KARACHI: A survey team assessing population of dolphins in the Indus River reached Tori Bund in Kashmore district on Tuesday.

The five-day survey led by the Sindh Wildlife Department (SWD) is being conducted after a gap of seven years. The last dolphin survey by the wildlife department was conducted in 2011 during which the population of the endemic species was estimated to be 918.

Other members of the team include experts from the irrigation department and a senior zoologist of Shah Abdul Latif University, Khairpur, and a zoology student of Sindh University.

‘We are very much aware of dolphin behaviour, which makes counting easier’

“It’s the first time we have local female zoologists in the survey team, which has a special focus on water quality assessment as there is genuine concern pertaining to growing river pollution,” said Mir Akhtar Hussain Talpur, SWD field officer and the team leader.

Sharing other details of the survey, he said that unlike the 2011 assessment conducted from Guddu to Kotri barrages, this survey would be restricted between Guddu and Sukkur barrages as at present there was no water downstream Kotri.

Asked whether observations from the naked eye are a credible method for dolphin counting, he said: “The area we have chosen is the dolphin hotspot and the method being used is authentic, though old. Besides, we are very much aware of dolphin behaviour, which makes counting easier.”

Elaborating, he said that the species lived in groups and did not move out of an area fast.

Dr Giorgio Pilleri, a Swiss expert who conducted the first Indus river dolphin survey in 1972 and also wrote a famous book (The Secrets of the Blind Dolphins), used the same method.

The team is using a wooden boat so that the river’s marine life is least disturbed.

Dolphin surveys had been a regular feature since the 1970s. Apparently, the population of this species has risen from 132 during the first survey in 1972 to 918, as counted in the last SWD 2011 survey.

Read: Declining dolphin numbers

“The species faces multiple threats, including accidental entanglement in fishing nets, increasing freshwater shortages mainly due to the construction of dams and barrages upstream, shrinking food chain, growing water pollution as well as the use of pesticides to catch fish,” Mr Talpur said.

WWF survey

A 2017 survey conducted by the World Wide Fund for Nature-Pakistan (WWF-P) reported a significant increase in the population of the species since 2001. It covered the dolphin distribution range from Chashma to Sukkur barrages.

It found that the total number of dolphins was 1,816, with 170 dolphins between Chashma and Taunsa barrages, 571 dolphins between Taunsa and Guddu barrages and lastly 1,075 dolphins between Guddu and Sukkur barrages.

The dolphin encounter rate was higher downstream the Indus with the highest population observed between Guddu and Sukkur barrages.

Explore: Is this a farewell for the Indus dolphin?

Locally known as bhulan, the Indus dolphin is the second most endangered freshwater dolphin species in the world, the first being the ‘functionally extinct’ Yangtze river dolphin.

This species is also referred to as the ‘blind dolphin’ as its eyes have not developed lenses. It relies on echolocation to find fish, shrimp, and other prey in the bottom mud.

The government of Sindh designated a 200-kilometre stretch of the Indus between Guddu and Sukkur barrages as the Indus Dolphin Reserve in 1974.

Once found in the Indus and in its major tributaries in Punjab’s Sutlej, Chenab, Ravi and Jhelum rivers, the species is now confined to the main channel of the Indus.

The Guddu-Sukkur river section is today the prime habitat of the freshwater dolphin and contributes the highest number to its total abundance. However, this river section also reports the highest dolphin mortality.

Published in Dawn, April 10th, 2019