Morphometry, Sexual Dimorphism and Size At Maturity of the White-Clawed Crayfish Austropotamobius Pallipes Pallipes (Lereboullet) From a Wild French Population At Deux-Sèvres (Decapoda, Astacidea)

Abstract

This paper describes patterns of sex and size dimorphism and allometric growth in a French population of the native crayfish species, Austropotamobius pallipes pallipes. The threatened status of this species shows the necessity to establish a suitable management to protect it. An efficient management requires an increase in our knowledge about existing populations. By using allometric relationships, we characterized the size at the onset of sexual maturity in both sexes and evaluated sexual dimorphism in this population. The size at the onset of sexual maturity appeared to be different in both sexes (20.1 mm POL in males and 18.17 mm POL in females). The sexual dimorphism, shown by the variables of claw length and abdominal width, was not closely related to the puberal moult. The growth rates of this population were very different from those shown by other European populations. Discriminant analysis was performed on the data, but it did not separate the juveniles of both sexes. This study provides fundamental results concerning the relative growth of A. pallipes which could be used to compare several French populations in the future.