Investigating the reproductive cycle and some maturation indexes of clams (Tapes dorsatus) collected from Thi Nai lagoon, Binh Dinh province
Clams Tapes dorsatus were collected from the coastal areas of Thi Nai lagoon to examine some reproductive parameters and conduct the maturation culture experiment. The results of examining the reproductive cycle showed that clamsget the highest value of condition index and gonad index from October to February of years. The gonado index GI the trial test of maturing mangrove clam was carried out in 7 periods with different treatments: the clamsreared in the plastic basketswithout sandy bottom; the clams directly reared on the sandy bottom of sandbank covered by net;the clamsreared in the plastic basketswith sandy bottom of 10-15 cm. The results of the experiment indicated that clams reared in the plastic basketswith sandy bottom of 10-15 cm obtained the highest weight, length and survival rate (these values were 51.6g, 49.2mm and 96,5% respectively after 60 days of rearing). Similarly, CI and GI were also highest for clams cultured in this treatment. The fecundity of the clams was highest, with 3,537±1,102 eggs/gfresh muscle and number of eggs/g total weight of clams 28,339±10,556 when they were reared in the plastic basketswith sandy bottom of 10-15 cm.