Prioritizing Barriers to Fish Passage in Lao PDR

Rapid riverine development is threatening the productivity and long term sustainability of Lower Mekong River capture fisheries. Over 200 new dam projects are approved every year to drive power generation and irrigation productivity. Few developments consider fisheries resources despite global recognition that infrastructure can substantially decrease productivity. Fish have a strong cultural, social and economic value. The total capture fishery harvest is approximately 2 million tonnes, which equates to 2% of global fisheries catch. It is widely accepted that decreases in fishery productivity will adversely impact for the 60 million people that rely on fish from the system. River development will impact capture fisheries by eliminating connectivity, providing a direct mortality source and through habitat and flow regime changes associated with impounding. Information on the size, type and number of fish migration barriers is limited in the Lower Mekong Basin. The number of barriers were quantified in three catchments within Lao PDR. Each site was visited, catalogued and then used in a three stage prioritisation process to guide investment into mitigation works in the catchment. The work provided essential information to inform the development of a fish passage restoration program needed to prevent possible fisheries declines.