Economic efficiency and optimum stocking densities in fish polyculture: an application of data envelopment analysis (DEA) to Chinese fish farms

Polyculture is commonly practiced in pond aquaculture where several fish species are reared together, creating a multi-output production structure. This study applied a nonparametric data envelopment analysis (DEA) technique for multiple outputs to: (1) measure economic or 'revenue' efficiency and its technical and allocative components for a sample of Chinese polyculture fish farms; and (2) derive the optimum stocking densities for different fish species. The mean economic efficiency was estimated to be 0.74. Technical inefficiencies accounted for most of the production inefficiencies in Chinese fish farms. On average, farmers should increase grass carp and decrease black carp stocking rates. Smaller farms and those from the developed regions were found to be relatively more technically and economically efficient. (C) 1999 Elsevier Science B.V. All rights reserved.