Studies On The Growth, Reproduction And Genetic Diversity Of Monopterus Albus (Zuiew) In Poyang Lake

From September,2006 to August,2007,a monthly sampling of Monopterus albus(Zuiew)in Poyang Lake were collected and its age and growth characteristics, reproductive biology and genetic diversity were studied.The main results were given as follows:1.Ages were determined by reading annuli on basihyal and vertebrae.The maximum ages were 6 and 5 years old for male and female,respectively.The individuals from two to four years old were dominant and represented 89.75%of total catch in Poyang Lake.Within the age interval,the body length ranged from 30 to 50 cm.The body length and body weight was in the relation of power function.The relationship equation of body length to body weight for the female was W=0.0004L³.2601,and that for the male was W=0.0014L².9008.The Von Bertalanffy equation were L_t=78.5[1-e^{-0.17402(t+1.2032)}],Wt=602.01[1-e⁽-0.17402(t+1.2032)]for female and L_t=102.3[1-e⁽-0.11845(t+1.3101)],W_t=947.32[1-e(-0.11845(t+1.3101)]².9008 for male. The growth performance indices wereφ=3.0303(♀)andφ=3.0934(♂).There was a significant difference in growth between the female and male(p<0.01).2.The sex ratio of male to female in the brood stock was 1:3.32.In all the brood stocks,the body length and body weight of the smallest female individual at the age of 1 were 27.8 cm and 22.88 g,respectively,while those for female at 2 years old were 35.4 cm and 49.04 g,respectively.There were both two peak values in the gonadosomatic index(GSI)for female and male,which arrived in May and July.The mean absolute and relative fecundity were 870±57 eggs and 15.48±0.73 eggs/g, respectively.3.RAPD method was applied to study the genetic diversity of five different brindled populations of M.albus in Poyang Lake.One hundred and seventy loci were detected with 13 primers,134 loci of which were polymorphic.The total genetic diversity(Ht)of M.albus was 0.2724,indicating that this population had high level genetic diversity.The average genetic diversity within the population(Hs)was 0.1948, accounting for 71.51%of the total genetic variation.This indicated that the genetic variation mainly existed within the population.The genetic distance was the smallest(0.0400)between small-brinded and black-yellow brinded,while the largest(0.1801)between the big-brinded and hidden-brinded,which indicated the different levels of gene flow between them.