By Peter Edwards
Following the 2nd International Symposium on Cage Aquaculture in Asia in Hangzhou, Zhejiang Province, China in July, I took advantage of a long standing invitation from AIT alumnus, Professor Qingjun Shao, Zhejiang University to show me recent developments in Chinese inland aquaculture. AIT students from China had long commented on my rather dated teaching of Chinese aquaculture based on an assignment I undertook there for NACA through FAO/UNDP in the early 80s. The change in aquaculture over the past 25 years from polyculture systems integrated with crops and livestock to predominantly pellet-fed monoculture of high-value species has been dramatic indeed. Right: Terraced rice-fish fields in mountainous Zhejian Province.
However, we did visit traditional rice/fish culture in mountainous Qingtian County about 300 km south of Hangzhou at the invitation of Ye Minger, Assistant Governor of the County, who also kindly sponsored our visit. I was asked to make a presentation to local officials of rice/fish culture systems outside China; and to provide an opinion on how to conserve and further develop the local system, albeit based on a very short visit.
It is documented that local farmers started to raise fish in terraced rice fields in Qingtian County more than 1,200 years ago. The system originated from the practice of irrigating rice fields by gravity from streams during which fish entered and started living in the fields. After a long period of domestication, the current red coloured soft-scaled, common carp evolved. Locally it is not considered to be a variety of common carp but a distinct fish referred to as Qingtian field fish. Left: Close up of fish in a ricefield.
Compared to the current farm gate price for normal common carp of Yuan 4-5 ($0.5-0.6)/kg near Hangzhou, the local fish has a farm gate price of Yuan 30-40 ($4-5)/kg for live fish. It is also sold dried at Yuan 100 ($12.5)/kg as overseas Chinese also consider it to be a delicacy; more than 30% of the population of the densely populated County have emigrated abroad to some 29 countries. At least 30 counties within China import it also. Of the carp produced in rice fields, 80-90% is consumed in the County, 10% is sold to neighbouring counties in the province, and the rest is sold abroad.
About 80% of the rice fields in Qingtian County are stocked with the carp, about 100,000 mu (almost 7,000 ha). In the traditional system the carp are bred in a corner of a rice field with the fry directly released into the field, with some on occasion being sold to other farmers. Bamboo shoots or tree branches are placed in the field for the fish to deposit eggs on. The fry are raised to table fish extensively without fertilization or feeding fish, although livestock manure is used as a basal fertilizer for rice before transplantation. Fry survival is low and surviving fish grow slowly, taking 2-3 years to reach table size. The stocking density is not controlled in the traditional system in which the fish production is from 25 up to 40-80 kg/mu (375 to 600-1,200 kg/ha). The value of rice cultivated alone is only Yuan 800 compared to more than Yuan 1,000/mu/year with fish stocked in the rice fields. As land is limited in the mountains (with an average family size of 4-5 people being allocated less than 0.5 mu/person, average farm size is only about 2.0-2.5 mu or 1,300-1,700 m2), the rice is used only for household consumption. Traditionally the fish are also only used only for domestic consumption. Right: A trench in a ricefield.
New technology has been introduced, starting 3-4 years ago, with the assistance of Wu Yiming from the Zhejiang Freshwater Aquaculture Institute who is working with farmers and local officials to increase fish yields and therefore benefits to farmers while simultaneously trying to maintain a balanced ecological system. Breeding sites have been set up to produce fry for 1,500 mu (100 ha) of more intensive rice/fish culture. Baseline traditional yields of 40-80 kg/mu (600-1,200 kg/ha) have been increased to 300 kg/mu (4,500 kg/ha) with better shaped but still tasty fish. Fry were initially nursed for 20 days to produce 1 g fingerlings with a higher survival rate but this has now been extended to 30 days to produce 5 g fingerlings. These are stocked in rice fields in June and fed formulated feed of different qualities for different stages and reach 250 g (up to 0.5-1 kg) in February. The best market size is 350-400 g. Left: Rice-fish farmers.
One crop of rice is grown in the intensified system rather than two crops in the traditional system, which places less stress on the fish which grow year round. Cultivating two rice crops requires a lot of labour which is increasingly in short supply as younger family members emigrate or leave the farm for better paid employment in factories and the city. The rice yield remains the same at 450 kg/mu (6,750 kg/ha) but the grain is of better quality with only one crop of rice. There is no government pressure for farmers in the County to farm two rice crops.
Producing higher fish yields requires a higher level of technology and investment. Concrete walls are being built around some rice fields to maintain deeper water to raise more fish. However, short stemmed rice varieties cannot be grown as a tall variety is required in the 30-40 cm deep water for fish grow-out. When the rice is transplanted at the start of the season and fry are stocked, the water is only 10 cm deep. The temperature of the shallow water is suitable for the fry as temperatures are lower in early summer and water flows through the fields. Furthermore, rice seedlings are nursed for more intensive fish culture so that they are not too short when transplanted. Right: Holding pond for fish harvested from rice fields.
Farmers were initially reluctant to intensify their rice/fish system. They were advised to stock 500 fish/mu (0.75/m2) but would not as they said there was insufficient natural food in the rice field. On observing that artificially fed fish grow well, they began to intensify as they wanted to earn more. Unfortunately some farmers stocked > 1,000 fish/mu (>1.5/m2) after 2-3 years as they said they wanted to harvest more fish which led to disease (red spot) due to poor water quality. One farmer interviewed obtained 350 kg fish from a 1 mu rice field with a trench, equivalent to a probably unsustainable yield of 5,250 kg/ha. He also obtained a reduced though still very high price of Yuan 24/kg ($3/kg) when he sold the fish to restaurants as the fish raised at high stocking density with artificial feed is of lower quality.
During discussions with local officials, it was reiterated that the main aim of government intervention is to protect the rice/fish culture system heritage. The traditional system has been sustainable for 1,000 years but there are major concerns about continued sustainability with recent developments. In recognition of the traditional Chinese rice/fish system, it has been listed by FAO, UNDP and the GEF (Global Environment Facility) as a Globally-important Indigenous Agriculture Heritage System (GIAHS) in 2005. Demonstration sites are being set up in a wide range of agro-ecologies to adapt local practice so that farmers may live with the new opportunities and challenges brought about by globalization The purpose of the GIAHS program is to develop appropriate policy, institutional support and technology to protect and promote important agricultural heritage such as the traditional Chinese mountain rice/fish system in Zhejiang Province. Left: A restaurant dish prepared from ricefield carp.
I structured our final round table discussion around five aspects of sustainability: social, economic, technical, environmental and institutional. A unique social feature of the rice/fish system is the production of a high-value fish species. Farmers can make a good profit from raising the species but the quality of the fish and market price decline with intensification. An important research issue is the balance between quality and intensification to provide maximum profitability. As the carp is farmed in a clean environment without chemicals (neither inorganic fertilizers nor pesticides are used), the issue of branding as an organic food was raised.
A major concern is the declining farm population i.e., who will raise the fish in future? Up to 50% of the population of the densely populated mountainous county has emigrated but most young people are still leaving the farm or have every intention of doing so once they leave school. It is unlikely, as well as undesirable, that the global trend of declining farm populations will not continue to take place in Qingtian County. This, however, should lead to fewer larger farms providing a more economically sustainable livelihood for the smaller number of people who wish to farm. While the intensified technology has led to increased production and profitability for a few trial farmers to date, the appearance of fish disease indicates a stressed system. Furthermore, intensification of fish culture usually leads to increasing eutrophication of the surrounding environment, especially in an intermittent or continuously flowing water system such as mountain rice terraces. Additional environmental problems raised were the need for increased amounts of water with intensification which the area may not be able to provide; and pond construction by some farmers which would increase problems of water supply and eutrophication if it were to become widespread. Fortunately, there is not a problem with deforestation adversely affecting the rice/fish system as the government is protecting the mountain watersheds. Right: Monument celebrating the traditional rice-fish system.
A supportive institutional framework is being developed for the County with local, national and international players taking part. However, considerable research is required to further the sustainability of the system. This should include surveys of current farmer practice, attitudes and aspirations and subsequently, participatory development with farmers of both technology and institutional support.
Unfortunately, I was unable to attend the workshop to agree on activities and a framework for decision making held at the end of July with local, national and international stakeholders due to a prior commitment. The workshop, Globally Important Agricultural Heritage Systems (GIAHS) Traditional Rice-Fish Agriculture Multi-stakeholders Process Workshop was organized by FAO and the Bureau of International Affairs, the Chinese Ministry of Agriculture, and co-organisers were Zhejiang Agriculture Bureau, Qingtian County, United Nations University, Wageningen University (The Netherlands), and the Institute of Geology and Resources of the Chinese Academy of Science. There were 80 officers, scholars, local leaders and farmers who attended. Participants visited rice/fish farms and about 20 speakers presented their opinions about how to protect the GIAHS and what the following action should be. Unfortunately for most of us, all the materials are in Chinese.
Dr Edwards is a consultant and Emeritus Professor at the Asian Institute of Technology in Thailand where he founded the aquaculture program. He has over 30 years experience in aquaculture education, research and development in the Asian region.
This article was published in Aquaculture Asia Magazine
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