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Life in the Southern Ocean
Factfile |
 Life in the Southern Ocean |
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Fish
A further area of sea-life that exists in the Southern Ocean is fish. Of the 20,000 or so species of fish in the world, only about 200 are found south of the Antarctic Polar Front. While the Antarctic has relatively few fish, most of those that do occur are found only in the Southern Ocean and nowhere else.
Patagonian Toothfish
Mostly slow growing, Antarctic fish have developed extreme adaptations to the near-freezing water. They have a protein in their blood and body tissues that acts like an anti-freeze. This antifreeze called glycoproteins (a mixture of sugar and proteins) acts like an antibody to any ice crystals. As they try to form, it wraps them up, preventing them from growing. By stopping the growth of ice crystals, the blood and tissues are prevented from freezing in the cold temperature.
The Antarctic Ice fish has adapted in this way, but is also special in that its blood is almost translucent. The missing red blood cells usually carry the haemoglobin, which transports oxygen around the body. Without the red blood cells, the thickness of the blood is reduced and the energy used up circulating the blood is lower. The Ice fish can therefore conserve more of its energy.
The practice of fishing is carefully monitored in the Antarctic area, to prevent disturbance of the natural balance of the ecosystem.
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