National Fisheries Extension Centre
Ministry of Agriculture
Beijing, P. R. China
Wei, Q. 2002. Social and economic impacts of aquatic animal health problems in aquaculture in China. p. 55-61. In: J.R. Arthur, M.J. Phillips, R.P. Subasinghe, M.B. Reantaso and I.H. MacRae. (eds.) Primary Aquatic Animal Health Care in Rural, Small-scale, Aquaculture Development. FAO Fish. Tech. Pap. No. 406.
The rapid development of fisheries in China has been noted worldwide in recent years, and aquaculture has played a very important role. In 1998, aquaculture production was 21.8 million mt, which accounted for more than 55% of total fisheries production. However, the negative impact of disease is becoming increasingly serious. Finding an effective resolution to this problem is the main topic for many international and regional activities, and the Government of China has paid great attention to management of aquatic animal health. The fisheries authorities at both the national and local levels in China have been closely assessing the disease situation, with the co-operation and support from the concerned institutions and academic bodies. An initial framework for aquatic animal disease control and a fish disease reporting system have been set up. In order to protect the livelihoods of the vast rural population, regional co-operation, intensive training and extension are urgently required.
The fisheries sector in China made rapid progress during the 1990s. The annual yield of aquatic products increased from 12.4 million mt in 1990 to 39.1 million mt in 1998 (see Fig. 1). The rapid development of the fisheries sector is closely related to the remarkable development of aquaculture, and the area under production is 1998 was around 6 million ha (Fig. 2). Of the total production in 1998, 17.2 million mt was from capture fisheries, while 21.8 million mt was from aquaculture, accounting for 44.2% and 55.8% of the total fishery production, respectively. The per capita supply of fisheries products in China reached 31.3 kg/annum in 1998. Aquaculture has been the key to the successful development of China's fishery. National production figures for 1998 are given in Table 1, and production by species is given in Table 2.
Currently, fisheries in China is one of the most important components in agriculture. In 1998, the total foreign trade volume of aquatic products was 2.14 million mt, with a value of US$3.86 billion. Apart from earning foreign currency, fisheries also provide the rural population with employment. In 1998, the fisheries population and fisheries labour were 19.32 million and 12.37 million people, respectively. The average per capita income for the fisheries population was 4,323 Yuan (US$522), while per capita income for fisheries labour was 7,285 Yuan (US$879), an increase of 349 Yuan (US$42) and 439 Yuan (US$53), respectively, from 1997 (Fig. 3). The average income of fish farmers is higher than for others living on the land. Fisheries, especially aquaculture, has always played a very important role in the development of the rural economy and poverty alleviation, as well as food security in China.
Table 1. National aquaculture production by culture environment, total area and average production per unit area for 1998.
With the development of intensive aquaculture and the appearance of more serious environmental pollution in recent years, aquatic animal disease has become a major problem. There are currently more than 200 diseases that have been identified in cultured aquatic species. Some diseases have caused serious damage, not only to the livelihood of fish farmers, but also to the future development of the industry. It is estimated that around 10% of the culture area is suffering from disease, with annual production losses of around 15%.
In freshwater aquaculture, apart from many bacterial, viral, fungal, protozoan and other diseases, bacterial septicaemia is considered to be one of the most important diseases in the history of Chinese aquaculture. From 1990 to 1992, it occurred widely in almost all major aquaculture provinces and regions in China. This disease mainly affected silver carp, bighead carp and crucian carp, which are the major species cultured in China. The main pathogens identified include Aeromonas hydrophila, Yersinia ruckeri and Vibrio fluvialis. When this disease first appeared in 1985, it did not attract much attention from scientists and farmers. From 1988, it quickly spread throughout the main culture area. Many small-scale fish farmers especially suffered because of it. By the early 1990s, the annual economic loss was estimated to be more than 1 billion Chinese Yuan (US$120 million). Since control methods have been devised following urgent scientific research, the prevalence has decreased, and the annual economic loss has decreased to about 600 million Yuan (US$72.4 million).
In marine and brackishwater aquaculture, shrimp disease is the major problem. In 1993, as with other major shrimp culture countries, China suffered a serious outbreak of white spot disease in the coastal provinces. The affected shrimp-pond area totalled 112,000 ha, or 76% of the total culture area. More than half of the shrimp ponds were unable to harvest anything, and shrimp production in 1993 dropped by 120,000 mt. The direct economic loss was estimated at more than 3.5 billion Yuan (US$420 million).
Table 2. Aquaculture production by species or species group in 1998.
In China, mollusc culture is another major component in marine aquaculture. Cultured shellfish production accounts for nearly 40% of total marine aquaculture production. However, in recent years, high mortalities have occurred during the culture period in Shandong and Liaoning provinces, where the main shellfish farms are located. Losses have been very significant. With scallop, for instance, production in 1998 was only 629,373 mt, 33% less than in 1997. So far, the cause of these losses has not been identified.
As well as the upward trend in traditional aquaculture, so called "specialist species aquaculture" has developed very rapidly in recent years. Along with the movement from a planned economy to a market economy, Chinese customers now prefer high quality species, such as soft-shell turtle, freshwater prawn, Chinese mitten crab and mandarin fish. Marine finfish cage culture has also been widely practised along the coastal provinces. As these culture techniques are comparatively new, farmers frequently encounter disease problems. An assessment of economic and social impact is difficult to carry out; however, estimated as a whole, the economic loss caused by disease is higher than that for traditional aquaculture, because of the higher value of the species cultured, and the situation is becoming more serious.
According to available estimates, the annual economic loss in Chinese aquaculture due to disease is more than 10,000 million Yuan (US$1.2 billion).
Case One. From 1995 to 1997, in order to promote the recovery of Chinese shrimp culture, a three-year shrimp health management demonstration project was carried out through the Budget of National Harvest Program. This project covered almost all the provinces where shrimp culture had been conducted. The main objective of this project was to promote awareness of shrimp health management among shrimp farmers. The key techniques included pond system reform, stocking healthy larvae, installation of aeration units, water quality monitoring and use of high quality pelleted feed. With financial and technical support from the project, the average per unit production of the experimental ponds was 133% higher than those ponds that continued with the old culture methods. Results of the project are given in Table 3. The economic benefits gained by the farmers convinced others to adopt the new technology. The shrimp culture industry in China has now begun to recover.
Table 3. Shrimp health management demonstration project (1995-1997).1
Case Two. An aquatic animal disease investigation examining the
current freshwater fish disease situation was conducted in Chongming County,
Shanghai City. Results are given in Table 4.
Table 4. Statistics for diseases of adult fish in Chongming County, June and July 1999.
Together with aquatic seed and broodstock management, aquatic animal health management is regarded as one of the top priorities by the fisheries authorities. In order to maintain the fast and sustainable development of aquaculture, the Chinese government has devoted significant funds and manpower to aquatic animal disease control and health management. Since 1995, the central government has continuously invested more than 23 million Yuan (US$2.7 million) to support the establishment of 29 provincial disease control centres and stations. It should be noted that investment figures do not include counterpart-fund input from local governments. According to latest statistics, in 1998, more than 24 million Yuan (US$2.9 million) of funding was invested in the improvement of disease control facilities. The establishment of a national aquaculture disease control centre has also been approved. With the main objectives of aquatic animal disease monitoring, environmental assessment, feed quality control, aquatic animal seed quarantine and information exchange, an initial framework for disease control and information feedback has been established.
Aquatic animal disease control is difficult to implement without the active involvement of all relevant personnel and organisations. In 1992, a national network for aquaculture disease control and prevention was formed, and it acted as a consultant or advisory body to the national Bureau of Fisheries and now, also, the National Fisheries Extension Centre. The members of this network were drawn from different organisations, including government, universities, research institutes and extension units. Many experts, not only from aquaculture, but also from the feed industry, marketing, environmental science and other related sectors, joined this network. This is critically important in order to ensure that information provided to policy makers is reliable and comprehensive.
The importance of aquaculture to the rural economy, poverty alleviation and food security has been demonstrated in many countries and regions. There is no doubt that aquaculture will further develop in the coming millennium. As there is more frequent exchange of aquatic animals between countries and regions, and, as aquaculture expands and intensifies and as more new and exotic species are introduced into aquaculture, disease problems, and the social and economic impact caused by them, will also increase greatly. In view of this, a strong commitment from government, and more intensive and comprehensive co-operation, public training and technology extension, are urgently needed.
There are many strategies that need to be further developed: