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Spatio-temporal Distribution of Bowhead Whales off Barrow, Alaska 2007-2012 (pg 1, 2, 3)

Detection and Peak Presence Dates

Cluster Year # of days  w/data # of days
w/calls
Date of first
call detected
Date of last
call detected
% of days
w/calls
# of days
w/peak presence
Start date of
peak presence
End date of
peak presence
% of days
w/calls w/peak presence
M2 2007 134 55 20-Aug-07 3-Nov-07 41.04 37 24-Aug-07 31-Oct-07 67.27
M3 2007 134 53 22-Aug-07 20-Nov-07 39.55 21 7-Oct-07 16-Nov-07 39.62
M4 2007 134 25 24-Aug-07 29-Oct-07 18.66 11 26-Sep-07 29-Oct-07 44.00
M5 2007 134 32 19-Sep-07 11-Nov-07 23.88 8 21-Sep-07 28-Oct-07 25.00
M2 2008 78 0 N/A N/A 0.00 0 N/A N/A 0.00
M3 2008 197 69 4-Sep-08 22-Nov-08 35.03 53 6-Sep-08 21-Nov-08 76.81
M4 2008 78 0 N/A N/A 0.00 0 N/A N/A 0.00
M5 2008 217 70 20-Aug-08 14-Nov-08 32.26 50 26-Aug-08 2-Nov-08 71.43
M2 2009 147 91 7-Aug-09 28-Nov-09 61.90 56 7-Aug-09 8-Nov-09 61.54
M3 2009 361 174 11-Apr-09 15-Nov-09 48.20 129 11-Apr-09 4-Nov-09 74.14
M4 2009 0 0 N/A N/A 0.00 0 N/A N/A 0.00
M5 2009 365 207 13-Apr-09 18-Nov-09 56.71 167 14-Apr-09 13-Nov-09 80.68
M2 2010 191 61 10-Sep-10 14-Nov-10 31.94 47 10-Sep-10 7-Nov-10 77.05
M3 2010 321 129 2-Apr-10 22-Nov-10 40.19 75 8-Apr-10 8-Nov-10 58.14
M4 2010 103 30 20-Sep-10 8-Nov-10 29.13 13 20-Sep-10 14-Oct-10 43.33
M5* 2010 217 109 1-Apr-10 5-Aug-10 50.23 80 2-Apr-10 5-Aug-10 73.39
M2 2011 346 165 25-Mar-11 26-Nov-11 47.69 128 25-Mar-11 12-Nov-11 77.58
M3 2011 365 154 29-Mar-11 28-Nov-11 42.19 135 29-Mar-11 12-Nov-11 87.66
M4 2011 359 184 27-Mar-11 20-Nov-11 51.25 140 28-Mar-11 11-Nov-11 76.09
M5* 2011 0 0 N/A N/A 0.00 0 N/A N/A 0.00
M2 2012 211 97 12-Apr-12 30-Jul-12 45.97 82 15-Apr-12 30-Jul-12 84.54
M3 2012 211 94 16-Apr-12 26-Jul-12 44.55 68 16-Apr-12 22-Jul-12 72.34
M4 2012 197 84 31-Mar-12 15-Jul-12 42.64 62 16-Apr-12 8-Jul-12 73.81
M5* 2012 0 0 N/A N/A 0.00 0 N/A N/A 0.00

* Incomplete data

Conclusion

  • Passive acoustic monitoring is an effective tool for monitoring bowhead use of the BOWFEST study area year round

  • Earliest spring migration was detected in 2011

  • The spring migration saw an extensive pulse of calling that was maintained at or near peak presence levels through August in all years, except for 2010 when levels dropped in July

  • The main pulse of the fall migration had a lower peak and was much more compressed than that from the spring migration

  • 2009 and 2011 show continual presence of bowheads in the study area throughout the summer and not just during the spring and fall migrations

 

Acknowledgements

  • Funding Agency: Bureau of Ocean Energy Management (Inter-Agency Agreement M08PG20021)

  • Captains and crews of the research vessels used to deploy and retrieve our moorings

  • Logistic Coordinators: North Slope Borough-Craig George & Fredrick Brower and Barrow Arctic Science Consortium (BASC)

  • Communities of the North Slope

By Stephanie Grassia, Catherine Berchok, and
Kate Stafford (Applied Physic Laboratory, University of Washington)

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