Abstract:
Five years field observation, Januari 2006 – December 2010, were carried out to document the presence of Pharella acutidens (Broderip & Sowerby 1828) smaller than 20 mm in the mangrove forest of the Riau University Marine Station, Dumai. It was done in order to describe the seasonally of spat settlement. The purposive sampling technik was used in this work. The psycochemical parameters of its habitat were also monitored every month. Not every month of the year the bivalve smaller than 20 mm was presence, but only from Agustus until November at the year. It was found at special substrate at the habitat where the waters was contained more than 4,2 mgl-1 disolve oxygen, pH arround 7, salinity 8,5- 20,5 ppt. It is supposed that the spat settle on substrate from Februari until Mei every year.
