Tourism threatens rare Irrawaddy dolphins

March 2nd, 2008 - 9:45 am ICT by admin  

By Jatindra Dash
Bhubaneswar, March 2 (IANS) The number of endangered Irrawaddy dolphins has registered a marginal increase in Orissa’s Chilika lake - Asia’s largest saltwater lake - but they are facing threats from tourist activity. In India, Irrawaddy dolphins (Orcaella brevirostris) are found only in Chilika, some 100 km from here. As per the latest census, their population has gone up from 135 in 2007 to 138 this year.

The lake is spread over Puri, Khordha and Ganjam districts of the state, with an area of around 1,165 sq km. The dolphins are mostly confined to an area of about 230 sq km within the lake, said Sudarshan Panda, chief executive of the Chilika Development Authority.

Around 50 percent of the dolphins were sighted in the outer channel of the lake where a large number of tourist boats operate, he said, adding that the tourism activity in their habitat was posing a big threat to their survival.

“We need to regulate tourism activities here very strictly,” Panda told IANS.

In 2001, there were just 20 tourist boats operating in the outer channel of the lake. However, their numbers have jumped to 500 at present, said Biswajit Mohanty, secretary of the Wildlife Society of Orissa.

This development has put pressure on the dolphins. Despite best efforts by the government to educate the tour and boat operators, the threats to dolphins continue, he said.

Around 30-40 boats chase dolphins at any point of time to offer tourists a glimpse of this rare aquatic species, Mohanty said.

Although there has been no casualty due to the boats, five dolphins have died in the lake between February 2007 and February 2008. Two died from old age, one in a shark attack and the cause of two other deaths is still under investigation, Panda said.

Around 18 teams comprising scientists, government officials and wildlife experts Monday and Tuesday took part in the dolphin census in Chilika, which also hosts the largest congregation of migratory birds in the country.

Scientists from Japan University, Tokyo, the Indian Institute of Technology, New Delhi, the Natural History Society, Mumbai and the World Wide Fund for Nature (WWF), besides other organisations, participated in the census.

The census was carried out by head count as well as by using a system that records the sound of dolphins, Panda said.

It is estimated that there are fewer than 1,000 Irrawaddy dolphins left around the world.

Apart from Chilika, Irrawaddy dolphins are found in the Sundarbans mangrove forests that straddle India and Bangladesh and in Thailand’s Songkhla Lake. Though it is difficult to spot dolphins in Thailand, they can be easily sighted in Orissa. Their population in the Irrawaddy, the river in Myanmar that gave them their name, has not been estimated for many years due to the unrest in that country.

Adult Irrawaddy dolphins range in length between 2 and 2.75 metres and are thought to reach sexual maturity at the age of three or four years. Adult females probably have only one calf every two to three years, according to experts.

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