(introduction...)

Carp breeding using off- season wheat fields

About 300,000 ha of wheat fields around Jabalpur, Madhya Pradesh in India are virtual rainfed ponds (havelis) from July to October. There being no source of irrigation, rainwater is Impounded in these fields (with about 1 m high dikes) until the onset of winter when they are drained, ploughed and the wheat is sown. This period lasts for 3-4 months wherein the field is utilized either for common carp seed production. Based on the input requirements for a 0.4 ha field, the following procedures could be followed:

Fish breeding

SEED PRODUCTION

Select a field near the road but away from flood-prone zone. Check the dikes and put meshed screens on the inlets and outlets, if provided.

Spray an emulsion of 201 diesel and 7 kg of cheap washing soap on the water surface to kill predatory aquatic insects as soon as about 60-80 cm of water gets accumulated in the field.

After spraying, release 4 healthy and fully ripe females along with an equal number of males, each weighing about 1 kg. Provide 2-3 kg of Hydrilla or Eich ornia at 3 or 4 places in the field. A fully-ripe, healthy female can be distinguished by its swollen bulging abdomen and a reddish genital region which is pit-like in the male. The males also ooze milk with gentle pressure on their abdomen.

The fish breed within 24-48 hours of stocking or take a day or two more, if they are not fully ripe. The eggs are laid on the weeds and hatch out within 48-72 hours.

Harvesting can be done after 15-20 days. Approximate yield is 100,000 fry of about 2530 mm size. If the field is fertilized with 2000 kg cowdung and the fish are fed with an artificial feed comprising groundnut oil cake and rice bran (1:1 by weight), the survival is high and the growth is fast.

The remaining fry attain a size of 40-60 mm by the time the fields are to be drained when these (about 20,000 fingerlings) are also harvested.

Sample rupee budget for carp in haveli wheat fields (0.4 ha)

COSTS:	Rs
Cost of 8 kg live brood-fish (4 females and4 males, 1 kg each) at Rs 25/kg	200
Transport cost	200
Soap oil treatment	125
TOTAL COSTS	525
INCOME
Sale of 50,000 fry at Rs 10/1000	500
Sale of 20,000 fingerlings at Rs 100/1000	2,000
Sale of 6 kg of fish at Rs 15/kg	90
TOTAL INCOME	2,590
Balance	2,065
Net Income/ha	5,162

1 US$ = 25.50 Rs

Prepared by: S.D. TRIPATHI & B.K. SHARMA

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

Nursery system for carp species

A nursery is a facility where fish seed (hatchlings/fry) can grow. Efficient fish pond culture requires special preparation of nurseries for receiving spawn and hatchlings. The ideal size of a nursery is 0.02 0.02. ha with a depth of 1.0 - 1.5 m.

POND PREPARATION (0.02 ha)

Remove all aquatic weeds (Day 1).

Drain or poison the pondwith Plscide-Phostoxin or Cellphos @ 1
tablet/210 cu ft water (Day 2).

Apply 5-6 kg lime which helps to release food nutrients available and to kill pathogenic organisms in the pond (Day 16).

· Refill water if necessary and fertilize (Day 19).

Apply fertilizer 3 days after lime application and 7-10 days before stocking.

· The most basic and reliable test involves filtering approximately 50 1 of water through a fine mesh into a 2.5 cm diameter specimen tube.

· Alternatively, a very simple field test in non-muddy water is to dip one's hand in the water to the elbow. If the hand is no longer visible, the plankton is probably sufficient.

STOCKING

Apply 80-100 g Dipterex at least 20-24 hours before stocking to kill the back swimmers or other aquatic insects in the pond (Day 29).

· Stock 60,000-70,000 hatchlings of 4-5 days old (200-250 9). The hatchlings should be of same age, uniform size, vigorous and released either in the morning or late afternoon (Day

Seed	Available
Common carp	January—March
Silver carp	February—August
Rohu Mrigal	April - July
Catla	May - July
Grass carp	May- August
Silver Barb	March - May

Stocking Procedures

Before the hatchlings/fry are introduced to a new environment, it is important that the temperature inside the plastic bag is approximately the same as the pond water.

Place the bags, unopened, in the pond for 10-15 minutes. Open slowly and introduce small quantities of pond water to equalize the temperature. The fry is now allowed to swim into the pond.

FEEDING

· It is often difficult to maintain a high level of natural food for growing fry and supplementary feeds become necessary (Day 31). A mixture of finely powdered oil cake (soya beans, mustard, etc.), rice or wheat bran and fish meal in the ratio of 5:4:1 is to be supplied to try daily.

Feeding

CARE OF FRY/FINGERLINGS

· Check the pond daily and see if there is an excess of green algae then; stop, application of supplementary feeds. Remove frogs/snakes, if any, in the pond. Increase feed by 10% of the rate mentioned above if the growth of the fish is not found steady and good.

HARVESTING AND TRANSPORTATION

· Harvest the try/fingerlinggs (Day 60) by using fry catching net, either in the morning or late afternoon and keep them in the enclosure (hapa) or cistern at least 3-4 hours before transportation (Day 60). Transport the fry/fingerlings in oxygenated plastic begs.

Before transporting, it is important that fingerlings are conditioned. The principle behind this is that they have time to empty their alimentary canal before being packed in high densities, so that the pollution of the carrying waters through excrete is reduced. Clean water from tube well should be used for conditioning the fingerlings.

Traditionally, young fish are transported in clay or aluminum pots. Recently, the use of plastic bags in compressed oxygen is becoming more widespread, as this allows the fish to be transported in higher densities and longer distances with substantially less mortality. Approximately, 5 1 of water

Harvesting and transportation

Density of fish (30 mm size) during transportation:

Species	Number per Liter
Rohu	50
Big head	50
Catla	33
Silver carp	60

Taka budget of 0.02 ha nursery pond preparation for fingerling production.

Costs	TK
Draining/refilling or poisoning of pond	75
Lime 5 kg	25
Cattle dung 200 kg	100
1.75 kg Urea and 2 kg triple superphosphate	20
Dipterex 0.2 kg	80
60,000 carp hatchlings	600
Supplementary feeds: 20 kg mustard oil cake + 10 kg rice	180
Netting, labor and others	400
Total cost	Tk 1480
Income from sale of 30,000 (3.5 - 4.5 cm) fry/fingerlings	Tk 3000
Balance	Tk 1520

US$1.00 = TK 38

Prepared by: MD. GOLAM AZAM KHAN

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

Fry nursing in rice-fish systems

Most Northeast Thai rice-fish culturists cannot control predators in their fields and finding seed fish 7 cm in length is difficult, if not impossible. Therefore, culturing small fry in a nursery where they can grow, safe from perdation, to a size when most of them can escape predation, is often advisable.

Nurseries come in several varieties:

· small pond in or near the field
· small rice-fish, well-supplied with water
· nursery cage in larger pond

NURSERY PONDS

A small pond, usually 100 sq m or smaller, is most common. During the dry season, the pond is dry or dried. Lime and manure are commonly added at about 3 kg and 10 kg/sq m, respectively. With the first rain, In new ponds, these rates should often be increased.

Once water begins accumulating, depth and color should be monitored. Is the water turbid? Adding more manure, straw or other fertilizer may help clear this up. If water is very clear, similarly, fertilizer should be added. This fertilizing in clear water should lead to the establishment of plankton, which gives the water a brownish to greenish color preferably the former. Checking the amount of plankton in the water Is easily done by observing at what depth the palm of the hand disappears. Ideally, the palm will become invisible around elbow depth. If the palm disappears in this 10 cm of the surface, the water Is too rich. Fertilization should be reduced or stopped and some new water added. if possible.

Poor plankton

Good plankton

Plankton bloom

The depth of water should preferably reach 70-80 cm prior to stocking. The farmer should feel reasonably sure that water should remain near this depth, as well. Two to three thousand 2-cm fry can be stocked in a 100 sq m pond, for culture up to fingerling size (5 cm). This is enough for a 1-ha field when fish are not fed. If the field is about 1000 Sq m, a 10-20 sq m pond will be large enough.

Following stocking, the pond can be fertilized and fed with fine, available materials (rice bran, termites, left-over). Feeding will be especially important in turbid ponds.

Early every morning, the pond should be checked to see if fish are gaping. This is a sign of insufficient oxygen and, if noticed, should be dealt with according to the situation. (Take note of this!)

Fish are usually held in the pond until the rice is well-established in the field (with 2-3 new tillers) and the fish have reached a length of around 5 cm. This usually takes about six weeks If there is stable

A nursery allows the farmer to stock fish earlier, thereby prolonging the growing season for the fish and possibly allowing purchase of a wider choice of fish than later in the season. A good nursery also assures higher survival for fry than would be the case in a rice field, when predation is uncontrollable. The farmer who is used to buying fingerlings will save money by investing in smaller fry.

A bad nursery, however, is worse than no nursery at all. If predators are present, seedfish cannot escape and mortalities will be very high. For similar reasons, pollution due to overfeeding or toxic chemicals can be dangerous. Overheating, particularly in very shallow water, can be another problem. A small patch of shade over the water may be needed, in this case, this should cover only a little of the water surface, since sunlight is needed to produce oxygen and natural feed. When an existing pond is used to hold water or fish all year round, it should not be used as a nursery. The farmer will do better to dig a small, shallower pond or cage to set a nursing cage of fine mesh in the existing pond. Fish stocked in such a cage will need daily or twice-daily feeding with good quality food.

NURSING CAGES

The Aquaculture Outreach project of the Asia Institute of Technology has developed with farmers a nursery cage technology which is becoming popular in Northeast Thailand. These fine-meshed cages assure an absence of predators, make management easy and give the farmers a chance to become more familiar with their fish. Feeding, however, becomes more expensive.

REQUIREMENTS

· Access to nylon netting material and nylon string.
· Livestock concentrate and fine rice bran.

Seed should be given twice daily as a mixed dry mash of duck or pig concentrate (40% crude protein) and fine rice bran (at a ratio of 2:1 by weight). This may appear rich, but has been found appropriate in trials with farmers. Feed can be mixed for 1 week and kept in a dry place.

Mixing feed ingredients weekly and storing in a dry place.

Nile tilapia is best raised in monoculture.

Common carp, mrigal, grass carp and silver barb all grow well in monoculture or polyculture to reach 6-10 cm size in 6-8 weeks.

The amounts should increase and be equivalent to:

10% body weight/day - week 1 & 2
8% body weight/day - week 3 & 4
5% body weight/day - week 5, 6, 7, 8

Other feeds can be given after week 4.

Use of sardine cans as the unit for estimating feed inputs.

Termites and green fodders (cassava leaf, morning glory and Euphorbia sp)

finely chopped and fed after week 4.

Fertilization of the pond or ricefield using urea and buffalo manure will improve growth and allow some reduction in quantity of concentrate given.

MAKING THE HAPA

Nylon hapas can be made by hand but are usually stronger when a machine is used. Attention should be given to making the reinforced corners. Hapas of two sizes have been found suitable for small-scale farmers depending on their requirement for seedfish.

Making the hapa

The hapa should be suspended using enough bamboo poles and nylon string. The bottom of the net is kept down using a rock attached to a string for easy removal.

After use, the hapa should be cleaned and dried before careful storage to avoid damage by rodents.

The AIT Outreach Project has developed with farmers a booklet explaining the hapa method. The AIT Outreach project is funded by the Overseas Development Administration (ODA), U.K.

Prepared by: DAVID LITTLE NICK INNES TAYLOR, DENNIS TURONGRUANG & JOHN SOLLOWS

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

Fingerling production in irrigated paddy

Fish fingerlings supply is scarce in Northern Bangladesh. It is usually expensive and laborious for fish farmers to procure fish seeds. The production of common carp (Cyprlnus carpio) fingerlings with different types of "boro" or irrigated paddy is an alternative. Although production figures are below the commercial rates, small farmers can grow their own fingerlings at minimal cost.

The four types of irrigated paddies for fingerling production (as practiced by poor farmers in Northern Bangladesh) the have following features:

soil	:clay loam	fish species: Common carp
water supply	:irrigated	rice variety: Bangladesh Rice
water depth	:maintained at7.5 -10 cm	(BR) 3, BR -8 , BR-9, BR-14, Tayap and China Pajam.
area range	:12.5 - 1,320 sq m

Fingerling production in irrigated paddy

ADVANTAGES

1. Fish hatchlings or fry can be reared in different types of "boro" paddy plot designs without altering farmer's normal practices in rice production.

2. Farmers' existing resources can be used.

3. Only minimum additional expenses are required.

4. When the fish get bigger than one inch, they control weeds, pests and insects in the paddy.

5. Fish feces serve as fertilizer for rice.

6. Can provide additional income.

7. Farmers can sell fingerlings when prices are highest.

CALENDAR OF ACTIVITIES IN FISH PRODUCTION

Paddy preparation

Transplanting rice

Apply Sumithion to kill predators d.25 mg/sq m

Stock with 2-week old fingerlings at 10/sq m

Monitor fingerling growth by weighing, done in weekly intervals. Maintain water depth at 7-10 cm in the paddy.

Harvest the fingerlings. Condition them in hapa before selling, or stock them for further growth.

Note: Apply pesticides for the rice crop only if needed. Malathion (suggested rate 27 ml/1000 sq m) has been shown to cause the least harm to fish. Deweed along paddy embankments to remove breeding places of and sheiter for predators.

WHAT TO CONSIDER BEFORE ADAPTING THE TECHNOLOGY

1.Paddy soil should have good water - holding capacity

2. Common carp is recommended for stoking:

- spawns earlier;
- fries are available at the same time as “boro” rice transplantation
- hardy fish

Tilapia can also be stocked.

3. Fish have higher survival rates in smaller paddies.

4. It possible, use fry (instead of hatchlings) for stocking because they have higher survival rates.

5. Use of supplementary feed, like fine bran or wheat bran, can help increase fingerling production at very minimum cost.

6. To reduce risks of paddy field drying out, use treadle pumps.

Production details between stock of fry and hatchlings (based on 1,320 sq m paddy).

	FRY	HATCHLINGS
Stocking rate/sq m	10	40
Stocking (#)	13200	52800
Survival rate (%)	40	5
Growth Cycle (days)	42	60
Yield (#)	5280	2673

Partial budget for common carp fingerling production in boro paddy (based on 1,320 sq m paddy).

	FRY	HATCHLINGS
COSTS	1075.64	4;20
Fry costs at Tk. 0.08/u	1056	-
-Hatchlings cost at Tk. 00875/unit	-	462.00
-Family Labor	-
-Interest on operating cost (16% per annum)	19.64	12.20
Income Return
(Fingerlings Tk. 0.5/unit)	2640	1336.50
BALANCE	1564.36	862.30

Comparative budget and income from 3 systems: rice; rice and common-carp hatchlngs' and, rice and common carp fry.

	Rice only	Rice and Hatchilngs	Rice and Fry
· Rice production
Cost
Inputs	684	601	601
Labor	492	509	509
Irrigation charges
(Tk. 500/bigha)	500	500	500
Interest on operating costs16% per annum(1.33 % /day)	89	85	85
Income	3855	3943	39¢3
Return for Rice	2090	2248	2248
· Fingerling Production:
Fingerlings (Tk. 0.50/pc.)
Cost	NA
Fish		462	1056
Family Labor
Interest on operating costs16% per annum (1.33% day		12	20
Income NA	NA	1337	2640
Return for Fish	NA	863	1564
Return for Plot	2090	3111	3812

Records from CARE/ODA/BRAC Rice/Fish Pilot Project. Rangpur 1991

1 US$ = Taka 38

1,320 sq m = 1 bigha, a standard area measurement used in Bangladesh.

Prepared by: FRRANCISCO NOBLE

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