One Australian Redclaw breeding colony consists of carefully selected healthy, sexually mature 4 females and 1 male that are ready to reproduce.
The key points to successful maintenance and reproduction of brood stock in indoor holding systems include:
- select healthy mature adults
- maintain warm temperatures (preferably 75 F to 85 F)
- maintain good water quality
- provide proper nutrition, and
- isolate berried females to hatching tanks
In a hatchery redclaw can spawn almost continuously throughout the year if conditions are suitable. Redclaw generally reach sexual maturity by the age of 6 to 12 months. Mature male redclaw develop a distinctive red or orange patch on the outside margin of the claws. Individuals of this same size without the reddish claw patch are usually females. The sexes are best identified, however, by examination of the genital openings on the underside of the cephalothorax at the base of the walking legs. Females have a pair of genital pores at the base of the third pair (counting from the head) of walking legs. Males have a pair of small genital papillae (small projections) at the base of the fifth pair of walking legs.
Individual females do not spawn when going through a growth phase (i.e.,molting). Each female will produce 100 to 1,000 eggs per spawn depending on her size and general health. The first spawn of young females usually has fewer eggs than latter spawns. Newly spawned eggs average 10 eggs per gram of female. About 30 percent of the eggs are lost during incubation, resulting in an average of 7 eggs (that hatch) per gram of female. For example, a female weighing 3 ounces (85 grams) would produce about 600 eggs. This can be used to estimate the number of eggs a female of a given size will produce.
Broodstock And Hatchery
Mature broodstock Redclaw crayfish can be kept at a density of 1 to 2 per square foot of tank bottom. The ratio of females to males in each tank should be between 1 to 4 females for each male. Good spawning success has occurred using tanks with water depths of 1 to 3 feet. Small rectangular tanks of 15 to 20 square feet have been used successfully, as well as large circular tanks of 15 feet in diameter with 1-3 feet of water. Example: a 20 sq. ft. tank 2 ft deep could be stocked with 5-10 males and 15-30 female mature Redclaw. Broodstock tanks should maintain a water temperature between 75 and 85 F for optimal reproduction.
Breeding tanks should be checked every one to two weeks for berried females (females carrying eggs). Once the fertilized eggs are affixed to the female’s pleopods, “swimmerets” situated on the underside of the tail, It is highly recommended that berried females be moved to a separate tank. Berried females should be carefully netted, keeping them with their abdomen curled around the eggs during transfer to hatching tanks. (to prevent egg loss). Incubation takes approximately six weeks and the newly hatched juveniles rapidly become independent. The hatching tank will then become the nursery tank for raising the young Redclaw.
“Homes” are essential, Redclaw have a low level of aggression, but do require housing. PVC pipe sections in multiple sizes, mesh bags, burlap, rocks, or anything that the crayfish can climb threw and hide in for shelter. Young crayfish will molt many times during their first year of life, as they grow quickly, while mature redclaw crayfish will molt only once or twice a year. The shed exoskeleton ( molted shell ) is used as a source of calcium and is typically eaten by its owner or other crayfish. Redclaw in tanks can handle a temperature range from 60-90 F. Temperatures below 55 and above 95 will result in casualties.