Pursat, Cambodia, 4 March 2020 – The community at Dun Ei, a fishing village 180 kilometers northwest of Phnom Penh, has been making a living through fishing along the Pursat River for generations. In recent years, however, river structures, such as dams and dikes, have been preventing fish from migrating upstream to their spawning and rearing grounds. For most of the year, fish have become scarce along the Pursat, forcing villagers to leave their homes in search of work. Those left behind face difficult livelihood and an uncertain future. 

To address the problem, the Cambodian Government partnered with the U.S. Department of Interior (USDOI), the Australian Center for International Agricultural Research (ACIAR), and the Mekong River Commission (MRC) to install a fish passage. A concrete ladder was constructed at Kbal Hong Dam in the Pursat River, a main tributary of Tonle Sap Lake, Southeast Asia’s largest lake, to provide a route for more than 100 fish species to swim past the 4-metre-high barrier, reopening around 100 km of the river.   

Horm Sovon, a 49-year-old fisher, is among hundreds of villagers to benefit. 

“Before, I could only catch fish three months per year. Now I am catching less fish than before, but there are fish to catch every day,” she said. “I have a stable income now, and I am happy that other villagers both upstream and downstream are also able to catch fish.”

Horn Sovon, 49, from Cambodia’s Pursat Province talks about how her livelihood has changed following the installation of the fish passage.

A solution for the wider Mekong Region

The situation faced by the villagers at Dun Ei is typical of a wider problem affecting communities across the Mekong River Basin. In the Lower Mekong Basin, a total fish catch estimated at 2.3 million tones (USD 11 billion). The sector supports the livelihoods of more than 60 million people.

However, the fisheries sector is threatened by tens of thousands of dams, dikes, weirs, and other water structures that have been built to store water for irrigation. According to the MRC, many of these structures make it difficult for fish to pass, affecting fish reproduction across the region.

Together with pressure from other water resources development projects, such as hydropower dams, increased populations, and exploitative fishing, the MRC Council Study estimated that the net present value (NPV) of the fisheries sector will decline by USD 16.5 million by 2020 and USD 22.6 million by 2040 in all the lower Mekong countries: Cambodia, Lao PDR, Thailand, and Viet Nam.

The Kbal Hong ladder is considered one of the most effective fish passages in the Mekong region and stands as an example of effective regional collaboration.

“This successful case implies that the construction of fish passages in the basin and some of its tributaries is essential,” Dr. An Pich Hatda, MRC Secretariat Chief Executive Officer, said. “Improved fish production will enhance the resilience of the entire ecosystem, benefit local economies and sustained local community livelihoods.”.

A concrete fish ladder in Pursat Kbal Hong Dam is considered as the most well-designed passage in Cambodia, enabling fish to swim pass the dam.


Deputy Director of the Inland Fisheries Research and Development Institute, Tob Chann Aun, attributes its success to the technical support provided by the international partners, and also to the MRC guidelines, which enabled identification of the Kbal Hong Dam as a priority for fish passage construction.

"Kbal Hong fish passage is a unique demonstration site that can be replicated elsewhere in the country or in the region," Mr. Chann Aun said.

The Kbal Hong fish passage will serve as a model for 22 fish passages that have been prioritized by the Cambodian Government along the Pursat River.

Other countries in the Mekong region are also benefiting from this joint effort. Ten barriers in Lao PDR, six in Thailand and three in Viet Nam have been identified for fish passage construction. Installations of fish passage in Lao PDR have been completed while preparations for fish passage construction in Thailand are well underway.

“I believe, through this partnership, we will be able to protect and restore river habitat,” said Mr. Boonsong Sricharoenham, Senior Fisheries Ecology Expert of Thai Department of Fisheries.

Fisheries team monitors fish species migrating through the fish passage in Savannakhet Province, Lao PDR.

The MRC Fish Passage Guidelines

In 2014, the MRC developed guidelines for fish passage installation: “Prioritizing Fish Passage Barriers and Creating Fish Friendly Irrigation Structures”. The guidelines set out best practice for identifying barriers to fish migration and processes for fish passage design, construction, and maintenance. Although the guidelines have proved effective supporting the identification of irrigation schemes in need of fish passages in the four lower Mekong countries, they remain a work in progress. 

“The current guidelines are too broad to be effective,” said Ms. Chamaporn Paiboonvorachat, Agriculture and Irrigation Specialist at the MRC Secretariat. “There are no specific recommendations on design and construction, and the maintenance and monitoring techniques are not practical.” 

An assessment of the guidelines therefore began in 2018 through a partnership with the USDOI and ACIAR. It is slated for completion in September 2020 with publication expected by the end of the year. 

In line with its Strategic Plan for 2016-2020, the MRC will continue to support the four lower Mekong countries to implement the fish passage guidelines, ensuring that the people of the Mekong are able to benefit from one of the region’s most important natural resources. 

Irrigation and agriculture and fisheries sectors are among the MRC’s key water related sectors of support and coordination. Since the 1990s, the MRC has been a major source of information on Mekong inland fisheries. Together with its member countries of the lower Mekong, the MRC strives to improve fisheries management by having fisheries monitoring, sharing technical know-how on fisheries management and raising awareness on the sector’s significance for the Mekong’s environment and its people.