KAMPONG PHLUK, Cambodia — Em Phat, 53, studies his eel tanks with the intensity of a man gambling with his livelihood.
For millennia, fishermen like him have relied on the bounty of the Tonle Sap in Cambodia, Southeast Asia's largest lake and the epicenter of the world's most productive inland fishery. But climate change, dams upstream on the Mekong River that sustains the lake, and deforestation in the region have changed everything.
There aren't enough fish and living by the lake has become dangerous as storms intensify due to global warming. ''Being a fisherman is hard,'' he said.
Phat hopes that raising eels — a delicacy in Asian markets like China, Japan and South Korea — will provide a way forward. He raises eels in different tanks: translucent eel eggs bob gently in Small glass aquariums. Voracious glassy larvae swim in plastic tanks. Larger tubs have bicycle tires to provide places for juvenile eels to hide.
Raising eels can be profitable but it's risky. Eels are notoriously difficult and expensive to raise. They need constant pure, oxygenated water and special food and are susceptible to diseases. Phat lost many eels when a power cut stopped his oxygen pumps, killing the fish. But he's optimistic about the future. Living on land, instead of on the lake, also means that his wife, Luy Nga, 52, can grow vegetables to eat and sell, so they are making enough money to get by.
''The eels have value and can also be exported to China and other countries in the future,'' he said.
That fishermen like Phat can no longer rely on the Tonle Sap, literally the ''Great Lake,'' for their livelihood reflects how much has changed. The lake used to more than quadruple in size to an area larger than the country of Qatar during the rainy season, inundating native forests and creating the perfect breeding ground for diverse fish to thrive.
The "flood pulse,'' a natural process of periodic flooding and droughts in the river system helped make the Mekong Basin the world's largest freshwater fishery, with nearly 20% of all freshwater fish worldwide caught there, according to the think tank Stimson Center in Washington. More than 3 million people live and fish by the lake: a third of all 17 million Cambodians rely on the fisheries sector and up to 70% of Cambodia's intake of animal protein is from fish.