A Research On The Early Propagation And Mass-breeding Technique Of Yellow Catfish (Pelteobagrus Fulvidraco)

Yellow catfish (Pelteobagrus fulvidraco), a species of Pelteobagrus genus in the Bagridae family of Siluriformes, mainly distributed in the Yangtze River, Pearl River and other large rivers. The meat is tender and delicious, nutrient-rich, and it has always been very popular. In recent years, catfish consumption demand increases annually, and catfish-mass farming has not carried out, low yield makes its sale prices keep higher at 40-50 yuan per kilogram. Therefore, the catfish has become one of the most popular varieties in aquaculture in recent years.In recent years, the yellow catfish has been widely investigated in terms of its biological characteristics, reproductive biology, artificial breeding, etc., but the research about its earlier breeding and mass breeding technique remains largely unknown. In this study, we carried out pilot experiments by enhancing pre-training, keeping water quality, and by transferring the parent fish into inside and strengthening cultivation via elevating the water temperature, and analyzed the effects of nutrition and temperature on the mature coefficient yellow catfish. Based on these studies, the effects of different female to male ratio on the fertilization rate and hatching rate were examined. Meanwhile, the effects of different breeding strategies on the body size and survival rate of yellow catfish were also analyzed in this paper. According to the above-mentioned studies, the main results were summarized as follows:1. At the end of April after training phase in catfish pond, the maturity coefficient of cultured female fish increased by 28.1% when compared with that of wild female fish, and that of cultured male fish by 29.0%; during the same period, female ovary the eggs of wild catfish neat, full of eggs, the male testes have glossy lots of branches, and can reach propagation stage.2. It was showed that no significant difference in fertilization rate was found when female to male ratio male was lower than 3:1, while the fertilization rate decreased when female to male ratio increased to 4:1, and significant decrease occurred when the ratio further increased to 5:1 (P<0.05). It indicated that the ratio at 3:1 was suitable for the artificial inducing spawning in yellow catfish.3. Compared fry culturing methods of direct transferring, training and non-cage oxygen cage made of three ponds, direct transferring was the lowest survival rate of fry cultivation, only 32.5%, and survival rate of second cage cultivation, reaching 66%, while the concentration of oxygen produced the highest survival rate, reaching 72% oxygen concentration the survival rate was significantly higher than the cage nurturing foster and nurture a direct transferring, and specifications on the concentration of oxygen was significantly greater than the direct cultivation and cage culture. Focus on aerobic training methods as simple equipment, easy to operate, but also assure the survival rate of fish is a worthy application and promotion of the fry culturing mode.4. Rating foster large-sized species will help improve the growth and survival of small individuals, for different kinds of species to provide adequate growth of resources and to avoid the kind of struggle within the potential disadvantages. In this experiment, the survival rate of fish is not grading 56% in between, the specification is only 8.25cm in length, while the survival rate of classification training 68.5% to specification to9.16 cm in length, sub-level training model was significantly better than the direct way of nurturing large sized species.