A comparison of clutch and brood size in the Red Claw, Cherax quadricarinatus (von Martens) and the Yabby, C. destructor Clark (Decapoda: Parastacidae)

Abstract

Data are presented on clutch and brood size in the freshwater crayfishes, Cherax quadricarinatus (red claw) and C. destructor (yabby) obtained under indoor hatchery conditions. Clutch size, measured as pleopodally attached eggs, and brood size, measured as newly independent juveniles, were positively related to crayfish weight. Regression coefficients were not significantly different from 1.0, consistent with theoretical expectations for clutch/brood size–weight relationships. ANCOVA indicated significance differences between species and between clutch and brood sizes. Based on size adjusted means, C. destructor was found to produce 1.5 times more offspring than C. quadricarinatus and average brood size was found to be 40.0% lower than average clutch size. Causes of egg and larvae loss, and reasons for the high degree of variability in clutch/brood size estimates amongst studies of these crayfish are discussed.