Water Resources in Aquaculture and Main Types of Water Supply in Aquaculture

 

The fish performs its physical activities in water frequently. Because the fish is completely dependent on water for feeding, growth, process of excretion of waste products, process of reproduction and maintaining the balance of salt. It is necessary to understand the physical and chemical properties of water for successful aquaculture practice. Water has a specific heat capacity with far reaching implications and can hold the greater amount of heat with a little change of temperature. It allows a water body to act like buffer against wide ups and downs of temperature. Rate of change of temperature depends upon the size of pond and quantity of water. If the size of water body is larger, the rate of change of temperature will be slower.

In addition, aquatic organisms change their body temperature according to the temperature of the water body therefore high speed changes in temperature are not tolerable by them. Water possess very distinctive feature of density. Maximum liquids solidify or acquire more density due to cooling. However, water becomes denser when its temperature reaches up to about 39ºF. When it cools beneath that degree, it shows less density and becomes solid after freezing at 32ºF. On developing into ice, volume of water elevated to 11%. Increasing volumes prevent ice from sinking instead it floats over water, a feature that prevents the water body from frozen solids .

There are two main types of water supply for aquaculture, underground and surface water. Groundwater also known as water of well or spring water mostly show variability in many features with water on the surface. Subsoil or underground water is generally regarded as the most important source of water for fish cultivation, as, on a given site, it is generally consistent in quantity and quality.

 According to Punjab fisheries, for fresh water fish culture, tube well water and irrigation canal water is best in quality and quantity. It also contains a large number of carnivorous/ trash fish.