Economics of joint production of sturgeon ( Acipenser transmontanus Richardson) and roe for caviar

Costs, revenues, net income and rate of return on investment of rearing sturgeon for production of both meat and roe for caviar are analyzed by a computer simulation model for three sizes of hatchery-growout operations: capacities for handling 5, 10, and 15 broodstock. Biological relationships regarding growth, feed consumption, sexual maturity, and mortality interact with management decisions about stocking density, age at which part or all of the fish are marketed, and size of plant to yield the economic performance measures under several scenarios. Spline functions are used to estimate functional relationships between growth (weight) and age while the mortality is described by logistic functions. The biological data were obtained from the University of California, Davis, Aquaculture and Fisheries Program, and various commercial sturgeon producing firms in California. When sturgeon roe prices are less than $331 per kg, the firm receives a greater rate of return on investment by marketing all production fish at 18.5 months of age. With roe prices greater than $331 per kg, higher rates of return on investment are obtained by retaining female fish through sexual maturity (from 6 through 10 years of age) and harvesting the roe as well as the meat. Results are presented under the specification that all but 4000 fish are sold at age 18.5 months. Two thousand females from those 4000 fish are raised beyond 36 months of age for roe production. Economies of scale were exhibited as the firm's capacity expanded to 15 broodstock.