Now showing items 1-2 of 2

    • Article

      Effect of different light intensities on the growth of the diatom Chaetoceros calcitrans 

      EC Jereos - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Batch cultures of C. calcitrans were maintained indoors at a temperature range of 21 to 25 C and continuously illuminated by 40-watt daylight fluorescent lights. Cultures were exposed to 5 different intensities from 200 to 25,000 lux. Population counts show that light intensity affects growth and reproduction of the algae cultivated. A comparison of population peak growths showed cultures illuminated by 12,000 lux to have higher cell counts than those exposed to higher or lower light intensities.
    • Article

      Methods of harvesting and preservation of the diatom Chaetoceros calcitrans 

      OM Millamena, EC Jereos & IR Gorriceta - SEAFDEC Aquaculture Department Quarterly Research Report, 1977 - Aquaculture Department, Southeast Asian Fisheries Development Center
      Diatom culture and larval feeding experiments were conducted to test the viability and acceptability of preserved algal concentrates. C. calcitrans is characterised by the presence of setae which keep them suspended in cultures and make autoflocculation very difficult. Flocculation was induced by the addition of a floc-forming chemical. Using the optimum conditions, it was possible to harvest the algae within 1-h settling time and with about 84% recovery. The viability of frozen Chaetoceros was determined by actual cell reproduction. Preliminary feeding experiments showed that Chaetoceros can be successfully used as a substitute for fresh diatoms as feed for Penaeus monodon larvae. Simple freezing techniques, with or without the use of protectants has been found convenient for preserving algal concentrates in small volumes for both feeding and culture purposes.