赤潮被害軽減を目的としたプリの人工種苗生産技術の開発

摘要

Yellowtail, Seriola quinqueradiata, is one of the most important target species of aquaculture in Japan. Although fundamental seed production techniques of the fish had been established including broodstock management and egg collecting methods, produced fingerlings were mainly supplied not for aquaculture but for stock enhancement purpose. On the other hand, summer season just before the shipping overlaps harmful red tide bloom period which sometimes causes serious damages to two- year reared yellowtail in sea cages. Therefore, yellowtail farmers urgently needed early shipment techniques for yellowtail fingerlings preventing from harmful red tide damages in the following year. Seikai National Fisheries Research Institute (SNFRI), Fisheries Research Agency, succeeded in collecting eggs from reared yellowtail broodstock on November, half a year earlier than usual spawning period of the fish by controlling environmental factors such as water temperature and photoperiod. SNFRI also succeeded in growing up the fingerlings to 30 cm in TL and 300 g in BW in May of the first year, and they finally grew up to 4 kg over in BW before the harmful red tide occurs around the following year in July.