Integrated Fish Farming System
In integrated fish farming system, one or several farming commodities are integrated with fish culture keeping the pond as the nucleus of the farm. The uniqueness of integrated fish farming lies in the fact that in this system of farming, the farm commodities are produced, in a complimentary manner. For example, by siting animal housing units (pig-sty, cattle shed, poultry coop, duck house etc.) on pond embankments or over pond surface, the animal wastes = and washings which are diverted into the pond, become readily available to the fish. In this process the stocked fishes not only utilize the feed spilled by the animals but also feed on their excreta which serve as a rich source of nutrients for the fish. As can be seen from their manorial value, the excreta also acts as manure for the pond and raises biological productivity of pond water and consequently increases fish production. Diagrammatic depiction of recycling of animal waste in integrated fish farming system.
In integrated fish farming, it is not always the fish which remains at the receiver end. In fact, it is both ways. The fish pond too, in turn, meets very many requirements of the counterpart commodity such as (1) pond humus containing fish wastes and other organic matter are utilised as manure for growing vegetable and fruit crops on pond embankments (2) pond water serves as a ready source of irrigation for horticultural crops (3) pond water also comes in handy for washing animal houses as also for bathing animals (4) pond embankments provide space for sitting animal houses as also for cultivation of horticultural crops (5) pond provides the much needed ration of natural food to commodities like ducks and geese (6) pond surface also lends space for growing aquatic plants like water hycinth, Ipomea etc. which serve as fodder for pigs.
The advantageous effects of integrated fish farming can thus be summarized in following points :
- better resource utilisation
- substantial savings in operational cost through waste recycling
- conservation of space for farming through vertical expansion i.e. by sit- ting animal houses and birds coops over pond embankments or over fish pond
- reduced investment risk through crop diversification
Integrated farming has bright prospects in India. This is largely be- cause fish culture in India is basically in the hands of people who are the most down-trodden lot of our rural com- munity. Although high-yielding fish culture technologies have been developed in India but they are of no avail to our poor farmers on account of the high cost involved in the purchase of essential inputs like fish feed and fertilizers. A marginal or small farmer of our country has too small a resource base to take to such cost-intensive operations of fish culture technologies. In such a situation, it is but natural that any effort at reducing this essential expenditure in fish culture would make the technology more popular for adoption in rural areas.
Types of Integrated Fish Farming System
Systems of Integrated Fish Farming Integrated fish farming can be conducted in various combinations. The more popular combinations are described below:
- FISH-DUCK Combination
- PADDY FISH INTEGRATION
FISH-DUCK Combination
Fish-duck combination, infact, is viewed as a means of reducing the cost of feed for ducks and a convenient and inexpensive way of fertilizing ponds for the production of fish food. Thus, more protein is produced per unit area by such a combination. An obvious benefit of this integration is that ducks feed on such organisms from the pond (like insects, insect larvae, tadpoles, frogs, molluscs, aquatic weeds etc.) which do not form food for carps. Thus, the protein content of the supplementary feeds which are necessary to achieve high production rates for ducks is reduced to 10 to 15%, when the ducks are raised on ponds. In addition, the pond also provides a clean and healthy environment for the ducks.
Two varieties of ducks, namely, Indian Runner and Khaki Campbell are generally considered for integration. Al- though Indian Runners are more hardy but they are not as good layers as exotic Khaki Campbell. A duck normally voids 125 to 150 g of droppings per day. Based on this estimate and considering the re-
PADDY FISH INTEGRATION
From time immemorial, paddy fields have been intimately linked up with the fisheries of inland waters. Inundated paddy-fields always harbour small population of fish which gain access with the water. These are ultimately caught by employing indigenous devices forming fishery of considerable local value. People perhaps took clue from this which finally gave rise to the practice of deliberate stocking and harvesting and thus the system of fish culture in paddy fields emerged. The trapping of young ones of prawns and fish in fallow paddy fields and growing them to market size is by using the flooded paddy fields after paddy is harvested, to raise one or more crops of fish and prawn – this is called as rotational or sequential culture.
By growing fish along with the paddy and harvesting the paddy and fish at the end of paddy growing season- this is called as combined or concur- rent system. Traditional culture of brackish water prawn and fish in paddy fields in West Bengal and Kerala in India are the best examples of rotational culture. The sys- tem which is practiced in West Bengal is called as “Bhasabada” or “Bheries”. In this system, the water level in the irrigation canal near paddy fields is maintained about 30 cm below the level of the fields until the outbreak of the southwest mon- soon (June-July) when the fields are manured and rice seedlings planted. In August, the water level in the canal rises because of the accumulation of rain water, and consequently its salinity decreases. The bunds surrounding paddy fields are then cut at places to facilitate ingress of wild fry and fingerlings of fishes and prawns, where they are reared with paddy.
The system followed in Malabar area of Kerala is called “Pokkali”. In this sys- tem, the cultivation of rice is restricted to a single crop from July to September, when the surrounding brackish waters are low in salinity. In October, after the har- vest of the paddy, during high tides, heavy ingress of young ones of fishes and prawns with the tidal water takes place where they are trapped and reared till December. The harvest mostly comprises prawns such as Penaeus indicus, P. semisulcatus, Metapenaeus monoceros, M. dobsoni, Macro- brachium rude and Palaemon styliferus.
The rest of the catch (20%) consists of fishes like mullets, pearl spot and chromides. About 4,400 ha of pokkali paddy-fields in Kerala are used for fish farming with annual per hectare yield varying from 785 to 2135 kg.
The most suited species of fish for culture in paddy fields are usually those which can :
- thrive well in shallow water,
- tolerate high temperature,
- withstand fairly high turbidity,
- grow at a fast rate, and
- achieve marketable size in short period.
Although combined culture of paddy and fish is carried out in a number of countries in a number of ways but the one recently demonstrated in India specially holds good for low lying area of the country with high rain fall.