Rivers of fortune

Usha PT and MA Upare present a fish-eye view of the new frontiers visible through the ever-widening windows of opportunity presented by inland fishery

India is blessed with colossal inland fishery resources. Consisting of 2.36 million ha of ponds, 1.3 million ha of derelict waters, 1,20,000 km of canal, 3.15 million ha of reservoir, 45,000 km of river, 2.7 million ha of estuary, and 1.42 million ha of brackish-water area, these resources could be put to different fish culture and capture practices.
Although, the extensive network of Indian rivers and canals constitutes one of the major inland fishery resources of the country, the presentday riverine fishery is below the subsistence level with an average yield of 0.3 tonnes/km, which is only 15 per cent of their actual potential.
The extensive flood plain wetlands in the form of oxbow lakes, especially in the states of Assam, West Bengal, Bihar and Eastern Uttar Pradesh, occupy an important position among the inland fisheries resources of India because of their magnitude as well as their huge production potential. Their yield can be increased to about one tonne/ha/year from the present average yield of 200 kg/ha/year.
Despite the huge open inland water resources in the country, the contribution from inland fisheries is of the order of 0.7 million tonnes, out of the total inland production of over 3 million tonnes. The present contribution of over 2.2 million tonnes from inland aquaculture indicates that the sector has the potential of producing over 4.5 million tonnes annually through the adoption of appropriate technologies.
Reservoirs form the most important inland water resource in the country with an area of 3.15 million ha. India has 19,134 small reservoirs with a total water surface area of 1,485,557 ha, 180 midsized reservoirs with an area of 527,541 ha and 56 large reservoirs with an area of 1,140,268 ha. The six peninsular states of Tamil Nadu, Karnataka, Andhra Pradesh, Kerala, Orissa and Maharashtra account for approximately 56 per cent of the total reservoir area in the country. At the present level of management and utilisation, the average fish yield is only 29 kg/ha/year.
Aquaculture has become the world’s fastest growing food production systems with a growth rate of over 9 per cent in the last 10 years. The major increase in global aquaculture production in the last decade has been witnessed by China, India and South-East Asia using systems that have already proven to be sustainable. In India, the area that could be brought under freshwater aquaculture in the form of tanks and ponds is estimated to be about 2.36 million ha, while an area of 1.42 million ha has been identified as suitable for brackish-water aquaculture.

FRESHWATER AQUACULTURE
Carps, catfish, prawns and mussels form the important varieties for culture practices in the country. In terms of cultivable species of fish and shellfish, the species available for cultivation are as diverse as the varied ecological conditions of water bodies across regions. The Indian major carp forms the mainstay of the inland fishery sector in India, its culture being supported by a strong traditional knowledge base and scientific input in all aspects of management. This sector contributes as much as 87 per cent of the total aquaculture production in terms of quantity. While the country possesses a large number of potentially cultivable carp species, only three Indian major carps – catla, rohu and mrigal – contribute the lion’s share. The important exotic carps contributing to production are the silver carp, grass carp and common carp.
Technologies are available for the breeding and cultivation of air-breathing (Clarias batracus, Heteropneustes fossilis) and non-air breathing catfish (Wallago attu, Mystus seenghala, Pangasius pangasius). With more-or-less similar pond management measures, production levels of 3-5 tonnes/ha could be achieved easily. These groups of fish can suitably be cultivated both in monoculture and polyculture systems, in swamps and derelict waters that could be effectively used for commercial fish-farming. The freshwater prawns, Macrobrachium rosenbergii and Macrobrachium malcomsonii, have already received a lot of attention with regard to the establishment of hatcheries and grow-out production systems. The ornamental fish-breeding sector has great potential for growth by way of the establishment of commercial breeding and culture farms as a cottage industry because of the minimum level of investment required.
Freshwater pearl culture is another important potential resource which could be tapped from the point of view of the commercial-scale availability of a natural stock of pearl mussels, the availability of wider areas for farming in many regions, the operational ease in managing freshwater environment, the absence of natural fouling, boring and predatory organisms, and certainly, its costeffectiveness.
India possesses over 50 species of freshwater mussel of which three species – Lamellidens marginalis, Lamellidens corrianus, and Parreysia corrugata – are found to hold a high potential for pearl formation....

contd...

TO READ FURTHER... SUBSCRIBE TO YOUR COPY TODAY!!!