Innovative Improvement Method of Ti dal Mud in Ariake Sea, Japan for Restoration of Sinonovacula Constricta Shell

Abstract

The Ariake Sea, which is one of the best-known semi-closed shallow seas in Japan, is famous for its various kinds of fisheries’ products and seaweed cultivation. Recently, a dramatic decrease in the catch of shells has been observed in the Ariake Sea. This study discusses an innovative improvement method that was used in the tidal mud of the Ariake Sea to restore the Sinonovacula constricta shells. Field investigations were carried out in the Iidatidal flat area by creating an improvement area comprising of dikes,sand and recycled waste glass. Results indicate that in the improvement area, water content was reduced to less than 200% in the upper layers of the mud and compares favorably with the non-improvement area that had a water content of 250%. Additionally, the acid volatile sulphide (AVS) value in the improvement area declined significantly and was measured within the safe limit for both the benthos living in the tidal mud and the adult shells.

Keywords: Ariake sea, tidal mud, improveme nt area, benthos, sinonovacula constricta, survival rate, geo-environment