DETERMINATION OF BACTERIAL COMPOSITION, HEAVY METAL CONTAMINATION AND PHYSICO-CHEMICAL PARAMETERS OF FISH POND WATER IN NIGERIA
Background to the Study
A fish pond is an artificial lake (reservoir, pond) intended for fish breeding. In the medieval times in Europe, it was typical for many monasteries and castles (small, partly self sufficient communities) to have its fish pond. Fish ponds are still common in Canada, Europe, especially in the Czech Republic, where common carp may be kept and in East Asia where koi may be kept. Such ponds are also being promoted in developing countries. They not only provide a source of income for small farmers from the sale of fish but can also meet irrigation needs and water for livestock (FAO, 2009).
A pond is a quiet body of water that is too small for wave action and too shallow for major temperature differences from top to bottom. Fish ponds are unnatural aquatic ecosystems that farmers must manage in order to produce fish crops. Physical characteristics of a fish pond directly impact pond water quality and indirectly the whole ecosystem and therefore, production management potential for the farmers. The influences are common to all pond technology systems and are not unique to 80:20 pond cultures. Once a pond is constructed, the physical characteristics are essentially permanent. Farmers are left without practical means of correcting site, design and construction flaws and must rely on excess management technique to compensate for them. However, it is often difficult to classify the differences between a pond and a lake, since the two terms are artificial and the ecosystems really exist on a continuum. Generally, in a pond, the temperature changes with the air temperature and is relatively uniform. Lakes are similar to ponds, but because they are larger, temperature laying and stratification takes place in summer and winter and theses layers turnover in spring and fall. Ponds gain their energy from the sun (dela Cruz, 1983; Bullock and Sneiszko, 1999).
The rapid expansion of agriculture during the past years may be attributed to a number of factors primarily related to the provision of food for human consumption. If aquaculture is viewed as a substitution for fishing, the fish can be reared to marketable size on farms to offset any lack of supply from the sea. At present, however, it seems unlikely that fish farming will replace deficiencies in annual catch rates from the sea because of the enormous differences in volume of production (Purdom, 1996).