Studies On Biology Of Stocks And Genetic Diversity Of Coreius Heterodon (Bleeker)

This paper studied the age and growth characteristic and resource status of Coreius heterodon (Bleeker) in Yangtze River after the Three Gorges Dam is built, and analysed genetic diversity of Coreius heterodon of different colonies of the upper and middle and lower reaches under the Yangtze River by mtDNA sequences. The main results are as follows:1. The Age of Coreius heterodon can be identified through the characters of annual rings on the scales, Otoliths and vertebrae; and agreement rate is 100% within one annuli reading error. But the scale is the most reliable material to define age.2. The annual rings on the scales can be divided into widely and narrow-spaced type and cutting type, and usually both appear in the same scale. The annuli was assigned to the last growth ring of the close zones adjacent to the outer wide zones. In the perspective light, otolith and vertebra are arrange alternately by wide opaque zones and narrow translucent zones, and the annuli was assigned to the outer border of opaque zones under perspective light.3. The relation between body length and body weight of Coreius heterodon can be expressed with the power function equation: W = 0.01347L^3.0141. The growth equation of Coreius heterodon can be described with von Bertalanffy factions of L_t =54.8156[l-e^[-0.2071(t+0.6139)]]and W_t =2347.4625[1-e^[-0.2071(t+0.6139)]]^3.0141. The inflexion points is 4.71years, and in this point the body length and body weight are 36.58cm and 693.21g, respectively.4. The growth of Coreius heterodon showed two apparent phases. The growth of the before-4-aged group is in creasing, while that of the after -4-aged group is declining.5. With the method of Jones length-based cohort analysis, when E_t were 0.6, the annual population size of Coreius heterodon in Wanzhou is estimate to 214524, 168817, 174645 , 131988, 124815 individuals in 2000 to 2004, with an average of 162958 individuals. Compared to 2000, the population sizes have dropped by 41.82%, 18.59%, 38.47%, 21.31% respectively in 2001 to 2004.6. The mtDNA D-LOOP of 41 individuals of Coreius heterodon collected from wanzhou, Shashi, Hukou, Changshu were amplified with PCR technique and sequenced.A scrept of 760bp were detemined. Number of polymorphic sites was 17, and most of themoccurred with in D-loop near tRNApro. Average number of nucleotide difference (k) and nucleotide diversity (pi) within population was 1.649 and 0.00218. Transition is 1.67 times as high as transversion. Total 12 haplotypes were detected from 41 individuals. Molecular phylogenetic trees (UPGMA and UJ) were constructed. Its result shows that genetic divergence among different populations was not obvious.