A COMPARISON OF CLUTCH AND BROOD SIZE IN THE RED CLAW, CHERAX-QUADRICARINATUS (VON-MARTENS) AND THE YABBY, CHERAX-DESTRUCTOR CLARK (DECAPODA, PARASTACIDAE)

Data are presented on clutch and brood size in the freshwater crayfish es, Cherax quadricarinatus (red claw) and C. destructor (yabby) obtain ed under indoor hatchery conditions. Clutch size, measured as pleopoda lly attached eggs, and brood size, measured as newly independent juven iles, were positively related to crayfish weight. Regression coefficie nts were not significantly different from 1.0, consistent with theoret ical expectations for clutch/brood size-weight relationships. ANCOVA i ndicated significance differences between species and between clutch a nd brood sizes. Based on size adjusted means, C. destructor was found to produce 1.5 times more offspring than C. quadricarinatus and averag e brood size was found to be 40.0% lower than average clutch size. Cau ses of egg and larvae loss, and reasons for the high degree of variabi lity in clutch/brood size estimates amongst studies of these crayfish are discussed. (C) 1998 Published by Elsevier Science B.V. All rights reserved.