(TibetanReview.net, Mar07’24) – Unsustainable development, especially proliferating hydropower dams in the upriver Tibetan Plateau region, threatens the health and diverse fish populations of the Mekong river, with one-fifth of fish species in Southeast Asia’s main artery facing extinction, reported the scmp.com Mar 4, citing a report by conservation groups.
The Mekong rises as the Zachu in Tibet, originating in the “three rivers source area” on the Tibetan Plateau in the Sanjiangyuan National Nature Reserve, and becomes known as the Lancang River in the upper half of its flow in China.
Stretching nearly 5,000km (3,000 miles) from the Tibetan Plateau to the South China Sea, it is a farming and fishing lifeline for tens of millions of people in China, Laos, Myanmar, Thailand, Cambodia and Vietnam, the report noted.
Citing a report compiled by the WWF and 25 global marine and wildlife conservation groups, the report said threats to the river’s fish include habitat loss, conversion of wetlands for agriculture and aquaculture, unsustainable sand mining, introduction of invasive species, worsening climate change and hydropower dams fragmenting the flow of the river and its tributaries.
However, “the biggest threat right now, and a threat that’s still potentially gaining momentum, is hydropower development,” fish biologist Zeb Hogan, who heads the USAID-partnered Wonders of the Mekong, one of the groups behind the report, titled as “The Mekong’s Forgotten Fishes”, has said.
Dams alter the flow of the world’s third-most biodiverse river, change water quality and block fish migration, he has said.
Proliferating Chinese-built hydroelectric dams upriver have blocked much of the sediment that provides essential nutrients to tens of thousands of farms in the Mekong River Delta, the report said, citing a Reuters report in 2022.
Some 19% of the 1,148 or more fish species in the Mekong are heading towards extinction, the conservationists’ report has said, adding that the number may be higher as too little is known about 38% of the species to gauge their conservation status.
Among those facing extinction are stated to be 18 species listed as “critically endangered” by the International Union for Conservation of Nature, including two of the world’s largest catfish, the world’s largest carp and the giant freshwater stingray.
“Some of the largest and rarest fish … anywhere on earth occur on the Mekong River,” Hogan has said.
The report makes it clear that the economic and other costs of not acting on the worsening situation could be devastating. Fish depletion in the Mekong – which accounts for more than 15% of the world inland catch, generating over US$11 billion annually – could harm food security for at least 40 million people in the Lower Mekong basin whose livelihood depends on the river, the report was cited as saying.