[MARMAM] New Publication: Availability correction factors for bowhead whales exposed to seismic operations

Frances Robertson frances.c.robertson at gmail.com
Fri Jun 9 09:49:55 PDT 2017


Dear Colleagues,



My co-authors and I are pleased to announce that the following publication
is now available.


*Correction factors account for the availability of bowhead whales exposed
to seismic operations in the Beaufort Sea. *

Robertson, FC, WR Koski, JR Brandon, TA Thomas, and AW Trites (2015). J.
Cetacean Res. Manage. 15: 35-44.


Abstract

The accuracy of estimates of cetacean density from line-transect survey
data depends in large part on how visible the target species is to the
observer. Behavioural data (i.e. surface and dive times) from government-
and industry-funded aerial observation programmes (1980–2000) were used to
calculate availability correction factors needed to estimate the number of
bowhead whales (*Balaena mysticetus*) from aerial survey sighting data.
Correction factors were calculated for bowhead whales exposed and not
exposed to seismic operations. Travelling non-calf whales were found to be
less likely to be available for detection than other whales, and their
availability further declined in the presence of seismic operations.
Non-calves were also less available to observers during autumn when exposed
to seismic operations than when not exposed, regardless of activity
(travelling or otherwise)*. *Such differences in availability appear to
reflect behavioural responses to the sound of seismic operations that
alters the surfacing and diving patterns of bowhead whales. Localised
abundance estimated from aerial surveys may range from 3% to as much as 63%
higher in areas ensonified by seismic operations if correction factors are
applied to account for differences in availability associated with the
presence of seismic operations, compared to abundance estimates derived
from assessments that only account for changes in availability of
undisturbed whales. These results provide the first empirical estimates of
availability for bowhead whales exposed to seismic operations and highlight
the implications of not correcting for disturbance-related availability in
density assessments in the vicinity of seismic operations.



This paper is open source and may be accessed through the following link:

http://www.distantfin.net/uploads/6/5/4/8/6548806/rs5745_15_pp35_44_robertson.pdf



Please direct any questions to

frances.c.robertson at gmail.com



Best regards



Frances


-- 
Frances C. Robertson, PhD

*Marine Mammal Biologist*

*~~~~~~~~~~~~~~~~~~~*


*Research Scientist SMRU ConsultingElevate Post Doctoral Fellow Simon
Fraser University~~~~~~~~~~~~~~~~~~~~~*
c: (+1) 360 819 9821
e: frances.c.robertson at gmail.com
t: @distantfins

www.distantfin.net
www.northeastpacificminke.org
www.coastalconnectionvancouver.com
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