A STUDY ON CULTURE TECHNIQUES OF HIGH DENSITY OF JUVENILE PRAWNS (PENAEUS ORIENTALIS) IN LABORATORY

The effects of food, salinity and other factoro on the survival rate and growth ofjuvenile prawns under high density cultivation in lab. were observed. Through ortho-gonal design of multi--factors, the additinal single--factors experiments and productiveexperiment, several key technical measures were explored.The results of the experiments as follows: 1. The fow limit of suitable and optimum salinities for juvenile prawns are 16‰and 22‰ respectively. The optimum cultivation value is 25%.2. Nauplius of Artemia salina were used to fed the post larvae of prawn in thefirst four days. The feeding ration from the first-day larvae was 125 individuals perjuvenile prawn. Latter on. the appropraite daily increasing of food was 90 individualsper prawn. The Tubifex sp, the ground Venerupis philippinarum meat or the brineshrimps could be fed to the post larvae of prawn during the period from the 5th day tothe 20th day. The feeding ration could be calculated as following:Wg×1^(-2)(P) = 0.2482e^(0.2064t)t: days of culture of juvenile prawn3. By keeping the Platymonas spp. a density of 0.5--1.0×10⁴ cell/ml couldremarkably decrease the amount of NH₃--N in culture seawater.4. By keeping terramycin a concentration at 0. 5--1. 0 ppm in culture seawatercould not only prevent diseases, but also accelerate the growth of juvenile prawn.5. In the productive experimental 1.41 million juvenile prawns with an averagelength of 0.95mm were harvested from 13 ponds of 23m³ seawater. The yeild was 61thousand prawns per cubic meter of seawater. The survival rate was up to 83.3%.