2001 Volume 14 Issue 2 Pages 153-158
To prevent water pollution by fish cultivation and to achieve the higher fishery production, a zero-emission model for fish cultivation was studied experimentally in combination with plant water-cultivation. This model was an ecological route of material flow from feed to plant (harvest) through fish (harvest), lost feed and excreta, microorganisms and salts. The experimental facility was composed of fish cultivating pond, bio-reactor to purify water and plant water-cultivating pond among which the water was circulated. To prevent propagation of algae which hinder the plant growth, ultraviolet ray was applied the circulating water. Hibuna, Carassius auratus, and water lettuce, Pistia stratiotes, were cultivated as models of fish and plant. The load of feed for fish was compensated by intake of materials by the lettuce and the pond water was maintained to be of a good quality. The material balance has been analyzed and the ability of lettuce for water purification has been determined as to be 147kg-wet biomass/m2/year, 531 g-N/m2/year an 1 l g -P/m2/years in April.
