Aquaculture refers to the farming of aquatic animals and plants, such as fish, shrimp, and sea weeds in water. It can be classified under two major heads—freshwater and coastal.
Sea farming refers to culture of organisms in cages, pens, rafts and long-lines in the open coastal waters and bays, whereas brackish water aquaculture relates to land-based farming systems using salt water from the estuaries and creeks as also from the sea in coastal areas. Coastal aquaculture uses many common species of fish, shrimps.
Although India has moved ahead on several fronts in the development of techniques for seafarming of organisms with high production potential, commercial scale operations are yet to take off. On the other hand, freshwater and brackish water aquaculture is making substantial progress.
The main requirements of aquaculture are seed, feed and water quality.
Water quality management includes all physical, chemical and biological factors, and these influence survival, growth, health and production offish in the ponds. Water quality is environment related and inputs such as liming for sanitation and correction of hydrogen ion concentration, fertilization stocking and feeding interact with the pond environment. Indian coastal areas have varied agro-climatic conditions and pond management needs to take all factors into consideration.
The inland saline and alluvial soils which are rendered unfit for agriculture can be effectively used for culture of marine fishes and prawns.
With a view to providing a greater boost to aquaculture research and development, the Indian Council of Agricultural Research in New Delhi reorganized the fisheries research institutes in 1987, which led to the establishment of three separate institutes namely: The Central Institute of Freshwater Aquaculture (CIFA) at Bhubaneswar; the Central Institute of Brackish-water Aquaculture (CIBA) at Chennai and the National Research Centre of Coldwater Fisheries (NRCCWF) at Bhimtal in Nainital. The Pond Culture Division of CIFRI later integrated into CIFA which has been instrumental in the development of several technologies used in freshwater aquaculture and with their dissemination through a number of first line extension projects.
Brackish water farming in India is an age-old system which was confined mainly to the bheries (manmade impoundments in coastal wetlands) of West Bengal and pokkali (salt resistant deep-water paddy) fields along the Kerala coast. With no additional input, except that of trapping the naturally bred juvenile fish and shrimp seed, these systems have been sustaining high production levels. The importance of brackish-water aquaculture was recognized only after the initiation of an All India Coordinated Research Project, (AICRP) on ‘Brackish-water Fish Farming by ICAR in 1973. The project developed several technologies pertaining to fish and shrimp farming.
With the development of more commercial hatcheries, a phenomenal increase in the area under shrimp farming occurred. The formation of Brackish-water Fish Farmers’ Development Agencies (BFDA) in the maritime states and the implementation of various government program to provide support to the shrimp farming sector assisted with its further development.
Demonstrations of semi-intensive farming technology coupled with credit facilities from commercial banks and subsidies from the Marine Products Export Development Authority (MPEDA) helped boost the shrimp farming sector.
The brackish-water aquaculture sector is mainly supported by shrimp production as well as giant tiger prawn (Penaeus monodon), which are responsible for the bulk of production followed by the Indian white prawn, P. indicus. Although India possesses several other potential species of finfish and shellfish, production of these is still very low.
Sewage-fed fish culture and rice paddy-cum- fish culture are two important culture systems practiced in certain areas of the country; sewage- fed fish culture in bheries in West Bengal is an old practice. The culture system usually involves multiple stocking and multiple harvesting approaches. Recently aquaculture has also been employed as a major option for the treatment of domestic sewage.
Paddy-cum-fish culture is undertaken in medium to semi-deep-water rice paddy fields in lowland areas with fairly strong dykes to prevent the escape of cultivated fish during floods; trenches and pond refuges in the paddy fields provide shelter for the fish. While the system mostly relies on natural stocking, modern farming techniques involving major and minor carps stocked at the densities of 5,000—10,000/ha alongside freshwater prawn are also practiced in several areas.
Studies on maturation and the breeding of shrimps were initiated by the Central Marine Fisheries Research Institute (CMFRI) in the early 1970s. In the late 1980s MPEDA established the Andhra Pradesh Shrimp Seed Production and Research Centre (TASPARC) and the Andhra Pradesh and Orissa Shrimp Seed Production and Research Centre (OSPARC) based in Orissa which provided assistance for the establishment of a number of private hatcheries.
Andhra Pradesh is a leading producer of shrimps, especially at Nellore. Many of the farm holdings located in Kerala and West Bengal belong to the traditional systems, of shrimp farming.
Mud crabs (Scylla serrata) are abundant in Indian estuaries, especially in Chilka lake Pulicat lake and Vembanad lake but the crab resources are getting over-exploited at present. A small quantity of mud crab is exported live to Singapore from Chennai. No commercial culture has been taken up so far, despite heavy demand and high price.
In India, commercial cultivation of brackish- water finfish is almost non-existent, though experiments on monoculture as well as the polyculture of milkfish, pearl-spot, mullets and sand whiting have shown their potential for farming.
The earliest attempt at mariculture in India was made at the Mandapam centre of CMFRI in 1958-1959 with the culture of milkfish (Chanoschanos). Over the last few decades, CMFRI has developed various technologies for a number of species including oysters, mussels and clams among sedentary species, as well as for shrimps and finfish.
The CMFRI initiated a pearl culture program in 1972 and successfully developed the technology for pearl production in Indian pearl oysters. Success in controlled breeding and spat production of the Japanese pearl oyster (Pinctada fucata) in 1981 and the black-lip pearl oyster (P. margaritifera) in 1984 was another important breakthrough.
CMFRI also took the lead in the development of the technology required for edible oyster farming during the 1970s. Intensive researches on various aspects of the culture of the Indian backwater oyster (Crassostrea madrasensis) have been made, and technology has also been developed for the hatchery production of seed.
Pearl oysters are abundant in Gulf of Mannar and Andaman and Nicobar Islands. Pearl production is already going on at Mandapam in southern Tamil Nadu in a small scale. If pearl oyster farming is developed in India, we will be able to meet our own domestic demand and also export to Japan and other countries.
In India, two species of marine mussels namely the green mussel (Pernaviridis) and the Indian brown mussel (P. indica) are found in rocky coastal areas. Investigation of the culture possibilities for mussels was initiated in early 1970s by the CMFRI which resulted in the development of a range of practices for the culture of these species. Among maritime states, Kerala was the first to recognize the advantages of utilizing mussel farming technology in rural development.
Seaweed contributes nearly 30 per cent to world aquaculture production. About one-third of seaweed resources of the Indian Ocean is along the Indian coast. The importance of seaweed is increasing day-by-day because of its wide range of application in the food, textile, cosmetic, pharmaceutical, fodder and fertilizer industries.
Seaweeds have valuable nutrients such as vitamins, minerals, trace elements and bioactive substances. Prepacked instant foods are growing popular and seaweed colloids are increasingly used. However, India has not done much to exploit this resource.
India’s potential for export of ornamental fishes and plants is unlimited but our export has so far been negligible. A survey in Lakshadweep and Andaman Islands and the North-East hill states has identified about 100 varieties of marine ornamental fishes from Lakshadweep, 90 varieties from Andaman and 53 species from North-East hill states of India. The North-East hill states are found to hold very rich resources for freshwater aquarium fishes and plants.
Freshwater aquaculture activity is prominent in the eastern part of the country, particularly the states of West Bengal, Orissa and Andhra Pradesh with new areas coming under culture in the states of Punjab, Haryana, Assam and Tripura.
The development of freshwater aquaculture in the country became established following the establishment of the Pond Culture Division at Cuttack in 1949 under the name of the Centre of Central Inland Fisheries Research Institute (CIFRI), West Bengal.
Significant developments took place thereafter with the standardization of induced breeding techniques and the development of hatchery systems and composite carp culture with the three Indian major carps and three exotic carps, including silver and grass carp, forming the basis for carp polyculture systems. An All India Coordinated Research Project (AICRP) on ‘Composite Culture of Indian and Exotic Fishes’ initiated by the CIFRI during 1971 virtually laid the foundation for scientific carp farming in the country.The Central Institute of Freshwater Aquaculture (CIFA):
Bhubaneswar has made significant advances in breeding and rearing the air-breathing cat-fish, popularly called magur, in a greater part of the country. The biotechnological approach has been adopted and the fish are implanted with hormonal pellets to advance maturity. These are then repeatedly spawned form April to October, in and out of the breeding season.
The CIFA has been transferring this technology for the past two years through regular training programs. Investigations on large scale seed production of the other air-breathing catfish, have been planned
Successful breeding and larval rearing of the giant river prawn (Macrobrachiumrosenbergii) and the monsoon river prawn (M. malcolmsonii) provided scope for the farmers to diversify their culture practices. The state of Andhra Pradesh dominates the sector of freshwater prawn sector followed by West Bengal. Mixed farming of freshwater prawn along with carp is also very much accepted as a technologically sound culture practice and a viable option for enhancing farm income.