Blind Indus Dolphin: Its Risk towards Extinction and Protective Measures

Abstract

The Indus River dolphin, sometimes known as the blind dolphin, is a freshwater cetacean that is exclusively found in Pakistan's Indus River. The IUCN Red List of vulnerable species lists the Indus River dolphin as endangered due to an 80% drop in its distribution range and a habitat that has been badly disrupted by dams and degraded by water diversions. The blind dolphin is a member of one of the oldest families of cetaceans, which separated about 29 million years ago, or roughly 22 million years before the emergence of contemporary dolphins. Its eyes are little and its vision is weak. Typically, indus dolphins are observed either singly or in small groups of two to three dolphins. They can occasionally be found in bigger groups of 20 to 30 people. On the Indus mainstem, there are still five subpopulations of indus dolphins, each of which is divided by irrigation barrages. In Bear River, India, there is a tiny, isolated colony of 18 to 35 Indus River dolphins.

The Indus River barrages capture the flowing water and redirect it into a vast network of irrigation canals that emerge from each barrage to meet the demand for water for agriculture. Dolphins from the Indus River frequently travel to irrigation canals using flow regulator gates that are adjusted to the barrages throughout the year. Dolphins become stuck after the canals are shut down for maintenance because of an unexpected water deficit. Since 1992, Sindh Wildlife Department and WWF-Pakistan have collaborated on a dolphin rescue initiative to carefully remove any stranded dolphins from canals and return them to the main river channel. Between 1992 and 2017, 147 dolphins were reported to be caught in canals. Of those, 130 dolphins were successfully recovered and released back into the river, while one dolphin perished in the process. Because they could not be saved. However, little is known regarding the post-release survival rate of the people that were rescued. A dolphin monitoring network has also been established by WWF-Pakistan and Sindh Wildlife Department in conjunction with pertinent stakeholders and neighborhood groups to keep an eye on the Indus River as well as its nearby canals and tributaries and to search for any dolphins that may be stranded there.

One of the main risks to Indus dolphins is intensive fishing, which raises the risk of dolphin entanglement in fishing nets and, ultimately, their mortality, especially when they travel near irrigation canals. After the devastating flood of 2010, there was a noticeable rise in illegal fishing between the Guddu and Sukkur barrages. In addition, the altered fishing system in Sindh province significantly increased the number of fishing licenses granted and exacerbated the negative effects of illegal fishing on the Indus River dolphin. In 2011, the Indus River dolphin's death rate peaked with 45 dolphins being reported dead, the majority of which were found while fishing was at its busiest. Since that time, the frequencies of dolphin fatalities have significantly decreased, but they are still not entirely under control. Especially in the Indus Dolphin Game reserve between Guddu and Sukkur Barrages, saving stranded dolphins from the irrigation canals is crucial to maintaining this dolphin population during the low flow season. Standard procedures and tools, such as a soundproof truck, are required for dolphin rescue operations