mcbem-2014-01-submission-wwf-en

No. of Detection Days
whales spread out to forage they continuously call out to each other through the dark sea to ensure all
members are present. Just as we walk into a room and use visual cues to detect our companions they
achieve this through sound.
Transient (Biggs’) killer whales often travel in complete silence. They are listening for the sounds of their
prey in order to feed themselves and family. Therefore they are dependent on a quiet ocean.
Overall Fin Whale Detection Days by Year
60
50
52
47
40
30
20
35
22
31 *
10
0
0 0
3 2 3
2004 2005 2006 2007 2008 2009 2010 2011 2012 2013
Year
Figure 7. Number of fin whale detection days per year at Cetacealab. Fin whales are now commonly
seen from land from early May to late September. Courtesy of Cetacealab. *Data for 2013 as of July 30.
Fin whales vocalize with low frequency calls, which indicate they are able to communicate with each
other at great distances. Ambient noise levels would have a direct impact on this ability as well their
ability to locate their prey. We spotted our first fin whale in 2006 with only a few sightings for the next
couple of years. Now it is a common occurrence even from land to see these giant cetaceans starting in
early May until late September (Figure 7).
Humpback whales migrate every spring from warm tropical waters to the nutrient rich waters of coastal
BC. In our research area from Douglas Channel to Caamaño Sound we document the arrival of every
whale with a photo ID. In 2004 and 2005 we documented 42 individual humpback whales – by the end
of 2012 that number was over 300.
When humpback whales bubble net feed they use a distinct feeding call with bubbles to force a bait ball
into a tighter group and towards the surface. This feeding call may also signal seals, sea lions, Dall’s
porpoise, and even other humpback and fin whales to the presence of food – a dinner bell of sorts. On
many occasion we have observed a single humpback whale take a direct line towards these feeding calls
from a great distance. There is another mammal that may also be attracted to this feeding call – the
Biggs orca – knowing a variety of prey may be available in one location.
Breaching, tail slaps, and pectoral fin slaps are extremely dynamic to witness. What is most interesting
though is what this sounds like underwater – it is explosive! When you witness this with a hydrophone
in the water it is shocking - you will hear the sound of the breach underwater before you hear it in the
air! When one whale starts to breach it is not surprising to see another one many km away also begin to
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