Khone Phapheng, Laos - For generations, Kampei Samneang's ancestors have walked on a homemade highwire that spans the largest waterfall in Southeast Asia.
In their search for enough fish to feed their children, they have been the only family that has ever dared to cross the slippery line over to a small island, just centimetres above the roaring waves.
Here, the fish are plentiful. "My father taught me how to do this; he was a very talented fisherman, and my grandfather showed me how to make the net. Now I am showing my children," Kampei said, sitting at the edge of the waterfalls before getting on the highwire.
A homemade fishing net is all he can carry with him. Any more weight, Kampei explained, would likely cause him to fall into the vast rapids underneath. "It's important that I am scared. I have crossed so many times, but if I lose my fear, I will fall and die," said the 50-year-old man, clad in yellow rubber flip-flops.
Other fishermen don't dare to cross and stay closer to the riverbank instead. They admire him for his bravery, Kampei said. "There are many fishermen here, so I have to go to the islands in the middle of the waterfalls to catch enough."
Soon, however, the construction of the 30-metre-high, 256-megawatt Don Sahong Dam - scheduled to be completed in 2018 - might leave the fishermen's nets empty. Scientists and environmentalists say the dam will not only affect fisheries within its vicinity, but also put at risk the integrity of the entire Lower Mainstream Mekong River.
It will be better because the dam will make it possible for more fish to swim up and down, and that has been proven by our consultants and experts.
Worldwide, the Mekong River ranks second in fish diversity after the Amazon, with more than 1,000 new plant and fish species discovered in the past decade, according to the World Fish Center. About 60 million people in Thailand, Laos, Vietnam and Cambodia are dependent on the Mekong for their livelihoods, according to the World Wildlife Fund.
"The Don Sahong [Dam] ... will block migratory fish, which is 70 percent of Mekong fish, from swimming upstream and down on the only channel that allows the fish to reach the upper part of the Mekong," said Ame Trandem, the Southeast Asia programme director at advocacy group International Rivers.
She said the dam, which will require 95,000 truckloads of riverbed to be removed, will devastate the region's fish and dolphins, the tourism industry, and the hundreds of thousands of fishermen whose livelihoods depend on the Mekong .
Chhit Sam Ath, executive director of NGO Forum Cambodia, has advocated against building the Don Sahong and other dams planned on the Lower Mekong.
"If the Don Sahong is built, it will have a huge, negative impact on the fish of the Lower Mekong Basin. We expect a huge difference for the fish migration and the number of fish, because the flow of the river will be blocked," he said.
Mega First Corporation Berhad, the Malaysian company in charge of building the dam, has dismissed these concerns, saying there are other channels the fish can use to migrate. Yeong Chee Neng, director of the Don Sahong project, said the dam would improve local livelihoods and fisheries, as shown by an environmental impact assessment that he said he could not share with the public.
"It will be better because the dam will make it possible for more fish to swim up and down, and that has been proven by our consultants and experts," Chee Neng said. He explained that traditional fish traps will be banned, and that a new fish passage will be built to allow them to bypass the dam.
However, scientists and fisheries experts are concerned over what they say is lack of evidence that fish would migrate through new channels. In an open letter penned in 2007, 34 scientists from universities around the globe warned the damage from building the dam would "far exceed the net returns from the project", and that it was not in the best interest of the region's people.
The extinction of the sensitive Irrawaddy dolphin as well as the critically endangered Giant Mekong Catfish are almost certain, Trandem said - and the Khone Phaphen Falls, now one of the region's major tourist attractions, would likely be left with less water.
Although the $3.8m Xayaburi dam in upper Laos, which is already under construction and will produce 1,285 megawatts, is much bigger, the Don Sahong will cause more damage because of its location at a critical point for fish migration, Trandem said.
'A lot of money'
Other possibilities for the dam have not been explored, said Ian Baird, an assistant professor of geography at the University of Wisconsin-Madison, who helped coordinate the scientists' open letter and has researched the Don Sahong extensively. He said the dam was sited on the Hou Sahong channel because when the project was first planned in the 1990s, researchers were still unaware of the channel's vital role for the ecosystem.
|Fishermen in Laos are worried about their livelihoods EPA]
"Once the Malaysian company had invested a lot of money in investigating the project and preparing engineering designs, they learned during the [environmental impact assessment] that the channel was vital for fish migrations.
"But by then [they] didn't want to change their plans, since they had already invested a lot of money," Baird said.
Chee Neng said Mega First had been working on the plans for the dam for more than eight years, and he did not understand critics' complaints.
"If we wouldn't know what we are doing, we wouldn't do it. We wouldn't do anything that is not good for the people. I am a God-fearing person, and I have to answer to my God as well," he said.
As for fishermen such as Kampei, who have lived on their traditional fishing methods for generations, they were unaware of the possible danger to their livelihoods that the dam could bring.
Despite the threat from the dam, Kampei said he expects his children will follow in his footsteps. "If I don't teach my sons how to fish, how will they be able to support for their families?"