INTENSIFICATION OF COMMERCIAL REDCLAW CRAYFISH Cherax quadricarinatus CULTURE IN BAJA CALIFORNIA SUR, MEXICO – PRODUCTION AND BIO ECONOMIC ANALYSIS
Freshwater crustacean crayfish production has been increasing at a rate of 15%/year worldwide: New technologies are needed to consolidate this growth. The culture of redclaw crayfish Cherax quadricarinatus has been adopted by several countries with varying degrees of success. Several culture techniques are used depending on the region. Advances in the commercial culture of Cherax quadricarinatus in Mexico have been hindered by a number of problems, such as the lack of sufficient investment. This is related to the paucity of information on the economic viability of the different culture technologies to help investors evaluate risk.
The Northwest Biological Research Center (CIBNOR) developed an intensive culture technology for redclaw crayfish C. quadricarinatus. The system is based on more than 20 years of research and development. Redclaw de Mexico, a private company, has tested this technology commercially in Baja California Sur, with yields over 5,000 kg/ha in 7-month cycles. The objective of the study was to evaluate the biological and economic performance of this cultivation technology using a stochastic bio economic analysis.
Trials were conducted in triplicate 2500 m2 (25 x 100 m) PVC-lined ponds with zero water exchange and two 2-hp aerators (Aire-O2) per pond. Concrete blocks with 4 orifices and bundles of nylon mesh were used as shelters. Juveniles (3.5±1 g) were nursed at 25/m2 for 105 days. At harvest, males and females (20±1.4 g) were separated and reared in monosex culture at 10 crayfish/m2 and fed daily at 08:00 and 17:00 with a 35%CP pelletized diet for 140 days. Zoo technical parameters showed that production was very consistent and there were no statistical differences among triplicates for juvenile, female or male culture.
With this database, we fitted a stochastic model to determine the consistency of simulations of total and commercial biomass over time. Of particular interest was the production of commercial-sized crayfish for two size classes (40-60 and 61-90 g). At harvest, mean final redclaw weight were 65 y 60 g, and yields were 4.95 y 4.20 ton/ha for males and females, respectively. Data of commercial biomass predicted by the model are presented. Using production costs at the commercial farm, we developed a bioeconomic model to estimate b/c and net gain, and determine risk factors affecting production and economic performance. System management, production and the use of the stochastic bio economic model to evaluate investment are discussed.