Activités reproductrices saisonnières des différentes classes de tailles d'une population de crabes verts Carcinus maenas (Linnaeus, 1758) dans le sud de la mer du Nord = Seasonal reproductive activities and size relationships of Carcinus maenas living in the south of North Sea
d'Udekem d'Acoz, C. (1993). Activités reproductrices saisonnières des différentes classes de tailles d'une population de crabes verts Carcinus maenas (Linnaeus, 1758) dans le sud de la mer du Nord = Seasonal reproductive activities and size relationships of Carcinus maenas living in the south of North Sea. Cah. Biol. Mar. 35(1): 1-13
In: Cahiers de Biologie Marine. Station Biologique de Roscoff: Paris. ISSN 0007-9723; e-ISSN 2262-3094, meer
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- d'Udekem d'Acoz, C., meer
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| Abstract |
In the Ostend population (Belgium, Southern North Sea) of green shore crabs Carcinus maenas, the animals mate immediately after the moult of the female, from April to November but mainly from June to October. Ovigerous females are found from December to August but they become scarce from July onwards. The size of the mating females gradually decreases from June to October. That is due to two facts. Firstly, most females that mate in June are old specimens that have bred at least once; the proportion of these females diminishes in the next months to leave place to young females that have never bred. Secondly, the size of the females mating for the first time decreases from July to October. Part of the small females that have already moulted and mated at the beginning of summer moult and mate for a second time from August onwards after a short sterile intermoult. The average carapace breadth of the females breeding in winter is large. The proportion of small ovigerous females increases in May and decreases afterwards. Part of females spawning in winter have again ripe ovaries in April-June. These females are mainly the large ones. Therefore it is suggested that large females can breed twice or three times each year in the same intermoult (in winter, in spring and sometimes at beginning of summer) and that the small females would breed usually only once, in spring. The average size of the mating males remains nearly constant through the season although there is a slight increase of the small males proportion in the couples after July. |
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