BIODIVERSITY USE AND TECHNICAL PERFORMANCE OF FRESH-WATER FISH AQUACULTURE IN DIFFERENT SOCIOECONOMIC CONTEXTS - CHINA AND ITALY

The availability of natural resources and the socioeconomic context in which aquaculture is performed condition the choice of aquacultural p roduction techniques. In this paper, we examine and compare the patter n of biodiversity use (the ecological side of the production process) and the technical coefficients (the economic side of the process) that characterize freshwater aquaculture in PR China and in Italy in relat ion to the role that freshwater aquaculture plays in these societies. The comparison between aquaculture in China and Italy covers the follo wing aspects: (1) history and general statistics of aquaculture; (2) c ultivated species and trophic structure of managed freshwater ecosyste ms; (3) technological characteristics of the production process, inclu ding inputs/outputs, yields, labor productivity, and fossil energy use ; (4) role of freshwater aquaculture in relation to its socioeconomic context. In Italy, where socioeconomic constraints (high opportunity c ost of labor and a food system dealing with a surplus of nutrients) ov erwhelm ecological constraints (through imports and technology), fresh water aquaculture operates with densities of nutrient flows outside th e range typical of natural aquatic ecosystems. Freshwater bodies used for production are artificial and generally contain only one carnivoro us species that depends for its survival on human management of inputs and waste disposal. In contrast, in China, up to nine different speci es (mainly herbivores) are kept in the same pond, and efforts are made to maintain as much as possible the natural mechanisms of regulation of matter and energy flows. This results in higher efficiency in terms of use of biological energy (from biological cycles) within the syste m, lower environmental loading, and less dependence on fossil energy i nputs. However, the better biophysical performance of Chinese aquacult ure is linked to low labor productivity. This makes it difficult to ad opt such an 'ecologically friendly' solution in developed countries, s uch as Italy, where the opportunity cost of labor is high. (C) 1997 El sevier Science B.V.