PROBLEM TO BE SOLVED: To provide a ground substance for cultivation of seedlings of an infaunal bivalve, particularly, Tresus keenae (species of trough shell), which can be stably used in all sea areas, which can be easily handled and which makes costs low.SOLUTION: A substance, in which earthenware hulls and rice hulls are blended in the range of a volume ratio of 1:2-2:1, is used as a ground substance for suspended cultivation of seedlings of an infaunal bivalve, particularly, Tresus keenae (species of trough shell).【課題】あらゆる海域で安定して使用でき、取り扱いが簡単で、低コストで済む埋在性二枚貝、特にミルクイ貝の種苗の養殖用基質を提供すること。【解決手段】埋在性二枚貝、特にミルクイ貝の種苗の垂下養殖用の基質として、陶器殻と籾殻を容積比で1:2~2:1の範囲で配合したものを使用する。【選択図】 図1