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Hibernating fish discovered in the Antarctic mongabay.com March 5, 2008
The research, described in the journal PLoS ONE, shows that the Antarctic 'cod' Notothenia coriiceps "effectively 'puts itself on ice' to survive the long Antarctic winter." The fish "activate a seasonal 'switch' in ecological strategy — going from one that maximizes feeding and growth in summer to another that minimizes the energetic cost of living during the long, Antarctic winter." In essence, the species goes into a dormant state to conserve energy. "Hibernation is a pretty complex subject. Fish are generally incapable of suppressing their metabolic rate independently of temperature. Therefore, winter dormancy in fish is typically directly proportional to decreasing water temperatures," said lead author Dr Hamish Campbell, a researcher at the University of Queensland in Australia. "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. 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."
"It appears they utilize the short Antarctic summers to gain sufficient energy from feeding to tide them over in winter. The hibernation-like state they enter in winter is presumably a mechanism for reducing their energy requirements to the bare minimum. The interesting question we still have to answer is why these fish greatly reduce feeding in winter when food is still available." The "Antarctic Cod" diverged from its warmer water cousins around 30 million years ago when the Antarctic circumpolar current was formed, according to BAS. News index | RSS | Add to MyYahoo! Advertisements: Organic Apparel from Patagonia | Insect-repelling clothing |
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