Bui Thanh Tam creator Machintosh, Donald J. Chairperson Lin, Chang Kwei Examination Committee Knud-Hansen, Christopher F. Examination Committee The Government of Australia Scholarship Donor text series technical report th Bangkok Asian Institute of Technology 1990 continuing eng 99 p. Three experiments were conducted to investigate the effect of light intensity, photoperiod, a nd inclusion of artificial sub - strates on the survival, growth, activity and behavior of Penaeus monad on post- larvae (PL 12 - PL35), each lasting 3 weeks, each experiment involved an in].ti.al stocking density of 20l?Ls/l in aquaria containing 501 of water and average conditions of 20ppt salinity and 28-29°C. Experiment 1 found that light intensities of 200 lux, 600 lux, 1,800 lux and natural light (over 3,000 lux) did not significantly effect the growth a nd survival of the shrimps. A light intensity of 600 lux was selected for further study as it is an easy and economical l eve l of illumination to provide in shrimp nurseries. Results of the second experiment which exposed shrimp to constant l ight intensity (600 lux) but different photoperiods (0:24, 8: 18, 12 :12, 10:8, and 24:U) revealed that continuous l ight (21:0) significantly improved the growth of shrimp post- larvae (p<0.01) but did affect their survival . Light acts as a stimulating factor on the activity a nd behavior of post-larvae, and in this way h ad a positive indirect affect on the growth of the shrimps in these experiments . The shrimps attent the average body weight of 76 . 4mg at PL33, body length of 22mm, total weight and length gain of 2,838% and 1.10% respectively and the daily weight arid length gain of 3.5mg a nd 0. 5mm per day . In Experiment 3, a combination of optimal l ight conditions (600 lux, continuous illumination) plus artificial substrates further improved post- larval growth and survival. Various substages were provided singly, or in combination: mixed gravel/sand; vertical nylon net; horizontal and vertical bamboo frame s . A combination of sand plus bamboo was the best substrate combination. The provision of substrates contributed beneficially to t he growth and survival of the post- larvae by (a) providing them with ho l ding and hiding surfaces, (b) providing an addition - a l source of food because of the build up of micro - organisms on the surface of substrates, and (c) indirectly by acting as a natural bio-filter in t he culture system. Under optimal lighting conditions (600 lux, continuous illumination) plus sand a nd bamboo frame substrates, the follow-ing performance was obtained: mean daily weight gain by post- larvae 5.3mg; length gain 0 . 7mm/day; specific growth rate in body weight: 11.8%/day , and in body length: 3 . 3%/day; total percentage weight and length gain 1,095% a nd 102% respectively and survival rate over 2 1 days : 91%. A thesis submitted in partial fulfillment requirements for the degree of Master of Science, School of Environment, Resources and Development Thesis (M.Sc.) - Asian Institute of Technology, 1990 Shrimp culture Asian Institute of Technology. http://203.159.5.9/ait-thesis/detail.php?q=B18278 http://203.159.5.9/ait-thesis/detail.php?q=B18278 111005 20260818095007.0