Alyna Sigel
The Irrawaddy dolphin (Orcaella brevirostris) is an endangered marine mammal native to Southeast Asia. The species can live in both freshwater and saltwater environments but typically live in rivers including the Irrawaddy, Ayeyarwady, and Mekong Rivers. The Greater Mekong subregion is inhabited by several notable endangered species from dolphins and catfish to tigers and elephants. This fosters curiosity about why species populations in this region are suffering, which can be understood by examining the decline of the Irrawaddy dolphin.
The endangerment of the Irrawaddy dolphin results from an array of threats. Though climate change, pollution, and habitat degradation are all harmful to the species’ population, the two most detrimental threats are dams and bycatch. The hydroelectric dams built along the Mekong River alter the flood cycles of the region, block migratory fish paths, and change habitats within and near the river. Additionally, the construction of dams disrupts the flow of the river which negatively impacts all aquatic species. Dolphins also fall victim to entanglement in fishing nets, causing them to drown, and being killed by electrofishing practices.
These threats caused the Irrawaddy dolphin to become classified as endangered in 2017, with a population that has continued to decline since. Multiple subpopulations of the species, including the Mekong River population, are listed as critically endangered. The significant decrease in the species’ population has resulted in environmental, cultural, and economic consequences.
Environmentally, the Mekong River ecosystem's health is dependent on the Irrawaddy dolphin. As top ecosystem predators and a keystone species, they are essential in controlling populations within their ecosystem and host multiple parasitic species. The Irrawaddy dolphin is also an indicator species. Their population and well-being are a reflection of the ecosystem’s overall health, so their endangerment is notably alarming.
Additionally, the Irrawaddy dolphin is considered sacred to Khmer and Lao cultures. A popular folk story in these cultures tells of a woman escaping into the river and turning into a dolphin. There are multiple versions of this tale but the story exemplifies the importance of the species in Southeast Asian cultures.
Though the species is economically important in the sense of cooperative fishing increasing the yield of fishers, they are also influential for ecotourism. Preah Rumkel, a commune in Cambodia, thrived from ecotourism due to its population of Irrawaddy dolphins. After the death of the last dolphin in the area, the commune lost 90% of its visitors and many residents migrated elsewhere due to the resulting lack of income. The commune now struggles to continue ecotourism in a manner that will attract enough visitors, though the idea of an Irrawaddy Dolphin Annual Festival has been discussed with hope.
The species is undeniably important to the environment, culture, and economy of the greater Mekong River subregion, so it is necessary to attempt to preserve their population. To protect the species, the threats need to be controlled. This means that focuses on pollution control, habitat restoration, and an array of conservation efforts are essential. Endangered Species International has taken steps to assist the species by training fishermen to help restore habitats and work with local communities. The World Wildlife Foundation has been conducting research, attempting to improve the Mekong ecosystem, and monitoring wildlife trade as a conservation effort. By supporting these and similar organizations, there remains hope for the restoration of the Irrawaddy dolphin population.
Citations
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Endangered Species International, Inc. (2018). Endangered Species International. Www.endangeredspeciesinternational.org. https://www.endangeredspeciesinternational.org/news_feb18.html
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IUCN. (2017, August 30). The IUCN Red List of Threatened Species. IUCN Red List of Threatened Species; Name. https://www.iucnredlist.org/species/15419/123790805
Kong, R. (2024, April). Cambodian villagers plan new attraction after last dolphin dies. Mekong Eye. https://www.mekongeye.com/2024/04/01/new-attraction-dolphins
Koss, M., Mahan, L., & Merrill, S. (2010). Orcaella brevirostris (irrawaddy dolphin). Animal Diversity Web. https://animaldiversity.org/accounts/Orcaella_brevirostris/
Levy, A. (2023, November 3). Freshwater Dolphins: Characteristics, Threats, and Conservation Efforts. Earth.org. https://earth.org/?endangered-species=freshwater-dolphin-endangered-species-spotlight
WWF. (2018). Irrawaddy Dolphin | Species | WWF. World Wildlife Fund.
WWF. (2020, April 13). Urgent action needed to conserve the endangered Irrawaddy dolphin. WWF Protecting Whales & Dolphins Initiative. https://wwfwhales.org/news-stories/urgent-action-needed-to-conserve-the-endangered-irrawaddy-dolphin
WWF. (2021a). Hydropower development in the Greater Mekong. Greatermekong.panda.org. https://origin-mekong.wwf-sites.org/challenges_in_the_greater_mekong/infrastructure_development_in_the_greater_mekong/
WWF. (2021b). Wildlife of the Greater Mekong. Greatermekong.panda.org. https://origin-mekong.wwf-sites.org/discovering_the_greater_mekong/species/
WWF. (2022, February 17). WWF-Laos is saddened by the death of the last known river dolphin in the transboundary pool in. Www.wwf.org.la. https://www.wwf.org.la/?372355/WWF-Laos-is-saddened-by-the-death-of-the-last-known-river-dolphin-in-the-transboundary-pool-in-the-Mekong-between-Laos-and-Cambodia