Finding the best ‘ways’ with fish passes around dams

The Lower Mekong Basin provides habitat for more than 480 species and 40 families of fish, many of which are endemic. The catchment provides 2% of the worlds commercial fish catch, with 2.2 million tonnes per annum extracted. Movement of fish through the Basin is vital to maintain fish populations, especially for migratory species. However, thousands of barriers have been installed throughout the Lower Mekong Basin hindering fish passage. Work is being undertaken to establish the best responses to the increasing number of barriers throughout the Lower Mekong Basin. Engineered structures are being designed to account for specific ecological objectives, hydrology and fish species within a site. This endeavour is not without challenges, and one size does not fit all. The Pak Peung Wetland Research site is located about 100 km to the north-east of Vientiane, the capital of Laos. The ACIAR-supported project started in 2008 and a fully commissioned cone fishway was installed in 2014. Monitoring has been an essential part of the project; to learn about the success of the fishway so similar projects can be successfully rolled out across the Basin. This talk discusses an example of an engineered fishway at Pak Peung, Laos, and some of the successes and challenges of fish passage design.