Researchers will use scanner and dolphin sounds to locate rare specie

Researchers belonging to Worldwide Fund for Nature, Tokyo university and IIT, Delhi are undertaking an experiment in Budhabalanga river of Orissa to find out how the blind Gangetic Dolphin locates its prey by generating high frequency sound.

"We want to catch the high frequency sound generated by a Gangetic Dolphin rehabilitated in a gorge of Budhabalanga river of the state," Project Coordinator, Gangetic Dolphin, WWF, Sandeep Behera, told PTI.

Behera said "the Gangetic Dolphins are generally blind and spot their preys in a unique way. The sound they emit is not audible. However, it reaches its prospective prey."

"Once the sound reaches the prey, the dolphin registers its image in its mind. Finally, it catches hold of the prey."

The researchers suspended hydrophones in water to pick the sound produced by the dolphin here.
"Our hydrophones have already started receiving the sound produced by the dolphin. We will soon analyse the sound," Behera said.

The objective of the study is to follow the migration path, food habit and other behaviour of the dolphins. He said once the research yielded the desired results, advanced hydrophones could be manufactured on the basis of the findings which have a huge business potential.

The experiment, the first of its kind in India, will be conducted on the dolphin for two days. Earlier, similar experiments were conducted on Baiji dolphins in rivers of China and on whales in deep sea, Behera said.

"Dolphins belong to predatory category and are at the apex of the aquatic food chain. Presence of dolphins indicate that there is healthy life under water. The experiment would also study this aspect."

The population of Gangetic Dolphins is less than 2,500 and the mammals are spotted in India, Nepal and Bangladesh. Professor Tamaki Ura and six researchers from Tokyo university, Rajinder Behl of IIT Delhi and two researchers from the state forest department are taking part in the experiment.

During last rainy season, two Gangetic Dolphins were first spotted in the upper catchment area of Budhabalanga river, which were believed to have migrated.

While one dolphin was found missing after a few days, the other could be seen for a few more days. Since the shallow water in the Budhabalanga river was not suitable to the dolphin, it was shifted to the gorge in January last.

Behera said "we will conduct a detailed survey for the next three months to find out the population of sweet water dolphin in Orissa."