Farming Shrimp for the Future: A Sustainability Analysis of Shrimp Farming in China.

Abstract

The intensification of the shrimp farming industry has generated much concern over its environmental, social and economic sustainability. The objective of this dissertation was to conduct a comprehensive sustainability analysis for Chinese shrimp farming. My results could be utilized to evaluate and improve shrimp production systems in terms of environmental sustainability, economic profitability, and social acceptability. Life cycle assessment was conducted to evaluate environmental performance of different shrimp farming systems. Intensive systems had higher environmental impacts per unit production than semi-intensive. The grow-out stage contributed on average 95% of the overall impacts, mainly caused by feed production, electricity use and effluents. To produce 1 tonne live-weight of shrimp in China, 38.3±4.3 GJ of energy and 40.4±1.7 tonnes of net primary productivity were required, and 23.1±2.6 kg of SO2 equivalents (eq), 36.9±4.3 kg of PO4 eq, and 3.1±0.4 tonnes of CO2 eq were generated. Changes in feed composition, farm management, electricity generating sources, and effluent treatment may result in future improvement. Mathematical models were developed to study nutrient dynamics and the effects of management strategies on nutrient dynamics and discharge. Management strategies had significant impacts on nutrient dynamics. Nutrient loading increased with farm intensity. On average, approximately 701 kg N ha-1 cycle-1 (100 days/cycle) and 176 kg P ha-1 cycle-1 were unutilized and wasted. Of them, 120 kg N ha-1 cycle-1 in dissolved form and 62 kg P ha-1 cycle-1 were discharged with effluents. Moderate stocking density and reduced water exchange could minimize environmental impacts of pond effluents and achieve high production. A socioeconomic survey of 100 shrimp farms was conducted to evaluate system profitability, disease risk, and changes in quality of life. Production costs per kilogram of shrimp were highest in intensive systems ($2.70), followed by semi-intensive ($2.10) and polyculture ($1.05) systems. Intensive systems had significantly higher profits ($9,500 ha-1 crop-1) than the other two systems (< $7,300 ha-1 crop-1). If disease occurred, an average of 78% and 36% of shrimp would die in the worst and most probable cases, respectively. Disease had highest influence on the intensive systems. Quality of life of farmers was significantly improved by shrimp farming.