Modelling growth and reproduction of crayfish species under a re-circulation system

Abstract

The aim of this study was to develop a series of simulation population models, using Mathlab software, for finding the optimal layout and management regime during the growth-out and reproduction phases of two freshwater crayfish species reared under a re-circulating system. The two species were Astacus astacus widely distributed in central Europe and Cherax quadricarinatus cultured in Australia, Asia and South America. Models were used to quantify the most important factors which are involved in growth and reproduction processes of a crayfish species (density, biomass, size class of animals, growth rate, survival, fecundity and water temperature). An age-structured matrix describing rates of survival and fecundity for each age was used. Statistical analysis was performed with the SAS package. Parameters of simulation models were compared and validated with historical data from the Department of Animal Science, University of Udine and literature articles. Sensitivity analyses were conducted to determine which inputs in each model contributed most to the output variability. Overall, simulated models were able to integrate previously collected data and produce expected productive and reproductive outputs. Population models are useful tools in order to optimize the management of resources during the production chain.