|A comparative study of the reproductive cycles of the cockles Cerastoderma edule and C. glaucum|
Boyden, C.R. (1971). A comparative study of the reproductive cycles of the cockles Cerastoderma edule and C. glaucum. J. Mar. Biol. Ass. U.K. 51(3): 605-622
In: Journal of the Marine Biological Association of the United Kingdom. Cambridge University Press/Marine Biological Association of the United Kingdom: Plymouth. ISSN 0025-3154, more
Reproductive cycle; Cerastoderma edule (Linnaeus, 1758) [WoRMS]; Cerastoderma glaucum (Bruguière, 1789) [WoRMS]; Brackish water
The reproductive cycles of the two cockles Cerastoderma edule (L.) and C.glaucum (Poiret) (= Cardium lamarcki Reeve) from a mixed population in the Crouch estuary, Essex, have been investigated. Reproductive maturity was estimated by assessment of gonad condition. A difference in maturity related to shore level was noted. The reproductive cycles of the two cockles were found to be essentially similar. Rapid gametogenesis occurred in both cockles in spring, C. edule then spawned in May, whereas C. glaucum did not spawn until July. The difference in time of spawning appears to be responsible for the maintenance of the two genotypes in a sympatric association, as hybridization experiments showed an absence of isolation at the gamete level. The relationship between C. edule and C. glaucum is discussed.