London, Mar 5 (UNI) It is generally perceived that animals only hibernate, but scientists have now discovered a fish that does the same-- the Antarctic cod.
It slows the processes of growth, metabolism and swimming activity in winter by entering a dormant state while sitting on the bottom.
The fish throws a seasonal switch between a high gear in which it maximises feeding and growth in summer and a low one where it maximises the energy used during the long, Antarctic winter.
Explaining the phenomenon, Dr Hamish Campbell, at University of Queensland, Australia said, '' The interesting thing about these Antarctic cod, Notothenia coriiceps, 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,'' he added.
The Daily Telegraph quoted Dr Keiron Fraser from the British Antarctic Survey as saying, ''It appears they utilise 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.'' ''But the interesting question we still have to answer is why these fish greatly reduce feeding in winter when food is still available,'' he quipped.
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