Wednesday June 28, 2023
Utah State University —
New research reveals an alarming decline in the number of fish species in the critical Mekong River system, a change connected to dam development on the world’s most productive river system.
Two tributaries of the river in Southeast Asia showed declines of the number of fish species, while an increase in diversity was noted in a third, largely free-flowing tributary.
“This is one of the first studies to show reduced fish diversity following dam construction, contrasted with increased diversity in less fragmented rivers in the Mekong River system,” said Sarah Null, water resources expert in the Utah State University Department of Watershed Sciences, and an author on the study.
The findings are especially important because the Mekong River, which runs through six Asian countries, supports the highest levels of fish harvest from any inland fishery in the world, sustaining the livelihoods of tens of millions of people. The region’s rapid pace of hydropower development, which includes 129 commissioned dams in the Lower Mekong Basin, threatens this remarkable productivity.