Morphological And Reproductive Characteristics Of Paramisgurnus Dabryanus Under Different Wintering Conditions

For oriental weatherfishes,wintering is the important stage in the life cycle. However is still poorly researched because of strict conditions in winter. The study included morphological differences and propagation characteristics of two kinds of oriental weatherfishes under manual control in winter, and the main results were as follows:1.The result of Morphological difference analysis of Paramisgurnus dabryanus and Misgurnus anguillicaudatus Formosa showed that:Morphological differences of Paramisgurnus dabryanus and Misgurnus anguillicaudatus Formosa(SST) farmed populations in Zhoushan archipelago were studied through ANOVA, principal component analysis, and discriminant analysis. The result showed that:(1)There were significant significant differences in 8 indices between 24 indexes.(2)Through principal component analysis, the accumulative variance percentage of five principal components whose eigenvalues were all larger than 1 was near 75.395%.(3) In discriminant analysis,discriminant functions could clearly distinguish the Misgurnus anguillicaudatus Formosa(SST)and Paramisgurnus dabryanus farmed populations. The result demonstrated that the discriminant accuracy rate was 100%.2. The result of influences of gonadal development under different overwintering conditions showed that:Through the study of 137 female oriental weatherfishes under three different conditions show that:(1) For Paramisgurnus dabryanus, the oriental weatherfishes in outdoor ponds lost weight significantly, and overwintering in the indoor greenhouses and at 25 ℃ increased weight.(2) Although Misgurnus anguillicaudatus Formosa all had different degrees of weight increase, overwintering in the indoor greenhouses and at 25 ℃ increased significantly.(3) For two kinds of oriental weatherfishes, GSI all increased under three different conditions.For Misgurnus anguillicaudatus Formosa, GSI increases less in the indoor greenhouse. For Paramisgurnus dabryanus, there was significantly decreased at 25 ℃.(4)After wintering, Paramisgurnus dabryanus sperm had increased and in turn increase. The survival rate for Sperms had no significant differences with an average of 0.4007.3.The result of influences of reproductive effects under different overwintering conditions showed that:Through incubating fertilized eggs after wintering under temperature gradient: 14,17,20,23,26,29 and 32 ℃(error ≤0.5 ℃) found that:(1) at a temperature within the scope of 14-32 ℃, the fertilized eggs were hatching, incubation time became shortened as the temperature increased. Different wintering conditions did not affect fertilized egg incubation time.(2) The hatchability showed an increasing trend and then decreased as the temperature increased. Malformation rate of hatched juvenile was relatively high in the high and low temperature environments. There were the highest hatchability and the lowest malformation rate in the range of 20-26 ℃. After wintering under different conditions, the incubation results of Paramisgurnus dabryanus and Misgurnus anguillicaudatus Formosa fertilized eggs had no significant impact.