Studies On The Biological Characteristics And Artifical Propagation Of Topmouth Culter In Xingkai Lake

The Topmouth culler in Xingkai Lake is a regional subpopulation of Topmouth cutter, mainly distribute in Xingkai Lake in the Heilongjiang Province of China. As the regional and water surrounding, a unique species in physiological trait was formation here.From April to October in 2008 at Nongken Zhenda Xingkai lake large white fish Research Institute, the fish specimens were random collected and investigated in order to analyze the age and growth rate, routine biology method was employed in this research to find the characteristic of age between growing , breeding specific property and embryonic development trait. In the purpose of abundance the biology data of The Khanka Giant White fish cultivation, and provide the reference of scientific cultivation and ecological releasing of Topmouth culter. Firstly, this study researched in the regularity of cultivates the Topmouth culter from larviculture to adult. And then further research in the artificial propagation technology in order to master a feasible artificial propagation technology operating instruction. The result would make the large production come true.The following are the main results:1. The body weight between stem lengths of Topmouth culter in Xingkai LakeThe body weight between stem length of Topmouth culter is W=0.0056L^3.0004 (R²=0.9952, n=800) .its growth regularity describe in Von Bertalanffy equation, the growth model of Von Bertalanffy can fitting the growth of Erythroculter ilishaeformis.the result are as follows:L_∞=117.54cm,W_∞=9111.15g,L_t=117.54×[1-e^{-0.093(t-0.034)}],W_t=9111.15×[1-e^{-0.093(t-0.034)}]^3.0004,thegrowth inflexion point was at ti = 11.86 years, corresponding to L - 78.36 cm and W = 2.70 kg. There were differences between aquaculture ponds and wild conditions in growth patterns of Culter albarnus in Xingkai Lake. The characters of growing course could be reflected by analyzing the growth rate and the acceleration growth curve. The result proves that the potential of Topmouth culter growth in pond can be generalized widely.2. Ovary development and Staging of Topmouth culter in Xingkai LakeThe oocytes of Topmouth culter was closed, male Topmouth culter remained inâ…¢stage all the winter, it begin to develop fromâ…¢toâ…£in May, and came toâ…£in June. The mature coefficient of ovaries began to increase from April and achieve its peak in June; then the mature coefficient of ovaries declined in July, and quickly decresed from august. The Value of gonad somatic index (GSI) changed from an average of 0. 73%-14.37% in a year. But the oocytes of Erythroculter ilishaeformi Bleeker in Taihu Lake at may were in stageâ…¢, GSI changed with an average of 2.4%-4.7%;It was in stageâ…£in the later of June, GSI changed with an average of 5.4%-6.4%.3. The reproductive ability of Topmouth culter in Xingkai LakeTwenty adult Male Topmouth culter specimens (560.2-4205.7g)were colleced at the breeding season from May to June, the result shows that the absolute reproductive ability was 8.07-24.64 thousand per fish and the average was 15.67 thousand per fish; The relative fecundity (F / W) was from 46.58-108.26 per gram and the average was 79.90 per gram.4. The embryonic development of Topmouth culter in Xingkai LakeThe mature semi-pelagic eggs were light yellow green or blue brown in color with0.86-1.22mm in diameter and grew to 4.42-5.58 mm after hydration. The embryo hatched 22hours after fertilization with accumulative temperature of 591.04℃·h.at water temperature(26.8±0.5)℃. The embryonic development is similar to other Culter alburnus except theaccumulative temperature. Maybe environment or other factors caused. The fertilized eggs of Erythroculter ilishaeformi Bleeker in Taihu Lake were average size of 0.8 mm in diameter and bulged to 1.2 mm in diameter after absorbing water. Egg envelope are thicker, it must stripping the envelope in order to observation the embryo development.5. Spawn type of Topmouth culler in Xingkai LakeAll the Topmouth culter ovocyte in ovary are in the same stage, they are immature until the generation season. The eggs are spawning at the same stage and are pelagic eggs...