Though gonad of Corbicula leana PRIME is in maturity all the year round, spawning takes place exclusively at the time when mean maximum water temperature for ten days is maintained more than 19℃. Even in the winter season, ovulation takes place if the minimal water temperature is kept above 19℃, and the spawned eggs grow up to D-shaped larvae. Therefore, this freshwater clam is productive all the year round if under a favorable temperature condition. Such a high temperature preference of this species suggests that Corbicula leana PRIME may be of tropical origin. Ovulating activity continues to few hours in the morning or in the evening. The temperature for the natural spawning varies by season, namely, 15℃-17℃ in April, while 18℃-22℃ during June to September. Maximal frequency of ovulation for a mother shell of shell length 25 mm has been six, and the mean for the whole population is two. The interval between successive ovulation is 103 days in maximum and 8 days in minimum. In the most case, it is about 30 days. Mother shell of shell length about 40 mm ovulates only once.
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