Why in News?

• Chilika Lake, the largest brackish water lake and wintering ground of the birds in the Indian subcontinent, saw a million of birds, including uncommon Mongolian gull, visiting the waterbody this year.

Chilika Lake

• Chilika Lake is a brackish water lake and a shallow lagoon with estuarine character spread across the districts of Puri, Khurda and Ganjam in the state of Odisha in eastern India.
• The lagoon can be broadly divided into four ecological sectors based on salinity and depth, namely the southern zone, the central zone, the northern zone and the outer channel.
• A number of islands are present in the lagoon, prominent among which are Krushnaprasad, Nalaban, Kalijai, Somolo and Birds Islands.

Feature of Chilika lake

• Chilika is Asia’s largest and world’s second largest lagoon.
• It has been designated as a Ramsar Site and a possible UNESCO World Heritage Site.
• Chilika Lake was declared as the first Ramsar Convention wetland of international importance in India in 1981.
• It is home to a number of vulnerable plant and animal species and is the major wintering site for migratory birds in the Indian subcontinent.
• Major attraction at Chilika is Irrawaddy dolphins which are often spotted off Satpada Island.

Water Bird Status Survey-2022

• The census was undertaken jointly by the Odisha State Wildlife Organization, the Chilika Development Authority (CDA) and the Bombay Natural History Society.
• A total of 3,58,889 birds (97 species) were counted in Nalabana Bird Sanctuary inside Chilika – a decrease by 65,899 from the previous year.
• The decrease is attributed to high water level and presence of water in cultivated fields in adjoining areas. Water birds love to flock on large mudflats.
• There was marginal decrease in the number of species such as the northern shoveler, tufted duck and red crested pochard.
• An increase in population of northern pintail, common coot and common pochard was noticed.
• The increase in numbers of flamingo at Nalabana mudflat indicates that, the restoration at Nalabana is effective. It is largely due to appropriate management of mudflats.
• The local resident species such as purple swamp-hen, purple heron, Indian moorhen, and jacanas were found in higher numbers.

Guest of Chilika

• Chilika lake hosts birds migrating from the Caspian Sea, Lake Baikal, Aral Sea, remote parts of Russia, Kirghiz steppes of Mongolia, Central and South East Asia, Ladakh and the Himalayas.

Ecological problems in the Chilika lagoon

• Siltation due to littoral drift and sediments from the inland river systems.
• Shrinkage of water surface area.
• Choking of the inlet channel as well as shifting of the mouth connecting to the sea.
• Decrease in salinity and fishery resources.
• Proliferation of fresh water invasive species, an overall loss of biodiversity, with decline in productivity adversely affects the livelihood of the community depended on it

Measures for restoring the Chillika Lake

• Abolition of shrimp culture and demolition of shrimp ‘gheris’ which disrupt the tidal flushing, reduced the level of salinity, squeeze grazing ground for juveniles and accelerate the process silting of marginal areas of the Lake.

Benefits after restoration efforts

• Chilika lagoon restoration shows that the restoration of the ecological characteristics of a site results not only in improvement of the lagoon ecosystem but also benefits the community dependent on the wetland.
• The average annual income of each family increased by more than Rs.50,000.
• This year’s greater flamingo count was highest in last one decade.