Les modalités de la reproduction de la coque (Cerastoderma edule) sur le littoral français de la Manche et de l'Atlantique

Abstract

Events in the reproduction of Cerastoderma edule were studied simultaneously during 1937, in eight intertidal zones, with relatively homogeneous edaphic conditions and distributed along the French Channel and Atlantic coasts. This approach was intended at identify the variability of spawning which may induce fluctuations in the recruitement from site to site and from year to year. Different stages of sexual maturity were used together with the condition index of Walne and Mann. Spawnings may occur from March to October, sometimes up to December. The number and intensity of cach spawning may exhibit différent patterns. The resting stage was observed between October and March. It seemed neccessary for an efficient spring spawning which may be stimulated by temperature increase. Other spawnings are correlated with the intensity of the first one. The variability of the reproductive scenarios was not linked with the latitudinal gradient. In all these sites, the condition index, associated with the maturity stages, was effective for a prediction of good conditions for recruitement. © 1990 IFREMER-Gauthier-Villars.