Dams could signal end for giant catfish
BANGKOK (VNS)- Damming the mainstream of the lower Mekong River will represent a significant new threat to the survival of the Mekong giant catfish, one of the world's largest and rarest freshwater fishes, according to a new study commissioned by the World Wide Fund for Nature. The study sheds new light on the status of this elusive species, including data on its numbers, distribution, threats, and measures needed to prevent its disappearance. While the exact population size is unknown, there could be as few as a couple of hundred adult According to the study, the Xayaburi dam in northern "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," said the study's author and associate research professor at the "These river titans need large, uninterrupted stretches of water to migrate, and specific water quality and flow conditions to move through their life cycles of spawning, eating, and breeding." Numbers are already in steep decline due to overfishing, habitat destruction, and dams along the In the The study claims that the controversial Xayaburi dam could disrupt and even block spawning, and increase mortality if the fish pass through dam turbines. "It is likely the Regional countries agreed at a Mekong River Commission meeting in 2011 to delay a decision on building the Xayaburi dam pending further studies on its environmental impacts. Puyry, the Finnish firm advising "You cannot 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," Dr Eric Baran of the World Fish Centre said. "Research is still needed to ensure mitigation efforts will work." Mekong giant catfish were once widely distributed through the Mekong river basin, possibly as far as Their numbers have since plummeted and the species is now limited to the Mekong and its tributaries in Catch figures also offer sobering evidence of the decline, with numbers dropping from thousands of fish in the late 1880s, to dozens in the 1990s, and only a few in recent times. Despite laws being in place in "Catches should be monitored to ensure that "Incidental catch should also be monitored since it is the only source of information about the distribution, life history, and abundance of this river giant." The study identifies key measures to prevent the fish's disappearance, like immediate efforts to safeguard migratory corridors and critical habitat, and increased international cooperation since the species occurs in an international river and crosses country borders to complete its life cycle. "The Mekong giant catfish symbolises the ecological integrity of the |
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Environment
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