The small freshwater Mekong River Irrawaddy dolphins are noted for their uniquely shaped round heads and short dorsal fins. They are like no other dolphin on Earth, and could soon be extinct. In fact, only about 89 of these animals remain alive, living in an 118-mile stretch of the Mekong River between Cambodia and Laos.
Though their entire species is contained in a single pinpoint on a map of the world, these dolphins are still facing threats from human activity.
According to the World Wildlife Fund for Nature, Irrawaddy dolphins are most commonly threatened by gill nets, development of upstream dams, overfishing, and illegal fishing practices.
The IUCN also maintains that gill net entanglement is the main cause of adult mortality, but polluted waters have caused far more insidious problems for the dolphins.
Pollutants in the Mekong River, dumped in the water from Cambodia through southern Laos, are compromising the animals’ immune systems and contributing to the death toll. As Endangered Species International reports, the dolphins are exposed to chemicals and sewage released from adjacent terrestrial activities, not to mention noise and disturbance associated with construction, vessel traffic and military activities.
Metals, pesticides and other toxins flushed into the Mekong have been accumulating over the last few decades. Scientific studies have shown just how dangerous the dolphins’ environment has become.
“Toxic levels of pesticides such as DDT and environmental contaminants such as PCBs were found during analysis of the dead dolphin calves — these pollutants may also pose a health risk to human populations living along the Mekong that consume the same fish and water as the dolphins,” reported the World Wildlife Fund. “High levels of mercury, which is dumped in the river from gold mining activities, were also found in some of the dead dolphins. The mercury directly affects the dolphins’ immune system, making the animals more susceptible to infectious diseases.”
The Mekong River is home to 1,200 fish species and has the second highest concentration of aquatic animals in the world, after the Amazon. The fish and crustaceans the Irrawaddy feed on are now increasingly threatened by overfishing and dams, putting the dolphins at greater risk.
The Irrawaddy dolphin is regarded as a sacred animal by both Khmer and Lao people, and is an important source of income and jobs for communities involved in dolphin-watching ecotourism.
According to Future Oceans, “Irrawaddy dolphins can be found in the shallow, coastal waters of the Bay of Bengal, Papa New Guinea and the Philippines and surrounding rivers and estuaries. Though most populations stick to the open waters, there are some subpopulations that live primarily in the fresh water river systems. They do not hold to migratory patterns like other ocean fairing dolphins, traveling long distances from one area to another, but instead remain in their local areas venturing out to feed during the day then returning to safer waters at night.”
A recent survey confirmed that the number of river dolphins in Cambodia has been holding strong for a few months, but the population size is still so small, the Irrawaddy will need more active protections if it is to avoid extinction. The Mekong River Irawaddy dolphin has been listed as critically endangered on the IUCN Red List of Threatened Species since 2004, the highest international threat ranking for endangered species.
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