Evolution du taux de présence de spermatophore chez les femelles de nephrops norvegicus (L.) (Decapoda : reptantia) et développement ovarien

Ovary development and the presence of spermatophore in females of Nephrops norvegicus (L.) (Nephropidae) from South Brittany were studied from July 1976 to October 1978 through size classes. Percentage of females bearing spermatophores increased slowly up to 1978 during which year a sudden and important decrease was observed. The percentage decreased to the lowest value obtained in 1976. A study of ovarian development showed that the proportion of small females taking part in reproduction was greater in 1978 than in 1977. The beginning of the decrease in the percentage of spermatophores present coincided with the beginning of spawning in each size class. It may be explained by the behaviour of ovigerous females which stay in burrows during the incubation season. The decrease is, however, very important as the proportion of mature females is high and because the time separating the autumn moulting from spawning is great. Spawning occurred in several months (4 months in 1978). The "mean size at first maturity" varied from year to year and also from month to month, even if the presence of spermatophores was taken as a criterion. [NOT CONTROLLED OCR]