Fisheries sector in India has witnessed a remarkable growth over the years, supporting the Indian economy significantly. Fish production since independence has shown unmatched surge, increased from 0.75 million tonnes in 1950-51 to 10.8 million tonnes during 2015-16, that placed the country as the second largest fish producer in the globe.
The export earnings of 33,441 crore in 2014-15 (US$ 5.51 billion), equaled about 18% of the export earnings from the agriculture sector. The possession of vast resources, including those of physical resources in inland and marine, and strong knowledge base created through research programmes of ICAR fisheries research institutions and other R&D organisations further have been offering immense opportunities for enhancing fish production both through aquaculture and open-water fisheries.
With the present share of about 90% of total aquaculture and 50% of total fish production in the country, the freshwater aquaculture further looked as the sunrise sector to meet demand for fish in years to come.
Taking advantage of the strong traditional knowledge base, and effective research and developmental backup, freshwater aquaculture during last five decades has grown in area coverage, diversification of culture species and methods, besides intensification of farming systems. This has increased the national average productivity of ponds and tanks from about 600 kg/ha on 1970s to a present level of over 3000 kg/ ha, over five-fold increase in last four decades.
Recent years have also witnessed increasing thrust on diversification with catfishes and freshwater prawns due to their higher market demand and economic advantages. A range of non-conventional culture systems like sewage-fed fish culture, integrated farming and hill stream-based flow through fish culture are also making freshwater aquaculture an increasingly growing activity across the country.
Aquaculture has been recognized as an important allied agriculture sector, which are effectively integrated with agriculture, horticulture and animal husbandry. Sewage-fed aquaculture, as in bheries of West Bengal, with incorporation of component of primary treatment of waste water, is forming as an important farming practice in the context of falling water resources. Although water is an important input in aquaculture, its consumptive use in the farming of fish is significantly low, with evaporation and seepage being the major reasons for its loss in the culture system. Cage culture of fish in reservoirs can justifiably establish this fact. Further, scientific studies have established that irrigation water could be nutritionally enriched if it passes through fish farms.
Freshwater Aquaculture Development
Carps have been the principal component group in freshwater aquaculture with contribution of about 85% of 5.5 million tonnes in the country. Scientific interventions over last six decades has led to development of a host of carp culture technologies with varied production potentials depending on the type and level of inputs. Further, the other produce like catfishes, freshwater prawns and molluscs for pearl culture have also been brought into the culture systems.
In addition, a range of other nonconventional culture systems, viz., sewage-fed fish culture, integrated farming systems, cage and pen culture, running water fish culture and so on has made freshwater aquaculture an increasingly growing activity across the country. Being mainly organicbased, the freshwater aquaculture practices are also able to utilise and treat a number of organic wastes including domestic sewage, enabling eco-restoration.
Farming of Carps
Carp seed production is no more confined to monsoon. Various carp species are domesticated to breed much ahead of monsoon and months beyond monsoon. The technology of multiple breeding of carps has been able to demonstrate 2-3 fold higher spawn recovery from a single female during season over conventional single breeding through 3-4 times breeding of same individual within an interval of about 45 days. The technological evolution of hatchery design and operation to the present day circular eco-hatchery provided scope to produce and handle mass quantities of eggs.
Milt cryopreservation from improved stock and its use is being suggested as an important tool for gamete exchange programme. The genetic improvement of rohu through selective breeding demonstrating 17% higher growth realization per generation after eight generations has been a significant achievement for the sector.
Carp farming in India over the years has grown in geographical coverage, diversification of culture species and methods, besides intensification of farming systems. The three Indian major carps, viz., catla (Catla catla), rohu (Labeo rohita) and mrigal (Cirrhinus mrigala) were the principal species cultured by the farmers in ponds since ages and production from these systems remained significantly low (at 600 kg/ha/year) till the introduction of carp polyculture technology. Today, farmers of several regions of the country have been able to demonstrate higher production levels of 8-15 tonnes/ha/year.
In a thrust towards diversification, concerted efforts have also been made or are being made for development of technologies pertaining to mass-scale seed production of several potential medium carps viz., Labeo calbasu, L. fimbriatus, L. gonius, L. bata, Cirrhinus cirrhosa, C. reba and Puntius sarana and protocol for their farming.
Farming of Catfishes and Other Live Fishes
Although catfishes possess considerable commercial importance and there have been significant efforts for their farming in recent past, with special focus on air-breathing catfishes viz., Clarias batrachus (magur) and Heteropneustes fossilis (singhi), non-availability of seed in adequate quantity has been the major issue for its low level of adoption.
Exotic Pangus catfish, Pangasianodon hypophthalmus are some of the recent entrants in freshwater aquaculture, which has been largely restricted to Andhra Pradesh. Its high growth and production potential triggered the farmers, especially in KrishnaGodavari Delta of Andhra Pradesh to take up commercial farming of the species. With provision of extruded floating feed most of the farmers have been able to produce 10-12 tonnes/ha/year, with some producing higher levels of over 20 tonnes/ha in static pond systems.
Considering high consumer preference of catfishes in different parts of the country, the management protocol for grow out farming of several other non-air breathing catfishes viz., Pangasius pangasius, Sperata seenghala, Ompok pabda, O. bimaculatus, Horabagrus brachysoma etc. have been developed/fine-tuned for their commercial faming.
Further, with the availability of the technology of mass-scale, seed production of murrels (Channa striatus and C. marulius) and koi (Anabas testudineus), aquaculture of these species are also receiving great interest of the farmers.
Farming of Freshwater Prawn
Monoculture of freshwater prawn has shown production levels of 1.0-1.5 tonnes/ha in a culture period of 7-8 months. Further, its polyculture with carps has also demonstrated to be an economically viable option for enhancing the farm income.
Although farming in the country showed a phenomenal increase from 1998 to 2005, with production of 42,670 tonnes in 1995, the slump in price for scampi in overseas market and the problem of white tail disease of late have affected the production, which reported to reduce to a level of about 10,000 tonnes at present.
Integrated Fish Farming
Under the integrated fish farming system, the wastes from different components, viz., livestock, poultry and agricultural byproducts are recycled as input for production of fish. While organized integrated farming systems are not very common in the country, use of organic manures in the form of cattle waste and poultry droppings are common in all most all farms of the country, especially in carp culture farms.
However, studies on integrated fish farming with cattle, pig, duck and poultry have shown its high potential with respect to increasing production, high economic advantage in terms low cost of production and environmental amelioration through use of animal and agricultural wastes. Production levels 3000-5000 kg/ha/yr of fish have been demonstrated from such an integrated farming practice.
Fish Production in Reservoirs, Lakes and Floodplain Wetlands
The reservoirs, lakes and floodplain wetlands are characteristically different water resources and yet considered to be minimally exploited and thereby possess high potential for enhancing fish production. While the fish yields in large chunk of the large and medium reservoirs have remained as low as 15-20 kg/ha, it has been about 50 kg/ha in small reservoirs. Scientific management of a few small reservoirs across the country has demonstrated impressive production levels of 200-300 kg/ ha.
The floodplain wetlands or beels form important open water resource in some of the eastern Indian states viz., Assam, West Bengal and Bihar, which offer great potential for both culture and capture fisheries. With proper stocking and management while production levels of 1,000- 2,000 kg/ha/year have been demonstrated in some of the beels, the present levels in unmanaged ones remain only at about 100- 150 kg/ha.
Commercial culture of fish in cages has received great importance during last five years, especially with Pangus catfish, P. hypophthalmus. Production levels of 3-4 tonnes in a culture period of 6 months in cages of 6 m x 4 m x 4 m are being realized in several reservoirs, with the states of Chhatishgarh and Jharkhand taking the lead.
Aquaculture today provides enough opportunity and flexibility to the farmers for enhancing the productivity and income. However, in order to meet the ever-increasing fish demand of the country, sustenance of the aquaculture growth as that of present level is of paramount importance; and in this regard, it is necessary to have a robust roadmap for aquaculture development of the country taking note on the potential resource availability of each of the states at district levels and formulating clear strategy for realizing the potentials, which include adoption of responsible farming practices; productivity enhancement in all cultivable waters, infrastructure development for seed and other inputs, establishment of aquashops and aquaculture estates, incorporation of high valued species for higher farm income, appropriate policy initiatives for leasing of waterbodies and community management, and above all required human resource development in different aspects of aquaculture.