Dear MARMAM community,
On behalf of my coauthors, I am pleased to announce the publication of our
work, “Spatial Analysis of Beaked Whale Foraging During Two 12 kHz Multibeam
Echosounder Surveys,” in Frontiers in Marine Science. This article is freely
available at: https://www.frontiersin.org/article/10.3389/fmars.2021.654184.
The abstract and full citation are included below for your convenience.
ABSTRACT:
To add to the growing information about the effect of multibeam echosounder
(MBES) operation on marine mammals, a study was conducted to assess the spatial
foraging effort of Cuvier’s beaked whales during two MBES surveys conducted in
January of 2017 and 2019 off of San Clemente Island, California. The MBES
surveys took place on the Southern California Antisubmarine Warfare Range
(SOAR), which contains an array of 89 hydrophones covering an area of
approximately 1800 km2 over which foraging beaked whales were detected. A
spatial autocorrelation analysis of foraging effort was conducted using the
Moran’s I (global) and the Getis-Ord Gi∗ (local) statistics, to understand the
animals’ spatial use of the entire SOAR, as well as smaller areas,
respectively, within the SOAR Before, During, and After the two MBES surveys.
In both years, the global Moran’s I statistic suggested significant spatial
clustering of foraging events on the SOAR during all analysis periods (Before,
During, and After). In addition, a Kruskal-Wallis (comparison) test of both
years revealed that the number of foraging events across analysis periods were
similar within a given year. In 2017, the local Getis-Ord Gi∗ analysis
identified hot spots of foraging activity in the same general area of the SOAR
during all analysis periods. This local result, in combination with the global
and comparison results of 2017, suggest there was no obvious period-related
change detected in foraging effort associated with the 2017 MBES survey at the
resolution measurable with the hydrophone array. In 2019, the foraging hot spot
area shifted from the southernmost corner of the SOAR Before, to the center
During, and was split between the two locations After the MBES survey. Due to
the pattern of period-related spatial change identified in 2019, and the lack
of change detected in 2017, it was unclear whether the change detected in 2019
was a result of MBES activity or some other environmental factor. Nonetheless,
the results strongly suggest that the level of detected foraging during either
MBES survey did not change, and most of the foraging effort remained in the
historically well-utilized foraging locations of Cuvier’s beaked whales on the
SOAR.
Kates Varghese, H., Lowell, K., Miksis-Olds, J., DiMarzio, N., Moretti, D., and
Mayer, L. (2021). Spatial Analysis of Beaked Whale Foraging During Two 12 kHz
Multibeam Echosounder Surveys. Frontiers in Marine Science 8, 1139. Doi:
10.3389/fmars.2021.654184
Thank you!
Hilary Kates Varghese
(she/her/hers)
PhD Candidate-Earth Sciences, Oceanography
University of New Hampshire, Durham, NH, USA
hkatesvargh...@ccom.unh.edu
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