We cooperate in arresting electrofishing boats in the Ayeyarwady dolphin conservation area and then transfer the suspects to the Department of Fisheries to face legal action, he said. While the cause of death of endangered Ayeyarwady dolphins varies, conservationists agree that most were killed by electrofishing and getting entangled in fishing nets. As battery fishing becomes more popular, the number of dolphin deaths is increasing, said U Han Win, deputy head of the department. Battery fishing is banned under the Myanmar Freshwater Fisheries Law, and those who violate it face fines of K30,000 (US$21), imprisonment of up to three years, or both. Latest records showed there are 79 Ayeyarwady dolphins in the river from Mandalay to Bhamaw township in Kachin State. On May 7, a female dolphin, 7-foot, 3-inches long and an estimated 40 years old, was found dead near Aye Kyun village in Madaya township in Mandalay. The dolphins, named after the Ayeyarwady River, live along a 373-kilometre stretch north of Mandalay, between Mingun in Sagaing Region and Bhamaw. The Ayeyarwady dolphin protection zone in Mandalay, and in Mingun and Kyauk Myaung in Sagaing Region, was established in 2015. The government declared the section of the river in Sagaing and Kachin a protected zone last August. The Ayeyarwady dolphin is found in discontinuous subpopulations near sea coasts and in estuaries and rivers in parts of the Bay of Bengal and Southeast Asia. Some sub-populations of the dolphin, including the Ayeyarwady, are classified by the IUCN as critically endangered species.