With its rich and diverse ecosystem, Cambodia's Tonle Sap Lake is often described as the beating heart of the country, supporting the livelihoods of more than one million people and attracting visitors from across the region.
Factors such as climate change and man-made pressures are contaminating the lake, resulting in a big reduction in fish stocks and lower water levels.
Earlier this year, the Global Nature Fund designated it as the world's most "threatened" for 2016.
"In recent years, the water volume continuously declined with negative impacts on fish migration and the import of sediments," GNF said in a statement.
For many years, the fisherman have earned a living from the lake's waters, which spread across 16,000 sq km. Many fisherman have had to look for work as other positions such as taxi drivers and other laborers.
The lake is vital for the region, and for a part of the population it is their only option to survive.
If the current situation continues, many may have to find other ways to earn a living.