Intensive culture of shrimp Penaeus vannamei in floating cages: zootechnical, economic and environmental aspects

Abstract

In the framework of the France–Brazil cooperation in Oceanology, experiments have been carried out in the State of Bahia (Brazil) from 1992 on, in order to design a new technology for culture shrimps in floating cages in an estuarine zone. The zootechnical research has focused on the species Penaeus vannamei which has been tested in different rearing conditions (density in the cages) and seasons (wet and dry). The results may be compared with the most intensive and costly technologies which are practised in Asian countries. The average growth rate is about 0.8 g wk −1 and the average final biomass is 800 g m −2. The achieved results are all the more important as they are obtained with a simple technology which does not require energy for pumping and mechanical water aeration. Investigations on the impact of this kind of technology, carried out on a pilot site with estuarine conditions after three years of farming activity, showed no measurable effect on the sediment (in terms of organic matter) and in the water (in terms of oxygen). Economic analysis was recorded from the very beginning of the project, making it possible to design a computerised simulation tool in order to assess the feasibility of such an operation and to help in decision making for future research and development. Initial results indicate that ex-farm production costs for shrimps weighing 15 g would be around US$ 4.7 per kg. The major competitive advantages of such a technique are the high yield, the quality of the product, the environmental friendliness and the positive social impact for a fishing community.