Report by Rashmi r Parida; Bhubaneswar: Dolphins population decreasing in Chilika lagoon as per the latest census. As per the latest report of Chilika Development Authority there has been marginal decrease in the total number of dolphins as compared to the census figures of past years 156in 2011. This year Irrawaddy dolphin population of chilika estimated to be 145 out of which there are 118 adult, 16 sub-adult and 11-calves.

The Chilika lagoon is the natural abode of highly endangered Irrawaddy dolphins (Orcaellabrevirostris). The present distribution range of this species is only in Asia i.e. from Chilika to Indonesia within south east Asia and South Asia. The total population of these animals in the world is estimated to be less than 7500 (highest 6400 reported from Bangladesh) and the population in Chilika is considered to be the highest single lagoonal population.

Chilika Development Authority has initiated many conservation measures for the protection and conservation of Irrawaddy dolphins in Chilika in close coordination with
Wildlife wing of State Forest Department such as: (1) Survey and identification of dolphin habitat in the lagoon for proper management, (2) Development of dolphin watching protocol for safe watching of dolphins, (3) Sensitization and training of tourist boat operators, (4) Deployment of dolphin protection squad in the outer channel area through the DFO, Chilika Wildlife Division, (5) Widening and deepening of Magarmukh channel for free movement of dolphins from Outer channel to the main lagoon, (7) Acousticsurvey of underwater behavior of dolphins through deployment of hydro phones in collaboration with Tokyo University.

The annual population estimation survey of Irrawaddy dolphins in Chilika lagoon was conducted on 17th January 2012 following line Transect method. The total number of survey transect were 18 numbers. This is in consensus with widely used methodology globallyi.e., Line Transect Method. The sampling of dolphin/group of dolphin in each transect was carried out by a team of three experienced persons. Each team was equipped with binoculars, GPS set, Rangefinder and data recording sheets etc. In total, 90 participants from different organizations such as Scientists from wildlife wing, Officials from WWF- India, New Delhi, Odisha Watershed Development Mission, BNHSMumbai, Regional Museum of Natural History, Bhubaneswar, Centre for Environment Education Bhubaneswar, Researchers & academicians from the University and colleges,Wildlife Society of Orissa, Chilika Wildlife Division, Senior Research Officers from the Office of Chief Wildlife Warden, Orissa, Chilika Development Authority, Officials from Animal Resource Development Department, Local NGOs, Members of local Motor Boat Associations etc. participated in the census operation. In addition, 40 local volunteers were deployed in 18 boats.

10 nos. of teams were deployed in the main lagoon (Central Sector and southern sector) and 8 nos. of teams were deployed in the Outer channel area for the survey. Briefing to the participants was held at WRTC, Chandraput and Visitor Centre, Satapada in the afternoon of 16th January, 2012. The survey was carried out from 6.30 AM to 2.00 PM on 17thJanuary, 2012 in thedolphin habitat of the Chilika lagoon. This year the local Motorboat Associations ( 5nos) in the outer channel area also cooperated in the census and did not operate the boats during the period of census on 17.01.2012. The tourist boats started operating only after the census was over. There has been marginal decrease in the total number of dolphins as compared to the census figures of past years 156in 2011. This year Irrawaddy dolphin population of chilika estimated to be 145 out of which there are 118 adult, 16 sub-adult and 11-calves. However the number of calves is found to be 11 last year only 4 calves were recorded. The causality of the dolphin was also reported to be 1 last year which is due to enhanced awareness of the stakeholders. The motor boat association also stopped plying of boats during the census operation on 17th January 2012.