Rice Paddy Aquaculture Integration

FISH CULTURE IN RICE PADDIES

Rice-fish culture is not widely practiced around the world. Most information comes from Asian countries, particularly the Philippines, Indonesia, and Japan, where traditional rice farming methods have been refined over centuries. Rice is the economically important crop. Fish may provide supplemental income and/or protein, but is not normally the primary crop. The addition of fish culture to rice production is an additional management consideration for farmers. In many cases, there may not be sufficient economic justification for this extra management.
Fish culture in rice fields may be practiced at several management levels. In its most simple form, fish stocks are not managed. Wild fish enter the paddy during flooding and are captured at the end of the rice growing season. This method of raising fish together or concurrently with rice is as old as rice culture itself. Other techniques are based on either managed concurrent culture of fish with rice, or on rotational production of fish and rice
crops. This manual discusses the concurrent production of rice and fish.
Potential advantages of rice-fish culture
1. Additional food and income in the form of fish.
2. Control of mollusks and insects which are harmful to rice.
3. Reduced risk of crop failure resulting from integration of rice and fish.
4. Continued flooding of the paddy and rooting activity of fish help control weeds.
5. Fish stir up soil nutrients making them more available for rice. This increases rice
production.
Potential disadvantages of rice-fish culture
1. Pesticide use must be restricted.
2. Rice-fish culture may require more water than rice culture alone.
3. Trenches must be dug about 40 to 50 cm below the paddy bottom. In many places,
this makes drainage difficult. Rice yield per area is usually reduced because paddy
area used for trenches is not planted with rice.
4. Fish produced with the system are often small and total production is lower than
what could be produced in a pond of equal size.
5. Because rice production is seasonal, fish are harvested at the same time by every farmer
and marketing may be a problem. Consequently, rice-fish culture may be more
appropriate for small-scale paddies where fish are consumed by the producing family.
6. Because rice paddies may be irrigated from a common water supply, it is difficult to
ensure that water used to supply the paddy will be pesticide-free. This may make
rice-fish culture impractical.
7. Substantial investment in fish and rice paddy modification increases risk to farmers.
8. Requires more labor than rice culture alone

Paddy Preparation and management
Traditional rice paddies normally require modification for concurrent culture of fish. One
important modification is the deepening of part of the paddy to serve as a fish shelter and
harvest area. The deepened areas are called trenches, canals, channels, or sumps (Figure 1).
Construction and placement vary, but these deepened areas provide several critical
elements for successful rice-fish culture:
1) Refuge when the water level is lowered
2) Passageways for fish to find food
3) Easier harvest of fish when the paddy is drained