A recent UN report highlights the alarming decline of migratory fish populations worldwide, prompting urgent calls for global conservation efforts. Over the past fifty years, these vital aquatic species have experienced a staggering 81% reduction in numbers, primarily due to habitat destruction, pollution, and overfishing. As a result, a coalition of international scientists has identified thirty flagship species, including the golden mahseer and goonch catfish, as priorities for conservation.
The State of Migratory Fish
Freshwater fish, which represent half of all fish species, are crucial to the livelihoods of hundreds of millions of people globally. Dr. Zeb Hogan, a prominent biologist and co-author of the report from the University of Nevada, Reno, emphasised their importance: “Migratory freshwater fish support food security for around 200 million people. Their diversity and migratory behaviour are essential for maintaining healthy ecosystems.”
The report marks a significant expansion of the UN’s focus on this group, which was first assessed in 2011 when only 3,000 species were reviewed. This time, the analysis encompassed over 15,000 species, culminating in the identification of 325 fish requiring urgent monitoring and support. Among these, thirty species have been highlighted, including several found in the UK, such as the Allis Shad and Atlantic Salmon.
Threats to Survival
The dual threats of overfishing and habitat loss are wreaking havoc on migratory fish populations. Michele Thieme, deputy lead for freshwater initiatives at the World Wildlife Fund US, describes the golden mahseer as an iconic species of the Himalayas, revered for its cultural and spiritual significance. However, it faces severe pressures from unsustainable fishing practices and the degradation of its natural environment.
“Habitat loss encompasses the construction of dams that disrupt river systems and alter their natural flow,” Thieme explains. This fragmentation prevents fish from accessing critical spawning grounds, ultimately threatening their survival.
Barriers to Migration
In Europe, the situation is particularly dire, with fish encountering barriers to their migratory routes every kilometre on average. These obstacles often include unnecessary culverts and weirs that could be easily removed. Dr. Janina Gray, head of science at the environmental charity WildFish, highlights the cumulative impact of these barriers: “Every barrier forces fish to expend energy that could otherwise be used for migration or reproduction. This not only reduces their chances of survival but also increases their susceptibility to disease and predation.”
A Call to Action
The need for coordinated international efforts to protect these migratory fish is pressing. Many species traverse national borders during their migrations, emphasising the necessity for collaboration among governments. The UN Convention on the Conservation of Migratory Species, established in 1979, serves as a framework for such cooperation. The UN is now advocating for the inclusion of the thirty identified fish species in this treaty at its next annual meeting in three years.
The success story of the saiga antelope, which rebounded after being listed under the convention following a catastrophic population decline, serves as a beacon of hope. Amy Fraenkel, the UN Executive Secretary for the Convention on Migratory Species, expressed optimism: “It is time for migratory freshwater fish to receive the same level of attention and coordinated action that has previously been reserved for more prominent species.”
Why it Matters
The decline of migratory fish is not merely an environmental concern; it threatens food security, cultural heritage, and biodiversity. Protecting these species is crucial for sustaining ecosystems and the communities that rely on them. The findings of this report serve as a clarion call for immediate action to safeguard our planet’s aquatic resources, ensuring that future generations can enjoy the rich tapestry of life that these remarkable fish represent.
