Cambodia’s Ministry of Agriculture, Forestry and Fisheries plans to expand fish pass monitoring to a third demonstration site on a major tributary of Tonle Sap Lake, Southeast Asia’s largest lake . As part of the Lower Mekong Fish Passage Initiative with the Ministry of Water Resources and Meteorology and the Ministry of Mines and Energy, the Inland Fisheries Research and Development Institute (IFReDI) has already monitored two fish passes on the irrigation barriers to fish migration on the Pursat River. in western Cambodia.
One of the fish passes is located on the Kbal Hong weir in Pursat town, nearly 30 km upstream from where the river enters the lake. Considered by the Mekong River Commission (MRC) to be one of the most efficient fish passes in the Mekong region, it was built as part of a Cambodian government partnership with the Australian Center for International Agricultural Research (ACIAR), the US Department of the Interior and the MRC. The second, located about 20 km upstream from the provincial town, was built under a separate partnership with the Japan International Cooperation Agency.
A nine-member team from IFReDI – part of the Cambodian Fisheries Administration – has been monitoring fish at the two demonstration sites for some years. Morning sampling at the Kbal Hong weir during the Catch and Culture – Environment visit in early November, for example, identified 16 species migrating upstream from the lake. These included slender horsehead loaches (Acantopsis ioa), red-tailed tin-leaf loaches (Barbonymus altus), silverbarbs (Barbonymus gonionotus), red-tailed loaches (Yasuhikotakia modesta), and skunk loaches (Yasuhikotakia morleti). In 2019, with monitoring funding from the U.S. Department of the Interior, IFReDI recorded 119 species using the fishway.
The team now hopes to expand this monitoring to a third site more than 50km upstream from town in the remote Veal Veng district where the Asian Development Bank (AfDB) completed construction of a dam last year. in the context of flood and drought. mitigation project. IFReDI Deputy Director Tob Chann Aun – the leader of the monitoring team who is also vice-chairman of an inter-ministerial technical working group on the Lower Mekong Fish Passage initiative – said that he hoped to start sampling at the new fishway in a few months.
With over 100 species of fish, the Pursat River is Cambodia’s priority watershed according to MRC guidelines on fish passage barriers and fish-friendly irrigation structures (others are the Nam Pa tributary in Laos, the Nam Kam tributary in Thailand and the Mekong Delta in Vietnam). Published in 2014, the guidelines note that the thousands of barriers to fish migration in the Lower Mekong are a “huge problem” for local fisheries and that the rehabilitation of many of these barriers is “desperately needed”. The guidelines – which are being updated in partnership with ACIAR and the US Department of the Interior – emphasize the importance of monitoring fishways in consultation with design team biologists.
The AfDB has published a report on fish passes for small-scale irrigation in Laos. “Despite the important role that inland fisheries play in human nutrition and rural income generation, ensuring the movement of fish in the design of irrigation infrastructure projects is often overlooked,” he says. But “with increasing investments in irrigation infrastructure and modernization, it is essential to reconcile irrigation and fisheries programs”.
The report notes that the AfDB’s strategy for 2030 emphasizes food security, poverty reduction and climate resilience. “Continued fish productivity is essential to achieving all of these goals,” the bank says. “The AfDB should therefore ensure that its infrastructure projects pose no threat to the already dwindling fish population and ultimately to food security. Ideally, in new AfDB infrastructure projects, construction of an effective fishway should be required and retrofitting of existing structures to incorporate fishways should be explored. »
According to the report, which was released in 2020, AfDB’s work with Lao engineers and fisheries experts from the National University of Laos and Charles Sturt University in Australia proved that the integration of passes in existing weirs was “effective in ensuring a functional and inexpensive measure”. to ensure fish productivity. In addition, the Lao experience of designing and constructing fishways “provided the empirical evidence needed to expand investment in fishways to other AfDB irrigation investment projects” .
The report concludes that fishway research is best achieved through ‘adaptive management’ which generates knowledge to build institutional and individual capacity, which is then translated into governance, policy and practice. “In strong adaptive management frameworks, research informs the changing development agenda as new knowledge is generated to make sound development decisions.”
IFReDI and the National University of Laos are among local partners in a four-year ACIAR project launched in 2020 to translate fish passage research and findings into government policies and legislation in Cambodia and Laos, as well as than in Indonesia and Myanmar. One of the objectives of the project is to understand why developers decide whether or not to include fish passes in irrigation projects. ACIAR says it also aims to fill the “critical knowledge gaps” needed to demonstrate proof of concept. “The fish passes have helped restore fishing in the Mekong,” says Dr Ann Fleming, head of fisheries research at the Australian centre. “And with that, we have also improved the food and nutrition security of people living in these areas.” AKP-Sao Da