Closed Ecological Recirculating Aquaculture Systems

Closed habitation experiments are essential for global environment improvement and maintenance of self-sustaining ecosystems. Hydro-ecosystems, which utilize aquatic organisms, are a promising prospect in habitation experiments. The utilization of aquatic organisms in closed systems can essentially be divided into three parts: (1) cultivation of phytoplankton for oxygen supply, (2) rearing of fish as a protein source, and (3) utilization of fish and shellfish for recycling of organic waste. Utilization of aquatic organisms (e.g., phytoplankton, zooplankton, and fish) to realize CO2 and O2 circulation and the construction of food chains are essential for the promotion of closed ecological systems. Recently, fundamental data were collected using the Closed Ecological Recirculating Aquaculture System (CERAS). Essential biomass was estimated from feeding trials between phytoplankton and fish, between phytoplankton and zooplankton, and between zooplankton and fish, and the CO2 and O2 budgets between phytoplankton and fish were investigated during development of the experimental equipment. In this chapter, we summarize simple CERAS food chains in freshwater and saltwater environments and give the results of photoperiod experiments.