Culture of short-cycle species in seasonal ponds and ditches of Bangladesh

Homestead seasonal ponds, ditches and road-side canals, which are formed either due to borrowing of soil for house or road construction or ponds dug for household uses (bathing, washing) or irrigation, can be used for aquaculture of short-cycle species, such as Silver barb (Puntius gonlonotus) or nile tilapia (Oreochromis niloticus). Even 80-100 sq m ditches as shallow as 70-80 cms can be used for culture of these species, using on-farm agricultural wastes and by-products, as inputs. Even ponds which retain water for only 3-4 months can be used for culture of these species. The culture practice is simple, requiring very low labor input and, hence, can be undertaken by women and children, producing fish for household consumption and for market. Landless farmers can also benefit from this technology by culturing fish in common property road-side ditches.

Material flow between homestead enterprises

Agroecosystem transect of mymensingh-sylhet flood plain area in Bangladesh.

TECHNOLOGY FOR CULTURE OF SHORT-CYCLE SPECIES

1. Pond Preparation

· Branches of trees on pond embankment should be cut or trimmed. Pond should be cleared of submerged and floating weeds as they utilize pond nutrients and obstruct penetration of sunlight into water, resuting in low production of fish food organisms.

Clearing away weeds

Trimming branches to allow sunlight

· For lowering of acidity, better utilization of fertilizer and for disinfection, lime need to be applied to the pond at the rate of 25 9 for each sq m. Spread lime on pond bottom if pond is dry or mix with water and spray if pond is with water.

2. Fertilization

· For good production of fish food organisms (plankton) in the pond on which depend growth of fish, the pond needs to be fertilized. Organic manures or chemical fertilizers can be used for the purpose. Cattle dung (100 g/sq m) or chicken manure (50 g/sq m) or urea (2 g/sq m) and triple superphosphate (5 g/sq m) need to be applied once every two weeks.

· Organic manure can be heaped in the corners of the pond while chemical fertilizers need to be dissolved in water and spread in the pond.

Fertilization

· A pond of 500 sq m needs every two weeks 25 kg of cattle dung or 15 kg of chicken manure or 1 kg of urea and 2.5 kg triple superphosphate.

3. Stocking

· Depending on farmer's choice, Nile tilapia or silver barb (P. gonionotus) can be cultured in the Pond.

· In case of Nile tilapia, 2 fingerlings/sq m, while in case of silver barb, 3 fingerlings/2 sq m need to be stocked.

Stocking

· If the pond retains water for more then 6 months, in addition to silver barb, 3 fingerlings/40 sq m of catla (Catla catla) or silver carp (Hypophthalmichthys molitrix) and 2 fingerlings/40 sq m of common carp (Cyprinus carpio). This will increase total fish production.

· Healthy fingerlings should be procured from a reliable hatchery or supplier. Better to stock 3-5 9 size, as they would reach table size early, especially in case of ponds which retain water for only 3-4 months.

4. Feeding

· For good production, supplementary feeds should be given in the pond. Kitchen waste, duck weeds, azolla, green leaves of kangkong, sweet potato and tender terrestrial grasses can be given. Rice bran or wheat bran wilt increase growth and production of fish.

Feeding

· Feeding should be done once or twice a day. Quantity of feed to be given increases with size of fish. A tentative schedule of feeding rice bran in a 500 sq pond is shown in chart. If kitchen wastes or weeds are given, quantity of rice bran shown in chart can be reduced.

5. Pond Management

· Green color of water indicates good production of fish food organisms (plankton). Clear water indicates lack of enough fish food. By dipping your hand in the water, seeing it half - way to the elbow indicates lack of enough fish food. In such case, increase fertilization. If the hand disappears haf-way to elbow, it indicates sufficient plankton. If it disappears after dipping the palm, it indicates plankton bloom, with deep green color and this can deplete oxygen in pond water, especially during night and cloudy days and can result in mortality of stocked fish. Stop feeding and fertilization till the water color becomes lighter.

Poor plankton

Good plankton

Plankton bloom

· Tilapia breeds in pond, leading to overpopulation. This results in poor growth of fish due to competition for food. Hence, tilapia fries which move in schools along the banks of pond can be removed, using a scoop net. They can either be sold or crushed and given as feed in the pond.

6. Harvesting

· Harvesting of fish can be started as soon as fish reach table size or when the water level in the pond goes below 4-50 cm. You can always harvest for family consumption or at one time for marketing. 75-100 kg of fish could be harvested from a 500 sq m pond in 5-6 months.

Feeding

7. Disease

· When temperature goes down to about 20°C and below during November-January, Silver barb is susceptible to ulcerative syndrome disease which starts as red spots on fish and later becomes a wound.

· When infection is seen, apply lime in pond at the rate of 25 g/sq m pond area.

Taka budget for puntius gonionotus and nile tilapia culture in a seasonal pond of 500 sq m for six months.

* 1 US$ = Taka 38

Note: If on-farm sources of cattle dung and rice bran are used along with family labor, then 690 Taka can be saved which will raise the balance to 2,707 Taka for Puntius and 1,932 Taka for Tilapia.

Prepared by: MODADUGU V. GUPTA

FARMER-PROVEN INTEGRATED AGRICULTURE AQUACULTURE:
A TECHNOLOGY INFORMATION KIT (IIRR-ICLARM)