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April
3, 2007 We are used to
hearing about the
effects of climate change in terms of unusual animal behavior, such as
altering
patterns of fish and bird migration. However, scientists at the “If
penguins are traveling
further or diving deeper for food, that tells us something about the
availability of particular fish in regions of the Antarctic. We may be
able to
assess the pressure exerted by king penguins on this ecosystem, and
look at the
effects of both climate change and overfishing in this region of the
world”,
says Dr. Lewis Halsey who will present his results on Wednesday 4th
April at
the Society for Experimental Biology’s Annual Meeting in
Glasgow. A new way of using
animals as
bio-indicators is to ascertain their energy requirements. Dr. Halsey
and
co-workers measured the heart rate and energy expenditure of king
penguins
whilst walking on a treadmill and whilst swimming in a long water
channel, and
obtained relationships between these two variables. They then implanted
heart
rate loggers in penguins going to sea such that they could infer the
energy
expended by these birds from the recorded heart rate. Researchers were
then
able to find out if there was a correlation between the energetic costs
of
foraging at sea and the levels of fish available to the penguins i.e.
did
penguins have to work harder when food was scarce. King penguins are
good candidates
as bio-indicators for several reasons. Firstly, while at sea foraging,
they
cover hundreds of kilometers and are able to dive to depths of several
hundred
meters, so they explore a relatively large portion of the expansive
Southern
Oceans. Secondly, the diets of several populations of king penguins are
well
known. Thirdly, while foraging for food is done at sea the penguins
also come
ashore to breed and moult, making them accessible to researchers.
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