Dolphin population in Chilika lake on the rise

BERHAMPUR: The population of Irrawaddy dolphins is on the rise in the Chilika Lake. A recent survey recorded the presence of 12 more dolphins in comparison with the 2008 figure, said an official. During the survey, 158 dolphins were counted, out of which 129 were adults and 29 juveniles, including neonates. Out of them, 86 were counted in the outer channel and 72 in the central and the southern sectors of the lake. Last year, 146 dolphins were counted in the lake, out of which 76 were recorded from the outer channel and 70 from the lake proper. An annual population estimation of Irrawaddy dolphins (Orcaella brevirostris) of the lake is carried out during the month of February by the Chilika Development Authority (CDA) in cooperation with the State Wildlife Wing and volunteers and experts from various institutions. The census is being carried out since 2003 to monitor the status and population dynamics of dolphin in the lake.

For the population estimation, the standard sighting method followed world over for estimation of aquatic mammals was adopted. A simultaneous survey along 20 transects by as many survey teams by using 20 boats was carried out. A total of 82 surveyors took part in the census. For precision, the track routes were predetermined through computer programming and the track points were preloaded into the handheld GPS. An observer can have surveillance of 200m in naked eye and binoculars shall be used beyond 200m distance. Each team comprising four members, three observers and a recorder, is to record the observation. On February 16, the briefing and necessary input to all the participants were done simultaneously at the Wetland Research Centre, Chandraput, as well as at Satapada. The following day, the actual census was undertaken. Dolphin, being at the top of the food chain, is a good indicator of the health of the lake ecosystem. The rise in the population of Irrawaddy dolphins is, thus, a healthy sign for the Chilika Lake, said an expert. In the northern sector, the population was recorded to be only two last year, while as per the current survey it was six.

Source: The Pioneer