Guess who is the greatest athlete on planet? It's 'fish'

Scientists have discovered that fish are the most effective at delivering oxygen throughout the body which gives them the athletic edge over other species or animals.

Lead author Jodie Rummer of the James Cook University said that fish exploited a mechanism which was up to 50 times more effective in releasing oxygen to their tissues than that found in humans.

Rummer said this was because their haemoglobin and the protein in blood that transports oxygen was more sensitive to changes in pH than ours and more than the haemoglobins in other animals.

This is especially important for the fish during times of stress to escape from predators, or when they are living in water that is low in oxygen. They can double or even triple oxygen delivery to their tissues during these critical times.

Now they have determined just how powerful that system can be and have compared the results with medical studies on humans.

Rummer said this information told them how fish had adapted this very important process of getting oxygen and delivering it to where it needed to be so that they could live in all kinds of conditions, warm or cold water, and water with high or low oxygen levels.

Colin Brauner of the University of British Columbia said that this trait might be particularly central to performance in athletic species, such as long distance swimming salmon or fast swimming tuna.

The study is published in the Journal PLOS ONE.