. In comparison, Rajagopal (1991) recorded signs of sexuality in P. viridis living in the cooling conduits of a power station located on the east coast of India, when the mussels were 7 mm in shell length. However, in natural habitats in coastal waters, Rajagopal (1991) observed signs of sexuality and gonad development in 12 mm long green mussels. The possible influence of unfavourable conditions (e.g., chemical stress from chlorine residuals) in the cooling water systems on the reproduction and growth of P. viridis has been emphasised (Rajagopal et al. 1998b). Based on experimental work on gonadal conditions of Atlantic and Baltic M. edulis over a period of 2 years, Seed (1969) and Kautsky (1982) concluded that sexual maturity was not related to size but rather to age and growth rate of mussels. Thus, it is possible that signs of sexuality and gonad development may be observed in P. viridis even in specimens7 mm in shell length, especially when they are growing under unfavourable conditions. In such cases, the
possibility of the mussels being older than what their shell size would indicate, must be considered.