Irrawaddy Dolphins in Chilika lake

Chilika lake

  • It is Asia’s largest brackish water lagoon.
  • It lies in Odisha state on the eastern coast of India, at the mouth of the Daya River flowing into the Bay of Bengal.
  • Because of its rich bio-diversity and socio-economic importance, Chilika was designated as a Ramsar site in 1981 to afford better protection.
  • It is the largest wintering ground for migratory birds on the Indian sub- continent.


Irrawaddy Dolphins in Chilika lake

  • Chilika lake is the natural abode of Irrawaddy dolphin.
  • It is considered to have the highest single lagoonal population of Irrawaddy Dolphins.


Reasons why Irrawaddy stopped visiting Rambha sector

  • Rambha (one of the extreme end of Chilika Lake) is the ideal sector for dolphins to play, flock and mate because of the stillness of the water in the bay area.
  • But Irrawaddy dolphins stopped coming to Rambha sector because of:
  • Illegal prawn enclosures- Enclosures hinder the movement of dolphins and squeeze the prey base of dolphins.
  • Unregulated boating- Dolphins had been under stress due to unregulated boating by the tourist in the Chilika lake.


Steps taken

  • To remove enclosures- The satellite imageries have found 14,590 hectare of the lagoon under manmade enclosures for illegal prawn cultivation which were removed by Chilika Development Authority’s (CDA).
  • To curb unregulated boating -CDA has enforced the stricter boating regulation.


Irrawaddy Dolphin 

  • It is an aquatic mammal that lives in brackish water near coasts, river mouths and in estuaries.
  • It has established subpopulations in freshwater rivers, including the Ganges, the Mekong and in the Irrawaddy River from where it takes its name.
  • The species has been classified in ‘vulnerable’ category in IUCN red list.
  • The species is listed in Appendix I of CITES.


Major threats

  • The estuarine and freshwater occurrence of this species makes it particularly vulnerable to threats from the human activities that occur in these environments. Threats include:-
  • Direct mortality from fisheries interactions (particularly gill net entanglement)
  • Vessel strikes
  • Habitat loss and degradation (e.g.declining or altered freshwater flows due to dam and embankment construction)
  • Deforestation
  • Gold, sand and gravel mining are causing major changes to the geomorphologic and hydraulic features of rivers and marine-appended lakes where Irrawaddy dolphins occur
Section : Environment & Ecology