Irrawaddy Dolphin Mekong


Wiki source

Irrawaddy dolphins have a seemingly mutualistic relationship of co-operative fishing with traditional fishers. Fishers in India recall when they would call out to the dolphins, by tapping a wooden key also known as a "lahai kway", against the sides of their boats, asking the Irrawaddys to drive fish into their nets. In Burma, in the upper reaches of the Ayeyarwady River, Irrawaddy dolphins drive fish towards fishers using cast nets in response to acoustic signals from them. The fishermen attempt to grasp the attention of the dolphins through various efforts such as using a cone-shaped wood stick to drum the side of their canoe, striking their paddles to the surface of the water, jingling their nets, or making calls that sound turkey-like. A herd of dolphins, who agree to work alongside the fisherman, will entrap a school of fish in a semi-circle, guiding them towards the boat. In return, the dolphins are rewarded with some of the fishers' bycatch. Historically, Irrawaddy River fishers claimed particular dolphins were associated with individual fishing villages and chased fish into their nets. An 1879 report indicated legal claims were frequently brought into native courts by fishers to recover a share of the fish from the nets of a rival fisher which the plaintiff's dolphin was claimed to have helped fill.