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No Thumbnail AvailableProjectThe effects of paddlewheel aeration and stocking density on water quality and production of Macrobrachium rosenbergii (de Man) under monoculture system
Establishment of a Network of Aquaculture Centres in Asia
1986Also available in:
No results found.The effects of aeration and stocking density on water quality and production of Macrobrachium rosenbergii were examined in six 0.54 ha ponds in Nakhon Pathom province, Thailand, during a grow-out period of eight months. The experiment comprised three treatments; T 1) 20 prawn/m2 stocking density with aeration, (T1), 2) 20 prawn/m2 stocking density without aeration (T2), 3) 10 prawns/m2 stocking density without aeration (T3). The ponds of treatment 1 were subjected to the aeration by means of ele ctric-powered paddlewheel aerators, after 3-months of stocking. Prawns were fed a formulated pellet feed once a day approximately at the rate of 5% of body weight. Prawns were partially harvested 3 times before total harvest. In all the ponds, the survival rates were very low (T1=18%, T2=15%, T3=18%). Because of the heavy mortality occurred during the grow-out period, much desired data could not be collected. However, when the collected data were statistically analyzed no significant differe nces were observed between the treatments with and without aeration or with varying stocking density on water quality and survival rate. Production was low in low density (551 kg/ha) compared to the high density (876–894 kg/ha). Mortality occurred during the experimental period was mainly due to sudden falls of temperature, high rates of liming, and DO depletion. Oxygen depletion was resulted from phytoplankton blooms and their sudden die-offs due to heavy rainfalls. Paddlewheel aerator used, proved to be insufficient to raise the DO (water depth 1 meter) level at such time. -
No Thumbnail AvailableProjectProduction, yield characteristics and economics of polyculture of Macrobrachium rosenbergii and various fish species under pond condition
Establishment of a Network of Aquaculture Centres in Asia
1986Also available in:
No results found.The effect of two densities of freshwater prawn Macrobrachium rosenbergii on production,yield eristics and economics under polyculture system were examined in four ponds of 1.75 rai each during seven months growing period.Prawns stocked at about 2 (L.D) and 5 (H.D) tails per sq.m with the average weight of 3–4 g.Fish stocked in each ponds are as follows:225,500,350 and 1250 tails per pond for common carp,giant gouramy,bighead and silver carp respectively.The average production of fish in L.D and H.D amounted to 2,295 and 2,125 kg per ha respectively.Common carp had a highest growth,while silver carp and bighead were the lowest.There was an indication that the production in H.D was higher.The average production of prawn in L.D and H.D reached 722 and 910 kg per ha.It is considered that the stocking rate of common carp should be lower,since the pond productivity was not enough to support the growth of silver carp and bighead carp.It is observed that the production of fish was not affecte d by the different stocking densities of prawn.The survival rate of common carp was the highest(92%),followed by bighead carp (83%& 93%),silver carp (89% & 80%)and giant gouramy (76%& 73%).For the prawn it ranged from 49.1–61.1%,except one replicate in L.D which comprised 95%. This may probably be due to second restocking. The F.C.R of fish,based on the F.C.R of prawn (2.5),were 0.85 and 1.12 respectively in L.D and H.D.The average weight (g) of male prawn ranged widely in each category (43–102 g) compared to female prawn (29–51 g). The percentage in number of female prawn ranged 65–72% in both L.D and H.D. There is a positive relationship between stocking density and the percentage both in number ans weight of female prawn as well as the marketable yield. The marketable yield comprised about 87% of total biomass both in L.D and H.D.*** -
Book (stand-alone)The potential of farming tilapia (Oreochromis niloticus) and freshwater prawn (Macrobrachium rosenbergii) in Vanuatu 2004
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No results found.Under the auspices of the Food and Agriculture Organization of the United Nations (FAO) Sub-Regional Office for the Pacific Islands (SAPA) in Samoa, a feasibility study on farming tilapia and prawns was undertaken by SPC Aquaculture Office in November 2003. The objectives were to survey the potential to develop Tilapia (Oreochromis niloticus) and Prawn (Macrobrachium rosenbergii) farming in Vanuatu (further details are given in the Terms of References in Appendix 2).
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