Dear Bioacoustics List-serve members,
On behalf of my coauthors, I am pleased to announce the recent publication of our work on the effect of two deep-water (12 kHz) multibeam echosounder surveys—used for ocean
mapping—on Cuvier’s beaked whale foraging behavior in southern California.
Please find the article, “The effect of two 12 kHz multibeam mapping surveys on the foraging behavior of Cuvier’s beaked whales off of southern California,” on
The Journal of the Acoustical Society of America website:
https://doi.org/10.1121/10.0001385
ABSTRACT:
The impact of multibeam echosounder (MBES) operations on marine mammals has been less studied compared to military sonars. To contribute to the
growing body of MBES knowledge, echolocation clicks of foraging Cuvier’s beaked whales were detected on the Southern California Antisubmarine Warfare Range (SOAR) hydrophones during two MBES surveys and assembled into foraging events called group vocal periods
(GVPs). Four GVP characteristics were analyzed Before, During, and After 12 kHz MBES surveys at the SOAR in 2017 and 2019 to assess differences in foraging behavior with respect to the mapping activity. The number of GVP per hour increased During and After
MBES surveys compared with Before. There were no other differences between non-MBES and MBES periods for the three other characteristics: the number of clicks per GVP, GVP duration, and click rate. These results indicate that there was not a consistent change
in foraging behavior during the MBES surveys that would suggest a clear response. The animals did not leave the range nor stop foraging during MBES activity. These results are in stark contrast to those of analogous studies assessing the effect of Naval mid-frequency
active sonar on beaked whale foraging, where beaked whales stopped echolocating and left the area.
Thank you,
Hilary Kates Varghese
PhD Candidate
Center for Coastal and Ocean Mapping
University of New Hampshire
24 Colovos Rd. Durham, NH 03824 USA