Freshwater Crayfish Growth Under Culture Conditions: Proposition for a Standard Reporting Approach

A review of approaches currently used to measure growth in freshwater crayfish under experimental and pond grow-out conditions is presented. The review examined 206 papers on growth and production of freshwater crayfish of which 34 were selected for detailed investigation. Selection was based on the amount of information provided in the published report and on the species studied. The review was restricted to six crayfish species: Cherax tenuimanus (marron), C. destructor (yabbie), C. quadricarinatus (red claw), Procambarus clarkii (red swamp crayfish), Astacus astacus (noble crayfish), and Pacifastacus leniusculus (signal crayfish). Growth indices reported included instantaneous growth rate (IGR), absolute growth rate (AGR), slope of log weight against time (GRE) and specific growth rate (SGR, IGR100). Studies were performed for varying time intervals under a wide range of stocking densities. Most reports did not express growth rate as an index but simply reported growth in terms of initial and final weights. The range of approaches used to express growth performance in freshwater crayfish growth studies hinders comparisons of growth rate and production findings. It is suggested that the reports of studies of growth performance in cultured crayfish include a growth rate parameter as well as initial and final weights. SGR is recommended as the parameter of choice since it is based on an exponential growth trend which is typically observed in measurements of weight increase with time in cultured juvenile and early adult crayfish.