Study On Age,growth,feeding Habit And Genetic Diversity Of Rutilus Rutilus In Xinjiang Uygur Autonomous Region

Rutilus rutilus?Leuciscinae,Cyprinidae:Cypriniformes?is one of the native commercial fishes in the Irtysh River.To study the biological characteristics of R.rutilus and its genetic diversity,435 individuals were collected from the tributary stream?HBH?and the main stream?BW?of the Irtysh River and the Ulungur Lake?UL?from July 2013to July 2016.The main results are as follows:1.The two age determination results of the same observer showed as follows.The sort of agreement rate was sectioned lapillus?93.79%?>scale?87.81%?>vertebrae?74.69%?>operculum?71.60%?.Age appraisal deviation chart indicated the agreement rate between scale and sectioned lapillus was higher than that in vertebrae and operculum.In comparison,sectioned lapillus was the best material for the age estimation of R.rutilus.2.The standard length?SL?of R.rutilus ranged from 58 mm to 227 mm,and weight?W?ranged from 3.2 g to 284 g.The age consisted of six groups,of which the number of the second age was the largest,accounted for 68.28%.The SL-W relationship of R.rutilus were describes as:W=5.799×10^-5TL^2.821 for females,W=4.801×10^-5TL^2.849 for males,and W=9.353×10^-5TL^2.703 for undetermined.The von Bertalanffy growth function for R.rutilus were describes as:L_t=304.4(1-e^{-0.187?t+0.882?})and W=588.3(1-e^{-0.187?t+0.882?})^2.821 for females,and L_t=340.4(1-e^{-0.154?t+0.884?})and W=785.0(1-e^{-0.154?t+0.884?})^2.849 for males.The age inflexion point for the growth of female was 6.51 years,while it for male was 2.92 years.3.Algae was the main food for R.rutilus,especially the diatom and green algae.The occurrence rate,the number percentage,weight percentage,and relative importance percentage for diatom were higher than other kinds of food.4.Sixteen pairs of microsatellite markers were used to analyze the genetic diversity and structure of R.rutilus from three geographical populations?the Beiwan section of the main stream,the Habahe River and the Ulungur Lake?in the Irtysh river basin.The average number of expected heterozygosity,alleles and polymorphism information content were 0.9168,18.9375 and 0.9029,respectively,suggesting higher level of genetic diversity.The genetic diversity of fish in the Ulungur Lake was relatively lower than that in the Irtysh River.The principal component analysis results showed the salinity might be the major factor for genetic diversity between the Ulungur Lake and other two sampling sites.Fst and UPGMA cluster showed that the three populations were almost non-differentiated.AMOVA analysis revealed a high genetic variation within individuals?88.47%?while the genetic variation among populations was low?1.83%?,indicating lower variation levels among populations.