and inform effective PAM efforts in naval ranges and planned operational training areas.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Nov 09, 2024
- Source ID
- N000142412452
Entities
People
- Peter Madsen
Organizations
- Aarhus University
- Office of Naval Research
- United States Navy