辽河口四角蛤蜊繁殖周期研究

Reproduction of Surf Clam Mactra veneriformis Inhabiting the Liaohe Estuary

对辽河口海域四角蛤蜊的繁殖周期及其与环境因子的关系进行研究,2018年3—10月,每月采集样品1次,进行四角蛤蜊的测量、组织学观察及条件指数(软体部干质量占壳干质量的百分比)分析,同时测定该海域的水温、盐度和叶绿素a含量。组织学观察结果表明,该海域四角蛤蜊每年排放配子2次,分别在4—6月与10月上旬,且第一次配子排放持续时间较长;配子成熟及排放期间,水温为15~21℃,叶绿素a含量较高。该海域雌、雄个体数量差异不明显,雄性略多,有雌雄同体现象。条件指数分析结果表明,该海域四角蛤蜊配子排放后,6—9月为恢复期,由6月的最低值8.66逐渐升至9月的14.43。

The reproductive cycle and relationship with environmental factors were studied in surf clam Mactra veneriformis inhabiting the Liaohe Estuary.From March to October 2018,samples were collected monthly for biometrics,histological observation and conditional index(dry weight of soft part/dry weight of shell×100%)analysis.Meanwhile,the water temperature,salinity and chlorophyll a content in the sea area were measured.Histological observation showed that gametes of the surf clam were discharged twice a year,once from April to June,another in early October,and the first gamete discharge lasted for a long time.The maturation and spawning was found at water temperature of 15-21℃with relatively high content of chlorophyll a.There was no significant quantitative difference between males and females in the sea area,but slightly more males and hermaphroditism was found.The conditional index(CI)showed that there was an obvious recovery period from June to September after the spawning in the sea area,and CI was gradually increased from the minimal value of 8.66(June)to the maximal value of 14.43(September).