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Association News
IAGC’s Dr. Bob Gisiner Responds to BRAHSS
Australian Humpback Whale Research
By Dr. Bob Gisiner
A recent publication by Dunlop et al. (2017) received considerable media attention for
showing that migrating humpback whales in Australia responded to seismic sound sources.
In fact, the derived quantitative dose- survey activity on the California coast,
“Such small response relationship revealed a relatively much of that activity occurring in or near
movements need to small effect with an average onset of the migratory corridor during periods of
be understood within response beginning only 1 to 3 km from migration. During that 20-year period of
the larger context the sound source and leading to an average extensive exposure to seismic survey sound,
of a migration that increase of only 100 meters in the gap the California gray whale population more
lasts for months and between the source vessel and the passing than doubled and was removed from the
extends for thousands animal, compared to when the vessel was Endangered Species List shortly thereafter.
of kilometers from present without the sound source being It seems unlikely, therefore, that any
subtropical waters active. Such small movements need to be substantive adverse consequences are to
to the edges of the understood within the larger context of a be expected from normal seismic survey
polar ice.” migration that lasts for months and extends activities in Australia, especially when
for thousands of kilometers from subtropical
waters to the edges of the polar ice. considered in the context of local humpback
whale population recovery and removal from
The Dunlop et al. (2017) findings the Endangered Species List similar to that
are remarkably similar to previous observed earlier for gray whales in California.
results obtained by Malme et al.
(1984) from gray whales migrating See Review Notes in the
along the coast of California. Members’ Toolbox HERE
Furthermore, the Malme et al. (1984)
study followed a period of more than
20 years of constant full-scale seismic
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