Abstract.The effects of density, cover, and individual versus communal holding on brood size and female survival during the breeding period were examined in a large‐scale experiment, involving 3591 mature noble crayfish,Astacus astacusL., females.Crayfish density during both mating/spawning and winter incubation had major effects on egg survival. In the high density experiment (67 and 44 individuals per m2during mating/spawning and winter incubation respectively) mean pleopod egg number in April was 18‐20. Lowering the density to 50 during mating/spawning (still 44 individuals per m2during winter incubation) gave mean pleopod egg numbers of 31‐38. In the low density experiment (50 and 33 individuals per m2during mating/spawning and winter incubation) mean pleopod egg numbers were 44‐46. Egg‐bearing females held in individual compartments with perforated bottom had a mean pleopod egg number of 25.Female survival during winter incubation was high, ranging from 91.8 to 98.3%. Covering the basins had no distinct effect on egg and female survival.InAstacus astacusculture we recommend that crayfish density should not exceed about 50 individuals per m2during mating/spawning and about 33 individuals per m2during winter i