Threat to giant catfish is mounting

A giant catfish on a fisherman’s boat on the Mekong’s Lower Tonle Sap River last October. Photo by Zeb Hogan

    20 June 2013

    By Shane Worrell and Phak Seangly

Hydropower dams on the Lower Mekong River, such as the controversial Xayaburi project in northern Laos, could spell the end for the already critically endangered Mekong giant catfish, a study commissioned by WWF says.

A Mekong Giant, released today, says the existence of the giant catfish – which experts say could number only a couple of hundred adults – is under further threat from the 1,285-megawatt Xayaburi dam, the first of 11 planned for the Lower Mekong’s mainstream.

“Impacts from the dam could conceivably cause the extinction of the species,” the report states.

The study’s author, Zeb Hogan, an associate research professor at the University of Nevada in the US, said the Mekong giant catfish likely uses and spawns in the stretch of river where the $3.5 billion Xayaburi dam is under construction.

The effects of the dam could alter the flow of the river and disrupt the giant catfish’s spawning cues, the report says.

“Mortality is likely if fish pass through dam turbines [and] . . . the cumulative impacts of the dam are a serious threat,” it adds.

Hogan said the Mekong giant catfish, which can grow up to three metres in length and weigh 300 kilograms, needs large, uninterrupted stretches of water in which to migrate.

“A fish the size of a Mekong giant catfish simply will not be able to swim across a large barrier like a dam to reach its spawning grounds upstream,” Hogan said in a statement.

Conservation groups have long expressed serious concerns over the potential effects the Xayaburi and other dams could have on millions of people downstream who rely on various species of fish for food and sediment flow for agriculture.

These same groups condemned Laos when it began building Xayaburi last November, accusing the country of ignoring requests from fellow Mekong River Commission (MRC) members Cambodia and Vietnam to examine potential trans-boundary effects.

Environmental group International Rivers (IR) has said that Cambodia, Vietnam and Thailand have a right to seek compensation for any harm caused by Xayaburi.

The three countries’ governments, however, have remained mostly silent since Laos broke ground at the site – possibly because of their own hydropower interests on the river.

“The governments of Laos, Cambodia, Thailand and Vietnam are planning to build eleven large hydropower dams on the Lower Mekong River,” IR said in a statement in March.  “If built, these dams would destroy the river’s rich biodiversity and threaten the food security of millions of people.”

Te Navuth, secretary-general of government body Cambodian National Mekong Committee (CNMC), said yesterday that he wasn’t aware of WWF’s findings and refused to comment on the Xayaburi.

“The Mekong River Commission has a fisheries program. But I have no comment on the Mekong giant catfish,” he said.

Officials from the Ministry of Agriculture’s fisheries department in Phnom Penh could not be reached, but Sean Kin, fisheries chief in Kratie province, said he had already seen evidence of the fish’s decline.

“[The report] was undertaken by foreign experts,” he said. “I agree with them that building Xayaburi will affect fish.”

Kin added that he had not seen a giant catfish for years.

“Our fishermen rarely see them either. Only a few remain in Kratie.”

Despite the giant catfish already being ravaged by overfishing, destruction of habitat and the construction of dams along the Mekong’s tributaries, it can still be saved, the report says.

“Measures to identify and safeguard Mekong giant catfish migratory corridors and critical habitat are urgently needed,” it states. “The Mekong giant catfish would also benefit from increased international cooperation, including a basin-wide management plan.”

Tim Chamreun, 25, a fisherman on tributaries in Stung Treng province for 10 years, hopes the species survives; he wants to catch a glimpse of one.

“People say how big it is – I want to see it with my own eyes,” he said.

PPP