Successful artificial incubation and juvenile-rearing of dropped eggs of a critically endangered freshwater crayfish (Cherax tenuimanus)

Authors

Rodney Duffy Dr., Department of Primary Industries and Regional Development, Western AustraliaFollow
Blaine Hodgson, Department of Primary Industries and Regional Development, Western AustraliaFollow
Amber Quinn, Department of Primary Industries and Regional Development, Western AustraliaFollow
Marcus Newman, Department of Primary Industries and Regional Development, Western AustraliaFollow

Document Type

Article

Publication Date

8-11-2025

Journal Title

Marine and Freshwater Research

ISSN

ISSN: 1323-1650, eISSN: 1448-6059

Keywords

Astacidea, captive breeding, conservation, egg disinfection, hairy marron, introduced species, Margaret River, Western Australia

Disciplines

Aquaculture and Fisheries

Abstract

One-third of the world’s freshwater crayfish species face extinction risk, necessitating extreme and urgent conservation measures such as captive rearing. Little information exists on these measures for most threatened species. The hairy marron, Cherax tenuimanus (Parastacidae), is a critically endangered freshwater crayfish endemic to the Margaret River in south-western Western Australia. C. tenuimanus is being rapidly replaced by the smooth marron, Cherax cainii, a translocated congener, causing its progressive decline in range, and now it faces imminent extinction in the wild. Attempts at captive breeding have resulted in few occurrences of egg laying of C. tenuimanus, which ended in complete loss of the clutch as eggs were progressively dropped by the female. To assess the potential of dropped eggs in captive rearing, we trialled ex situ artificial incubation techniques by using eggs dropped from a captively held female. Of 41 dropped eggs, 85% were successfully hatched in suspension upwellers, and 74% of the subsequent juveniles were reared successfully for 111 days in a purpose-built recirculating aquaculture system. We describe our protocols and facilities in detail because captive rearing of dropped eggs was demonstrated to be a viable option for improved success of captive reproduction. These approaches may be applicable for conserving similar crayfish species.

Recommended Citation

Duffy Rodney E., Hodgson Blaine, Quinn Amber, Newman Marcus (2025) Successful artificial incubation and juvenile-rearing of dropped eggs of a critically endangered freshwater crayfish (Cherax tenuimanus). Marine and Freshwater Research 76, MF25063. https://doi.org/10.1071/MF25063