AKP Phnom Penh, Cambodia’s Ministry of Agriculture, Forestry and Fisheries is considering plans to extend fish-pass monitoring to a third demonstration site on a major tributary of the Tonle Sap Lake, the largest lake in Southeast Asia. Under 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 been monitoring two fish passes on 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, almost 30 km upstream from where the river flows into the lake. Considered by the Mekong River Commission (MRC) as one of the most effective fish passes in the Mekong region, it was built under a Cambodian government partnership with the Australian Centre 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 a couple of years. Morning sampling at the Kbal Hong Weir when Catch and Culture – Environment visited in early November, for example, identified 16 species migrating upstream from the lake. These included slender horseface loaches (Acantopsis ioa), red-tail tinfoils (Barbonymus altus), silver barbs (Barbonymus gonionotus), red-tail loaches (Yasuhikotakia modesta) and skunk loaches (Yasuhikotakia morleti). In 2019, with funding for monitoring from the US Department of the Interior, IFReDI recorded 119 species using the fish pass.
The team now hopes to extend such monitoring to a third site more than 50 km upstream from the town in the remote district of Veal Veng where the Asian Development Bank (ADB) completed the construction of a dam last year as part of a flood and drought mitigation project. IFReDI Deputy Director Tob Chann Aun – the monitoring team leader who also serves as deputy chair of an inter-ministerial Technical Working Group on the Lower Mekong Fish Passage Initiative – said he hoped to start sampling at the new fish pass in a few months.
With more than 100 fish species, the Pursat River is Cambodia’s priority catchment under 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 rehabilitating many of these barriers is “desperately needed”. The guidelines – which are being updated in partnership with ACIAR and the US Department of the Interior – highlight the importance of monitoring fish passes in consultation with design team biologists.
The ADB has meanwhile published a report on fish passes for small-scale irrigation in Laos. “Despite the important role that inland fisheries play in the hu-man diet and rural income generation, ensuring fish movement in the design of irrigation infrastructure projects is often overlooked,” it says. But “with growing investments in irrigation infrastructure and modernisation, it is critical to reconcile irrigation and fisheries agendas.”
The report notes that the ADB’s strategy for 2030 emphasises food security, poverty reduction, and climate resiliency. “Continuity of fish productivity is essential in reaching all these goals,” the bank says. “ADB should, therefore, ensure that its infrastructure projects pose no threat to the already diminishing fish population and, ultimately, to food security. Ideally, in new ADB infrastructure projects, effective fishway construction should be required, and retrofitting of existing structures to incorporate fishways should be explored.”
According to the report, which was published in 2020, ADB work with Lao engineers and fishery experts from the National University of Laos and Charles Sturt University in Australia proved that integrating fishways into existing weirs was “effective in ensuring a functional, low-cost measure to secure fish productivity.” Moreover, the Lao experience with designing and building fishways “provided the empirical evidence needed to expand the investment in fishways into other ADB irrigation investment projects.”
The report concludes that fishway research is best carried out through “adaptive management” that 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 development agenda that changes as new knowledge is generated to make sound development decisions.”
Both 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 outcomes into government policy and legislation in Cambodia and Laos as well as Indonesia and Myanmar. Among the project’s aims are understanding why developers decide whether or not to include fish passes in irrigation projects. ACIAR says it also aims to fill “critical knowledge gaps” needed to show proof of concept. “Fish passes have helped restore fisheries in the Mekong,” says Dr. Ann Fleming, manager of fisheries research at the Australian centre. “And with that we have also improved the food and nutritional security of people living in those areas.”
Source: Agency Kampuchea Press