Perkembangan Gonad dan Musim Pemijahan Kerang Sepetang (Pharella acutidens) di Ekosistem Mangrove Dumai, Riau

Perkembangan Gonad dan Musim Pemijahan Kerang Sepetang (Pharella acutidens) di Ekosistem Mangrove   Dumai, Riau

Efriyeldi¹, Dietriech G. Bengen², Ridwan Affandi³

dan Tri Prartono²

¹Mahasiswa  Program Doktor Institut Pertanian Bogor

²Departemen Ilmu dan Teknologi Kelautan FPIK, IPB

³Departemen Manajemen  Sumberdaya Perairan FPIK, IPB

Received 02 Februari 2012; received in revised form 20 Maret 2012;

accepted 05 April 2012

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 index

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