Since whales and seals feast upon krill, their disappearance led to a huge "krill surplus" in the Southern Ocean. It was then that the penguins shifted to this salty, crunchy high-energy prey.
Keith Hobson, a scientist at Environment Canada's Canadian Wildlife Service, told Discovery News that he was "truly surprised at the abrupt change... these results indicate for laying females via their eggs."
However, Hobson pointed out, the shift could have been due not only to a surpluss of krill, but also a scarcity of fish.
He hopes "that this work acts as a catalyst for others to examine the ecological interrelationships occurring in the Southern Ocean.
In the meantime, both he and Emslie are concerned about the current penguin food situation, since krill are in steep decline in the Southern Ocean. Emslie attributes this to "global warming and increased krill fisheries." With many fish species also declining, "Adelie penguins face few foraging options in future," he said.
Emslie hopes implementation of a recent proposal calling for protection of the entire Ross Sea region as an ecological reserve might help to prevent humans from indirectly starving penguins there to death.
