Studies On Biological Comparisons And Hybridization Of Two Geographic Populations Of Coelomactra Antiquata

Coelomactra antiquata is one of the valuable and important commercially exploited bivalve in China.Due to overfishing and habitat destruction,its populations have been severely declining in the coast of China during the last two decades.In order to make corresponding measures for resource conservation and feasibility of hybridization,two populations of C.antiquata from Fujian Zhanggang and Jiangsu Qidong,were analysed morphologically and free amino acids.Then,crossbreeding was performed using the two populations.The results suggest that:1.Based on shell colour,shell cubage,shell density and morphological characters of populations of C.antiquata from Fujian and Jiangsu,the result of discriminant analysis revealed that there were significant differences among the two population.The discriminant functions of two population were established,and the total discriminant accuracy was 91.76%.The functions were:Y_FJ=35.950×shell length+38.847×shell width—262.449 Y_JS=19.457×shell length+61.992×shell width—205.9472.This contribution of nutritive composition is similar with Fujian and Jiangsu populations. Nutritive composition revealed that C.antiquata was a good seafood with high protein and low fat.The contents of Glu,Asp,Gly and Ala in Fuzhou population(56.88%)were higher than Jiangsu(49.07%),which has a unique delicate meat texture and sweet taste.3.The effects of salinity on sperm motility,fertilization and hatching-rate of C antiquata were observed on the condition for different experimental salinity.The results suggest that the optimum salinity range for fertilization of C.antiquata is from 25ppt to 30ppt,and 28ppt is the best optimum salinity.4.Larval of four groups were obtained from mating and crossing within and between Fujian population and Jiangsu population of C.antiquata.Comparisons of egg size,embroyonic development rate,larval settlement rate,larval metamorphosis rate,larval survival rate and growth among four groups were made.The results revealed that the hybridization groups showed heterosis of various degrees on them.Especially,Fujian♀×Jiangsu♂group was significant differences on growth(20.14%)and capability of resist to extreme conditions compared to self-fertilized groups(73.26%,77.61%,447.8%,280.24%).