Irrawaddy Dolphins - Samary Mayo

The Irrawaddy Dolphin
Orcaella brevirostris 
By: Samary Mayo 

https://c402277.ssl.cf1.rackcdn.com/photos/6784/images/story_full_width/HI_301421_natureplcom_Roland_Seitre_WWFCanon_mini.jpg?1397660815

Ecology of the Irrawaddy Dolphin

• Physical description:
• 198-440 lbs.
• 5.9-9 ft.
• Bulging forehead, short beak
• Dark blue-gray to medium gray or pale blue coloration
• Diet:
• Fish and Cephalopods
• A common hunting strategy is that they spit water to attract more fish 
• Irrawaddy Dolphins are non-migratory species who live in various habitats, mostly encompassing freshwater. They are most likely to be found in the relatively deep pools of rivers, shallow coastal waters, lagoons and lakes. 
• The Irrawaddy Dolphin are dependent on low salinity (small amounts of salt in the water), moderate to high water depths, high temperatures and channel confluences (where two channels cross paths). 
• There can be some circumstances in which Irrawaddy Dolphins are found in lower reaches of the river, for example in the Rajang River in Sarawak, Malaysia. The range of the Irrawaddy Dolphin sometimes overlaps with those of Finless Porpoises and Indo-Pacidic Humpback Dolphins. 
• Their lifespan reaches an average of twenty years. 

Geographic and Population Changes

• Irrawaddy Dolphins are native in south and southeast Asia. Some of the countries include: Thailand, Lao, Cambodia, India, Brunei Darussalam, Bangladesh, Malaysia, Phillippines, Vietnam, Singapore, Myanmar.
• They are distributed in coastal waters of the tropic and subtropic Indo-Pacific.
• The Critically Endangered riverine subpopulations, Mekong, Ayeyarwady and Mahakam are found respectively in Cambodia and Lao, Myanmar and Indonesia. The riverine subpopulations tend to occupy the deep pools of rivers which are the junctions of two rivers and above and below rapids. 
• The Malampaya Sound and Songkhla Lake are two other subpopulations.
• Although a map of the geographic distribution of Irrawaddy Dolphins would suggest continuity in the species’ range throughout coastal areas, subpopulations are actually fragmented. For example, Irrawaddy Dolphins are present in the coastal waters of Trat Province in Thailand, but are absent in the upper Gulf of Thailand, which is a neighboring province. 
• The current population is decreasing, however there are no extreme fluctuations in population. 
• The riverine subpopulation has approximately 78 to 91existing individuals. 

http://maps.iucnredlist.org/map.html?id=15419

Recovery Plan 

• There are six proposed strategies to help reduce bycatch:
• Establishing conservation areas in which gillnetting is banned or restricted
• Promoting net attendance rules and providing training for how to release an entangled dolphin safely
• Rewarding fishermen who safely release entangled dolphins. This can be in the  form of monetary or material compensation for damaged nets.
• Provide alternative jobs for gillnet fishermen   
• Encouraging alternative, non-harming fish gear or increase gillnet use fees
• Experimenting with other fishing gear like acoustical deterrents and reflective nets
• Some of these proposed strategies are underway in Myanmar and the Mekong River. The Department of Fisheries and Wildlife Conservation Society are collaborating to execute a plan for the Ayeyarwady Dolphin Protected Area. The River Guard Program in the Mekong River is designed to provide surveillance for the compliance of rules and regulation to protect the Irrawaddy Dolphins and fisheries.
• Conservation efforts in the Mahakam River have been directed to the training of fishermen to rescue and release entangled dolphins safely, as well as encouraging other employment for fishermen involved in this issue.
• Since 2012, three wildlife sanctuaries have been established in Bangladesh. The sanctuaries were not specifically designed to protect Irrawaddy Dolphins, instead to protect the Ganges River Dolphins, however both species co-inhabit the areas. In 2014, a priority sanctuary for Irrawaddy Dolphins were declared in Bangladesh, which includes an area of 233km^2. 

http://www.iucn-csg.org/index.php/2017/02/08/progress-protecting-mekong-river-dolphins-undermined-by-proposed-dams/

Why are they important? 

• The Mekong Irrawaddy Dolphin They are crucial to the health of the Mekong River, home to about 1,100 fish species.
• They are sacred animals to the people of Khmer and Lao. 

Listing Type and Date

• Red List Category and Criteria: Endangered A2cd+3cd+4cd; Published 2017 
• 2008 - Vulnerable (VU)
• 1996 - Data Deficient (DD)
• 1994 - Insufficiently Known (K)
• 1990 - Insufficiently Known (K)
• 1988 - Insufficiently Known (K)
• Mekong, Ayeyarwady and Mahakam, the three riverine subpopulations, are categorized as Critically Endangered.

Main Threats

• In the 1970s, threats of hunting and trade were major in the decline of the population of Cambodia and the species is now extirpated from the area. However, today this doesn’t seem to be a major factor explaining the endangerment of the Irrawaddy Dolphins. 
• Some of the main threats include being bycatch from small-scale fisheries, habitat degradation and human activities. 
• Bycatch seems to be the most severe threat for the Irrawaddy Dolphin populations. According to fishermen from Bagladesh, the dolphins are getting entangled in gillnets, causing many incidental mortalities.
• In the Mekong River, there were 15 confirmed deaths due to bycatch (gillnets) from 2001-2005. 
• In the Mahakan river an average of 4 deaths occur annually due to bycatch (gillnets) as well. There is a higher percentage of adult Irrawaddy Dolphins getting caught in the nets. 
• 32 of 49 deaths in Bangladesh, from 2007 to 2016, also occurred due to bycatch (gillnets). 
• The decline in habitat quality, or habitat degradation, is due to quite a few reasons. For the Irrawaddy Dolphins that are populated in freshwater, the existing and planned dam constructions, for example like in the Mekong and Ayeyarwady Rivers, is one threat. In Coastal waters, the increasing commercial vessel traffic is also a threat. 
• One of biggest concerns in regard to hydropower projects are the four projects proposed in the Mekong River. The construction of The Don Sahong Dam, which began in 2014, has already resulted in the loss of population of Irrawaddy Dolphins and has restricted the Dolphins to stay in one area while construction. The other three dams are proposed and awaiting further determination for construction, but they are most likely to contribute to a great loss in population and/or the fragmentation of the population. 
• Deforestation and gold, sand and gravel mining are also contributing to habitat degradation because of the changes in the hydraulic features of the rivers and lakes that the Irrawaddy Dolphins inhabit. For example, deforestation is leading to an increase in sedimentation that results in the decline of water depths in the Songkhla, Chilika and Jempang Lakes. 
• For both coastal and freshwater Irrawaddy Dolphins, noise and pollution is another threat. The most common pollutants that have degraded their habitat include: oil, pesticides, industrial wastes and coal dust. The poor land practices that allow pollutants to enter the bodies of water have caused siltation. 
• The fragmentation of the population makes the Irrawaddy Dolphins more susceptible to contact with human activities because they occupy the same areas.
• An approximate 50 % of population will decrease because of the increasing magnitude and range of dam construction and coastal development, in the next 60 years.
• The Recovery Plan consists of providing multi-use protected areas for the Irrawaddy Dolphins and strategies for reducing bycatch. 

What can you do? 

• Human activity is currently the main threat to the survival of Irrawaddy Dolphins, so you can help save them! 
• If you are currently employed to work in the fishery district, experiment with new strategies that lessen the risk of bycatch, therefore lessening the incidental mortality of Irrawaddy Dolphins. Encourage your employer and co-workers to follow in your footsteps and to be trained for dealing with the safe removal of entangled species. 
• For those not directly in contact with Irrawaddy Dolphins, you can do your part as well. Political action is always key to bringing change, so take action in your community by requesting for laws and regulations that encourage wildlife conservation.
• The Irrawaddy Dolphins need your help to live prosperously! 

https://c402277.ssl.cf1.rackcdn.com/photos/6784/images/story_full_width/HI_301421_natureplcom_Roland_Seitre_WWFCanon_mini.jpg?1397660815

Resources

• Learn about them at: http://www.iucnredlist.org/details/15419/0
• See them swim! https://youtu.be/xQ5BN_xMgq0

Works Referenced

• (2014, April 17). Irrawaddy Dolphins: The Smiling Faces of the Mekong. Retrieved from: https://www.worldwildlife.org/stories/irrawaddy-dolphins-the-smiling-faces-of-the-mekong
• Irrawaddy Dolphin: Facts. Retrieved from: https://www.worldwildlife.org/species/irrawaddy-dolpin
• Irrawaddy Dolphin: Oracaella brevirostris. Retrieved from http://us.whales.org/species-guide/irrawaddy-dolphin
• Kraft, Lauri. (2014, March 9). Irrawaddy River Dolphins and Endangered Animals. Retrieved from www.wildernessclassroom.com/irrawaddy-river-dolphins-endangered-animals/.
• Minton, G., Smith, B.D., Braulik, G.T., Kreb, D., Sutaria, D. & Reeves, R. (2017). Oracaella brevirostris. Restrieved from http://www.iucnredlist.org/details/15419/0.