Crucian carp: Courtesy Jacob Horia

How long can you hold your breath? Crucian carp (Carassius carassius), a close relative to the goldfish, is capable of living for months without oxygen. Scientists at the University of Oslo have recently unpacked the mechanisms allowing Crucian carp to exhibit superior breath holding skills.

First, lets gain some background knowledge about this extraordinary carp. Crucian carp inhabit lakes, ponds and slow-moving rivers throughout Europe and Asia. They are considered a medium-sized cyprinid (weighing less than 3.3 pounds) and commonly exhibit a dark green back, golden sides and reddish fins. Crucian carp are commonly caught for sport and occasionally are found in freshwater aquariums.

What allows the Crucian carp to survive months without oxygen? Lets take a look. Professor Goran Nilsson, University of Oslo, discovered the Crucian carp is able to change its gill structure to avoid becoming oxygen deprived (known as anoxia). The carp also has a high affinity for oxygen when compared to other vertebrate therefore resorts to producing alcohol and tranquilizers when oxygen supplies are limited. With these mechanisms, the Crucian carp is able to spend days, even months without a fresh breath of air.

So what does this mean? Researchers are hoping to understand how different animals cope with the lack of oxygen giving way to clues about how humans can go longer without direct oxygen supplies. As stated by Nilsson, "Anoxia related diseases are the major causes of death in the industrilized world." What professions or situations do you see benefiting most from prolonged breath holding?