The Effectiveness of Manila Clam Maintenance Measures in Wajiro Tidal Flat of Hakata bay

Abstract

We identify environmental coalitions which influence growth and survival ratio of the manila clam through field and laboratory experiments, and inspect effects of the maintenance measures of the clam in Wajiro tidal flat. The hardness of the sediment is reduced by tideland cultivation and the softened sediment shows lower temperature when heated by sunlight This shows a possibility of maintaining higher fatness of the clam during summer periods. Setting the protection net on the surface of the tideland prevents the increase of the sulfide in the sediment caused by the corruption of the Ulva, and it maintains the survival ratio of the clam. Consequently, it is shown that these measures are effective for the maintenance of manila clam resources.