Hibernating Antarctic Fish

Scientists have discovered Antarctic fish that act like bears: When the going gets tough in winter they essentially hibernate.

Reporting this week in the journal PLoS ONE, the online journal from the Public Library of Science, scientists from British Antarctic Survey (BAS) and the University of Birmingham reveal, for the first time, that the Antarctic 'cod' Notothenia coriiceps effectively 'puts itself on ice' to survive the long Antarctic winter.

Apparently this behavior is triggered not by plummeting temperatures but by a lack of sunlight.

"The interesting thing about these Antarctic cod is that their metabolic rates are reduced in winter even though the seawater temperature doesn’t decrease much," said Lead author Hamish Campbell, formerly at the University of Birmingham, UK but now at University of Queensland, Australia. "It seems unlikely that the small winter reductions in water temperature that do occur are causing the measured decrease in metabolism. However, there are big seasonal changes in light levels, with 24 hour light during summer followed by months of winter darkness – so the decrease in light during winter may be driving the reduction in metabolic rates."     

The discovery may change scientists' thinking about hibernation.

"Why these fish chose to adopt this hibernation-like strategy during winter is currently unclear, but it presumably provides energetic benefits," said Keiron Fraser, a researcher at BAS. "The traditional views of hibernation are being challenged constantly. This study introduces a new group of animals that appear to utilize a hibernation-like strategy that allows them to survive during the long winters in one of the harshest environments on Earth."

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