Research
on blue whales near shipping lanes in the Santa Barbara Channel, 2008-2009
At least five blue whales were killed in fall 2007 as an apparent result
of ship strikes in the southern California area
(see publication
on blue whale ship strike mortality off California, March 2010). Three of these animals were
discovered in the vicinity of the Santa Barbara Channel. This level of mortality
was far higher than had been seen in any previous year and if there were
additional deaths of animals that did not wash up, could be significant to this
endangered species. Cascadia Research in collaboration with Scripps Institution
of Oceanography and with the support of the Channel Islands National Marine
Sanctuary and National Marine Fisheries Service initiated research in 2008 on
some of the factors possibly responsible for this mortality.
In August 2008 we began conducting small-boat surveys examining blue whale
distribution and behavior in and around the shipping lanes in the Santa Barbara
Channel. We have been able to gather extensive information on the behavior and
movements of whales in the shipping lanes through 7 deployments of two
types of suction-cup tags (two dual deployments of both types of tags)
all on animals in and near the shipping lanes. The two tags were the Bprobe
acoustic tag and Wildlife Computers Mk10 Fastlock GPS tag. Both tags provide an
overlapping set of data (depth, temperature, etc.) with the Bprobe providing
acoustics and animal body position and orientation and the Mk10 providing for
the first time frequent GPS positions of the whale.
Our
observations and the data from these tags will help us address several of our
key objectives:
-
We
have gathered data on the behavior of blue whales in the shipping lanes
including documenting their specific feeding and diving pattern in this
area.
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The
GPS tag with over 30 hours on one animal provided detailed movement patterns
of the whales present in the shipping lanes in the day and throughout
the night (something we could not do before). This represents the first
successful suction-cup tag deployments of this Fastlock GPS technology on
baleen whales.
-
We
had at least three close approaches to whales by ships (less than 1nmi) including
one to <200m of our tagged whales. We had the portable AIS received
on board providing detailed data on these ships. Other passages likely
occurred while we were not present but the combination of archived AIS data
and the tag data should allow us examine evidence of any behavioral
reaction.
Links to photographs:
A blue whale in the shipping
lanes being monitored with a suction-cup attached tag dives as a car carrier
approaches. Photo 15 August 2008 by John Calambokidis, Cascadia Research.
One
of a pair of monitored blue whales in the shipping lanes in the Santa Barbara
Channel surfaces just after a cargo ship passes approximately 200 yards
from the whales. Photo 16 August 2008 by John Calambokidis, Cascadia Research.
Two
blue whales being studied in the Santa Barbara Channel shipping lanes. The whale
to the left has two suction-cup attached instruments to monitor underwater
behavior and reaction to ships.
Photo 15 August 2008 by John Calambokidis, Cascadia Research.
