Recirculation aquaculture systems (RAS) represent a new and unique way to farm fish. These systems are used all around the world for the production of many fish species in a more efficient controlled environment. Instead of the traditional method of growing fish outdoors in open ponds and raceways, this system rears fish at high densities, in indoor tanks with a "controlled" environment. Recirculation systems filter and clean the water for recycling back through fish culture tanks.
New water is added to the tanks only to make up for splash out and evaporation and for that used to flush out waste materials. In contrast, many raceway systems used to grow trout are termed "open" or "flow through" systems because all the water makes only one pass through the tank and then is discarded. Fish grown in RAS must be supplied with all the conditions necessary to remain healthy and grow. They need a continuous supply of clean water at a temperature and dissolved oxygen content that is optimum for growth. A filtering (Biofilter) system is necessary to purify the water and remove or detoxify harmful waste products and uneaten feed. The fish must be fed a nutritionally-complete feed on a daily basis to encourage fast growth and high survival.
Benefits of RAS:
RAS indoor fish farming offer to the fish producers a variety of important advantages over open pond culture. Some benefits are given below-
