Abstract

The experiment on giant freshwater prawn (Macrobrachium rosenbergii) culture was carried-out in Long An village, Long Ho District and Long Phu village, Tam Binh District,VinhLongProvincefrom May to November, 2003.  Two different stocking densities of 8 (treatment 1) and 12 juvenile/m2 (treatment 2) were randomly designed in six ponds of 1000 - 1200 m2 /each.  The initial size of  prawns were 0.46 - 0.71 g, 3.12 - 3.43 cm.  Prawns were fed by 50 % pellet feed (32 ? 36 % of protein) and 50 % freshwater trash fish.  Feeding rate and feeding frequency were 3 ? 7 % /total body weight /day and two times per day, respectively.  The results showed that the water quality in cultured system such as water temperature, water pH, transparency, oxygen, N-NH4+, N-NO2- and H2S were acceptable values for the freshwater prawn growing and developing.  The survival rate of freshwater prawn in earthen ponds obtained in treatment 1 (39.8 ±  2.2 %) was not significantly higher (P > 0.05) than those in treatment 2 (34.9 ± 2.2 %) after 180 days.  The growth rate of prawn obtained in treatment 1 (0.22 g /day) was significantly higher (P < 0.05) than that in treatment 2 (0.18 g/day).  The highest yield of freshwater prawn trial in earthen ponds was 1,130 kg/ha.  Freshwater prawn culture at 8 juvenile/m2 in earthen ponds could be utilized for improving farmer?s income in theMekongDelta.

Key words: Freshwater prawn, Stocking density, Feeding rate

Title: Experimental culture of giant freshwater prawn (Macrobrachium Rosenbergii De Man, 1897 ) at different stocking densities in earthen ponds