Stochastic analysis of production dynamics of male and female redclaw crayfish ( Cherax quadricarinatus ) reared under commercial intensive cultivation

We used a stochastic model to simulate, over time, total biomass production of male and female Australian redclaw crayfish ( Cherax quadricarinatus ), so as production of commercial‐sized crayfish (40–60 and 61–90 g). The model was calibrated with a database from an intensive commercial farm. Results showed that uncertainty in obtaining production of the 61–90 g grade diminished with time. In the case of 40–60 g grade and total biomass, uncertainty was minimal at 69 days (males 40–60 g grade), 84 days (females 40–60 g grade), 92 days (male total biomass) and 94 days (female total biomass). The model predicted that, at harvesting time, there is 95% confidence intervals that males produce 2.96–3.29 t ha −1 (mean = 3.13 t ha −1 ) and females produce 2.49–2.72 t ha −1 (mean = 2.60 t ha −1 ), of biomass, closely approximating biomass production registered in the database. When increasing sample size from one pond to 16 ponds, variability in production was reduced in 75.5% (males) and 65.2% (females). Sensitivity analysis showed that individual weight, and percentages corresponding to the total commercial population and the 40–60 g size were the variables mostly influencing the variance of yields. The results showed that the dynamics of production of commercial biomass strongly differ among ponds. We conclude that the model is a useful tool for analysis of the stochastic processes governing production dynamics of redclaw crayfish biomass.