Asia Life

Xayaburi Dam Threatens Mekong River’s Giant Catfish

The Xayaburi Dam poses a problem for the Mekong River’s fish and the people living beside it.

The giant catfish is a singular creature. Found swimming in the Mekong River, the beast can weigh as much as 650 pounds and grow up to ten feet long, dwarfing a grown man. A member of the shark catfish family, found throughout Asia, it is not surprising to learn that it is the largest, scale-less freshwater fish in the world.

It is an herbivore that subsists primarily by gulping massive quantities of algae and other waterborne bits. It is light-gray with a white or yellowish underbelly and has a gaping, toothless mouth and eyes that gaze downward. Propelled by its massive tailfin, it is referred to as an “underwater steam train” due to its impressive stamina and power. But its time may be up, according to a study by the World Wildlife Fund (WWF): the giant catfish now faces extinction because of the Xayaburi Dam.

In the past 20 years giant catfish numbers have dropped by around 90 percent to just a few hundred scattered throughout the lower Mekong. Regional governments – Laos, Burma, Thailand, Cambodia and Vietnam – have helped numbers bounce back a bit by protecting it from being fished from the river’s murky depths. But the dam may pose an insurmountable obstacle – literally – to the great fish.

Namely, the Xayaburi project is blocking the behemoth from swimming upstream – a necessary part of its lifecycle – and is wreaking havoc on the fish’s spawning and breeding grounds. There is discussion about the possibility of building “fish passages” into the dam so fish can swim upriver, past the structure’s turbines. However, for creatures as large as the giant catfish – which can grow to roughly the size of a small economy car – that may not be enough.

“You can’t expect fish ladders to work without understanding your target species, their swimming capabilities, and the water current that will attract these fish toward the pass entrance,” said Eric Baran of the World Fish Centre. “Research is still needed to ensure mitigation efforts will work.”

In other words, overfishing dealt the largest blow in the bigger picture, but being overly hasty to build the dam could be the species’ coup de grace.

“The Giant Catfish is endangered, but there’s still a chance for it, and all the countries involved have gotten on board to restrict fishing – but just when we solved one problem we’re now facing this new one,” Zeb Hogan, associate research professor at the University of Nevada, told The Christian Science Monitor.

Flickr (3059349393)As the newspaper notes, the giant catfish is in fact one of anywhere between 23 and 100 species of fish in the river (other giants of the region can be seen here) for which the migration routes will be thwarted by the dam. According to a report compiled in 2011 by a body of experts working for the Mekong River Commission, a ten-year delay on the project was in order to gather more information about how the hulking concrete structure would alter the river’s ecological balance.

“The Mekong giant catfish sym­bolizes the ecological integrity of the Mekong River because the species is so vulnerable to fishing pressure and changes in the river environment,” Lifeng Li, director of the WWF’s global freshwater program, said in a statement.

Amid controversy, the Laotian government decided to begin construction of the $3.5 billion dam last November, which is expected to take seven years to complete. Calling off the dam project is no simple matter. Laos plans to sell some 90 percent of the energy produced by the 1.26 gigawatt-hydropower dam to neighboring countries – money that the fledgling economy needs.

Nonetheless, the ecological impact is undeniable and the giant catfish’s fate is only the beginning of the problems it poses to the river. The Mekong River is the richest river basin on Earth in terms of fish biodiversity, with more than 1,100 species living within its depths.

Ultimately this extends to the fishing villages along its banks, along which some 60 million villagers live and fish. Estimates suggest that the livelihoods of as many as 200,000 people will be directly affected by the project, which will also impact food security for millions more in the broader region.

“The Mekong is incredibly important to people’s livelihoods,” Dr. Hogan said. “It’s important not to make decisions about the Mekong lightly.”