Bioeconomic modelling of the intensive production of white-leg shrimp (Litopenaeus vannamei) in a photo-heterotrophic hypersaline system, with minimal seawater replacement

We use a bioeconomic approach to analyse the production, and economic performance of shrimp (Litopenaeus vannamei) reared in a photo-heterotrophic, hypersaline intensive system with minimal water replacement during spring-summer (SS) and summer-autumn (SA) production cycles in the semiarid region of Baja California Sur, Mexico. Salinity was maintained at 45 +/- 2.0 (SS) and 46 +/- 2.5 g L-1 (SA), dissolved oxygen at 4.8 +/- 0.5 (SS) and 4.4 +/- 0.4 mg L-1 (SA), pH at 7.9 +/- 0.3 (SS) and 7.8 +/- 0.2 (SA), and temperature at 28.4 +/- 2.4 (SS) and 31.6 +/- 0.7 degrees C (SA). The bioeconomic analysis indicated that the mean production in SS is 13.2 t ha(-1), and that mean net revenues of 12 600 $USD ha(-1) and a benefit-cost ratio of 1.31 could be obtained. For SA, mean production was 17.7 t ha(-1), and mean net revenue and the benefit-cost ratio were 38 930 $USD ha(-1) and 1.93, respectively. The optimum harvesting times were at 90 (SS) and 92 days (SA) when the economic indicators and the confidence of obtaining them were maximized. Superior economic performance of SA was a consequence of faster shrimp growth and higher shrimp prices. More stable conditions of water quality resulted in better production in SA. A sensitivity analysis showed that shrimp price was the most important factor influencing net revenue, and that final weight of shrimp, dissolved oxygen and temperature had intermediate influence. Positive economic outcomes indicate the potential of the photo-heterotrophic technology for shrimp production in semiarid regions.