LAUSR

The size and relative growth rates of prawns vary in different culture environments. We subject the highly productive and commercially valuable giant freshwater prawn Macrobrachium rosenbergii to a prawn–plant (M. rosenbergii–Hydrilla verticillata) symbiotic culture environment in which water-quality and habitat are adequate. Through introduction of an additional parameter to the Gompertz function, we develop an extended Gompertz model (EGM), which quantifies prawn growth data from the prawn–plant symbiotic system. We investigate the mathematical properties of this EGM, compute important properties, use a nonlinear least squares method to estimate model parameters, and discuss the existence and consistency of estimates. The EGM can capture the different forms of M. rosenbergii relative growth rate, and better quantifies growth accurately than alternative, more conventional models.