Japanese scientist to study underwater dolphin behaviour

A Japanese team of scientists have embarked on a project to study the behaviour of Irrawaddy dolphins found in Orissa's vast Chilika lagoon by using specially designed state-of-the-art technology.

The study, being undertaken following a Memorandum of Understanding (MOU) signed between the Chilika Development Authority (CDA) and the University of Tokyo in April last year, includes observation of dolphin behaviour as also estimation of its population size.

Prof Tamaki Ura, an expert at the Underwater Technology Research Centre of the Institute of Industrial Science at University of Tokyo, who is leading the Japanese team said that a continuous monitoring system was being developed for observing Irrawaddy dolphins in real time from a base centre set up at the CDA office at Satpada, a tourism hub on the edge of the lake.

"The experiment began as a pilot project last year. But we conducted static and dynamic tests of the acoustic technology between January 28 and February Three, the results of which are yet to be analysed," Ura told a news conference here on Sunday night.

Ura's team is being assisted by Prof Rajender Bahl, group head, signal processing at IIT, Delhi as also researchers from WWF-India and Wildlife wing of the Orissa Government.

CDA Chief Executive Officer Sudarshan Panda said according to an enumeration conducted last year, there were 123 Irrawaddy dolphins in Chilika, mostly in the outer portion of the lagoon connected to the Bay of Bengal through a channel.

Panda said, CDA planned to conduct a visual survey of the dolphins on February 19 and 20 next. "The data will be compared with the underwater information being collected by the team of scientists and researchers from Japan," he said.

Altogether sixty persons would be deployed for the enumeration in 18 groups, Panda said.
According to Ura, five hydrophones--underwater microphones -- were used for the experiments and found to be very efficient.

He pointed out that small cetaceans such as dolphins and porpoises emitted sonar pulses, which they used as an echolocation tool for finding prey and for navigation.

These sound pulses appear as clicks of specified signal duration and bandwidth to an observer. These clicks could be observed with specially designed underwater hydrophones, he said.

These passive observation methods could also be automated to allow day-night observation in turbid waters without causing any disturbance to the animals.