By Rafael Guererro III

The Tonle Sap (“Great Lake”) is the biggest and most productive lake in Southeast Asia located in Cambodia. The lake has an area of 250,000 hectares, depth of 1-10 meters and surface elevation of 0.5 meter. It is connected to the Mekong River through the 120-kilometer long Tonle Sap River. In the dry season, the lake serves as a reservoir of the Mekong River (traversing Cambodia, Thailand and Vietnam) with the backflow of the Tonle Sap River; during the wet season, however, it regulates the floodwater downstream.

The Tonle Sap has one of the richest inland fisheries in the world. It provides most of the 400,000 metric tons (mt) of fish produced in Cambodia and contributes 16% to the GDP (gross domestic product) annually. There are an estimated 1.2 million people, most of whom are poor, who are dependent on the lake for their food and livelihood. With a population of about 15 million, fish consumption in Cambodia is 52 kilos per capita.

The lake is inhabited by 149 species of fish, 11 of which are threatened and six are near-threatened. The Mekong giant catfish (Pangasianodon gigas), one of the largest freshwater fish in the world that can grow as long as three meters, is found in it. Declared as a Biosphere Reserve by a Royal Decree in 2001, the Tonle Sap has been identified by the UNESCO as an Ecological Hotspot.

A fish cage used in the Tonle Sap.

An interesting species of reptile present in the Tonle Sap is the freshwater Siamese crocodile (Crocodylus siamensis) which is native to Asia. Due to overfishing, the reptile almost disappeared in the wild in 1996. Through farming, the crocodile is now abundant again and is providing a source of livelihood and income for those who produce crocodile leather goods.

The fishermen in Tonle Sap use various gears for fishing. One such gear is the cone-shaped net that can catch as much as 2-3 tons of fish per day. Eighty percent of the fishes caught in the lake are small in size. The large fishes are sold whole in boxes with ice in wet markets for cooking in households or grilled in fast-food restaurants. The small fishes are salted or dried under the sun for preservation. The fishes are also processed into fish sauce locally known as “prahok.”

When we visited the Tonle Sap recently, we found out that the Nile tilapia and red tilapia are grown in cages with commercial pellet feeding.

The red tilapia is cultured to a size of one kilo each in eight months and served in high-end seafood restaurants as “red fish.”

Despite government regulations and protection, there is rampant illegal fishing in the Tonle Sap that is typical of developing countries (including the Philippines) with an “open access fishing policy.” As a result, the fisheries of the lake declined from 347,000 metric tons in 1940 to 116,000mt in 2008. The Cambodian government through its Ministry of Agriculture, Forestry and Fisheries has taken measures to alleviate the poverty of the subsistence fisherfolk and to promote sustainable fishing and aquaculture practices.

This appeared in Agriculture Monthly’s August 2018 issue.