Freshwater migratory fish, crucial for ecosystems and human livelihoods alike, are facing a dramatic decline, with populations plummeting by an alarming 81% over the past fifty years. A recent report from the United Nations has spotlighted the plight of these species, urging immediate conservation measures to safeguard their future. Among the 30 highlighted fish in dire need of protection are the golden mahseer and the goonch catfish, emblematic of a broader crisis affecting aquatic biodiversity.
The Crisis Unfolds
The report, which analysed over 15,000 species of freshwater migratory fish—constituting half of all fish species—reveals a stark reality: these creatures are under siege from multiple fronts, including habitat destruction, pollution, and unsustainable fishing practices. As Dr. Zeb Hogan, a biologist at the University of Nevada, Reno and co-author of the report, noted, “Freshwater fish support hundreds of millions of people around the world, so for humans, they’re very important.” These fish provide sustenance for approximately 200 million people globally, highlighting their critical role in both ecological and economic systems.
The UN’s previous assessment in 2011 only considered a mere 3,000 species, but advancements in research have now allowed for a more comprehensive examination. This updated evaluation has identified 325 fish species that require urgent attention under a global conservation agreement, including several that are native to the UK, such as the Allis shad and Atlantic salmon.
Overfishing and Habitat Loss: The Dual Threat
The report underscores that overfishing and habitat loss are the two primary threats facing migratory fish. Michele Thieme, deputy lead for freshwater at the World Wildlife Fund US, emphasised the cultural significance of some species, stating, “For example, the golden mahseer is an iconic fish of the Himalayas… many in that region value that fish for cultural and spiritual practices that go far beyond economic values.” Yet, overexploitation and the construction of dams that disrupt river systems are severely hindering their ability to spawn and thrive.
Dams and other barriers fragment river ecosystems, fundamentally altering the natural flow and making it increasingly difficult for fish to access their breeding grounds. Dr. Janina Gray, head of science at WildFish, highlighted the issue of these barriers, explaining that even small obstructions can have a significant cumulative impact on fish populations, leading to increased stress, susceptibility to disease, and less optimal spawning conditions.
A Call for Coordinated Conservation Efforts
The geographical scope of migratory fish movements necessitates international cooperation in conservation efforts. Prof. Hogan pointed out that many species traverse national borders, complicating their protection. The UN’s Convention on the Conservation of Migratory Species, established in 1979, aims to facilitate such collaboration among countries. The UN is advocating for the inclusion of the 30 priority fish species in this treaty during its upcoming annual meeting in three years, marking a pivotal step in global conservation efforts.
Historical precedents exist for successful recovery of species through coordinated international efforts. The saiga antelope, once on the brink of extinction, has seen its population rebound to over a million following targeted conservation strategies. Amy Fraenkel, the UN Executive Secretary for the Convention on Migratory Species, expressed optimism that migratory freshwater fish could similarly benefit from renewed focus and action.
Why it Matters
The dramatic decline of migratory fish is not merely an environmental issue; it is a wake-up call about the interconnectedness of ecosystems and human well-being. Freshwater fish are not only vital for biodiversity but are also integral to the livelihoods and cultural practices of millions across the globe. Addressing the threats they face is essential not just for the survival of these species but for the health of our rivers, lakes, and communities that depend on them. The time for action is now—before these vital aquatic resources slip further into decline, taking with them the ecosystems and communities that cherish them.
