A lagoon is a shallow water body separated from a larger water body by Islands or reefs or shallow ridge. Chilika lake is the largest brackish water lagoon in India and is also the estuary of River Daya draining into the Bay of Bengal. A 32 km long channel forms the mouth of the river joining the sea. This estuarine region is a unique combination of freshwater, brackish water and marine ecosystems. The wetland ecosystem of Chilika is the first Indian wetland of international importance under the Ramsar Convention.
The Ramsar Convention on Wetlands is an international treaty on Wetlands as waterfowl habitat, of importance around the world. Chilika is home to a large variety of resident birds and is also the wintering ground for numerous migratory birds. Apart from the avian species, it is also the home to a wide range of floral and faunal species among which many are under the threatened and endangered category.
This brackish water lagoon is unique in different ways. The estuarine and the coastal nature along with the vastness has tended to different characteristics to this wetland ecosystem. Four ecological sectors depending on the depth and salinity of the water have been marked within this lagoon – the northern zone, central zone, the southern zone and the outer channel.
The tidal inflow of saline water and the drainage of the freshwater changes in accordance with the period of the year. During the dry months, the lagoon experiences a major inflow of the marine water while during the monsoon the flooded river joined by many other drains into the sea and thus with this continuous siltation process the river mouth shifts annually.
The floral life here is broadly classified as terrestrial island vegetation and aquatic vegetation. Phytoplankton and seaweeds with numerous subspecies form the major part of the algal vegetation in the water. A few mangroves and other coastal scrubs form the terrestrial island vegetation. There are many inhabited and uninhabited islands within this lagoon among which the known names are Krushnaprasad, Nalaban, Kalijai, Somolo, Honeymoon, Breakfast and Birds Island.
The lagoon is home to a wide range of faunal species that include terrestrial birds, waterfowl, waders, raptors among the avian species; endangered species like the Irrawadi Dolphins, Barakudia limbless skink; numerous species of reptiles, amphibians and mammals are also found in this ecosystem. Thus it forms a rich ecosystem making it highly productive and revenue generating area.
The lagoon is the major source of income for the fishing community residing in 132 villages in the terrestrial and the adjoining areas. With the increase in popularity and the proximity to the popular tourist destination of Puri, it attracts a huge number of tourists all through the year which multiplies during the winter months of November and December. Regular boat trips are available on hourly or three hours basis. The hourly trip includes the dolphin ride within a certain region of the lake and the three-hour trip covers comparatively more area with a few island visit.
Boat trips and approach to Chilika can be done from three areas of Sadapada, Balugaon also known as Barakul and Rambha. Sadapad is closest to Puri and Barakul and Rambha are on the way and close to Ganjam. Fisheries have been the major source of economy in this region with tourism taking the second place. With the increase in popularity and with time, the ecosystem has been under various threats.
Threats are in the form of commercial aquaculture mostly of prawns which are adversely affecting the balance and natural fish and bird population. Manmade constructions and abuse of free resources have taken its toll. Other threats are the littoral drift due to siltation, decrease in salinity, shrinkage of water surface area and dwindling of seagrass bed, the introduction of freshwater and invasive species and choking of the inlet channels. The lake came under the threatened list of Ramsar sites (in the Montreux Record).
In recent years, the Chilika Development Authority (CDA) based on the Ramsar guidelines has worked for the restoration and effective management of the biodiversity of this unique ecosystem. The recovery of seagrass beds has resulted in the re-colonization of endangered dugongs. Other positive changes were in the form of regulation of the salinity gradient keeping the channels open for the tidal influence, revival of lake fishery, encouragement of community-based eco-tourism. With all such positive changes, we hope to see a better Chilika in future. As a traveller (or tourist) let us take the onus of responsible tourism to do our part to save this fragile ecosystem.