Physical, chemical and biological variation among freshwater crayfish (Cherax albidus Clark, 1936) research ponds

Previous workers performing classical agricultural field experiments and aquaculture pond trials have emphasized that in order for results from experiments to be analyzed and evaluated, it is important to either demonstrate that the experimental units are homogeneous or quantify any variation between plots, ponds or blocks of these experimental units. Moreover to ensure that results of aquaculture experiments are applicable to industry, research ponds must have similar characteristic.,, to those of industry. Physical, chemical and biological characteristics of 24 research ponds were recorded at the Avondale Research Station, Western Australia. This demonstrated that: (a) The ponds behaved in a manner similar to farm dams typical of the Western Australian wheat belt; (b) The water chemistry and turbidity profiles of the ponds were within the range recorded for wheat belt farm dams; (c) The average % organic matter of the sediments was 3.49%, which was within the range recorded for farm dams in Western Australia (d). The coefficient of variation for growth of yabbies (Cherax albidus) among the ponds at the Avondale Research Station was 9.26%. The comparatively low level of variation among, the ponds was attributed to a number of factors including the age and design of the facility, and the homogeneous water supply for all ponds. Power analysis has been applied to determine the number of replicates required for experiments in these research ponds.