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Fish and Cold Water

Despite the extreme harshness of the environment, there are many reasons for marine fish to attempt exploitation of polar and sub-polar oceans. In addition to the relative greater availability of oxygen in cold water (15), there are rich food supplies, making expansion into these regions a potentially good strategy at the evolutionary level. In order to survive and thrive in such a habitat, polar fish have evolved physiological, biochemical and behavioral compensatory mechanisms to minimize the effects of exposure to the frigid waters. The mechanisms examined here not only allow these fish to exploit a rich habitat but also enhance their ability to expand their populations even further in the polar oceanic realms.

The low ambient water temperature seen in the oceans of polar regions profoundly impacts the marine life which is exposed to it. The most obvious danger is that of freezing; seawater temperatures in these regions can plunge to -1 to -2 ¦C. Unless prevented by some means, ice crystals in internal water columns can seed additional formation of ice through body fluids, with the obvious and expected results of respiratory and systemic organ collapse and massive tissue destruction (6).

To combat freezing, polar fish have evolved a variety of physiological adaptations. Many teleost fish found in polar, subpolar and even cold temperate waters produce macromolecules that, when admitted to the blood, essentially perform as anti-freeze (4), a mechanism of obvious importance. Fish which routinely inhabit temperate marine oceans have plasma freezing temperatures between -.5 and -.8 ¦C, with fish exposed to lower temperatures facing a significant risk of freezing (6). The 1¦ difference between environment and plasma fluid is large enough to cause freezing, in part because supercooling of fluids in the presence of ice cannot occur. If migration is not an option for the organism, the production of components, either as salts o...

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Fish and Cold Water. (1969, December 31). In LotsofEssays.com. Retrieved 06:46, March 29, 2024, from https://www.lotsofessays.com/viewpaper/1707258.html