Thursday December 18, 2025
Mongabay —
Southeast Asia’s Mekong River is one of the world’s most diverse and productive freshwater ecosystems, home to more than 1,000 fish species, including both the critically endangered Mekong giant catfish (Pangasianodon gigas) and giant barb (Catlocarpio siamensis). Many of these species migrate long distances and depend on the timing and extent of the annual flood pulse that expands habitat and triggers spawning.
But that seasonal rhythm is shifting as monsoon seasons become increasingly erratic — the result of climate change, with upriver dams adding to the water level fluctuation problem. There have been years in which Cambodia’s Tonle Sap Lake, the region’s major nursery ground, has failed to expand as it did in the past, reducing habitat for migratory fish.