The Wildlife Conservation Society (WCS) has discovered a huge population of rare dolphins in South Asia. Nearly 6,000 Irrawaddy dolphins, which are related to orcas or killer whales, were found living in freshwater regions of Bangladesh’s mangrove forests adjacent to the Bay of Bengal—an area where little marine mammal research has taken place. 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. In 2008, they were listed as vulnerable in the IUCN Red List based on population declines in known habitats.
Photo courtesy of Sun Star – Thanks to Maggie G. for submitting the story tip!
The results of the study were announced yesterday at the First International Conference on Marine Mammal Protected Areas in Maui, Hawaii.
“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 Dr. Steven E. Sanderson, President and CEO of the Wildlife Conservation Society. “WCS is committed to conservation of these iconic marine species from dolphins, sea turtles, sharks to the largest whales.”
Despite finding this extraordinarily large population, the study’s 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 Irrawaddy dolphin grows to some 2 to 2.5 meters in length (6.5 to 8 feet) and frequents large rivers, estuaries, and freshwater lagoons in South and Southeast Asia. In Myanmar’s Ayeyarwady River, these dolphins are known for “cooperative fishing” with humans, where the animals voluntarily herd schools of fish toward fishing boats and awaiting nets. With the aid of dolphins, fishermen can increase the size of their catches up to threefold. The dolphins appear to benefit from this relationship by easily preying on the cornered fish and those that fall out of the net as the fishermen pull it from the water. In 2006, WCS helped establish a protected area along the Ayeyarwady River to conserve this critically endangered mammal population.
WCS is currently working closely with the Ministry of Environment and Forests in Bangladesh on plans for establishing a protected area network for both Irrawaddy and Ganges River dolphins in the Sundarbans mangrove forest. Funding is critical to sustaining these activities along with WCS’s long-term efforts to study the effects of climate change on this habitat, support sustainable fishing practices, and develop local ecotourism projects.
The Wildlife Conservation Society saves wildlife and wild places worldwide. We do so through science, global conservation, education and the management of the world’s largest system of urban wildlife parks, led by the flagship Bronx Zoo. Visit or donate at: www.wcs.org