Tri’s house is less than a minute’s walk from the ranger station where he and Cu have their fishing gear checked by park rangers before they enter the park each morning. When they are done fishing, they return to the station to report their catch and have it weighed. They are committed participants in this management system, which helps keep Tram Chim’s natural bounty in balance. Once cleared by the rangers, they head home.
At Tri’s house—a patchwork of wooden beams with gaps that let in the sunshine—his wife Trau hovers over a huge wok that is scratched and burned from years of use. Mud carps sizzle in oil, salt and chili. When Tri hands off his morning’s catch of crabs, she immediately begins cleaning and cooking those as well.
It’s only 10 a.m., but the family has been up for almost six hours, and the belly of their 11-year-old son Khanh is grumbling. In a diet that consists almost entirely of fish and rice, he says, fried snakefish is his favorite food.
It’s a similar picture around town: Every little food stall and restaurant seems to serve fish exclusively, whether it's turned into savory fried patties; used in omelets, soups and stir-fries; or transformed into fish sauce, the region’s ubiquitous condiment.
None of these fish would be in Tram Chim if it weren’t for the park’s connection to the Mekong. The rich alluvial silt that flows downstream forms the basic environment in which fish can grow. A healthy hydrology also nurtures couch grass, sedges and watermeal, as well as small crustaceans, which in turn entice water birds. And the river carries the necessary nutrients to help grow rice at four times the yield that was seen in this region four decades ago.
“If it weren't for the silt from the Mekong, the park wouldn’t be as unique,” says park director Nguyen Van Hung. But Tram Chim’s relationship with the river is also its biggest weakness. Hundreds of miles upstream, Cambodia and Laos, under pressure to develop new energy and economic resources for their people, are building dams on the Mekong and its tributaries. Those dams, which will not only block fish from migrating but keep sediment from flowing downstream, are the “biggest and most significant threat” to the park’s fragile ecosystem, Hung says.
Dams cause changes in “water quality, water quantity and the timing of water flow changes,” he says. “This means, for example, that the flooding season that historically started in July now starts later.” He adds that once the population of any one species—a water plant or crustacean, for instance—diminishes, other species that depend on them could quickly follow.
Dams, however, are only one example of the mounting pressure that the socioeconomic development of the region is having on the ecosystem. In addition to upstream activities like agriculture, deforestation and pollution, which damage both water quality and water quantity downstream, there are the effects of climate change. Scientists have already observed irregular river flows and flooding periods, as well as a reduction in the river-carried sediments and nutrients that refresh Tram Chim and restore the coast of the Mekong Delta. In fact, evidence shows that the delta is actually sinking and shrinking, leading to the infiltration of saltier water farther and farther upstream—and putting Tram Chim in yet another squeeze.
“I am really not sure if we can maintain the same biodiversity or if some species will become extinct,” says Hung. “The water flow really changes the conditions.”