The Tonle Sap, the largest fresh water lake in Southeast Asia, is a combined lake and river system and is of great importance to Cambodia. It is, since 1997, a UNESCO biosphere. Biosphere reserves are sites established by countries and recognized under UNESCO’s Man and the Biosphere Programme (MAB) to promote sustainable development based on local community efforts and sound science.
The flow of the Tonle Sap changes direction twice a year and the lake shrinks and expands dramatically as the seasons change. During the dry season in Cambodia, from November to May, the Tonle Sap drains into the Mekong River at Phnom Pehn. Getting into the rainy season during June, the Tonle Sap raises back up to form the monstrous lake.
The river reaches maximum flow in August and September, as the Mekong River swells massively because of water collected from heavy monsoons in its upstream drainage basin, which runs through five different countries, and from the Himalayas, as the ice atop them begins to melt. Converging with the lake near the capital, Phnom Pehn, the massive amount of water surges back up and onto the Tonle Sap floodplain.
When the Tonle Sap floods, enlarging the lake, the area becomes a prime location for fish to breed. During this time fishing in the area is illegal, so as not to disrupt massive re-population of the many fish species. As the water recedes fishing is again allowed and fishermen install floating houses along half of the river. The other half is left open for navigation.
Actually catching the fish is simple, as you would expect, that is until the water begins to drop. As the water recedes again it naturally carries away with it many thousands of fish. So as to catch as many as possible as this happens, the fishermen set cone-shaped nets off the sides of their floating houses, lifting them back out after only seconds. This method yields 2-3 tonnes of fish each time, sometimes amounting to over 10 thousand tonnes of fish in a single week.
The area is home to many Vietnamese and various Cham communities, living in floating villages around the lake. Over 1 million people living in the greater Tonle Sap area use the waters to make their living by fishing. Cambodia produces 400,000 tonnes of fish per year, the majority of that coming from the Tonle Sap.
The beginning of the dry season is also the beginning of rice season, which is the only source of wealth for peasants. A good harvest will provide enough rice for them to survive for the entire year, but if the floods are too big or too small, rice can become scarce. Because of this uncontrollable instability, many celebrations are held in honor of gods and genies that can influence nature and bring about a good harvest.
At the end of the rice season, villagers celebrate by marching in a procession to the pagoda. This is a chance for everyone to relax after the long labor of the harvest season. As well, it provides an opportunity to have fun and bond with the community. All the villagers wear their nicest clothes, musicians sing and dance, and men take the opportunity to court young women. Upon arrival, believers circle the temple three times and then proceed to present gifts such as clothing, dishes, furniture, and food. These donations, named Kathen by Buddha, provide help for bonzis, who in turn give blessings. This act of donation is essential in accumulating good karma for reincarnation, so eventually to reach Nirvana, or ultimate salvation, as well as for future harvests.