Freezing Resistances of Polar Fish Blood Sera

Freezing Resistances of Polar Fish Blood Sera 

Marine waters normally have salinities that cause their freezing points to be below — 1.8°C. In polar seas there are particular areas in which the temperature of the water may remain constant at these temperatures, the equilibrium temperature of the ice—salt water mixture. Where there is a permanent ice pack and some restrictions on flow of water, such as in a bay, fjord, or sound, the temperature of the water may remain nearly constant throughout the year, providing there is no seasonal dilution of the sea water by fresh water. But fish remain in the normal-salinity waters and consequently are exposed to temperatures below — 1.8°C. 

Scholander and co-workers (1953, 1957 Gordon et al., 1962) made some of the initial significant observations on freezing resistances in fishes that could be interpreted on a molecular basis. They reported that the blood sera of Arctic fish had lower freezing temperatures than did the blood seras of fish not adapted to the cold. But, most important, they observed that the substances in the serum that helped to lower the freezing temperature were not due to salts, and that on chemical fractionation of the serum these substances were found in the fraction soluble in trichloroacetic acid. Other workers (Lievestad, 1965) also conducted related studies but in a more physiological vein. 

Investigations of an interesting antifreeze substance earlier noted by Scholander and co-workers were then undertaken in the Ross Sea 

The Arctic marine environment is very different from that of the Antarctic. Most of the Arctic can best be described as an area of water surrounded by many areas of land, while the Antarctic is a body of land surrounded by water. Fish in the Arctic consequently are found around or near many different types of land with different climatic conditions and in waters of very different temperatures. Much of the water of the Arctic is comparatively inaccessible because it is covered with sea ice. In contrast to the Antarctic, large fish like the D. maw-soni are not currently reported in the Arctic, but many varieties of fish are found. 

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II. Freezing Resistances of Polar Fish Blood Sera.193... 

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