2000 Volume 13 Issue 1 Pages 13-17
As a food supply system for the future manned space activities, CERAS (Closed Ecological Recirculating Aquaculture System). containing phytoplankton, zooplankton and tilapia, Oreochlomis niloticus, has been studied. The system is relatively large and a large amount of energy will be consumed for the food production. However for use in space stations or developing stage of Luna-base, small and low-energy system will be requested. Accordingly, to establish the compact fish-culturing system, removal of zooplanktons from CERAS is expected.
It was known that tilapia fry feeds selectively zooplanktons. Subsequently possibility of culturing tilapia fry using only phytoplankton as diet must be studied. As the first step, we were examined survival rate of the fries that fed Chlorella vulgaris. It was no remarkable difference to the survival rate of the fries that took no food. Whereas in the following experiments the fries that fed Spirulina platensis or Euglena gracilis instead of Chlorella survived as well as the fries cultured with commercial diet. So it was suggested Spirulina and Euglena are suitable for diet of tilapia fry, and zooplanktons are not necessary to the tilapia culturing system.
