HELSINKI, Finland, Aug. 25 (UPI) -- A Finnish study has found the crucian carp's physiology allows it to avoid predators and survive without oxygen during certain months.
The study says cooling water temperature in the fall prompts the carp, a cousin of the goldfish, to store vast amounts of glycogen in its brain and vastly reduce the amount of energy its brain needs to function from February to April, when there is no oxygen in its ponds because of ice cover.
Glycogen, an energy supply that the carp brain uses, was found to be 15 times higher in February, compared to brain glycogen content in July, when oxygen in the pond is at its peak, says the study. Simultaneously, the carp brain's sodium-potassium pump activity, a measure of energy demand, decreased 10-fold to its low point between February and April, says the study's lead author, Vesa Paajanen at Finland's University of Joensuu.
The findings, appearing in the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology, help explain how the carp is able to survive for months in a nearly anoxic state.