THE RELATIVE GROWTH OF CHELIPEDS AND ABDOMEN AND MUSCLE PRODUCTION IN MALE AND FEMALE REDCLAW CRAYFISH, CHERAX-QUADRICARINATUS VONMARTENS

The relative growth of chelipeds and abdomen and muscle production in male and female redclaw crayfish (Cherax quadricarinatus) were studied. In the sample of animals measured, a rapid increase in the relative growth of chela width and cheliped length occurred in males with a carapace length of 43 and 45 mm, respectively. Males larger than this size had wider chelae and longer chelipeds than females with a similar carapace length. A comparison of the ratio of abdomen width to carapace width points to difference in the growth pattern of the abdomen between sexes. In males with a carapace length shorter than 42 mm, the ratio increased with carapace length while it decreased in those with a carapace length longer than 42 mm. In females with a carapace length shorter than 49 mm, the ratio increased with carapace length while it was constant in those with a carapace length longer than 49 mm. Due to the compensation of muscle production from chelae in males and from abdomen in females, total muscle production in relation to carapace length was similar between sexes. However, the percentage of muscle to body weight varied with carapace length and the highest percentage (34%) occurred in the animal with a carapace length of 74 mm. The possible application of these findings is discussed in relation to the definition of sexual maturation and cropping strategy for this species.