[MARMAM] New publication in Marine Fisheries Review

Kim Shelden - NOAA Federal kim.shelden at noaa.gov
Wed Feb 7 12:19:53 PST 2018


Dear colleagues,

My co-authors and I are pleased to announce the publication of a new
article in the journal Marine Fisheries Review:

Shelden KEW, Mocklin, JA, Goetz, KT, Rugh, DJ, Vate Brattstrom, L, Friday,
N. 2017. Late Summer Distribution of Cetaceans near Barrow, Alaska: Results
from Aerial Surveys Conducted During the Bowhead Whale Feeding Ecology
Study, 2007–11. Mar. Fish. Rev. 79(2):1-22. doi:
https://doi.org/10.7755/MFR.79.2.1

Extended Abstract:

—The aerial survey component of the Bowhead Whale Feeding Ecology Study
(BOWFEST) was designed to document patterns and variability in the timing
and distribution of bowhead whales, Balaena mysticetus, and to provide an
estimate of temporal and spatial habitat use near Barrow, Alaska. Aerial
surveys were conducted from late August to mid-September during the period
2007–11 for a total of 171.1 hours flown. In addition to the focal species,
observed species included gray whales, Eschrichtius robustus; one humpback
whale, Megaptera novaeangliae; beluga whales, Delphinapterus leucas; ringed
seals, Phoca hispida; bearded seals, Erignathus barbatus; walrus, Odobenus
rosmarus; and polar bears, Ursus maritimus. Small pinnipeds, such as ringed
seal and spotted seals, Phoca largha, were often difficult to differentiate
and identify to species given the relatively high survey altitude of 310 m
(1,000 ft).
     Habitat partitioning was evident among the cetacean species observed
in greatest numbers: bowhead, gray, and beluga whales. Abundance estimates
during this time period ranged from 22 (CV 0.80) to 213 (CV 0.30) bowhead
whales, 1 (CV 1.01) to 18 (CV 0.28) gray whales, and 0 to 948 (CV 0.66)
beluga whales. Standard deviation ellipses showed each species occupied a
unique region within the study area with slight overlaps occurring in some
years. Bowhead distribution was oriented along the barrier islands and 20 m
isobath on the continental shelf and also included parts of the Barrow
Canyon and shelf break that were close to shore. Gray whale distribution
oriented along the Barrow Canyon shelf break near the 50 m isobath; while
beluga distribution ellipses centered over Barrow Canyon and offshore slope
waters. A four-parameter presence-absence model (bathymetry, bathymetric
slope, distance from shore, and distance from the shelf break) found both
distance from shore and shelf break were significant in predicting the
presence of bowhead whales. All four parameters were significant in
predicting gray whale presence. Only bathymetry was significant in
predicting beluga whale presence.
     During the 5-year study, 664 unique bowhead whales were identified
from 1,415 photographic images. Observers noted feeding behavior during
7–50% of sightings and 15–49% of photographed whales exhibited feeding
behavior in any given year. Of the individual whales that were visually or
photographically identified as feeding, 81–90% were in shelf waters, and
the majority of those were clustered around the 20 m isobath. More feeding
behavior was observed and photographed during years when most sightings
occurred on the shelf (2007, 2009, and 2010) but not necessarily in years
when bowheads were most abundant in the study area (e.g., 2008 and 2010).
The lowest percent feeding both visually and photographically occurred in
2008, the only year whale swim direction was predominately westerly, and
open mouth (skim) feeding behavior was not observed.
     Although the paucity of individual resightings (based on photographic
recaptures) between survey days (3 matches out of 664 identified whales)
suggested very low residence times, the photogrammetric sample (654 whales)
was largely comprised of juveniles (65%). Young whales typically are
unmarked and, therefore, not matched (only 3–6% were highly or moderately
marked in at least one zone on the body). All intrayear matched whales
moved east of their original sighting location, which was not expected so
close to the westbound fall migration.
     The BOWFEST aerial study provides a 5-year record of late summer
presence
of cetaceans in the western Beaufort Sea, adding to the growing body of
knowledge on these species and their habitat preferences in this region.
This information is particularly important since the western Beaufort Sea
is undergoing rapid change as the bowhead whale population continues to
grow, other species extend their ranges and increase their numbers in the
area, and industrial activity, commercial fishing, and shipping operations
are expected to increase in the Arctic as sea ice decreases.


The full article is available online at
https://spo.nmfs.noaa.gov/content/mfr/late-summer-distribution-cetaceans-near-barrow-alaska-results-aerial-surveys-conducted

and the entire issue is at
https://spo.nmfs.noaa.gov/marine-fisheries-review/mfr-792


-- 


*Kim E.W. Shelden, M.M.A.*
Marine Biologist, Cetacean Assessment & Ecology Program
Marine Mammal Laboratory, Alaska Fisheries Science Center
7600 Sand Point Way N.E., Seattle, Washington 98115-6349
(206) 526-6275 office, (206) 526-6615 fax, www.afsc.noaa.gov/nmml/

*Humans think they are smarter than dolphins because we build cars and
buildings and start wars, etc., and all that dolphins do is swim in the
water, eat fish, and play around.  *
*Dolphins believe that they are smarter for exactly the same reasons.*  -
Douglas Adams
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.uvic.ca/pipermail/marmam/attachments/20180207/f8a44e89/attachment.html>


More information about the MARMAM mailing list