AILSA CHANG, HOST:
Southeast Asia's largest lake is under threat, and with it, an entire ecosystem. Dams, overfishing and this year, drought, have brought the Cambodian lake to what may be a breaking point. Michael Sullivan reports.
MICHAEL SULLIVAN, BYLINE: They partied at Cambodia's annual water festival in Phnom Penh this week. Next year's celebration may be more subdued. A devastating drought this year left the Mekong River at its lowest level in recorded history. And as the Mekong goes, so goes the Tonle Sap. And the fishermen there are already feeling it.
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SULLIVAN: It's just after daybreak in the village of Chhnok Tru at the bottom of the Tonle Sap Lake, where fishermen bring their catch to brokers waiting at the water's edge.
KHOUT PHANY: (Foreign language spoken).
SULLIVAN: Broker Khout Phany clutches a thick wad of Cambodian bank notes as she barks at her underlings and weighs the fishermen's catches. She says business is down nearly 70%.
PHANY: (Through interpreter) Last year, when the fishermen came, they'd have 10 to 20 pounds of fish to sell. This year, they're only bringing two or three pounds.
SULLIVAN: Fewer fishermen, fewer fish and smaller fish, she says, and less variety, too.
One of the fishermen, 31-year-old Sam Sokeng, says he spent two nights on the water. But his meager catch, he says, means he'll be lucky to break even.
SAM SOKENG: (Through interpreter) Last year, I could earn almost $75 a day. This year, I barely make enough to pay for gas and bait.
SULLIVAN: Another fisherman, Tim Chhoeun, says he and his wife were out all night.
TIM CHHOEUN: (Through interpreter) Last year, I could catch about 20 pounds of fish a day. But today, you see I caught only five.
SULLIVAN: His wife says if things don't get better, she'll have to go work on a Chinese company's cassava plantation to earn enough money to survive. Here's why their stories about fewer fish matter.
BRIAN EYLER: The Tonle Sap is the world's largest inland fishery, hands down. And it's the beating heart of the Mekong.
SULLIVAN: Brian Eyler is the Southeast Asia director at the Stimson Center and author of the new book "Last Days Of The Mighty Mekong."
EYLER: It's the miracle of the Mekong that produces 500,000 tons of fish each year for the people of Cambodia and then translates into 2.6 million tons of fish caught throughout the rest of the Mekong Basin.
SULLIVAN: That amazing productivity is due to a unique phenomenon that occurs each year when the seasonal monsoon swells the Mekong River so much it pushes water into the Tonle Sap River, causing it to reverse course and fill the lake to five times its dry-season size.
EYLER: And not only brings in a lot of water but massive amounts of sediment go in that forms the basis of a food web to feed the massive amount of fish and fish eggs and fish larvae and adult fish that go into the lake. And they find habitats to thrive.
SULLIVAN: Not just fish, but endangered water birds from all over the world. When the floodwaters recede, the river reverses again, taking the sediment and fish and their eggs back into the Mekong. Normally, this process takes several months. This year, it was over in weeks. For a population that relies on fish for 70% of its protein, that's a huge problem.
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SULLIVAN: And it's a problem that's got many worried. Back at the lakeside village of Chhnok Tru, I meet with 62-year-old Phap Palla, who works with fishermen and local NGOs and has lived here more than 40 years. And this year, she says, is the worst she can remember.
PHAP PALLA: (Through interpreter) Next month should be the height of the fishing season, but the water and the fish are already gone. So what will the fishermen catch?
SULLIVAN: Many, she says, will have to move to the cities or find work abroad as manual laborers to survive. And drought isn't the only threat. Overfishing and dams built on the Mekong by China and Laos upstream are already impeding fish migration and sediment flow downstream, and more are planned. The Tonle Sap, experts warn, is now on the brink and with it, the food security of tens of millions.
For NPR News, I'm Michael Sullivan in Phnom Penh. Transcript provided by NPR, Copyright NPR.