Surinder Sud: Angling for a better environment

FARM VIEW

A fisheries-based eco park in Kolkata can provide valuable lessons in eco-management.

A striking example of how a dumping ground of urban sewage and industrial effluents can be transformed into a fisheries-based money spinner eco-park is on display in Kolkata.

What is significant is that the people behind it are fishermen who were forced to migrate to this area in the early 1940s due to degradation of river Damodar.

They formed a co-operative society with a token cash contribution and self-labour to take up industrial waste water-based fisheries for their subsistence. Over the years, the project has grown into a well-run commercial venture, generating employment as well as income for its members.

This society, called Mudialy Fishermen's Co-operative Society (MFCS), sold fish worth nearly Rs 50 lakh last year, besides earning income from other sources.

This fisheries-cum-nature park is situated about 20 km south-west of the heart of Kolkata and the wetlands used for this purpose are owned by the Calcutta Port Trust and have been taken on lease by MFCS.

This project has been developed with three broad objectives "" to improve the quality of waste water before releasing it in the Hooghly; using the waste water as a medium to raise fish; and to develop an ecologically-balanced system to accommodate several fish, animal and plant species.

The technology being used is simple, though scientific. The society has dug out a series of six ponds to carry out different stages of water cleaning and fish rearing operations.

The average daily intake of sewage water "" approximately 23 million litre "" is a mix of 70 per cent industrial sludge and 30 per cent domestic sewage.

The first pond, called the anaerobic tank, is used for treating water manually with lime and other similar biochemical material. Water hyacinth, normally considered a weed of water bodies, is used to absorb oil and grease in the effluent. This tank also facilitates sedimentation of wastes and, therefore, has to be dredged periodically to remove the sludge.

The second pond, to which water flows through a narrow passage, is used as a breeding ground for chiefly exotic fish species that can thrive in poor quality water and harsh living conditions.

These include omnivorous fish like Tilapia and Nylotica and air-breathing fish like Singi, Magur and Koi that can withstand some level of toxicity.

In the subsequent ponds, as the water quality improves at each stage, other fish, including the Indian major carps, such as Catla, Rohu, Mrigala and Bata, and some local fish species, are reared. Finally, the cleaned water is released into Manikhal canal system that eventually joins the Hooghly.

Notably, the society has set up an in-house water testing laboratory to monitor water quality. In case the quality is unfit to be released in the river, a system has been put in place to take it back and let it go through the entire process once again.

Aware of the need to keep the costs down, MFCS relies on conversion of organic waste into protein-rice micro algae for use as fish feed. This reduces and, at times, even eliminates the need for supplementary feeding.

This apart, the society has planted nearly 1 lakh trees of suitable species to provide supplementary feed for fish and animals as well as benefit the environment.

Of these, about one-third belong to leguminous group like subabul, which has protein-rich leaves; another one-third to species like Akand and Neem that can absorb chemicals; the rest are horticultural and other plants.

The leguminous plants have been planted close to the water bodies so that their leaves fall in the ponds and serve as nutritious fish feed. These trees also help prevent soil erosion around the ponds.

MFCS has also developed a part of the water area for public amusement activities like boating. Animals like deer, rabbits and tortoise have been introduced in the tract.

As such, an eco-system has been created that attracts a large number of birds as well, including some migratory birds, to act as an added attraction for picnickers.

Impressed with the success of this venture, the National Co-operative Development Corporation (NCDC) has sanctioned nearly Rs 54.7 lakh to this society to further expand the fisheries activities.

The West Bengal Fishermen's Co-operative Federation (Benfish) has also given it Rs 53.9 lakh for the development of a fish nursery and adult rearing ponds.

Indeed, through its efforts, this successful co-operative venture has developed a model that can be emulated elsewhere as well. And the society is only too willing to share its expertise with others through its contract-based consultancy service.

The Kolkata Zoological Gardens has already entered into a contract with MFCS for treating the zoo lake. Others, too, can capitalise on this expertise.