Harvesting time optimization and risk analysis for the mariculture of K appaphycus alvarezii ( R hodophyta)

Kappaphycus alvarezii (Rhodophyta) is an important source of carrageenan, which is commercially cultivated with economic benefits worldwide. In this study, we determined the optimal harvesting time and risk analysis for the mariculture of K. alvarezii in a semi‐intensive commercial cultivation farm using a simulation model. Different growth models were analysed (Von Bertalanffy, Potential, Logistic and Gompertz) for the bioeconomic model developed in this study. Seawater temperature and solar irradiance functions were included as variables with major influence on seaweed growth. The Gompertz growth equation was chosen in accordance with Theil′s statistics and the difference between observed and simulated data. Under the conditions and assumptions considered for this analysis, the scenario that generated the highest profits ( USD $ 3353.11) was that for a culture cycle of 135 days and a total biomass production of 13 708.47 kg dry weight cycle −1 . Uncertainty was also included using probability density functions through random variables for seawater temperature, solar irradiance and sale price. Different harvest scenarios were obtained through Monte Carlo analysis; decisions under risk conditions and probabilities of being above or below reference points are presented. The results indicated lower risk at optimum harvesting time when the probability of exceeding the established target reference point for the present value ( USD $ 2515.15) and biomass produced (34 271.17 kg fresh weight) were around 19.26% and 56.47%, respectively. Discussion on the implications of the use of this analysis for seaweed cultivation management is presented.