Look Who’s Talking: Identifying the bioacoustic signals of sound-sensitive cetaceans and new applications for the DMON

T. Aran Mooney, Biology, Tom Hurst, Jim Partan, Applied Ocean Physics and Engineering

Abstract

The waters surrounding the State of Hawaii form the habitat for more than 20 species of
federally protected marine mammals including melon-headed whales (Peponocephala electra)
and false killer whales (Pseudorca crassidens). The region is also of high U.S. Navy activity
and substantial federal management because of the Hawaiian Islands Humpback Whale National
Marine Sanctuary and U.S.’s largest marine protected area, Papahānaumokuākea Marine
National Monument. These species are of particular interest to Naval and management agencies
because (a) the Hawaii insular stock of false killer whales (FKWs) are expected to be listed
under the Endangered Species Act due to evidence of a population decline, low population
estimates, and potential vulnerability to stochastic events, and (b) a recent melon-headed whale
(MHW) near-mass stranding event was associated with U.S. Navy exercises.
We propose to employ passive acoustic recording tools (DMONs) in two advanced methods to
characterize the broadband sounds from MHWs and FKWs and initiate a passive acoustic
monitoring program for these and other species in Hawaiian waters. DMONs will be adapted to
both a short-term drifter and a tow-body. Data collection will leverage an existing field project
which is employing DTAGs on both FKWs and MHWs. Integrating DMONs into this project
using two new means will facilitate the collection of free-field signals, substantially increasing
our analysis capabilities. The analyses and classifications of whistles and clicks will yield novel
sound descriptions for these species. Using the tag data, we will correlate the DMON recorded
sounds with likely behaviors. With the combined application of these three passive acoustic
tools (tags, drifter and tow-body) we will construct a unique array which can effectively localize
and facilitate acoustic and behavioral analyses of multiple vocalizing animals within the study
groups. Finally, the acoustic records will enable the development of detection algorithms for
these species and lead to real-time detecting and monitoring of these and other species. Overall,
we seek to use passive acoustics to examine and monitor the acoustic ecology marine mammal
“species of concern”. Our baseline data can help mitigate anthropogenic impacts. We directly
address the MMC’s themes of basic research, tool development and conservation. The tools
developed and data collected will directly contribute to future proposals. This proposed work is
an exceptional opportunity to leverage current resources, enhance abilities to acquire future
support, build new collaborations, and highlight WHOI’s efforts to study the newest addition to
the Endangered Species List.