As fish culture appears to be the basis for fishery development in inland waters of China, it is not surprising that methods have been evolved for farming small rivers.
In the Tang Sha People's Commune, Xinhui County in Guangdong Province, the study group saw an example of fish cultivation in rivers. The main river used is the Tiensha, which is 50 km long, with some 140 km of tributaries. Because of the large area covered, embracing several production brigades, fish cultivation in the river is done by the commune as a whole, while individual production brigades cultivate the smaller branches of the river.
The total water area used in river cultivation in this commune is 5 800 mu and the production in 1977 was 240 000 jin (i.e. 41 jin/mu), although the brigade output averaged 100 jin/mu.
The main features of river fish cultivation are:
- stocking with large-sized (over 9 cm) fingerlings:- provision of blocking devices in tributaries and gates in the main river, allowing the passage of boats, but preventing the escape of fish;
- rearing fry in dry season pools before releasing them into the river;
- the eradication of predatory fish by selected fishing.
Table 6 Fish Production in some Chinese Freshwater Lakes in 1977
|
Lake/ Province |
Area ha |
Average Depth |
Fish Stocked |
No. Fingerlings Stocked |
1977 Production |
Average Yield/ha |
|
|
(mu) |
(m) |
(Main Species*) |
|
(tonnes) |
|
|
Taihu |
225 000 ha |
2 |
Big head* |
(not available) |
12 000 |
53 |
|
(Jiangsu) |
(3 375 000 mu) |
|
Bream |
|
|
|
|
Ting Shan |
7 000 ha |
4 |
Silver carp* |
10 million |
1 000 |
143 |
|
(Shanghai)
|
(105 000 mu) |
|
Grass carp* |
(16 g size) |
|
|
|
|
|
Black carp |
|
|
|
|
|
|
|
Big head |
|
|
|
|
|
|
|
Mullet |
|
|
|
|
|
|
|
Eel |
|
|
|
|
|
Tanghu |
1 467 ha |
4 |
Silver carp* |
4 million |
660 |
450 |
|
(East Lake) |
(22 000 mu) |
|
Big head |
(16-17 cm fingerlings) |
|
|
|
(Hubei Province) |
|
|
Grass carp |
|
|
|
|
|
|
Black carp |
|
|
|
|
|
|
|
Plagiognathops microlepis |
|
|
|
|
|
Paitan |
400 ha |
2 |
Silver carp* |
30 million fry |
300 |
750 |
|
(Hubei) |
(6 000 mu) |
|
Big head* |
1 million large- sized fingerlings |
|
|
|
|
|
Bream |
|
|
|
|
|
|
|
Crucian carp |
|
|
|
|
|
|
|
Grass carp |
|
|
|
|
|
|
|
Black carp |
|
|
|
|
|
|
|
Common carp |
|
|
|
|
|
|
|
Wuchan fish |
|
|
|
Fig. 25 Blocking devices made of wood, bamboo and netting used for fish farming in rivers (a)
Fig. 25 Blocking devices made of wood, bamboo and netting used for fish farming in rivers (b)
In 1977 the following numbers of fish were stocked by the commune and brigades:
|
Big head |
130 000 |
|
Silver carp |
50 000 |
|
Grass carp |
140 000 |
|
Common carp |
80 000 |
A small number of other fish, such as wuchan fish, were also stocked. The rivers and other tributaries were not fertilized, nor was there any form of supplementary feeding. The run-off from the surrounding cultivated land enriches the river water.
The use of natural dry season pools which appear on the edge of the river during low water for cultivation of fingerlings enables the raising of large fingerlings for stocking in the river. Three- to four-day-old fry are purchased and stocked in these pools where they grow to about 300 g, before they are released into the river by the flooding of the pools during the rainy season. The survival rate of fingerlings has been estimated to be between 60 and 80 percent. Because of the success of this method, the commune plans to build additional artificial pools for fry rearing.
In all, 56 persons are engaged in river fish culture in the commune and their work includes the stocking and harvesting of fish and control of the river gates. With an annual production cost of only Yuan 6 000 and an income of about Yuan 28 000 from the harvests, river fish culture appears to be very profitable.
Although the cultivation of fish in rivers is feasible in China, there will be a number of difficulties in introducing it in other countries, which would include legal, environmental and technical problems. The collective ownership and commune system of administration make this practice possible in China.
