Mekong’s Freshwater Giants Face a Rapid Decline

The Mekong River has long supported the world’s largest freshwater fish, a result of its vast size, high productivity, and seasonal flood pulses that provide abundant food and habitat. In 2022, a giant freshwater stingray weighing 661 pounds was caught and released in northern Cambodia, setting a record for the largest freshwater fish ever documented. Older fishers recall that in the early 1980s, massive catches of striped catfish and Mekong giant catfish were routine, with some single nets hauling dozens of adult giants.

National Geographic

Since the 1990s, a series of upstream interventions have altered the river’s natural dynamics. China’s cascade of dams on the Upper Mekong, expanding hydropower projects in Laos, and intensified sand mining have disrupted the flood pulse that migratory fish rely on for spawning and feeding. Overfishing compounded these pressures, leading to fewer giant specimens and occasional catches of oversized fish that made consumers ill.

National Geographic

The cumulative impact threatens both biodiversity and regional food security, prompting calls for more sustainable river management and protection of critical habitats.

National Geographic

• “If you’re looking for the planet’s freshwater giants, you look to the Mekong,” — Hogan. In

National Geographic

• “The Mekong is a system that has been engineered in ways that work against fish, and against the tens of millions of people who depend on them for food,” — Brian Eyler

National Geographic