黄河三角洲青蛤的繁殖生物学研究

The Reproductive Biology of the Venus Clam,Cyclina sinensis Gmelin,from the Yellow River Delta

以我国沿海重要的经济贝类青蛤为研究对象,自2007年4月~2008年3月对黄河三角洲海区环境因子(温度,盐度,叶绿素a含量)和青蛤的繁殖周期进行了研究。环境因子的分析结果表明温度和叶绿素a含量存在明显的季节变化,而盐度则无明显变化。组织学研究表明配子发生开始于低温期1月;大部分卵子在6、7月成熟,此期条件指数的值为全年最高峰;产卵排精开始于水温和叶绿素a含量分别为全年最高的夏末秋初,伴随着条件指数的急剧下降;9月大部分成熟精卵都已排放,此时水温为21℃适于幼虫的生长,浮游植物含量最多有助于提高幼虫的成活率。本实验结果对于黄河三角洲青蛤种质资源的管理保护、养殖开发与可持续利用具有重要的应用意义。

The venus clam Cyclina sinensis(Gmelin) is a commercially important bivalve species along the coast of China.Seasonal variations in the environmental parameters(temperature,salinity and chlorophyll a) and the reproductive cycle of C.sinensis from the Yellow River delta were investigated from April 2007 to March 2008.The analyses of the environmental parameters indicate that there were significant seasonal variations in temperature and chlorophyll a concentration,but not in salinity.According to histological observations,the cycle of gametogenesis began at a low water temperature in January;most gametes riped in June-July when the condition index(CI) peaked;spawning started in late summer and early autumn when the temperature and chlorophyll a concentration were at their highest.The curves of the CI and oocyte diameter decreased sharply after spawning,as most larger,mature ova had been released.In September,most individuals of the C.sinensis population were spent,and the plentiful phytoplankton and higher water temperature(21 ℃) were fit for the larvae to grow.The information obtained in this study is important for sustainable management of wild stocks as well as for the development of clam aquaculture in the Yellow River delta.