Tonle Sap

Tonle Sap in the dry seasonThe remarkable Tonle Sap is a river that becomes a freshwater lake in the centre of Cambodia, the largest in Southeast Asia, and then flows down to join the Mekong River just past Phnom Penh. During the dry season, the river feeds the lake and continues to flow downriver.

When the monsoon breaks in June, the flow reverses as the Mekong floods and forces enormous quantities of water uphill into the lake, swelling it to five times its size and thus acting as a gigantic natural reservoir.

Tonle Sap at the end of the wet seasonThis unique natural phenomenon reduces the force of the torrent rushing towards the sea, and is a major factor in the steady expansion of the Mekong Delta.

Fish spawn in the newly flushed lake, covering a seventh of the country at its peak. As the waters recede, the lake teems with fish, some of which have evolved to flop across land to follow the disappearing water.

Mangrove swamps ring the lakeThe highly fertile mud left behind is excellent for rice. A unique strain of rice has been developed to suit the conditions – it grows in the rising water reaching a stem length of several metres.

The lake, now a National Park, is a key element in Cambodia's economy. Approximately two-thirds of the protein consumed in Cambodia comes from fish from Tonle Sap.

One of the most endangered species in the world is the Mekong's giant catfish. It’s the world's largest freshwater fish - a mature catfish reaches three An average size Mekong giant catfishmetres in length and averages 300kgs in weight. Last year, a fisherman caught a giant weighing almost 650 pounds - the largest freshwater fish ever recorded.

It appears to migrate out of the Tonle Sap Lake and into the mainstream Mekong River at the end of the rainy season.

The giant catfish are considered sacred by the Thai people, and special ceremonies are performed to seek permission from the Water Spirits and other higher beings to capture these sacred ‘Pla Buek’ giants.

The species is now under grave threat. Although over fishing is a problem, the main danger is the construction of dams and, in particular, the Pak Mun dam's impact on the catfish population in the Mekong river basin.

Infant siamese crocodilesA large crocodile farming industry thrives on and around Tonle Sap. The main species is the Siamese crocodile, critically endangered in the wild. The lake also provides a habitat for 13 different species of turtle.

From a tourism point of view, the lake offers an alternative, more leisurely, route from Phnom Penh to Siem Reap and vice-versa - the ‘express’ boat takes around five hours.

This is an option for serious travellers: the boats are often overcrowded and uncomfortable but the views compensate.

One of Ton Le Sap's many floating villagesIn 1997, the entire Lake was designated as a protected area under UNESCO's ‘Man and Biosphere’ programme. There are three ‘core zones’, but the most interesting is the Prek Toal Bird Sanctuary, not far from Battambang.

The best time to visit is the dry season, when the water level falls and the birds are concentrated in a comparatively small area. Apart from large numbers of storks, pelicans and ibis, there are many rare species, such as the Painted Stork, the Darter and the Masked Finfoot.

If you travel with Haivenu, we can arrange a chartered boat trip for you to visit both the bird sanctuary and the floating villages on the lake.

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