Fish from the frozen continent can handle the heat

3 May 2005

Fish from the frozen continent can handle the heat

Researchers using what they describe as a fish treadmill have found that fish accustomed to freezing Antarctic waters can thrive in warmer conditions, suggesting that some species may have a greater chance of surviving climate change than previously thought.

The team - led by University of Canterbury biologist, Associate Professor Bill Davison – have been travelling to Antarctica to collect bald rock cod.

The fish, which are found under the sea ice, normally live in constant water temperatures of -1.8 degrees Celsius.

Using aquarium facilities at Scott Base and Canterbury University the fish were acclimated in waters of 4 degrees Celsius.

Professor Davison says the fish were made to swim through a tunnel in waters of varying temperature.

He says fish fresh from the ocean swam well in water measuring up to 2 degrees Celsius but became less efficient as the temperature rose.

However, the acclimated fish swam well in water measuring as high 8 degrees Celsius as their systems adjusted to the warmer conditions.

The bald rock cod belongs to a group of animals known as stenotherms which, until these latest findings, had been thought to have been capable of doing well at one particular environmental temperature but incapable of surviving in any other environment.

This latest research has found that these fish can change their cardiovascular physiology and also the enzymes that power the swimming.

“This research is extremely exciting as it shows that Antarctic fish are much more flexible than was previously thought,” says Professor Davison.

“Global warming is affecting the whole planet, but the biggest changes are happening in Antarctica. The fact that these fish can cope with what is quite a massive change in temperature gives us some hope for the future of the Antarctic fauna.”

“However”, what we really need to be looking at is the whole ecosystem, rather than one component”.

ENDS

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