CONCEPT RAS

The aquaculture industry that began developing in the late 1960s has exploded into a major global industry of 60 million tonsa year, with huge annual revenues in excess of US$ 70 billion (FAO,2006). With the current increase in environmental awareness andthe consequent stringency in environmental legislation, a newapproach to dealing with the ecological problems associated withaquaculture has been developed—recirculating aquaculture systems. This approach was originally developed to provide a solutionto the environmental problems generated by the traditional pondand flow-through aquaculture systems, since it enables thetreatment of polluted water within a closed loop, offers improvedcontrol of effluent discharge, and allows complete environmentalcontrol (van Gorder, 1994; Shnel et al., 2002). Moreover, RASconfers ecological and economic advantages in that it facilitates areduction in the amounts of water and energy required andreduces land use. In addition, it provides growers with thegeographical freedom to set up aquaculture systems in ‘‘nontraditional’’farming areas (Shnel et al., 2002); for example, small RAS,such as the one presented in this study, producing lucrativeseafood species might be suitable for small-scale aquaculture forfood production in urban areas (Zohar et al., 2005). Thus, RAS couldcontribute to meeting the demand for protein foods in highlypopulated urban centers.