Crowding female red claw crayfish, Cherax quadricarinatus, under small-tanks hatchery conditions: what is the limit?

Previous studies on reproduction in the red claw crayfish, Cherax quadricar inatus, have successfully employed broodstock densities of up to 20 crayfis h m(-2). This study attempted to increase the density of broodstock in orde r to intensify production of young in indoor hatcheries. Adult crayfish wer e stocked in 0.3 m(2) tanks at a 1:5 M:F sex ratio at three densities: 6, 1 2 and 18 crayfish per tank (corresponding to 20, 40 and 60 m(-2)). The numb er of berried females was noted at weekly intervals during 14 weeks. There was no difference among densities in survival rate and percentage of spawni ng and molting, nor in clutch size (pleopodal egg counts) of females. The r esults indicated that breeding red claw females are insensitive to crowding over a wide range of densities. They suggest that a broodstock density hig her than 60 crayfish m(-2) is feasible under indoor hatchery conditions. (C ) 2000 Elsevier Science B.V. All rights reserved.