Freshwater fish seed resources in China.
China, one of the countries with the richest aquatic resources in the world, has more than 800 varieties of freshwater fish species. Based on production, the top 10 cultured species are: (1) grass carp (370 million tonnes); (2) silver carp (346 million tonnes); (3) common carp (236 million tonnes); (4) bighead carp (208 million tonnes); (5) crucian carp (194 million tonnes); (6) tilapia (90 million tonnes); (7) blunt snout bream (52 million tonnes); (8) freshwater eel (48 million tonnes); (9) river crab (41.5 million tonnes); and (10) white-leg shrimp (Penaeus vannamei) (40 million tonnes from freshwater culture). According to an investigation report in 2001, there were 16 435 seed production units (hatcheries) and 8 072 were well equipped for hatching and juvenile rearing. Total production from all hatcheries are estimated at 13 385 billion individuals which meet the needs for grow-out production. The 16th Item of the "Fisheries Law" requires that hatcheries producing aquatic seed are required to get a license from the local government. According to current statistics, approximately 50 percent of aquatic seed are produced by licensed hatcheries. With respect to seed quality, the following are major issues of concern: (i) fish species with good strain are not currently the lead producers in aquaculture, (ii) lack of high quality seed and (iii) more emphasis placed on licensing than fish seed quality. There are a number of services which provide support to China's freshwater fish seed production sector. The innovation service is responsible for breeding using selective breeding and newly developed breeding techniques. The examination service is responsible for morphological characteristics and farming performance of freshwater fish seed. The extension service provides extension and demonstration activities for both hatchery and grow-out operators on good breeding techniques, evaluation of risks, testing and expansion of introduced or new species. There are two major problems which need to be addressed: firstly, hatchery techniques for some important species has not yet been established and secondly, seed exchange and transportation between different places lack a valid surveillance. Future prospects and recommendations for China's freshwater fish seed sector are: (i) consider the sustainable development of aquaculture, exploit and utilize aquatic genetic resources strategically, (ii) develop genetic breeding programs and improve the quality of aquatic seed, (iii) train farmers how to get good quality seed for farming, (iv) reinforce risk assessment on introduced species and minimize their harm to native genetic resources and (v) improve the regulation of seed management and to make it work efficiently.