The Chilika lake in Odisha has emerged as the single largest habitat of Irrawaddy dolphins in the world with the spotting of 155 such animals. The ‘Annual Monitoring’ was conducted by the CDA to count the number of the marine mammals and to study the hydrological impacts of removal of pen culture (locally known as gherries). he number is more compared to the last year’s figure of around 100 dolphins during the annual census.
The dolphins are colonising new areas in central and southern sector where they were not seen before. The dolphins are now sighted at different sectors of the lake including areas near Kalijai and Rambha. Removal of obstructions in the lake may have helped their migration.
The CDA in association with the Wildlife Wing had initiated several conservation measures for the protection of Irrawaddy dolphins in the lake. Besides survey and identification of habitats for proper management, dolphin watching protocol was formulated and tourist boat operators sensitised.
The mass demolition of prawn gheris in the recent years and regular cautions for responsible tourism seem to have resulted in maintaining the quality of the habitat for the endangered species and stabilisation of their population.
Several areas were made free from encroachments by gheris. There are enough signs of the dolphins migrating from Satpada side to other areas. The take away from the census is that the population is likely to increase in next couple of years.
Summary of Census 2020
- 146 dolphins sighted in the lagoon.
- 18 teams undertook the census.
- GPS tracking binocular used for first time.
- Motorised boats by fishermen and tourist boats barred during the day.
- 113 dolphins sighted in 2019.
- 162 spotted in 2018.
About Irrawaddy dolphins
The Irrawaddy dolphin (Orcaella brevirostris) is a euryhaline species of oceanic dolphin found in discontinuous subpopulations near sea coasts and in estuaries and rivers in parts of the Bay of Bengal and Southeast Asia.
Although the species gets its common name from the Irrawaddy River in Myanmar, where it also lives, it was first described in 1866 from a specimen found in the Vishakapatnam harbour in present day Andhra Pradesh on India’s east coast. Its range extends from the Bay of Bengal to New Guinea and the Philippines. Besides the Irrawaddy River, it is also found in India’s Ganges, and Southeast Asia’s Mekong River. However, it is not a true river dolphin and prefers to live in estuaries and brackish water near coasts. Following the opening of the sea mouth in Chilika in 2002, and the consequent increase in water depth, dolphins have reportedly been recorded in more areas of the lake than before, perhaps indicating an expansion of suitable habitat.
Irrawaddy dolphins can grow to a length of 2.3 m and attain a weight of 130 kg. This species is closely related to the killer whale, a much larger, oceanic dolphin that can grow to 8m and weigh in excess of 6 tonnes.
Irrawaddy dolphins are classified as ‘Vulnerable’ in the IUCN Red List of Threatened Species. In Chilika they can be seen singly, in pairs or as small groups of 4-6 individuals. They are fairly slow swimmers.
About Chilika Lake
Chilika Lake is a brackish water lagoon, spread over the Puri, Khurda and Ganjam districts of Odisha state on the east coast of India, at the mouth of the Daya River, flowing into the Bay of Bengal, covering an area of over 1,100 km. It is the largest coastal lagoon in India and the second largest brackish water lagoon in the world after The New Caledonian barrier reef. It has been listed as a tentative UNESCO World Heritage site.
It is the largest wintering ground for migratory birds on the Indian sub-continent. The lake is home to a number of threatened species of plants and animals.The lake is an ecosystem with large fishery resources. It sustains more than 150,000 fisher–folk living in 132 villages on the shore and islands.
In 1981, Chilika Lake was designated the first Indian wetland of international importance under the Ramsar Convention.
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