The purpose of this project is to assist governments of the Lower Mekong Basin to respond to increased environmental pressure on food security and biodiversity due to hydropower dam development. In this project we propose to survey fish migrations through the Khone Falls in Laos and use this area as a natural laboratory to assess the swimming capabilities and the hydro-geomorphologic requirements of dominant fish species. The information gathered will inform the design of fish passes adapted to Mekong fish species and will underpin the development of operational mitigation measures for dams. This project will include four main activities: A1: Identify the fish species that migrate at different time of the year through specific channels of the Khone Falls A2. Identify the current speed, step dimensions and slope gradients in the channels used by dominant migratory fishes at different times of the year A3. Couple the migrations of target fish species with passable current speed and river bed conditions A4. Communicate actively the findings of this project to stakeholders in the hydropower sector