Abstract
The study investigated the relationship between five moult stages and the osmoregulatory capacities (OC), moisture content of hepatopancreas (HM%), hepatosomatic indices (HIwet, HIdry) and growth of 6 weight classes of 235 marron (Cherax cainii) and 235 yabbies (Cherax destructor) under laboratory conditions. In each moult stage, OC increased linearly with the increase in wet body weight. Intermoult stage C showed the highest OC significantly lower than premoult stages D0, D1, D2 and postmoult stage AB in every weight class in both crayfish. HM% decreased from AB to D2, while both HIwet and HIdry reduced from C to D2. Percentage dry matter of whole body carcass was highest in stage C and lowest during the AB stage with a significant difference between the two species. Larger than 15-g marron and yabbies differ with each other in OC, HIwet, and HIdry, moult intervals and growth rates.
Acknowledgements
The authors would like to thank Jane Fewtrell, Simon Longbottom from Department of Environment and Aquatic Science, Curtin University for support and help in the ordering of materials and chemicals, to use in some of the new facilities and equipment in the laboratory, and to set up my experiments. Thanks to Louis Bourdon for proof reading service. This research was co-supported by Vietnamese government and Curtin University, Western Australia.