A stark new report highlights a dramatic decline in migratory fish populations, with numbers plunging by an alarming 81% over the past 50 years. The United Nations has now identified 30 species requiring immediate conservation measures, urging global stakeholders to act swiftly to protect these crucial aquatic organisms and the ecosystems they inhabit.
Damning Findings on Freshwater Fish Species
Research conducted by a team of international scientists has cast a spotlight on the precarious state of migratory freshwater fish, which represent half of all fish species. Over the course of the last five decades, human activities—ranging from dam construction and pollution to overfishing—have severely disrupted the natural migration routes essential for breeding.
“Freshwater fish are vital for the livelihoods of hundreds of millions worldwide,” emphasised Dr. Zeb Hogan, a co-author of the report and a professor of biology at the University of Nevada, Reno. He further noted that these species provide sustenance for an estimated 200 million people globally. The report details the immense diversity of migratory fish, some of which can weigh over 650 pounds and travel more than 7,000 miles.
A Call for Global Conservation
The UN’s 2023 assessment builds on its 2011 report, which evaluated only 3,000 migratory fish species. This time, the analysis expanded to more than 15,000 species, leading to the identification of 325 fish requiring monitoring and support under a global conservation agreement. Among the highlighted species are the Allis Shad, River Lamprey, Brook Lamprey, and Atlantic Salmon—some of which are native to the UK.
Michele Thieme, deputy lead for freshwater at the World Wildlife Fund (WWF) US, stressed the cultural significance of several species on the list, such as the golden mahseer, revered in the Himalayas for both spiritual and economic reasons. Unfortunately, both overfishing and habitat loss threaten these iconic fish.
Barriers to Migration: The European Context
In Europe, the challenges facing migratory fish are particularly acute, with barriers such as small culverts and weirs obstructing their natural routes every kilometre on average. Dr. Janina Gray, head of science at environment charity WildFish, remarked on the compounded effects of these barriers: “They increase the energy expenditure fish use to navigate their paths, making them more vulnerable to disease and predation.”
The report urges coordinated efforts across national borders to tackle these issues, emphasising the need for collaborative initiatives to restore fish stocks. The Convention on the Conservation of Migratory Species (CMS), a UN treaty established in 1979, serves as a framework for such international cooperation.
Path Forward: A Treaty to Protect Migratory Fish
The UN is advocating for the inclusion of the 30 prioritised fish species in the CMS at its upcoming annual meeting in three years. This initiative is reminiscent of successful conservation efforts for other species, such as the saiga antelope, which rebounded from near extinction due to international anti-poaching actions.
UN Executive Secretary for the CMS, Amy Fraenkel, acknowledged the historical focus on more charismatic species but emphasised that it is now time for migratory freshwater fish to reap the benefits of such coordinated efforts.
Why it Matters
The plight of migratory fish is not just an ecological concern; it extends to the economic and cultural fabric of communities worldwide. As these fish populations dwindle, the ripple effects can jeopardise food security and disrupt traditional practices that rely on them. The UN’s call to action underscores a critical moment for global environmental policy—one that demands immediate attention to safeguard the future of these vital species and the ecosystems they support. If we fail to act, we risk losing not only the fish themselves but also the livelihoods of millions who depend on them.
