Washington, April 4 (IANS) Thousands of rare dolphins have been sighted in the fresh waters off the Sundarbans and the Bay of Bengal, according to Wildlife Conservation Society (WCS).
WCS researchers estimated that nearly 6,000 Irrawaddy dolphins, related to orcas or killer whales, were found living in freshwater regions of Bangladeshi Sundarbans and adjacent waters of the Bay of Bengal - an area where little marine mammal research has taken place up to this point.

Prior to this study, the largest known populations of Irrawaddy dolphins numbered in the low hundreds or less. Each discovery of Irrawaddy dolphins is important because scientists do not know how many remain on the planet.

In 2008, they were listed as vulnerable in the IUCN Red List based on population declines in known populations.

“With all the news about freshwater environments and state of the oceans, WCS’s discovery that a thriving population of Irrawaddy dolphins exists in Bangladesh gives us hope for protecting this and other endangered species and their important habitats,” said WCS President and CEO Steven E. Sanderson.

“This discovery gives us great hope that there is a future for Irrawaddy dolphins,” said Brian D. Smith, the study’s lead author.

However, study authors warn that the dolphins are becoming increasingly threatened by accidental entanglement in fishing nets. During the study, researchers encountered two dolphins that had become entangled and subsequently drowned in fishing nets - a common occurrence, according to local fishermen.

The results of the study were announced Friday at the First International Conference on Marine Mammal Protected Areas in Maui, Hawaii and published in the Winter issue of the Journal of Cetacean Research and Management, said a WCS release.

Authors of the study include Brian D. Smith, Rubaiyat Mansur Mowgli, and Samantha Strindberg of the Wildlife Conservation Society, along with Benazir Ahmed of Chittagong University in Bangladesh.