A report issued last week revealed that, worldwide, migratory freshwater fish have declined by 76% since 1970.
This result joins a growing and dispiriting list of dramatic declines for biodiversity and wildlife. However, it also highlights a continuing threat to food security for many regions of the world.
Freshwater fish provide the primary source of protein for at least 200 million people globally—particularly in rural communities in Asia and Africa—and migratory fish are often a major component of freshwater fish harvests. For example, migratory fish represent approximately one-third of the harvest from the Mekong River basin, the world’s largest freshwater fishery at over 2 million tons annually, nearly 20% of global freshwater fish harvests.
But what does this decline in migratory fish have to do with energy?
Quite a lot, actually. Hydropower dams are one of the primary reasons for the decline of migratory fish – and expansion of hydropower is a key threat to some of the largest runs of migratory fish that remain.
Thus, hydropower development triggers a set of difficult tradeoffs between energy and food security.