[MARMAM] New gray whale publications

burnhamr burnhamr at uvic.ca
Mon Dec 9 14:43:11 PST 2019


My co-author and I are happy to announce the publication of two new
papers of the acoustic ecology of gray whales. 

The first:"Gray whale calling response to altered soundscapes drive by
whale watching activities in a foraging area" is published the Journal
of Ocean Technology and can be found here:
https://www.thejot.net/article-preview/?show_article_preview=1090 

Abstract: The gray whale (_Eschrichtius robustus_) is subject to
elevated ambient noise in much of its range.Here we characterized the
acoustic environment of a summer foraging bay, also used for nursing and
weaning, on the west coast of Vancouver Island. This area is also
subject to whale watching.We examined changes in whale call number,
rate, and structure received on a passive acoustic monitoring system
deployed in an altered acoustic landscape. In particular, increased
anthropogenic noise was examined, using representative 1/3 octave
frequency bands generated by whale watching vessels and float
planes.Whale watching traffic significantly shaped the acoustic
landscape of the foraging locale, with distinct diurnal patterns in
ambient noise. Calling rate (calls/hour/individual) was unchanged
relative to the ambient condition, yet the number of core calls heard in
the recordings increased,and the number of motherese-type calls
decreased with elevated ambient noise. Calls were generally lower in
frequency and shorter in length in increased ambient noise conditions.
This may represent a calling response or a masking effect from the noise
additions. It shows, however, that calling between conspecifics could be
affected by human-derived noise additions. Similar changes in received
calls were seen in periods of increased wind and wave noise, although
less so for abiotic natural, than anthropogenic noise. Changes in
calling, or accuracy in call reception and interpretation, may
negatively influence prey acquisition, conspecific communication, and
reunion of cow-calf pairs.

The second: "The use of passive acoustic monitoring as a census tool of
gray whale (_Eschrichtius robustus_) migration" is available from Ocean
and Coastal Management here
https://www.sciencedirect.com/science/article/abs/pii/S0964569119309391?via%3Dihub


Abstract: Passive acoustic monitoring adds to knowledge of whale
presence and distribution over space and time. The gray whale
(_Eschrictius robustus_) undertakes an annual migration between remote
feeding and breeding locales, with its highly sonorous nature suggesting
employment of low-frequency calls to be inherent to travel behaviours,
perhaps aiding navigation and social cohesion. We consider whether these
calling behaviours can be used to better understand the process of
migration, where call presence and relative abundance might represent a
means to track the progress of migrating whales. Passive acoustic
recordings made on the west coast of Vancouver Island, a mid-way point
of gray whale migration, were first analysed for abundance over time to
examine the progression of migration. Then the acoustic record was
compared to shore-based recordings undertaken from Point Vincente,
California to better assess their use as a census tool. The timing in
peaks of calling, particularly of far-ranging moan-like calls, and shore
counts showed a high degree of congruence when considered with a lag
time of 8 days to account for travel time between the two survey
locations. This suggests that passive acoustic monitoring could
complement the long running and shore-based counts in recording annual
population movement, and add to our understanding of gray whales on
poorly known segments of their migration route or at times when visual
observations are not possible. 

If you have any questions or would like to discuss the papers further
and are at the WMMC in Barcelona  please find my self or my co-author,
with both have poster presentations. I am happy to also answer over
email and provide pdf copies of the papers. 

Rianna Burnham, PhD
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