PROBLEM TO BE SOLVED: To provide domestically produced biofeed which can be stably produced with low cost, is capable of absorbing sufficient nutrients such as carbohydrates and lipids into a body of larvae and juveniles, and is easy to intake.SOLUTION: Pachydrilus nipponicus Yamaguchi (Oligochaeta, Tubificidae, Pachydrilus nipponicus Yamaguchi) which contains a strong fluorescent substance, often ingests seaweed (Eisenia bicyclis, Ecklonia cava and Sargassum horneri, Undaria pinnatifida and the like) and sea grass (Zostera marina L., Zostera caulescens.) which drifted ashore, and increases amazingly by repeating the processes of cleavage and regeneration in asexual reproduction is fed with hen's eggs for enhancing nutrients of docosahexaenoic acid.SELECTED DRAWING: Figure 2【課題】低コストで安定的に量産でき、十分な炭水化物や脂肪等の栄養を仔稚魚の体内に吸収可能で摂取されやすい国産生物餌料を提供する。【解決手段】強い蛍光物質を含有し、また、海岸に打ち上げられた海藻（アラメやカジメ、アカモク、ワカメ等）と海草（アマモ、タチアマモ）を良く摂取し、無性生殖で切断・再生という過程を繰り返す事によって、驚異的に増殖するイソヒメミミズ（貧毛鋼、イトミミズ目、イソヒメミミズ、Ｐａｃｈｙｄｒｉｌｕｓ ｎｉｐｐｏｎｉｃｕｓ Ｙａｍａｇｕｃｈｉ）にドコサヘキサエン酸の栄養強化を目的とした鶏卵を給餌した。【選択図】図２
