The Reproductive Cycle of Mytilus edulis L. from Lough Foyle

Mytilus edulis L. populations have widely different growth rates and reproductive cycles. Mytilus paradoxically couples high fecundity with an iteroparous life cycle and can be a relatively short lived opportunist or a long lived community dominant in terms of biomass and energy flow. This flexibility has allowed Mytilus to become a highly successful species with wide geographic and local distribution in a variety of habitats. Lough Foyle mussels have been extensively studied by Briggs (1978, 1979, 1982) though information on the reproductive cycle is presently slight. Mature gametes were most common in the summer months though he did note their presence throughout the year (Briggs 1979). Details of meat condition index and biochemical changes are given in Briggs (1978). The present study is part of a larger investigation of the biology of Foyle mussels, the full results of which can be found in McKenzie (1982).