The alarming decline of migratory fish populations worldwide has prompted urgent calls for conservation efforts. A recent report from the United Nations highlights the devastating impact of human activities, including dam construction, pollution, and overfishing, which are preventing these vital species from reaching their breeding grounds. As a result, the UN has prioritised 30 flagship fish species for global protection, including the golden mahseer and goonch catfish, amidst a staggering 81% reduction in their numbers over the past 50 years.
A Grim Assessment of Freshwater Fish
A team of international scientists conducted an extensive review of over 15,000 freshwater migratory fish species, which represent half of all fish species globally. Their findings are stark: population numbers have plummeted by roughly 81% since the 1970s. The report’s authors emphasise that these fish are not only crucial for ecosystems but also for the livelihoods of millions of people worldwide.
Dr. Zeb Hogan, a professor of biology at the University of Nevada, Reno and co-author of the report, stated, “Freshwater fish support hundreds of millions of people around the world, so for humans, they’re very important.” He noted that these species provide sustenance for approximately 200 million people globally and possess an incredible diversity that warrants immediate protection.
The Threats Facing Migratory Fish
Among the species highlighted for urgent conservation are iconic fish such as the piraíba and the golden mahseer, both of which are facing dire threats from overfishing and habitat degradation. Michele Thieme, the deputy lead for freshwater at the World Wildlife Fund US, elaborated on the challenges, stating, “Habitat loss includes things like dams that fragment a river system and can change the natural flow regime of a river, which results in fish not being able to connect to their spawning habitats.”
The report also identifies specific species of concern, including the Allis shad, river lamprey, brook lamprey, and Atlantic salmon, all of which are found in the UK. These fish face a multitude of obstacles as they attempt to migrate, with many encountering barriers such as weirs and small culverts that disrupt their paths.
The Need for Coordinated Action
The situation is particularly critical in Europe, where fish are impeded by a barrier every kilometre on average. Dr. Janina Gray, head of science at the environmental charity WildFish, pointed out that even minor barriers can have significant consequences for migratory fish. “It can have a massive impact in terms of the energy reserves fish are using to get over the barriers,” she explained. This energy depletion makes them more vulnerable to disease and predation, while also compromising their spawning capabilities.
As these fish traverse international borders during their migrations, a concerted effort between governments is essential to mitigate these threats. The UN is now advocating for the inclusion of the 30 prioritised fish species in the Convention on the Conservation of Migratory Species, a global treaty aimed at fostering cooperation among nations to protect migratory wildlife.
A Beacon of Hope: Successful Conservation Stories
The potential for recovery is not out of reach. The saiga antelope, once on the brink of extinction, has rebounded significantly since being listed under the Convention on Migratory Species. After a devastating mass die-off in 2015, international conservation efforts have helped the population surge to over a million individuals. Amy Fraenkel, the UN Executive Secretary for the Convention on Migratory Species, noted that it is time to extend this focus to migratory freshwater fish, which have long been overshadowed by larger, more charismatic species.
“While attention has been given to well-known species like big cats and whales, it is now the turn of migratory freshwater fish to benefit from coordinated action,” Fraenkel stated.
Why it Matters
The decline of migratory fish is a pressing environmental crisis that affects not only biodiversity but also the livelihoods of millions reliant on these species for food and cultural practices. As ecosystems become increasingly strained by human activity, the call for urgent action to protect these fish becomes ever more critical. The fight for their survival is not just about preserving wildlife; it’s about safeguarding the future of countless communities worldwide that depend on the health of our freshwater systems. Immediate and decisive action is essential to halt the decline and ensure that these migratory fish can thrive once more.
