FISHERIES DEVELOPMENT IN XINJIANG, CHINA

by
Guo Yan
Fishery Research Institute of the Xinjiang Uygur Autonomous Region,
Urumqi, 830 000 China

Abstract

Xinjiang is located in the hinterland of Eurasia. It is the largest province in China, covering an area of 1.6 million km² and accounting for one sixth of China’s territory. Prior to the 1950s Xinjiang had almost no fishery. Since then, with the economic development, its fishery has made enormous progress. In 2000 the output of the fishery in Xinjiang reached 58 835 tonnes, of which aquaculture produced 49 761 tonnes, i.e. 64.6 percent of the total. Capture fisheries and aquaculture include reservoir fisheries, net-cage culture, culture in warm water and cold water. Fish species captured and/or cultured are common carp, silver carp, bighead carp, golden carp, grass carp, Megalobrama amblycephala, rainbow trout, tilapia, Clarias leather and some other fish. Crabs, soft-shelled turtles and shrimps are also cultured. As the fisheries are still developing, many problems are emerging, such as lowering of the ground water level, eutrophication, disappearance of the local fish species, spread of fish diseases. The increasing rate of water diversion and water consumption for irrigation and other purposes is partly responsible for this.

1. Background

The Xinjiang Uygur Autonomous Region is situated in northwestern China, adjacent to Gansu and Qinghai provinces in the east, the Tibet Autonomous Region in the south, with Pakistan, India and Afghanistan in the southwest, Tajikistan, Kyrgyzstan and Kazakhstan in the west, and Russia and Mongolia in the north and northeast. Xinjiang is equally distant from both the Pacific and the Atlantic oceans, i.e. about 4 000 km from each. Xinjiang covers 1.6 million km² and represents one sixth of the territory of China. It has a population of 18 million, mainly Uygurs, Han, Mongols, Kazakhs and Hui.

Xinjiang is surrounded by high mountains: in the north and northeast are the Altay Mountains, in the northwest the Tarbagatai Mountains, in the west and southwest the Pamir and Karakoram Mountains, in the south the Kunlun Mountains, and in its central section are the Tien Shan Mountains crossing it from east to west and dividing Xinjiang into two parts, the Tarim Basin in the south and the Dzhungarian Basin in the north. The average altitude of Xinjiang is about 1 000 m above sea level, with the highest mountains of Tien Shan and Kunlun reaching over 6 000 m. In the middle Tarim Basin the elevation is 800-1 300 m, in the Dzhungarian Basin 500-1 000 m. Lake Aydingkol in the Turpan Basin is the lowest point at 155 m below sea level. Sixty percent of Xinjiang is covered by desert, 30 percent by steppes, and the rest is oases, forests, agricultural areas, lakes and other waterbodies.

Xinjiang is an arid region. In summer it is very hot, in winter it is very cold. There are differences of up to 20 ^oC between the night and day temperatures. The highest average July temperature in northern Xinjiang is 25 ^oC, in southern Xinjiang 28 ^oC. The lowest temperatures are reached in January, down to -18 ^oC in the north, -9 ^oC in the south. Xinjiang has the highest number of sunshine hours per year in China, with most areas receiving 2 900 hours. The annual solar radiation is estimated at 130-140 kcal/cm².

Dry weather is a characteristic feature of Xinjiang. The average annual rainfall is only 150 mm, and more than half of the plains receive less than 100 mm. It rains more in the north than in the south, and more in the west than in the east. The south receives 30-50 mm, the west and north 40-70 mm, the east 20-40 mm, and the Altay and Tien Shan mountains 100 mm. The north and west have a lower evaporation rate than the south and east. The average annual evaporation differs, is lowest in the north and northwest (1 600-2 000 mm), and highest in the east (2 800-3 000 mm).

There are 570 rivers in Xinjiang, of which 144 are in southern Xinjiang, and 426 in northern Xinjiang. They originate from the northern and southern slopes of Tien Shan, western slopes of Altay, northern slopes of Kunlun, and eastern slopes of the Pamir. They are fed by ice and snowmelt and by rainfall precipitation. There are also 139 lakes larger than one square kilometer each, covering a total of 513 000 ha, and 479 reservoirs.

2. Xinjiang fisheries

Prior to 1958 fish production was limited and on a small scale. Subsistence fishermen used primitive gear to capture a few fish for their families. It was the farmers and herdsmen who were mainly fishing, using forks and hooks. There was no aquaculture at that time. This was followed by a period of fishery development from 1958 until 1971. This was a gradual process, which included the start of aquaculture, induced breeding, and fish species introductions. The fishing gear became more sophisticated and fishery was better managed. Since 1972 there has been a rapid expansion of fish pond culture, use of formulated fish feed, and intensification of aquaculture on a large scale. Reservoir fisheries enhancement has included introduction of fish culture methods and fertilisation of some reservoirs to increase their productivity. Fish producers have been trained in new fish culture technologies. New species have been introduced in aquaculture which has led to an increase in income. There have been improvements in fish processing as well. Fisheries laws and regulations have been promulgated and enforced.

The present capture fisheries concentrate predominantly on two lakes: Lake Bosten and Lake Ulungur, and three rivers: Ertix = Irtysh, Yili=Ili, and Tarim. Prior to 1980 the fish captured from these waters represented 60 to 80 percent of the total Xinjiang fish production. Lake Ulungur covers 100 000 ha. The following fish have market importance: the indigenous species Perca fluviatilis (perch), Leuciscus leuciscus (dace), Rutilus rutilus (roach), Carassius auratus gibelio (golden carp), and the introduced species Hypophthalmichthys molitrix (silver carp), Aristichthys nobilis (bighead carp), Abramis brama orientalis (bream) and Hypomesus olidus. During the period 1958-1999 there were two exceptional peaks in fish production from this lake: in 1976 - 4 500 tonnes, and in 1999 - 5 100 tonnes, but mostly the fish production was around 3 000 tonnes per year.

Lake Bosten covers an area of 90 000 ha, and has a salinity of 1.5 g/litre. The average annual fish catch is 2 500 tonnes. The following fish species have market value: endemic species Aspiorhynchus laticeps, Schizothorax (Racoma) biddulphi, and the introduced silver carp, bighead carp, golden carp, grass carp (Ctenopharyngodon idella), Hypomesus olidus and several other species. The indigenous fish have disappeared from catches, A. laticeps disappeared by 1974, S. (R.) biddulphi by 1985. All three species of Chinese carps and Hypomesus olidus were firmly established in catches by 1994. Common carp, golden carp, perch and dace were a regular component in all catches during the 1972-1999 period. During the same period there was a gradual increase in fish catches from 200 tonnes in 1972 to 2 000 tonnes in 1979, followed by a slow decline to 1 700 tonnes in 1985, which was followed by an increase to 3 000 tonnes in 1988, eventually reaching a maximum of 3 500 tonnes in 1996 and a decline to 3 300 tonnes by 2000.

The Ertix (Irtysh) River drains north and eventually, after passing through Kazakhstan and Russia, it enters the Arctic Ocean. The annual fish catch ranges between 200 and 400 tonnes. The major fish species captured are Abramis brama orientalis, Esox lucius (pike), Leuciscus idus, L. leuciscus baikalensis, Rutilus rutilus, common carp, and perch. In the Ili River, which flows west, entering Kazakhstan and eventually ending in Lake Balkhash, the major fish species captured prior to the 1960s were Schizothorax (Racoma) argentatus and S. (R.) pseudaksaiensis, but these soon disappeared and were replaced by Abramis brama orientalis, Aspius aspius, common carp, Silurus glanis (wels), grass carp, silver carp, and several other species. The annual fish catch ranges from 100 to 300 tonnes. The Tarim River is the largest river in Xinjiang. Again, the initially fished indigenous species Aspiorhyncus laticeps and S. (R.) biddulphi soon disappeared and were replaced by the introduced common carp, grass carp, silver carp and bighead carp. They have been supporting fisheries of up to 200 tonnes annually.

The first aquaculture farms were established in the 1960s. At present ten of them work well and their production potential is 300 million fry per year. In the year 2000 there were 74 state-owned enterprises and 3 158 households engaging in aquaculture production. The total number of fishermen was 18 177. The following fish were produced under aquaculture conditions: common carp, golden carp, silver carp, Megalobrama amblycephala, Clarias leather, rainbow trout, tilapias, and also freshwater shrimps and crabs.

For aquaculture production in Xinjiang in year 2000 see Table 1.

Table 1
Aquaculture production in Xinjiang by type of waterbody

Table 1 indicates that most of the aquaculture production comes from fish ponds, followed by reservoirs, pit ponds, other types of waterbodies, and the smallest amount comes from aquaculture in lakes. The highest yields are achieved in ponds, which also produce the highest percentage of fish from all types of waterbodies; the lowest yields and percentage production of the total come from lakes.

In 2000 the total fish production in Xinjiang was 58 835 tonnes, of which aquaculture produced 49 761 tonnes (84.6 percent) and capture fisheries 9 074 tonnes (15.4 percent). The state-owned fishery produced 43.6 percent and the private fishery 56.4 percent.

For additional information on Xinjiang fish and fisheries, published in English, the reader may wish to consult Walker and Yang (1999).

3. Current problems of fisheries in Xinjiang

For an arid region such as Xinjiang water is the most essential resource for human activities. During the last 50 years the population of Xinjiang has experienced fast growth, and the demand for water has increased accordingly. The area of irrigated land has increased, there are new industries, and the increasing population needs more water as well. As a result of the increasing uptake and diversion of water the lower courses of rivers have been receiving less water, and some sections have desiccated completely. The level of ground water has been declining. Terminal lakes are receiving less water or no water at all as the river and stream water does not reach them any more. Soils are getting more alkaline, and water more saline. The large scale irrigation efforts have destroyed the environment of the original fish fauna, and as a consequence indigenous fish species have gradually disappeared; overfishing has also contributed to this. The following are some of the major impacts of changes in the use and redistribution of water.

The original fish fauna of the Tarim River and Lake Bosten had the valuable species Aspiorhynchus laticeps and Schizothorax (R.) biddulphi. In spite of that during the 1960s additional fish species were introduced from the Chang Jiang (=Yangtze) and Ertix rivers. These introductions, combined with high fishing pressure and water resource development projects, led to a rapid decline in stocks of both species. The species are now listed as protected. The same happened in the Ili River with Schizothorax (R.) argentatus and S. (R.) pseudaksaiensis. In the Ertix River three other species were impacted in the same way: Stenodus leuciscus nelma, Acipenser ruthenus and A. baeri. These three species and S. (R.) argentatus are now believed to be extinct.

During the 1970s there was a rapid development of fish ponds, and by the early 1990s they covered 10 000 ha. Most fish ponds were constructed close to cities and supplied with ground water. This has had a negative impact on the level of ground water, which not only will result in shortage of water for aquaculture in the future, but is already affecting agriculture production.

The introduction of semi-intensive and high density aquaculture, and the use of fertilizers, fish feed and net-cages in the reservoirs Tajiaowan, Luigong, Beijiantan, Daquangou and Moguhu, increased the yields to 3 000 kg/ha, but water quality has deteriorated along with the accumulating organic matter on the bottom of these reservoirs. To avoid fish mortalities, it has been necessary to reduce the density of fish in these cultures.

Other problems have also appeared, such as reduction in the genetic quality of the cultured fish stocks, deterioration of fish feed quality, and increasing occurrence of fish diseases, probably due partly to the previous two factors. There has been an increase in fish mortalities especially during winter. The continuous production of common carp, golden carp and silver carp in the same ponds might also have led to the increased mortalities. What is becoming more and more clear is that there is a need not only for improving the quality of the cyprinid fish produced for markets, but also for culturing fish species of a higher quality, such as non-cyprinids.

4. Discussion

Future fisheries development in Xinjiang will have to consider the compatibility of the intensified aquaculture with the rising demands for water resources. Overexploitation of indigenous fish species, which in some cases has led to their local extinction, followed by aquaculture using introduced species, has led to further problems. These include the deterioration of the aquatic environment due to the intensification of fish production, diminishing of water resources available for aquaculture, especially groundwater supply, impacts of other uses of water such as irrigated agriculture, municipal and industrial water supply, which cause water diversion and sometimes water pollution, and also may lead to desiccation of the lower courses of rivers and terminal lakes.

Further development of aquaculture and enhanced fisheries may depend on the identification and production of better quality fish. Water-saving aquaculture methods need to be tested and introduced in all available suitable waterbodies. The use of fertilizers, both organic and inorganic, should be more judicious, and water quality should be improved through planting aquatic macrophytes and other measures. If fish species introductions are still to be considered, strict quarantine measures should be maintained before any introduction is made. Better fish strains are needed for aquaculture, which has been using the same fish stocks for many years. There is also need to test new methods and methodologies of fish production and improve fish processing. Introducing better quality fish species into culture will result in a better income for fish farmers.

References

Walker, K.F. & Yang, H.Z. 1999. Fish and fisheries in Western China. In: Fish and fisheries at higher altitudes: Asia (Petr, T. ed.). FAO Fisheries Technical Paper. No. 385: 237-278.