Abstract
Aquatic animals have adapted to and exploited almost all of the various aquatic climates available on earth. Only the very extreme have not been significantly colonized. Of the 30,000 or so species the fish species which have been produced by nature man selects about 150 for the bulk of his consumption and even then only about 50 species are the most import for supplying food. Within this group there are major representatives from fresh water, salt water and brackish water regions. There are also representatives from the cold, cool, and warm water environments. This means that the fish farmer has a lot of raw material to choose from to produce products.
In wild fisheries fish are dependant on having an environment that will support all of the fish’s life cycle requirements. Changes in water temperature and or ocean circulation can produce conditions that affect a small part of the life cycle and yet can have profound affects on the well being of the population. This occurs in the case for salmon, which have relatively narrow requirements for completing their life cycle. If the freshwater part of the cycle is either too warm or too cold the salmon has trouble with successful reproduction. If ocean currents are affected then there is the potential for poor survival due to a loss of food supply. Farmed fish are not nearly as sensitive to these changes because the farmer can both modify the temperature of the water the fish are being reared in and supply the fish with alternate food supplies.
The farmer is able to exploit the changes that are expected from global warming. The farmer can take advantage of warmer water to grow fish more quickly and to increase the variety of fish they produce. Global warming will have a positive influence on the success of aquaculture. This will be especially true in Canada where for the most part present day fish farming production is temperature
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