Using electric power obtained by marine wind force and a tide, sea water is electrolyzed to produce fresh water, sodium, magnesium, calcium, potassium, caustic soda, chlorine, hydrochloric acid, sulfuric acid, hydrogen, oxygen or the like, at the same time, unloaded malts, saw dust and the like are fermented to brew ethanol, carbon dioxide generated here is used for photosynthesis to culture vegetables and oxygen generated here is supplied to a fish preserve and an under reef where fish live to culture fishes and also returned to sea water dropped in the concentration of oxygen to suppress the generation of a red tide.