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Abstract MILESTONES IN THE STUDY OF DIVING PHYSIOLOGY: Gerald Kooyman McMurdo Sound, Antarctica is the best place to conduct diving physiology
studies on marine birds and mammals under free-diving conditions.
Both emperor penguins and Weddell seals live naturally in areas
of extensive sea ice under which they dive and hunt for prey. The
first experimental diving studies were conducted on Weddell seals
in 1964 using the isolated breathing hole protocol for the first
time. Sea ice, two meters thick, covers McMurdo Sound until late
December. Below the ice is the deepwater environment where Antarctic
predators hunt their prey. Here in the Sound diving studies involve
attaching a recording device to a seal or bird and releasing it
into the hole cut in sea ice. This procedure sets the stage for
a bird or mammal to hunt without competition, and the only restrictive
condition is that they must return to the release hole to breathe.
On surfacing the attached recording devices can be retrieved and
the information downloaded. Results from using this experimental
protocol range from determining the first foraging patterns of any
diving mammal, to the first blood and muscle chemistry variations
during the extended and unrestrained dives. These experiments are
the standard for understanding the hypoxic tolerance of diving animals,
their aerobic diving limits, and their strategies of foraging, to
mention a few. The protocol will continue to be used in 2007 for
studies of both emperor penguins and Weddell seals by several investigators.
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