Around 19% of fish species in the Mekong River are at risk of extinction due to habitat loss and unsustainable fishing, according to a study by WWF and 25 global conservation and fisheries organizations.
The third most biodiverse river in the world.
WWF released a report on March 4, titled “Forgotten Fishes of the Mekong,” which details the river’s extraordinary fish biodiversity, with at least 1,148 species recorded across its nearly 5,000-kilometer length from the Tibetan Plateau to the South China Sea. This makes the Mekong the third most biodiverse river in the world, after the Amazon and the Congo. The Mekong is considered the lifeblood of farming and fisheries for tens of millions of people across China, Laos, Myanmar, Thailand, Cambodia, and Vietnam, covering a drainage basin of 795,000 square kilometers and with an average annual discharge of around 15,000 cubic meters per second and an annual total discharge of 475 billion cubic meters at its delta. It also hosts one of the largest animal migrations on Earth, with an estimated 5 billion fish moving up to 5,000 kilometers.
The report emphasizes the vital role these fish play in sustaining the health of the Mekong Basin and providing food security and livelihoods for tens of millions of people in the region. The Mekong boasts the largest inland fishery in the world, contributing over 15% of the global inland capture fisheries production, worth over US$11 billion annually and serving as the backbone of food security and livelihoods for more than 40 million people in communities across the basin.
Fish Facing Multitude of Threats
However, the fish are under increasing pressure, with one in five species threatened with extinction. The report details the multitude of threats facing Mekong fish, including habitat loss, conversion of wetlands to agriculture and aquaculture, unsustainable sand mining, invasive alien species, increasingly severe climate change impacts, and the construction of dams that fragment the river’s flow and tributaries. These threats are devastating fish and fisheries, with fish catches in the Tonle Sap decreasing by 88% from 2003 to 2019 and the economic value of the Mekong fishery estimated to have fallen by a third from 2015 to 2020.
According to the assessment, at least 19 percent of the species are now estimated to be threatened with extinction. Notably, 18 fish species are listed as “critically endangered” by the International Union for Conservation of Nature (IUCN), including the world’s largest carp, the world’s two largest catfish species, and a giant freshwater stingray. However, a shocking 38 percent of species are considered “Data Deficient,” meaning there is too little information to assess their conservation status, so the true number of threatened species is likely to be much higher.
Yet the Mekong’s fish continue to be dramatically underestimated by decision makers, and hydropower development continues apace. Dams fragment the Mekong River, alter water quality, and block fish migrations.
The upper Mekong (Lancang River) in China’s Yunnan Province has been planned for a cascade of dams since the 1980s, with 25 planned dams on the mainstream with a combined installed capacity of 25,870 MW and 120 hydropower stations on tributaries with a combined installed capacity of 2,600 MW. Currently, eight large dams are operating or under construction on the Lancang River. In addition, Laos is planning to develop 23 hydropower dams, including the large Ban Koun Dam with an installed capacity of 2000 MW. Thailand has plans to revive the construction of dams on the Mekong, with a planned combined capacity of 4,000 MW, in addition to the two existing dams, the Pak Mun Dam, the second dam downstream from the Khone Falls, and the Pak Chom Dam, immediately upstream of the Khone Falls. Cambodia is also planning two dams, the Sambor and Stung Treng dams, with a combined capacity of 3,600 MW.
Dams in China and reservoirs in Thailand, Laos, and Cambodia have slowed the natural flow of the river, causing large amounts of sediment to be deposited in the reservoirs, changing the river’s dynamics and causing erosion downstream; the dams block migratory fish from completing their reproductive cycles and also change the river’s nutrient and plankton content, affecting the reproduction and growth of fish species and negatively impacting the livelihoods of riverside communities. Notably, sediment from China’s upper Mekong accounts for about 40% of the Mekong’s total sediment load. Meanwhile, people in the Mekong Delta annually await the arrival of floodwaters (also known as the floating season) to exploit aquatic resources, clean their fields, and collect fertile sediment. In the provinces along the Vietnam-Cambodia border alone, the annual floating season generates approximately VND4,500 billion in revenue.
Consequences of Ecosystem Decline
Lan Mercado, WWF-Asia Pacific’s Regional Director, sounded a dire warning, emphasizing the urgent need for action to reverse the alarming trend. “The alarming decline in Mekong fish populations is an urgent wake-up call to act to save these iconic and critically important species that underpin not only the social and economic fabric of the region, but also the health of the Mekong’s freshwater ecosystem,” said Mercado.
The report also warns that the loss of fish could exacerbate deforestation in the region as millions of people who previously relied on the river for their livelihoods are forced to turn to farming. “We are clearly risking a new biodiversity crisis for the Mekong basin. But it is not too late!” said Herman Wanningen, Executive Director of the World Fish Migration Foundation.
Urgent Collective Action Needed
Zeb Hogan, fish biologist and leader of the Wonders of the Mekong team, one of the teams that produced the report, said that it is “not too late” for countries in the region to work together to reverse the detrimental impacts on Mekong fish populations. “If we act, and act collectively to develop the river sustainably, there is still hope,” said Hogan.
The report’s recommendations call for Mekong nations to protect and restore the river’s ecosystems and to commit to the Freshwater Challenge (FWC) – an initiative aiming to support, connect, and accelerate the restoration of 300,000 km of degraded rivers and 350 million hectares of degraded wetlands by 2030, and to conserve intact freshwater ecosystems. So far, 46 countries are understood to have joined the initiative.
Urgent action is needed by all countries through which the Mekong flows to reverse these alarming trends. Alongside protecting and restoring freshwater ecosystems, Mekong countries need to implement the 6-Pillar Action Plan for Emergency Recovery of Freshwater Biodiversity. This comprehensive plan – which includes allowing rivers to flow more naturally, improving water quality and ending unsustainable resource extraction – can deliver solutions at the scale needed to reverse the declines in Mekong fish populations. It is essential that fishers and local communities, who possess knowledge, expertise and solutions – such as Community Fish Conservation Areas – that have been proven to work successfully, are enabled to help secure the fish and their river. But local communities cannot protect the entire Mekong by themselves – decision-makers need to factor Mekong fish into their decisions and scale up effective actions to restore the health of the river and the precious life it supports.
In Viet Nam, according to Professor Tran Thanh Van, President of Vietnam’s Science and Technology Association, Viet Nam is heavily impacted by climate change, particularly in coastal areas.Salinization and droughts have strongly affected agriculture and aquaculture, especially in the Mekong River Delta. Viet Nam needs to strengthen environmental management and effectively protect ecosystems to minimize the impacts of pollution and stop the degradation of habitats and ecosystems, while ensuring sustainable development of the Mekong River Delta.
(Source: https://tongcucthuysan.gov.vn/)