瀬戸内海安芸灘におけるアカエビの成長と成熟

抄録

This paper describes the growth and maturation of Metapenaeopsis barbata and discusses the presence of the short life generation previously stated. The shrimps were collected by a small trawl in 1987. Monthly changes in carapace length distribution and gonad somatic indices (GSI) were obtained. Carapace length distribution was usually bimodal except during the period from July to September. The larger cohort was one year older than the smaller cohort. The lifespan was estimated at two years. Rapid growth was observed from July to October in the female and from June to November in the male. The spawning season was from June to October, when the temperature of habitats were higher than 18°C in the area. In females, the 2-year-old cohort matured one month earlier than the 1-year-old cohort. This species could therefore have two spawning seasons before death. However, the 0-year-old female cohort never matured. Consequently, no short life generation was observed in this area.