Morphological Variations And Genetic Diversity Of Coilia Ectenes In Differeent Years

Coilia ectenes, as a migrating species, swims back from the sea to the river for reproduction at the beginning of spring. It is wildly distributed in the Bohai Sea、Yellow Sea、East China Sea、 Yangtze River and the lackes nearby Yangtze River. In the past decades,, the stocks of Coilia ectenes have been anxiously depleting and the productivity of natural Coilia ectenes from Yangtze River has been reducing. In this study, five Coilia ectenes populations from2006to2010, all fished in Yangtze River (located inYangzhou), were analyzed by morphology and ISSR methods, and statistically analyzed with Chi-square test among different years of Coilia ectenes were occured in the morphological characters、age、Body-weight and Body-length. The study also achieved the the genetic diversity of Coilia ectenes in Yangtze River. Our results may be beneficial to future brood stock selection, the resource protection and exploitation of Coilia ectenes. The main results of this paper were listed below:1. The age analysis results of Coilia ectenes populations showed that the main age of2006、2007and2009population is2and3years old, furthermore, the main age of2008and2010population is3years old.2008and2010showed significant differ with the population of2006、2007and2009at age of3years old (P<0.05). There was significant differ among different years at age of4years old (P<0.05).2. Body-weight analysis results of Coilia ectenes populations showed that as the body-weight was<40g the percentage was significant different among the populations of2008、2009and2010. As the body-weight was<40<60g the percentage was no significant different among5populations. As the Body-weight was<60<80g the percentage was significant different between the populations of2008and2009、2006and2010. As the body-weight was <80<150g the percentage was no different among3populations of2006、2007and2008.3. The Body-length analysis results of Coilia ectenes populations showed that as the body-length was<21<24cm the percentage was significant different between the population of2010and other4populations, and it was no different among other4populations. As the body-length was<27<30cm the percentage was significant different between the population of2008、2009and other3populations, and the percentage was no different between the population of2008and2009, furthermore, it was no different among the population of2006、2007and2010.4. The age structure、body-length structure and body-weight structure of Coilia ectenes for2006-2010showed a unsignificant downwtrend, and it was a trend of fluctuation in5years.5. The31morphological characters were analyzed for Coilia ectenes populations in Yangtze River, and below11morphological characters were no differ in3populations at2years old:HL/BL、HL/BL、PFL/BL、4-6/BL、8-9/BL、7-5/BL、1-2/BL、4-1/BL、4-5/BL、6-7/BL、8-7/BL, Other20morphological characters showed significant different among3populations. Below5morphological characters were no differ in5populations at3years old:TF/BL、PFL/BL6-8/BL、8-9/BL、7-5/BL. Other26morphological characters showed significant different among5populations.6.147samples for5populations of Coilia ectenes collected from2006to2010were investigated by using inter-simple sequence repeat (ISSR) method. There were42loci occurring in the5populations assayed by ISSR-PCR with5primers, and39within42loci were polymorphic loci. POPGENE analysis result that percentage of polymorphic bands was77.62%, expected heterozygosity was0.2728and Shannon’s Information index was0.4049suggested a high level of genetic variation of Coilia ectenes among5populations.5populations were divided into2groups, the population of2006and2007was a group, and other3popoulations was a group.From the fore mentioned findings it could be concluded that:1) There was a significant differ between the population of2008、2010and other3populations.2) There was a significant differ among5Coilia ectenes populations at31morphological characters, and the differ was more significant at3years old than at2years old.3) It was suggested a high level of genetic variation of Coilia ectenes, and there was genetic diversity among5populations.4) The Coilia ectenes showed a unsignificant downwtrend at age、body-length and body-weight, and it was a trend of fluctuation in5years.