Perkembangan Gonad Dan Musim Pemijahan Kerang Sepetang (Pharella Acutidens) Di Ekosistem Mangrove Dumai, Riau

Abstract

This research aims to study the gonadal development and spawning seasonof “sepetang” clam (Pharella acutidens).The study was carried out over 12 month period from November 2010 to October 2011 at Dumai mangrove ecosystem.“Sepetang” clam samples were obtained from the Dumai mangrove ecosystem monthly at three station. The clam collected from plot 1 x 1 m2on quadrat transect. Reproductive aspects such as sex ratio, gonadal development,gonadosomatic index (GSI), and oocytes diameter were studied.The result showed that “sepetang” clam can be sexed at the size more than 35 mm. No specimens hermaphroditism was observed. The male to female ratio was 1 : 1.12. Histological analysis indicated that P. acutidenshadfour distinguishable gonad development in male and female clam, namely early active, late active, ripe and partially spawned. Mean oocyte diameter did not showed pattern monthly, except onMay to July, mean oocyte diameter small. Based on gonadal development, GSI and mean oocytes diameter, “sepetang” clam spawning continued throughout the year and peak spawning season my be on May-July. Keywords : “sepetang” clam, histological, sex ratio, gonadosomatic inde