Settlement of juvenile southern rough shrimp, Trachysalambria curvirostris in Osaka Bay

摘要

Settlement of juvenile southern rough shrimp, Trachysalambria curvirostris in Osaka Bay was examined by towing of a small sized mesh sledge net. It was found that specific chromatophores are useful in identification of juvenile southern rough shrimp.The newly settled shrimp appeared from late June to late October. Considering the density trend, it seemed that the main settlement season of this species in Osaka Bay is from July to November. The newly settled juvenile shrimp were caught at all the sampling stations, and there was no significant correlation between the numbers of the newly settled shrimp and environmental factors of the stations (depth, grain size and the value of total sutfide of the bottom soil). Thus, it appears that settlement ofjuvenile southern rough shrimp occurs widely in the Bay, although hypoxic bottom water could affect its distribution in August.