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Ecology of Redclaw - (Cherax quadricarinatus) - Freshwater crayfish
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Redclaw are native to the Gulf River Drainage basin of Far North Queensland and the Northern Territory (see map). This region of Australia is subjected to hot and wet summers and dry winters which can become very cool at night. Redclaw are able to survive in these areas with wide fluctuations in environmental conditions and are considered very hardy. They can survive in salty coastal areas and crystal clear mountain streams. Crayfish are detrivorous which means they survive off just about all organic matter that accumulates in the benthic regions. In general they are opportunistic feeder, however the juveniles are able to hunt and catch zooplankton and small water invertebrates. |
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Redclaw are the most fecund (fertile) crayfish currently known. If conditions are right they can reproduce all year round, although environmental clues such as the increasing temperature and increased daylight lengths associated with the coming of spring will generally illicite the largest mating response. Males deposit a sperm packet (spermatophore) on the underside of the female’s tail. She will then lay her eggs which adhere to the swimmerets under her tail. The eggs incubate under her tail for around 6 – 8 weeks and undergo hatching and two larval moults before they take on their final form.
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Being crustaceans they have a hard exo-skeleton which they must shed as they grow. This process is quite complicated and the emergent redclaw is quite soft and helpless for a few days. During this time the redclaw is quite vulnerable until the shell hardens. |
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