Chinese river crab is a rather recent entry as an aquaculture species, the first farmed production being reported to FAO in 1989. Its culture evolved from the release of collected natural crab seed into lakes that had been isolated from rivers by water-gates in Jiangsu province of China in the late 1970s, a form of fisheries enhancement.
True aquaculture of this species began in small lakes in the lower reaches of the Yangtze River and is characterized by the stocking either of artificially propagated seed or wild seed, together with supplementary feeding. The farming of Chinese river crab expanded very rapidly since the 1990s in China and has been gradually introduced to various aquaculture environments, namely earthen ponds, pens in shallow lakes, and paddy fields, etc.
Chinese river crab farming is now an important component of the freshwater aquaculture industry in China. The Republic of Korea is the only other country that reports cultured Chinese river crab production. There have also been reports on the experimental culture of this species in Germany and the United States of America (California) by local Chinese people.
Although only two countries (China and the Republic of Korea) report farmed production of Chinese river crab to FAO, some production is know to occur in a number of other countries, mainly in northern Europe.
The first reported production of cultured Chinese river crab was from China in 1989 (3 305 tonnes). Rapid expansion has occurred, reaching over 368 000 tonnes in 2003, and an unofficial level of nearly 416 000 tonnes in 2004. Production in the Republic of Korea is, by comparison, small and variable; first reported in 1994 (3 tonnes), it has never yet exceeded its peak of 31 tonnes in 1997.
Market and Trade
Almost all the commercial production of Chinese river crabs occurs in China itself. The product is locally consumed and generally marketed live, although processed products are emerging. The Chinese river crab used to be a rather high priced commodity but it has become more affordable to ordinary consumers in recent years. Chinese river crab are marketed at a fairly large range of prices (USD 5–25/kg) according to the size and environments where the crab is produced.
In 2004, China exported about 800 tonnes of live Chinese river crab, which were valued nearly USD 6 million, according to national statistical data. Exports increased by more than 70 percent compared with 2003. Actual exports may be even greater, because China also report exports of some 7 000 tonnes of unspecified crab products. The major export markets are in Hong Kong SAR of China, Japan and the Republic of Korea.
Status and Trends
Chinese river crab used to be an important wild caught aquatic product. It is favoured by consumers in China and some other Asian countries. Depleted natural production and increasing market demand played an important role in the rapid expansion of farmed mitten crabs since the late 1980s. Its culture is also promoted by the Chinese government as part of its efforts to diversify aquaculture species. Success in the artificial propagation of this species with natural and artificial saline water has provided the most important stimulus for expansion.
Due to the strong adaptability of the species to various small-scale farming practices, Chinese river crab culture is now contributing significantly to the income of rural farmers in many areas of China. Due to its relatively short history of development, its farming is still far from technical or managerial perfection. Currently, major achievements are being made on artificial propagation and seed rearing techniques and on special feed additives that can enhance the moulting process of the crab. Progress on nutrition, feed and optimal farming models is rather limited, however. This causes great variation in production levels, size of product, survival rate and economic efficiency. More effort is needed to further improve culture technology, in order to improve production efficiency and economic returns.
It takes time for the market to digest the rapid increase in production, although consumer demand is increasing steadily. The expansion of growth should be decelerated to ensure a reasonable market price and economic return for farmers.
Major efforts are needed to improve product quality and production efficiency. Expansion in the international trade in Chinese river crabs is expected, as they are becoming more popular in other countries. However, expansion is not expected to be rapid; for the moment most crabs will still be marketed locally.