Crucian carp can 'hold breath' for months

A species of carp closely related to the common goldfish can live for months without oxygen a scientist announced today.

Professor Gran Nilsson, of the Division of General Physiology at the University of Oslo in Norway, told delegates at the Annual Meeting for the Society for Experimental Biology that the Crucian carp, Carassius carassius, has evolved to cope with anoxia.

Nilsson says that the Crucian carp is able to change the structure of its gills to prevent them becoming anoxic, thereby avoiding suffocation.

Nilsson's study showed that the species also has unusual blood for a teleost fish and has a much higher affinity for oxygen than any other vertebrate known.

In order to cope with low oxygen levels, the carp produces tranquiliser like chemicals and alcohol, which allow the fish to go for days or even months without oxygen, depending on the water temperature, while still remaining active.

Said Nilsson: "Anoxia related diseases are the major causes of death in the industrialized world. We have here a situation where evolution has solved the problem of anoxic survival millions of years ago, something that medical science has struggled with for decades with limited success".