Indoor Spawning and Egg Development of the Red Claw Crayfish Cherax quadricarinatus

In 1991 and 1992, indoor hatchery experiments were conducted with red claw crayfish Cherax quadricarinatus a large tropical crayfish from northern Australia. Six fiberglass tanks were stocked with 40–190 g mature red claw crayfish at 10/m² and a 1:2 male to female ratio. Water temperature was maintained at 28 ± 1 C. Photoperiod was provided by natural daylight in 1991 and controlled lighting in 1992.
With natural lighting, monthly spawning rates (% of females spawning/month) ranged from an average of 15% during months with less than 12 h of light per day to over 35% in months with more than 12 h of light per day. Peak spawning occurred from May to July, too late to obtain juveniles for spring stocking. During the second year, photoperiod was increased from 10L:14D in December to 14L:10D in February and maintained at this level until July. Red claw spawning increased with increasing day length. Peak spawning rates of 50% per month and higher occurred from March to May. Spawning rates decreased dramatically after May, even though photoperiod and temperature remained constant. Eggs per spawn increased with an increase in female size. Fecundity average 7.3 juveniles per gram of body weight for females from 40 to 190 g, regardless of size. Egg color was useful for predicting stage of development.