The plight of migratory fish species has reached a critical juncture, with alarming reports indicating that their populations have plummeted by approximately 81% over the past fifty years. As a result, the United Nations has prioritised 30 key species for urgent conservation measures, highlighting the necessity of safeguarding these vital aquatic inhabitants which are crucial for both biodiversity and human livelihoods.
A Crisis Beneath the Waves
Migratory fish, which undertake impressive journeys through rivers, lakes, and oceans, are facing an unprecedented array of challenges. Dams, pollution, and unsustainable fishing practices are severely disrupting their natural migratory routes, preventing them from reaching essential breeding grounds. Species such as the golden mahseer and the goonch catfish have been identified in a recent UN report as flagship species in need of immediate protection.
Dr. Zeb Hogan, a prominent biologist from the University of Nevada, Reno and co-author of the report, emphasises the importance of these fish: “Freshwater fish support hundreds of millions of people around the world, so for humans, they’re very important.” He notes that these species not only provide sustenance for approximately 200 million people globally but also embody an incredible diversity that demands preservation.
The Scale of the Decline
An extensive analysis conducted by an international team of scientists evaluated over 15,000 species of freshwater migratory fish, revealing a stark decline since the UN’s initial assessment in 2011, which covered merely 3,000 species. The latest findings underscore that a staggering 325 species require monitoring under international agreements for threatened migratory animals, with 30 of these identified as high-priority for conservation efforts. Notable among them are the Allis Shad, River Lamprey, Brook Lamprey, and Atlantic Salmon, all of which call the UK home.
The report highlights the dual threats of overfishing and habitat destruction confronting these species. Michele Thieme, deputy lead for freshwater at the World Wildlife Fund US, elaborates on the golden mahseer’s significance: “It’s called the tiger of the river, and many of the people in that region value that fish for cultural and spiritual practices that go far beyond the economic values.” The combined pressures of overfishing and habitat degradation pose a significant risk to the future of these culturally significant species.
The Barriers to Migration
One of the most pressing issues hindering migratory fish is the presence of barriers such as dams and weirs, which are prevalent across Europe. Dr. Janina Gray, head of science at the environmental charity WildFish, points out that, on average, fish encounter a barrier every kilometre. These obstacles not only impede migration but also exhaust the energy reserves of fish, making them more susceptible to disease and predation. “They will spawn in suboptimal grounds,” she warns, further endangering their survival.
The need for coordinated international action is paramount, as many fish traverse national borders during their migrations. Prof. Hogan stresses that governments must unite to address these challenges collectively. The Convention on the Conservation of Migratory Species (CMS), a global UN treaty established in 1979, obligates countries to collaborate in protecting migratory species. The UN aims to include the 30 identified species in the CMS at its upcoming annual meeting in three years, marking a pivotal moment for aquatic conservation.
Success Stories and Hope for the Future
The potential for recovery is not just a dream; it is a reality demonstrated by successful conservation efforts in other areas. The saiga antelope, once on the brink of extinction following a catastrophic die-off, has rebounded thanks to international anti-poaching initiatives. Amy Fraenkel, the UN Executive Secretary for the CMS, acknowledges the historical focus on more charismatic species like big cats and whales, stating, “It is now the turn of migratory freshwater fish to benefit from coordinated action.”
The time has come to extend the same level of commitment to migratory fish that has been afforded to more visible species. As the UN mobilises for action, the opportunity to restore these vital ecosystems and the communities that depend on them hangs in the balance.
Why it Matters
The decline of migratory fish populations is not merely an environmental issue; it is a profound indicator of the health of our planet’s ecosystems and the sustainability of human livelihoods. These fish are integral to food security, cultural heritage, and biodiversity. Protecting them is crucial not only for the survival of countless species but also for the millions of people who rely on them for sustenance and economic stability. As global efforts ramp up, now is the time to advocate for the preservation of these magnificent creatures and the habitats they traverse.
