Reproductive Cycles Of Cerastoderma Glaucum (Bruguiere) And C. Edule (L.) With Special Reference To The Effects Of The 1981-82 Severe Winter
Gonadal changes in two species of Cerastoderma occurring in discrete populations in South Wales were monitored by stereological analysis during the breeding seasons of 1981 and 1982. Fecundity and spawning efficiencies were determined quantitatively. The relationship between reproductive activity and changes in meat condition are discussed. Both species are opportunistic breeders. Their normal patterns of reproduction are similar, consisting of minimum activity in winter and peak activity during spring/early summer. The two species were affected differently by the severe winter of 1981-82— C. glaucum exhibited a single, ‘epidemic’ spawning and resumed gametogenesis after a 4-month resting period. C. edule adopted a ‘polycyclic’ pattern without a resting period. Both of these unusual reproductive strategies, augmented by reduced predation resulted in heavy spatfalls.