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Once teeming with fish, the river is now filled with forlorn fisherfolk who say they’re lucky to have catch at all, as more hydropower dams are built up and down the river

Activists say dam operators and the Mekong River Commission must be accountable for the ecological impact, while experts are urging fisheries to turn to solar and wind power

A fisherman checks his net along the Mekong River in the northeastern Thai province of Nong Khai. File photo: AFP


The sight of Thai fishermen forlornly casting their nets, with scant hope of a decent catch from a great river once teeming with fish, reflects the sad decline of the mighty Mekong, now reeling from over-exploitation and the feverish proliferation of hydropower dams.

Laos has two dams on the Mekong River, with seven more scheduled to be constructed. Upstream, in China, 11 dams are currently in operation.

“Our Mekong is dying,” laments environmental expert Dr Chainarong Settachua from Maha Sarakham University in Thailand’s northeastern Isaan region.

The scholar has for years researched the plight of the fishing communities in Nong Khai province and other surrounding Thai provinces. “Our fish losses could be more than 70 per cent (of their previous catch), if we include fish from Mekong tributaries,” he said.

Prayoon Sean-ae, a fisherman in Chiang Khan province, says the situation could get worse, as the Lao government pushes to build the Sanakham dam project, only 2km from the border with Thailand.

The leader of a local fishing group, Prayoon said he feared having a dam “so close, it is under my nose”.

It was a very different story of fish abundance prior to 2010, when there were no dams on the lower Mekong and fewer dams upstream in China.

Then, the mighty Mekong boasted 2.3 million tonnes of fish a year, making the world’s largest inland fisheries, according to data from the Mekong River Commission (MRC), providing food security for 70 million inhabitants of this river basin.

The impact of dams blocking fish migration has resulted in “reductions in fishery production that will affect the nearly 50 million people dependent on Lower Mekong Basin fisheries for food and livelihoods”, according to a 2019 paper.

Villagers buy and sell fish in Pakse Laos in 2015. Photo: Tom Fawthrop

‘Destructive’ impact

In interviews with This Week in Asia, fishermen of Chiang Khan and Nong Khai provinces said they felt they were already losing their livelihoods and way of life.

“We have so few fish to catch now that only 20 out of 100 fishermen are still working in Ban Muang,” said Chaiwat Parakun, the deputy village chief and former fisherman from Ban Muang in Nong Khai province.

In Chiang Khan province, where the Mekong marks the border between Thailand and Laos, fisherman Prayoon Saen-ae claims the main reason they have so few fish dates back to the completion of the Xayaburi dam 314km upstream.

“After the Xayaburi opened its gates (in 2019), we had huge impacts. The erratic ups and downs of the water … created confusion for the fish,” Prayoon said. “Before the dam started, one fisherman could get 10kg of fish a day, but now we are lucky to get 4-5kg a week – and some weeks, nothing.”

The controversial 1,285-megawatt Xayaburi dam completed in 2019 was the first dam built on the lower Mekong. It was funded by Thailand’s four biggest banks and built by Thai corporation CH Karnchang, also known as CK Power in Laos. About 95 per cent of the power it generates is sold to Thailand.

Dr Chainarong points to the Xayaburi dam as the main cause of the depletion of fish stocks in northeast Thailand.

“In the past, fish were plentiful and it was the cheapest protein,” he says. “Now, people in Loei province and other provinces of the northeast are suffering fish scarcity, lack of food security and a poorer diet.”

The Xayaburi Dam on the Mekong River in northern Laos. Photo: Shutterstock

Before it was built, there was fierce opposition against the Xayaburi dam over its Environmental Impact Assessment (EIA) provided by a Thai company, and calls for the project to be cancelled.

The WWF in 2011 warned the Xayaburi project would become “one of the world’s most potentially destructive dams because of the serious impact it will have on fisheries for tens of millions of people”.

CH Karnchang made several amendments to the dam design, adding elaborate fish ladder and a sediment flush technology, in an attempt to project an image of a more environmentally sensitive dam.

A fish ladder is a man-made structure which consists of a series of pools with small steps installed near hydropower dams or other river barriers. Its aim is to enable fish to swim or leap like a salmon up the ladder and bypass the barrier to their normal migration route.

Sediment flushing is required to prevent the build-up of sediment deposits which could block the hydropower which could damage the turbines. It is carried out by periodically opening hydraulic valves installed below the turbine. However, during sediment flushing the water flow to the hydropower turbines is considerably reduced, which lowers the amount of electricity generation.

For many years, organisations including the World Bank, the Asian Development Bank (ADB) and the MRC have argued that fish ladders and sediment flushes can effectively mitigate the environmental damage from dams, and have argued in favour of so-called “good dams” as opposed to bad dams.

A “good dam” has been defined as a hydropower project that has a suitable location site, and engages in stakeholder dialogues where all parties can discuss the EIA and potential mitigation of the environmental impacts. This is incorporated in the MRC consultation process. The ADB cites the Nam Theun 2 dam in Laos as a so-called “good dam”.

The MRC, an intergovernmental body with representation from Cambodia, Laos, Thailand and Vietnam formed in 1995, has a mandate to protect the environment of the river as well as promoting economic development.

In response to questions about fisheries the MRC secretariat accepted there had been a major decrease in fish biodiversity at sites in Laos’ Xayaburi province and Thailand’s Loei province.

Nonetheless, the agency said it did not have any data to “scientifically prove yet, that fish loss or extinction is either directly or indirectly the result of the Xayaburi dam”.

A fisherman in Chiang Khan, northeast Thailand. Photo: Tom Fawthrop

Meanwhile, the credibility of the MRC has come under increasing attack from civil society and environmental charities.

Activist Channarong Wongla takes all claims by Xayaburi dam’s operators about fish ladders with a pinch of salt.

“We laugh about fish ladders. The Xayaburi has fish ladders, but still we lose most of our fish,” said Channarong, who has a degree in hydropower dam design and works in Chiang Khan with the Thai group, People’s Network of the 8 Mekong Provinces.

“We used to have more than 100 different fish species but since the Xayaburi dam started operations, now only 20 species remain. It is a 100 per cent certainty that fish mitigation does not work.”

Before 2018, fish stocks were abundant in the Mekong in southern Laos. Photo: Tom Fawthrop

At a recent MRC-organised forum, Cowx pointed out that “experience from the rest of the world shows that fish passage mechanisms don’t work with large dams on tropical rivers”.

Two more dam projects are scheduled to go ahead in 2022 based on a decision by the Ministry of Energy to buy electricity from the Pak Lay and Luang Prabang dams Ngos in three MRC countries Cambodia Thailand and Vietnam have all called for these dams to be suspended.

When asked if the MRC would consider the policy option of calling for a moratorium on dam-building, the Vientiane-based secretariat responded: “Our efforts are much better spent on exploring ways we can avoid, minimise, and mitigate the impacts of developments.”

Speaking at the MRC-organised forum on June 27, fisheries expert Simon Funge-Smith from the UN Food and Agriculture Organisation regional office, observed that many large tropical rivers in the world had lost significant amounts of their fisheries.

A study published in the PNAS journal in 2020 showed that dams along the Amazon, Niger, Congo and the Mekong had been the primary cause of fish reduction by 25 per cent or more.

“Things must not go the same way. We must ensure it is not inevitable that the Mekong will go the same way whereby water development planning and policy does not take fisheries into account,” he said.

But current water development and planning only appears to offer a marginal space in the wider scheme of water resources management, where dams and irrigation usually occupy top billing.

The Mekong River Commission in Vientiane. Photo: Tom Fawthrop

In the same vein, Cowx stressed it was important “to maintain (fisheries), and to elevate fisheries in decision-making on water resources and energy and look for better alternative energy mixes” than hydropower, such as solar and wind power.

Fisheries in the four member countries were estimated by the MRC in 2015 to be valued at US$11 billion, or US$17 billion including fish farms.

If the MRC were to follow the advice from the fishery experts, they would be obliged to discard their well-worn mantra of sustainable hydropower, given the growing consensus that large dams on tropical rivers around the world have failed to demonstrate any sustainability for fisheries.

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