The reproductive biology of Sergia lucens (Hansen) in Suruga Bay, Japan (1): Development of ovary, copulation and number of spawnings of individual females

Abstract

This study concerns the reproductive biology of the commercially important sergestid shrimp Sergia lucens in Suruga Bay, Japan. It includes observations on oocyte development, copulation and the number of spawnings of an individual female during the spawning season. Histological sections of the ovary revealed 10 developmental stages of gametogenesis. In the ovary there were always oocytes of different developmental stages. Spermatozoa are retained in the female’s sperm receptacle after spawning. They are also found in the thelycum of immature females, suggesting that the shrimp copulate several times, since the females are not fully matured. Based on the data from the monthly occurrences of eggs in Suruga Bay from 1981 to 1989 and from laboratory spawning experiments in July, August and September in 1992 and 1993, it was estimated that one female spawns 7–8 times between May and November at an average interval of 19 days.