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 as 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”.