Irrawaddy Dolphins occur in varied habitats. In rivers, they occur almost exclusively in relatively deep (10-50 m) pools located at confluences or above and below rapids. In coastal waters, Irrawaddy Dolphins most commonly occur in areas affected by freshwater inputs and they may enter the lower reaches of rivers (Smith 2017). In the Rajang River in Sarawak, Malaysia, Irrawaddy Dolphins were observed both in the lower reaches of the river and as far as 86 km upriver (Bali et al. 2017). In the coastal areas of Sarawak, Irrawaddy Dolphins were statistically more likely to be observed within 6 km of shore, with a mean water depth of 4.2 m (standard deviation (SD) = 2.4) and salinity of 31.2 ± 2.3 ppt with their distribution shifting inshore during high tide and offshore during low tide (Peter et al. 2016a). In Malampaya Sound, Philippines, 76% of sightings occurred in waters shallower than 6 m (Dolar et al. 2002) with a mean salinity of 28.3 ppt (Smith et al. 2004a). In Chilika Lagoon, 75% of 517 dolphin groups occurred in waters 0.6-2.5 m deep, with a maximum depth of 5.2 m for all groups, while salinity ranged from 1-22 ppt (Sutaria 2009). In coastal waters of Bangladesh, sighting locations had a mean depth of 7.5 m (range 2.7-16.0 m) and a mean salinity of 16.1 ppt (Smith et al. 2008). In Balikpapan Bay, Indonesia, Irrawaddy Dolphins occur in slightly deeper (mean 14.6 m; n = 94; SD = 9.3; range = 2-46 m) and higher salinity (mean 26 ppt; n = 35; SD = 3.1; range = 21-33 ppt) waters (D. Kreb pers. comm. 2017). Irrawaddy Dolphins have been observed in the same areas as Indo-Pacific Finless Porpoises (Neophocaena phocaenoides) in coastal waters of Bangladesh and Myanmar (Smith et al. 2008, Smith and Tun 2008), and their range overlaps those of both Finless Porpoises and Indo-Pacific Humpback Dolphins (Sousa chinensis) in coastal areas of Borneo (Kamaruzzan et al. 2011, Minton et al. 2011). Irrawaddy Dolphins also co-occur with Ganges River Dolphins (Platanista gangetica) in a relatively small portion of their range in the Sundarbans mangrove forest (Smith et al. 2006). In waterways of the Sundarbans mangrove forest, Irrawaddy Dolphin distribution shifts downstream and upstream according to high and low freshwater flow, respectively, and is conditionally dependent (P < 0.05) on low salinity, moderate to high water depths, high temperature and increasing numbers of channel confluences (Smith et al. 2009).

Irrawaddy Dolphins have a discontinuous distribution in coastal waters of the tropical and subtropical Indo-Pacific, and are predominantly associated with freshwater inputs (Stacey and Arnold 1999, Smith 2017). Coastal and estuarine populations occur from Borneo and the central islands of the Indonesian Archipelago north to Palawan, Philippines, and west to the Bay of Bengal, including the Gulf of Thailand. There are also freshwater subpopulations in three large rivers: Ayeyarwady in Myanmar (up to 1,400 km upstream from the river mouth), Mahakam in Indonesia (with a suspected current range between 90 km to 500 km upstream from the river mouth and the area of highest density between 180 and 280 km from the mouth), and Mekong in Cambodia and Lao People's Democratic Republic (a range of less than 200 km between Kampi pool, near Kratie, Cambodia, and Khone Falls, Laos, some 690 km from the river mouth). Within the extent of Irrawaddy Dolphin occurrence in these rivers, their area of occupancy is concentrated in deep pools associated with confluences and above and below rapids. Three other subpopulations inhabit marine-appended brackish water bodies: Chilika Lagoon in India, Songkhla Lagoon in Thailand, and Malampaya Sound in the Philippines.

Although the map accompanying this assessment implies a continuous distribution throughout the coastal areas of the species’ range, subpopulations are known to be fragmented and patchily distributed, with long stretches of coastline where the species is now absent, either due to lack of freshwater inputs or likely local extirpation.  For example, while Irrawaddy Dolphins are present in the coastal waters of the Trat Province, Thailand, they appear to be absent in the neighbouring provinces of Chanthaburi and Rayong in the upper Gulf of Thailand (Hines et al. 2015). Similarly, while populations were documented in Kuching Bay and Similajau in Sarawak, Malaysia, the species was not observed during repeated cetacean surveys off the coast of Miri and the Baram River, where the species is known to have been present historically (Minton et al. 2011, Pilleri and Gihr 1974).

The Irrawaddy Dolphin is listed in Appendix I of the Convention on International Trade in Endangered Species (CITES) as well as the Convention on Migratory Species (CMS).

The Action Plan for the Conservation of Freshwater Populations of Irrawaddy Dolphins (Smith et al. 2007) noted that multiple-use protected areas will play a key role for conserving freshwater subpopulations of Irrawaddy Dolphins. Protected areas could be a particularly effective conservation tool due to the fidelity of the species in freshwater systems to relatively circumscribed areas, as this can facilitate management. The Action Plan also provided details on strategies for mitigating bycatch that included (1) establishing core conservation areas where gillnetting is banned or severely restricted; (2) promoting net attendance rules and providing training on the safe release of entangled dolphins; (3) initiating a program to compensate fishermen for damage caused to their nets by entangled dolphins that are safely released; (4) providing alternative or diversified employment options for gillnet fishermen; (5) encouraging the use of fishing gears that do not harm dolphins by altering or establishing fee structures for fishing permits to make gillnetting more expensive while decreasing the fees for non-destructive gears; and (6) experimenting with acoustical deterrents and reflective nets.

In some countries conservation progress is underway. In Myanmar, the Department of Fisheries is collaborating with the Wildlife Conservation Society (WCS) to implement the Management Plan for the Ayeyarwady Dolphin Protected Area (ADPA) (Thomas and Gulland 2017). In the Mekong River, a River Guard Program administered by the local governments in relevant provinces and supported by WWF-Cambodia has stationed 68 River Guards at 16 different outposts along the Mekong from Kratie to the Cambodian-Lao border to help ensure compliance with laws and regulations designed to protect fisheries and dolphins (Samnang in Thomas and Gulland 2017).

In the Mahakam River, East Kalimantan, Indonesia, conservation efforts have focused on training fishermen to rescue dolphins when they are entangled and raising awareness among communities and government authorities. A local non-governmental organization also encourages alternative livelihoods, for example aquaculture and nature-oriented tourism. Since 2002, there have been eight successful releases of dolphins entangled in nets and three dolphins have been rescued from swamp areas when they were unable to return to the main river. The designation of a protected area (24,000 ha core, 51,000 ha total) is currently in progress and will include core dolphin habitat as well as freshwater swamps (Kreb et al. 2010, Kreb in Thomas and Gulland 2017).

In Bangladesh three wildlife sanctuaries for freshwater dolphins have been in place since 2012 in the eastern Sundarbans. While primarily designed to protect Ganges River Dolphins rather than Irrawaddy Dolphins, the sanctuaries include areas where both species regularly co-occur. In 2014, the Government of Bangladesh declared a 1,738 km² marine protected area in the Swatch-of-No-Ground submarine canyon and adjacent estuarine waters. This includes 233 km² of priority habitat for Irrawaddy Dolphins.