Kolleru lake aquaculture

Kolleru is one of Asia's largest freshwater lakes.
It is located in Andhra Pradesh, and is a famous habitat for a number of resident and migratory birds, including the vulnerable grey pelican.
Situated between the Godavari and Krishna river basins, it is an invaluable wetland ecosystem.

1. KOLLERU LAKE AQUACULTURE

2. AQUACULTURE Aquaculture is the process of rearing, breading and harvesting of aquatic species, both animals and plants, in controlled aquatic environments like the oceans, lakes, rivers, ponds and streams. 

3. KOLLERU LAKE Kolleru is one of Asia's largest freshwater lakes. It is located in Andhra Pradesh, and is a famous habitat for a number of resident and migratory birds, including the vulnerable grey pelican. Situated between the Godavari and Krishna river basins, it is an invaluable wetland ecosystem.

4. Fish, prawns and algae are the most reared in India, especially in Kolleru .  Many birds migrate here in winter,  such as Siberian crane, ibis, and painted storks.  The lake was declared as a wildlife sanctuary in November 1999 under India's Wildlife Protection Act of 1972, and designated a wetland of international importance  in November 2002 under the international  Ramsar  Convention

5. During the 1970s the fishermen were encouraged to form co-operatives and loans were sanctioned for seasonal cultivation. Because of repeated floods, the banks and government encouraged them to convert agricultural land to fish ponds and tanks. In the early 1990s aquaculture boomed. The problem was that it needed saline water to flourish and borewells were sunk in the lake bed to pump out saline water for the aqua ponds.

6. Consequently the lake bed and banks sank and the tides brought in more saline water. The aquaculture practice requires chemical fertilizers, manure and chicken waste. Once the harvest is over, the water stagnates and pollutes surrounding water. As a result, the drinking water of dozens of island villages has been polluted and the lake has undergone chemical and biological changes that have contributed to its depletion and pollution.

7. CURRENT SITUATION OF KOLLERU LAKE Thousands of fish tanks were dug up effectively converting the lake into a mere drain.  This had great impact in terms of pollution, leading to difficulty in getting drinking water for the local people. 

8. This is in addition to the loss of ecological diversity and intrusion of sea water into the land masses and its fallout in terms of adverse influence on the rainfall pattern in this region.  This imbalance has an adverse effect on the thousands of acres of crop in the upper reaches of sanctuary in view of stoppages water flow into the sea because of obstruction by bunds of the fish tanks that appeared illegally.

9. The area under aquaculture consisted of 1050 fish ponds within the lake and 38 dried-up fish ponds, which together covered an area of 103 km2.  The agricultural encroachments were mostly rice paddies. Surprisingly no clear water could be found in the satellite image.  The rest of the lake is being diminished by water diversions or was infested with weeds like elephant grass and water hyacinth.

10. CONSERVATIVE MEASURES In 2006, considering the ecological importance of the KOLLERU lake sanctuary, the Supreme Court had ordered the demolition of illegal fish tanks. The Aziz committee also clearly mentioned that the reduction of the sanctuary area from +5 contour to +3 contour should not be carried out. According to the wetland rules of 2010, the state government has a responsibility to protect wetlands. For several years now, public interest litigations and cases had been filed in the high court and in the Supreme Court by environmentalists to conserve lake. After the Supreme Court’s demolition order, illegal fish tanks were demolished, but sadly after sometime the tanks were built again.