The Mekong River, home to the world’s largest inland fishery, supports millions of people who rely on its waters for food and income [1] [2]. Central to this river region are the migration routes used by many fish species, which are increasingly under threat [3]. In our latest article, we apply the Global Swimways Concept, a framework that helps identify and protect these vital migration pathways to the Lower Mekong region.
Swimways are migration routes used by fish and other aquatic species to move between different habitats necessary for their life cycles, such as spawning, feeding, and refuge areas. These pathways can span vast distances in rivers, lakes, or coastal environments, and they are crucial for the survival of migratory species. Fish depend on unimpeded swimways to complete their migrations, which are often triggered by seasonal changes in water flow or temperature.
In river systems like the Mekong, swimways can include both longitudinal migrations (up and downstream) and lateral movements (between tributaries, floodplains, and main channels). The disruption of these swimways by dams, infrastructure, or environmental changes can severely affect fish populations by blocking access to critical habitats, leading to declines in biodiversity and fishery yields. Conservation of swimways is essential for maintaining healthy ecosystems and ensuring the survival of migratory species.
The Mekong river is home to over 1,300 fish species, 21% of which are migratory. These species account for about 70% of the region's fish catch. However, various pressures, including hydropower development, agricultural expansion, and environmental changes, are disrupting migration patterns, placing 35% of these migratory species under threat.
By applying the Global Swimways Concept to the Mekong, the study identifies key zones in the river where migratory species are most vulnerable and require immediate conservation action. The article also includes several case studies that illustrate the complexity of fish migration in the Mekong. For instance, the case of Pangasius krempfi, an anadromous species with multiple genetic lineages, demonstrates a diversity of migratory pathways, with long migratory pathways that needs to be protected to maintain the diverse genetic origins and complexities in the lineages of the species in the LMB [4].
Key recommendations from the study for maintaining swimways in the Mekong include:
- Improving knowledge of migratory pathways
- Addressing environmental pressures from development
- Focusing on conservation efforts that enhance both biodiversity and fishery yields
- Promoting transboundary cooperation and integrated regional planning for long-term sustainability
These recommendations highlight the complex challenges facing the Mekong's swimways and the need for a multifaceted approach to their conservation.
Read the full article to learn more about the challenges and solutions for preserving fish migration in the Mekong.
