Officials of Wildlife and Nature Conservation Division (WNCD) of Khulna said on Saturday that they had collected two dead otters contaminated by the spilled oil from the bank of River Shela.
They also acknowledged that after autopsy they found the presence of furnace oil in the lungs of the both the dead animals.
After 13 days of the oil spillage the government has, for the first time, accepted the negative impact of the spilled oil on the animals. Otter is an amphibian animal, once available in the Southern Western part of Bangladesh is now found in the Sundarban.
The otter has been considered as endangered species and has been included in the International Union for Conservation of Nature (IUFCN).
The National Geography Channel and other Wild Life-based organizations are doing research on it at present.
Before the news of the death of the otters, some newspapers published news and photographs of a dead dolphin which raised huge attention in the national and international domain. The scourge of the spilled oil is also posing threat to some of the bird species especially those belonging to the carnivorous group, such as vultures, kites and eagles, which usually eat the carcass of dead animals.
A number of zoologists expressed concern over the news of the death of the otters. They said that other birds could also die if they eat these contaminated death animals.
Prof Dr Md Abul Bashar of Department of Zoology of University of Dhaka, said that the food chain will affect a number of species in the area.
"If a vulture eats the dead bodies of animals contaminated by the oil, it will also be contaminated," he said.
He also said that the number of the dead could increase when the high tide enters the forest areas of the Sundarban during full moon.
Jahidul Kabir, an official of the WNCD, said that they are sending monitoring teams, primarily for three months, to spot dead animals although he thought that the situation was not that alarming.
Just a few days back the Environment and Forests Ministry formed a nine-member committee to investigate the situation in the affected areas of the Sundarban, among them, Prof Dr Dilip Kumar Datta, of the Department of Environment Sciences of the University of Khulna while talking to The Daily Observer said that the oxygen level of the River Shela is normal.
Even the tests carried out on the Shela and Phasur rivers by the Environment and Forest Ministry also suggest that the oxygen level in both the rivers were not threatening to plants or aquatic animals.
Prof Abdullah Harun Chowdhury of the Department of Zoology of University of Khulna, said that at present the oil spill has depleted oxygen level in the rivers to a danger level.
"It is threatening species like crabs, prawns, deer, planktons, plant micro-organisms and fish breeding," he said.
Only three days back Environment and Forest Minister, Anowar Hossain Manju, while talking to journalists said that the oil spill would obviously cause no harm to the aquatic life of the Sundarban.
He made this comment while visiting the spot with top forest officials 10 days after capsize of an oil tanker with around 3.58 lakh litres of furnace oil in the River Shela.
Similarly, the Shipping Minister, Shahjahan Khan, also made same comments which brought much criticism from different corners.
The UNESCO World Heritage Centre (Dhaka office), and the Ramsar Secretariat have expressed serious concern over the impact of the spill on the world heritage site known as the Sundarban.
A 17-member UNDP team of experts would hold a formal meeting with the forest officials on Sunday before leaving Dhaka for the Sundarban.
The team would help the government conduct an assessment of the impact of the spill and advise on recovery and risk reduction measures and extend support to the government's cleanup efforts.