The Chilika lagoon is a gift of the Eastern Ghat and the Bay of Bengal. It is a wet land with distinct eco- system. The lake comes under the convention of Ramsar International wetland treaty. Various types of wildlife are seen within the areas comprising the lake.
The general characteristics of wetland vary widely due to local and regional differences in topography, hydrology, vegetation and other factors. As many as 52 rivers and rivulets join the lake, which are mainly fed by the great Eastern Ghat. Similarly, the total area of islands comes to 223 sqkm. The lake mouth was previously near Arakhakud, but presently it functions near Moto village. The hydrodynamics always supports the flora and fauna of the Chilika ecological biosphere, which is unique in the globe.
During last Phailin the natural mouth of the lagoon was extended very close to the older one. The water dynamism divides the ecological process of the lagoon into four distinctive divisions, which specify northern sector, central sector, southern sector and outer channels. The depth varies from 0.38 to 4.2 metre. The areas of the catchment come to 3,560 sqkm. About 12,363 fisher families residing in 132 revenue villages get their livelihood from the lake, which extends economic support to larger sections of people of the region and beyond.
There are 66 primary cooperative societies only for trading fish harvested every day from the lagoon. Similarly, there are 12 fishing jetties for collection of fish. There are nearly one million water fowl in the lake which are generally residential, semi-residential or migratory. The winter brings out a visual treats for the visitors who seek to enjoy its rich wealth of avifauna. About 156 bird species are noticed in the lagoon.
The Nalabana bird sanctuary is a famous island in the lagoon for birds. The lake is a Ramsar site because —
(1) Millions of migratory water — fowl and seashore birds spend winter on this land from the time immemorial. This becomes a migratory fly way for large members of winged visitors;
(2) The lake sustains rich biodiversities. Here 400 vertebrate species are noticed and recorded;
(3) Here three types of unique aquatic species of marine, brackish water, as well as fresh water species are found;
(4) The whole wetland covers more than one lakh hectares which creates bioclimatic zone of the region;
(5) Several endangered, rare, threatened as well as vulnerable plant and animal species are noticed and
(6) The major economic advantage is that it supports fishing community comprising over a lakh of population which contributes to international trade. The total number of fish species found in the lagoon is 225. Other than fish it supports phytoplankton, algae and aquatic plants, which are food of fish and other aquatic creatures. The Zoological Survey of India in 1985-87 carried out a survey of fauna of Chilika lagoon. This includes a number of rare threatened and endangered species like skink found in Barakudia Island. Skink is a lizard found only in Africa and Asia having short limbs and elongated body. It is a rare.
The lagoon is a highly productive ecosystem with rich fishery resources. But the traditional devices are gradually abandoned and mechanised fishing is replacing the natural fish catching, proving it detrimental to sustainable management of fish resources.
The traditional devices cum practices like Janao, Bahana, Dian,Uttapani and Dhaudi are gradually abandoned for better catch of fish, which leads to overharvesting. The lagoon is also identified for conservation and management by the national wetland mangroves and coral reefs committee of the Union Ministry of Environment and Forests (MoEF).
The water spread areas of the lake vary between the monsoon and summer seasons. A 32km- long channel connects the lagoon with the Bay of Bengal at Arakhokuda. The high tides drive the salt water of the sea into the lagoon through this inlet during the winter. During rainy season, the rain water received from various rivers pushes the sea water out of the lagoon.
As a result of such dynamism, the position of inlet mouth of the lagoon constantly changes its position. The prominent and vulnerable islands of the lagoon are Nalabana, Kalijai, Somolo, Honeymoon, Breakfast and Bird Island. They are ecologically important for sustainable health of the lagoon.
The ecology as well as the biosphere of the lagoon is quite affected for various activities pertaining to prawn cultivation. The migratory birds that throng the lake during the winter come as far as from the Caspian Sea, Baikal, remote parts of Russia, Magnolia, Central, South and East Asia, ladakh and the Himalayas. Already, 40,000 to 50,000 of migratory birds have already arrived in the Chilika in the ongoing winter.
(The writer is a former senior forest officer and an environmentalist. Tel no 9937460649)