REPRODUCTIVE CYCLES OF CERASTODERMA GLAUCUM(BRUGUIERE) AND C. EDULE (L.) WITH SPECIAL REFERENCE TO THE EFFECTS OF THE 1981-82 SEVERE WINTER |
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Authors: | YANKSON KOBINA |
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Department of Zoology, University College of Swansea Singleton Park, Swansea SA2 8PP, Wales, U.K |
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Abstract: | Gonadal changes in two species of Cerastoderma occurring indiscrete populations in South Wales were monitored by stereologicalanalysis during the breeding seasons of 1981 and 1982. Fecundityand spawning efficiencies were determined quantitatively. Therelationship between reproductive activity and changes in meatcondition are discussed. Both species are opportunistic breeders. Their normal patternsof reproduction are similar, consisting of minimum activityin winter and peak activity during spring/early summer. Thetwo species were affected differently by the severe winter of198182C. glau-cum exhibited a single, epidemicspawning and resumed gametogenesis after a 4-month resting period.C. edule adopted a polycyclic pattern withouta resting period. Both of these unusual reproductive strategies,augmented by reduced predation resulted in heavy spatfalls. (Received 20 March 1985; revised 20 March 1985; |
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