Spawning periodicity of three species of Nodilittorina in Hong Kong

Abstract

The spawning periodicity of Nodilittorina trochoides, N. radiata and N. vidua from two rocky shores of different wave exposure, Big Wave Bay (more exposed site) and Cape d'Aguilar, in Hong Kong was monitored for one year (November 1994-November 1995). The breeding season was similar for the three species, mainly during the summer (June-September). The spawning duration was 9 months for N. vidua and 7 months for the other two littorinids. Spawning was initiated at different times for the two sites. At Big Wave Bay, spawning occurred between May-November for N. trochoides; March-September for N. radiata and March-November for N. vidua. At Cape d'Aguilar, the spawning period of N. trochoides and N. radiata was similar (April-October), whilst for N. vidua, spawning extended up to December. A decrease in monthly fecundity was recorded during July and August at Big Wave Bay and Cape d'Aguilar respectively. A weak relationship was found between the size of reproductive females and egg production. The seasonal fecundity of N. trochoides and N. vidua was similar at both sites and estimated as 10000 and 7500 eggs per female respectively. Fecundity of N. radiata varied between sites, with 15 000 eggs and 9000 eggs per female being recorded from Cape d'Aguilar and Big Wave Bay respectively. © 1998 Kluwer Academic Publishers.