The alarming decline in migratory fish populations worldwide has catalysed a call for urgent conservation action. A recent report by the United Nations highlights a staggering 81% reduction in the numbers of these vital species over the past fifty years, primarily due to habitat destruction, pollution, and overfishing. Among the 15,000 species assessed, the golden mahseer and goonch catfish have emerged as key targets for global conservation efforts. This new focus on migratory fish underlines their critical role in sustaining human livelihoods and maintaining ecological balance.
The Plight of Migratory Fish
Migratory fish, which traverse vast distances across rivers, lakes, and oceans, are essential not only for biodiversity but also for the millions of people who depend on them for food and cultural practices. Dr. Zeb Hogan, a biologist at the University of Nevada, Reno, and co-author of the report, emphasises the significance of these species: “Freshwater fish support hundreds of millions of people around the world, so for humans, they’re very important.” He notes that these fish, some of which can weigh over 650 pounds and migrate thousands of miles, represent an incredible diversity that is increasingly under threat.
The report marks a significant expansion from the UN’s 2011 assessment, which only evaluated 3,000 species. The latest findings indicate that the plight of migratory fish has often been overlooked, despite their substantial contributions to food security and ecosystem health.
Key Species in Need of Protection
The UN report has identified 325 fish species requiring urgent monitoring and support under a global conservation framework, with 30 species prioritised for immediate action. Notable among these are the Allis Shad, River Lamprey, Brook Lamprey, and Atlantic Salmon, all of which are native to the UK. Michele Thieme, deputy lead for freshwater at the World Wildlife Fund US, explains the cultural importance of certain species, like the golden mahseer, revered in the Himalayas for its spiritual significance.
However, these iconic fish face multiple threats—overfishing and habitat degradation through dam construction disrupt their migratory patterns, making it difficult for them to reach spawning grounds. Thieme highlights that “habitat loss includes things like dams that fragment a river system, and can change the natural flow regime of a river,” further complicating their survival.
The European Context
The challenges for migratory fish are particularly pronounced in Europe, where barriers such as weirs and culverts obstruct their routes with alarming frequency—one every kilometre on average. Dr. Janina Gray, head of science at the environmental charity WildFish, notes the severe impact of these obstacles: “It can have a massive impact in terms of the energy reserves fish are using to get over the barriers. That makes them more susceptible to disease.” This disruption not only threatens fish populations but also jeopardises the ecosystems that rely on their migration patterns.
A Collaborative Effort for Recovery
The report underscores the need for coordinated action among nations to address these threats. Many migratory fish species traverse international borders, necessitating collaboration for effective conservation. The Convention on the Conservation of Migratory Species, a global UN treaty established in 1979, aims to foster such cooperation. The UN intends to propose the inclusion of the identified 30 fish species in the treaty at its next annual meeting in three years.
Examples of successful conservation efforts abound, such as the recovery of the saiga antelope, which rebounded from near extinction thanks to international anti-poaching initiatives. Amy Fraenkel, the UN Executive Secretary for the Convention on Migratory Species, highlights the need for similar attention to migratory freshwater fish, which have historically been overshadowed by more prominent species.
Why it Matters
The decline of migratory fish is not merely an environmental concern; it poses a significant threat to global food security and cultural heritage. As these fish populations dwindle, the ripple effects on ecosystems and communities could be catastrophic. By prioritising the conservation of these essential species, we are not only safeguarding biodiversity but also protecting the livelihoods of millions who depend on them. The UN’s renewed focus on these migratory fish represents a crucial opportunity to address a pressing global issue, ensuring a more sustainable future for our planet’s aquatic life and the communities that rely on it.
