QUANTITATIVE-DETERMINATION AND SEPARATION OF WASTES IN HIGH-DENSITY CULTURE-MEDIUM FOR MARINE ROTIFER

In high density culture of rotifer, a large amount of suspended organi c matter accumulates in the culture medium. Such wastes are mainly com posed of rotifer feces, amictic egg shells, microbes (bacteria, protoz oa, fungi etc.), the food organism Chlorella and flocks of various siz es are formed and coagulate. The increase of flocks in culture medium causes clogging of the nets in harvesting of rotier and also causes po llution of the larval rearing tank by providing pathogenic microorgani sms. In order to remove the hocks, a filtration unit was developed, wh ich was composed of nylon filtration mats and stainless steel frames t o aid mixing of the culture medium. In order to investigate its effici ency, changes in the quantities of rotifer and wastes (the large amoun t of suspended organic matter) were determined by the centrifuge metho d. The culture of rotifer was carried out in two 500 l tanks by the se mi-continuous method with or without filtration for five and nine days . While the flocks increased in the culture medium without filtration, the hocks larger than 30 mu m could be efficiently removed with filtr ation and culture was feasible at a rotifer density of 10(4) ind./ml.