著者

Tan Hongxin

巻号頁・発行日

2009-11-07

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Food and Agriculture Organization of the United Nations predicts that worldwide harvest output of aquatic products will be stagnant or decreased whereas the consumption of aquatic products will be increased at the speed of 1.0% to 2.9%. The increase of aquatic product output will mainly be attributed to the development of aquaculture. For a developing country, especially for a country with a large population and fast developing pace as China, aquaculture in the 21st century will not only face favorable developing opportunities but severe challenges as well. 1. A brief introduction to the development of Chinese aquaculture. China has a very long history in aquaculture. Chinese aquaculture industry has witnessed the growth rates of more than 10 percent every year. Since 1989, China's aquatic product output has been in the first place of the world. At present, it accounts for 40% of the world's aquatic product output, among which the aquaculture output accounts for 70% of that of the world. China thus becomes the only fishery country that aquaculture output exceeds fishing yield, with 9 billion US dollars of export volume which accounts for 30% of the total export volume of agricultural products. Export of aquatic products has enhanced China's international competitiveness in the field of fishery, thus promoted the development of domestic aquaculture and aquatic processing. In 2006, the freshwater aquaculture area was 60,200 hectares and the aquaculture output was 19.5 million tons which accounted for 97% of the total output of cultured fishes. Aquaculture is a vibrant industry in China, Chinese aquaculture producers are rapidly upgrading their technology to produce species such as black carps, grass carps, silver carps, bighead carps, tilapia, catfish, eel, shrimp, abalone, sea bass, turbot, sea bream, red drum, crab, flounder, trout, mussels, salmon and more. 2. A major challenge for Chinese aquaculture. China suffers from environmental pollution and a shortage of freshwater resources. The problems of shortage of water resources and water quality-induced water shortage become more and more prominent in China. The current fishery pattern costs a great deal of resources and we need to shift the fishery pattern to the resource saving and environmentally friendly orientation. This is not only a scientific issue but also a social issue. However, the current scientific development of fishery in China does not meet the transformation of fishery growth modes. 3. Aquaculture should be resource saving and environmentally friendly. How to make aquaculture be shifted to the resource saving and environmentally friendly orientation? Simply speaking, in order to realize the goal of shifting to the resource saving and environmentally friendly orientation, sustainable aquaculture mode will become the direction of China's aquaculture. Sustainable aquaculture must consider the ecological, social, and economic aspects of development. Recently, governments and industry have realized that the focus of aquaculture must evolve into the development of an industry that is both environmentally and socially sustainable in the long term. Positive changes are being made with this growing interest and awareness of improving the sustainability of aquaculture. With the expected expansion of aquaculture in the coming years it will be vital that sustainable practices be implemented and further developed to avoid environmental and social problems. There are a number of alternative ways forward in the development of aquaculture, which can offer more sustainable solutions. In some cases these methods have been around for centuries, but they have rarely been adopted in the modern aquaculture industry, and in other cases they are innovative practices that can be explored by aquaculture proponents. Alternatives include ecological aquaculture, organic aquaculture, polyculture, mollusc farming, and closed and low discharge systems. These alternative practices have been successfully implemented in different areas of the world; however, they must be examined for their application on a wider scale. Concerns for water conservation and reduced waste discharges have prompted the increased use of closed recirculating aquaculture systems. The systems are made up of three basic components: culture tank, settling tank, and biological filter. Recirculating systems have less of an impact upon the environment because of their closed nature - wastes and uneaten feed are not simply released into the ambient environment in the manner that they are with netpens and exotic species and diseases are not introduced into the environment. In recirculating systems, wastes are filtered out of the culture system and disposed of in a responsible manner. Recirculating systems can be built just about anywhere, including in urban settings where they can use existing structures and be placed close to markets, thereby reducing transportation costs. Recirculating systems can be used to grow a wide variety of fish species year-round in controlled environments. Species commonly grown in recirculating systems include hybrid striped bass and tilapia. Additionally, much research has been dedicated to developing recirculating systems for marine species of fish and this technology holds much promise. Ecological aquaculture has been defined as "an alternative model of aquaculture research and development that brings the technical aspects of ecological principles and ecosystems thinking to aquaculture". Ecological aquaculture focuses on the development of farming systems that preserve the environments in which they are situated and enhances the quality of these environments while at the same time maintaining a productive culture system. All aspects of the operation are interconnected in order to minimize negative impacts on the community, both natural and social. Ecological aquaculture can also be incorporated into sustainable fisheries management and coastal zone management. In 2007, Shanghai has launched the construction of standard ecological aquaculture bases, as a means to transform its traditional aquaculture model. The base will form an ecological system, with 20 ponds with distinct functions such as seedling raising, prawn-farming, a fish pond and artificial wetland. A 1200 hektares ecological aquaculture area will be completed during the 11th five-year-plan period. Shanghai will explore a low-cost and highly efficient way to popularize the application of aquaculture model.