Studies On Biological Characteristics And Farming Technology Of Hybrid "Taihu No.1" Of Macrobrachium Nipponense

Oriental river prawn, Macrobrachium nipponense, was also called river shrimp. It was a famous aquatic product with many characteristics such as good taste and was rich in nutrition. It is an important species for aquaculture in China. However, its economic characters seriously declined due to genetic retrogression in recent years. Because of the late beginning and very less work in genetic breeding, the relevant research cannot match the demand of production. As a result, it’s very important to strengthen the investigation of genetic background, establish the feasible techniques of genetic breeding and develop excellent varieties in Oriental river prawn. The hybrid "Taihu NO.1" of Macrobrachium nipponense was a new breed with fine quality obtained by Freshwater Fishery research center in8years. It was approved and admitted to be the first new breed of freshwater crustaceans by the National certification committee of aquatic and breed variety in January,2009.In this paper, the breeding biology and ecology of the hybrid "Taihu NO.1" of Macrobrachium nipponense was studied and the results showed the spawning time of the hybrid "Taihu NO.1" was from April to October in a year. Its reproductive potential was higher in spring and summer than in autumn. The sex ratio (♀:(?)) in the population was ranged from0.83to6.53with the average of2.18. The absolute fecundity F varied from1910to5915in spring and summer while varied from450to1847in autumn. The relative fecundity RL ranged from44.62to106.65in spring and summer while ranged from38.33to79.61in autumn. The relationship between spawning time Rw and body weight W could be expressed as Rw=[(0.1635W-0.0486)×6168]/W.The growth parameters of the hybrid "Taihu NO.1" and normal oriental river prawn from Taihu Lake were compared under the same conditions for90days. The results showed that the absolute growth rate of body weight of the hybrid "Taihu NO.1" was0.0281g/d and the instantaneous growth rates (IGR) was2.181%/d; the absolute growth rate of body weight of normal oriental river prawn from Taihu Lake was为0.0209g/d and IGR was1.817%/d. Both two parameters indicated that the growth performance of the hybrid "Taihu NO.1" was better than normal oriental river prawn from Taihu Lake.The oxygen consumption rate of the hybrid "Taihu NO.1" was also studied in this paper. The samples with the average body weight of2.15g were tested in different temperature ranged from18to20.5℃.The results showed that the average daily oxygen consumption rate (OCR) of the hybrid "Taihu NO.1" was0.3319mg/(g·h). It reached the top in6pm [0.5725mg/(g-h)] and fell into lowest in2am.[0.1905mg/(g·h)]. The asphyxiation point was1.92mg/L,1.98mg/L、1.96mg/L.The parameters of pH and DO were monitored continuously in experimental ponds of oriental river prawn. The results suggested that the right amount of weed, compound microbial agents and enclosed or half-enclosed environments could cut down the wastewater pollution of shrimp culture to natural waters and was helpful to protect water resources and increase the breeding benefits.