Heilongjiang River Fishery Research Institute, China 150070
The paper gives a history of trout farming which in China started in 1959, but has developed fully since the 1970s. By 1998 more than 500 rainbow trout farms were established in 22 provinces, and by 2000 they reached annual production of 10 000 t. At present up to 28 million eyed eggs are produced annually. Most of the market size trout comes from Shandong, Gansu, Beijing, Liaoning, Heilongjiang, Yunnan and Zhejiang provinces. There are now 127 rainbow trout farms which serve tourism and recreational fishing which is becoming an important economic activity especially in the Beijing area. Regarding cold waters in remote areas, the potential for cold water fishery of some water resources in the south and west of China still needs to be assessed. There is also considerable potential in northwestern China.
In China cold water fish farming is sometimes called salmon and trout farming because the major fish species cultured in China is rainbow trout. Cold water aquaculture in China is of a relatively late date being practiced for only some 40 years. In spite of that fishery researchers and managers in China have been making good progress in popularizing the knowledge and techniques of cold water fish farming.
China began cold water fish culture in 1959 when it received 50 000 eyed eggs and 6 000 fry of rainbow trout from the Democratic People's Republic of Korea (DPRK). While in Europe and Japan cold water fish culture had existed for already more than 80 years China started to culture the trout from scratch. The Fishery Department of China allocated the Heilongjiang River Fishery Research Institute (HRFRI) the responsibility for testing the rainbow trout culture. In 1959 the first experimental cold water fish farm was built in the town Hendaohezi of the city of Hailin. It produced the first generation parent fish of rainbow trout in 1963, and at the same time rainbow trout was successfully reproduced in hatchery conditions. The experimental farm was then moved to Bohai town of Ningan city in 1965. It produced two million eyed eggs that were distributed to several provinces of the Huang River region and the culture technique of rainbow trout were popularized. In 1964, 24 broodstock fish and 200 rainbow trout fry were received from the DPRK. At that time the rainbow trout culture was tested at Taiyuan city in Shanxi province and Yingyou county of Liaoning province. About ten years later, the technology of rainbow trout aquaculture was fully established, but it took more than ten years before rainbow trout farming in China took off.
In 1978 the Bohai experimental fish farm became the key center for further rainbow trout culture studies. The HRFRI has been researching and disseminating the culture techniques of cold water fish in collaboration with foreign experts from Europe and Japan. The Department of Agriculture and some provinces/cities sent their fishery specialists to other countries to study cold water aquaculture, and experts from Japan and Denmark came to China to give lectures and demonstrate trout culture techniques. The former National Fishery General Bureau organised the first training in cold water aquaculture in 1981 at the Beijing Fishery Research Institute, the first training course in Heilongjiang was organised in 1984. We invited Japanese experts to give lectures at the HRFRI on research progress of rainbow trout aquaculture in 1984 and 1988. The Fishery Society of China organized and held an international symposium on cold water fish farming and promoted further development of rainbow trout culture.
The cold water fish culture then started rapidly expanding. By 1998 more than 500 rainbow trout farms were established in 22 provinces, producing more than 4 000 tons of rainbow trout per year and using 18 cubic meters of running water per second. By year 2000 the production reached 10 000 t. By volume of used water and culture installations the HRFRI and the Zuanxin Lake Rainbow Trout Farm of the Ningan city have the biggest trout production capacity in China. 150 tons of market size rainbow trout and 6 million eyed eggs have been produced in the two farms annually. The other farms are relatively small, such as the Benxi rainbow trout farm in Liaoning province, the Huairou rainbow trout farm of Beijing city, the Sishui rainbow trout farm in Shandong province, the Jinchuan gorge rainbow trout farm in Yongchang county of Gansu province, the Shentou rainbow trout experimental station in Shanxi province, the Zhanghe reservoir rainbow trout farm in Hubei province, and some others.
At present 25-28 million eyed eggs of rainbow trout are annually produced, 90% of which come from Heilongjiang, Liaoning, Beijing, Hebei and Shanxi. Most market size rainbow trout come from Shandong, Gansu, Beijing, Liaoning, Heilongjiang, Yunnan and Zhejiang.
The rainbow trout fishery business for tourism and recreational fishing has developed in some areas with good economic conditions. 127 rainbow trout farms covering 8 800 m2 have been constructed for tourism and recreational fishing in six areas of Beijing suburbs, such as Huairou and Yanqing. One million kg of rainbow trout have been produced, with a gross output value of 40 million and profit of 8 million Yuan per year. Rainbow trout culture and fishing promoting the development of the tourist business have become an important economic activity in these areas.
3.1 The first period (1959-1966)
Fertilized eggs were hatched in improved Atkins incubators that were once used to hatch chum salmon. The fry of rainbow trout was fed with paste feed from 1959 to 1966. Because of the unbalanced nutrition, only about 30% of fry survived. The first generation parent rainbow trout weren't successfully produced until 1963. The artificial fertilization technique broadcasting the sperm directly onto eggs and the hatching technique in running water were mastered.
3.2 The second period (1978-1984)
Rainbow trout culture became established between 1978 and 1984. The Bohai experimental station of HRFRI converted the earthen ponds into cement tank raceways which resulted in a more efficient use of water. A closed hatching room with running water and shaded from direct light was constructed. Rainbow trout farming developed in some provinces, supported by research stations and this laid foundations for the rapid development of research on rainbow trout culture.
3.3 The third period (1984-present)
From 1984 on China has been exchanging information on culture techniques with experts from Japan, France, Denmark and some other countries. This has assisted further the development of rainbow trout culture in China. Today there are more than ten organizations and more than sixty experts involved in this research in China. The research includes reproduction physiology, nutrition, complete formulated feed, breeding techniques, research into some native cold water fish, and potential for introducing other exotic cold water fish species. The role of reproductive organs in growth and sex differentiation and the physiological function of sexual hormones have been studied. The technique of isolating IPN and IHN in trout as well as diagnostic methods of trout virus diseases have been mastered. We also isolated from rainbow trout Vibrio anquillarum and some pathogens causing streptococcicosis. The pathogen and the cause of diplostomiasis in rainbow trout were researched and the prevention and cure for some parasitic diseases, such as gyrodactylosis, were applied in rainbow trout. The technique of polyploid cultivation and gynogenesis were applied and the transgenic technique was tried in rainbow trout breeding. We systematically analysed the research history of trout culture in Japan and the techniques of rainbow trout culture in France. Starting in 1987 we began researching the biology of Brachymystax lenok and Hucho bleekeri for their potential for aquaculture. We also successfully introduced brown trout, landlocked Oncorhynchus masou, yellow rainbow trout (Salvelinus leucomaenis) and some other species. The landlocked form of Salmo salar was introduced in 1998. Some problems that retard the development of cold water fish have been solved. Among our achievements is the doubling of the survival rate of rainbow trout fry.
Cold water aquaculture has rapidly developed in China during the last 20 years and is catching up with especially trout culture in other countries of the world. However, some problems still need to be solved and some practices improved.
The pail-like incubator for fertilized eggs and the troughs placed side by side for hatching of fry were introduced from France in the 1980s, but most farms still use self-made incubators. The egg-eyed rate and incubated rate of fertilized eggs of rainbow trout range from 50% to 80% and from 60% to 80%, respectively. Fingerlings and adults are fed with complete formulated diet but the feed conversion ratio is between 2 and 3. Because the technique of controlling maturity of gonads of rainbow trout by the means of a photo-control has not been yet popularized, eyed eggs are available only in winter and autumn. The technology of the preparation of complete formulated feed for rainbow trout has been mastered since the mid 1980s, but not yet widely applied. Most farms still produce semi-dried or wet feed. Some problems exist in producing pellet feed, such as non-standardised processing programme, not homogeneous enough raw materials, low fat content, shortage or poor quality of some ingredients, etc. We can prevent and cure some common bacterial and parasitic diseases of rainbow trout, but prevention of viral epidemic diseases is still to be mastered. Most trout farms treat the infected rainbow trout, but cannot prevent the diseases. The research work on breeding began so late that the question of genetic degeneration of rainbow trout was not highly thought of. The technique of gynogenic diploid cultivation has been achieved but it is not fully applied. Except for simple machines for preparing fish feed, most of the work done on rainbow trout farms is done by hand. Intensive fish culture in cement raceways is still at the very beginning. Mechanisation of rainbow trout culture in China is expected to substantially increase the fish production.
While cold water aquaculture in China is still largely at a low level, the foundations have been laid and much progress has been made. Several proposals are put forward for improving the production of cold water fish, both through capture and culture fisheries.
Tapping the native cold water fisheries resources
China's territory is 9.6 million km2, and 50% of it is located north of the latitude 30oN. There are also many mountains and plateaus in the south and west of China, rich in cold water and cold water fisheries resources.
Some of these resources have not yet been fully investigated. It is believed that there is a considerable potential, for example in northeastern China, in provinces in the Huang He region, etc. There are 56 species of native cold water fish that belong to 12 families and 30 genera in China. Some of them could be assessed for their potential for cold water culture, or where necessary, for enhancement of the diminishing fish stocks.
Studies on cold water fish introductions
After the introduction of rainbow trout, other salmonids such as brown trout, landlocked Oncorhynchus masou, yellow rainbow trout (Salvelinus leucomaenis), landlocked Salmo salar were also introduced and they adapted to the conditions in China. There may be a potential for bringing some of these species into culture.
Research on breeding salmon and trout
Rainbow trout is a major cold water fish farmed in China. It is important to prevent the genetic degeneration of this species.
Research on large-scale production of cold water fish
Rainbow trout culture is still using a simple aquaculture technology, which makes for an inefficient use of cold water resources. It is important that China adopts large-scale technologies, including mechanisation, developed in western countries, and also rationalise the administration of the fish culture process.
Salmon and trout ranching using sea water
We have tested the possibility of salmon and trout ranching in sea water but the high temperature of sea water made salmon and trout farming unsuccessful in July and August. This is an important problem.
Need for rules to prevent virus epidemics and other diseases of cold water fish
At present there are no rules for prevention of epidemics of virus diseases of cold water fish.
Research on high fat content in feed for cold water fish
We intend to investigate the potential for replacing high concentration of proteins by fat in fish feed, following the trend in Denmark and some other countries of northern Europe.