A concerning report from the United Nations reveals that migratory fish species are in peril, with populations plummeting by a staggering 81% over the last fifty years. This alarming decline, driven by habitat destruction, pollution, and overfishing, has prompted a global initiative to protect thirty key species, including the golden mahseer and goonch catfish. As these aquatic travellers struggle to reach their breeding grounds, urgent action is required to safeguard their future.
A Crisis for Aquatic Migrants
Fish that undertake extensive migrations across rivers, lakes, and oceans are facing unprecedented threats. The Atlantic tarpon, which migrates hundreds of miles along the US coast, is emblematic of a broader crisis. The degradation of its mangrove habitats has led to significant population declines, reflecting a trend seen across many species.
Dr. Zeb Hogan, a leading biologist and co-author of the UN report, emphasised the importance of these fish for global livelihoods. “Freshwater fish are vital for the sustenance of hundreds of millions of people,” he noted. “They provide food for 200 million people worldwide and represent an incredible array of biodiversity that must be protected.”
The UN’s Bold Initiative
In a comprehensive evaluation of over 15,000 freshwater migratory fish—half of all fish species—the UN has identified 325 that require urgent monitoring and support. Among these, thirty species have been prioritised for conservation efforts, with some, like the Allis shad and Atlantic salmon, found in the UK. The UN’s previous assessment in 2011 only included 3,000 species, highlighting the urgency and scale of the current crisis.
Michele Thieme, deputy lead for freshwater at the World Wildlife Fund US, explained the significance of the priority list. “These fish are not only ecologically important; they hold cultural and spiritual significance in many communities,” she said, citing the golden mahseer as an example. This iconic species of the Himalayas, revered for its cultural value, is now at risk due to overfishing and habitat loss.
Disruption and Decline
The primary threats to these migratory fish include habitat loss from dam construction and pollution, which severely disrupt their ability to spawn. In Europe alone, fish encounter barriers approximately every kilometre, which can hinder their natural migration routes. Dr. Janina Gray from WildFish described the cumulative impact of these barriers. “They expend significant energy overcoming obstacles, making them more susceptible to disease and predation, and they often spawn in less than ideal locations.”
The challenge is not confined to the UK; migratory fish traverse international borders, necessitating a coordinated response from governments worldwide. The Convention on the Conservation of Migratory Species, a UN treaty established in 1979, seeks to facilitate this cooperation, and the UN plans to propose the addition of the thirty prioritised species at the treaty’s upcoming annual meeting in three years.
A Path Forward
The plight of migratory fish is not without hope. The saiga antelope, which experienced dramatic population declines, has rebounded significantly thanks to international conservation efforts. Amy Fraenkel, the UN Executive Secretary for the Convention on Migratory Species, pointed out that while attention has often focused on more charismatic species, it is now time for migratory freshwater fish to receive the coordinated action they desperately need.
“Historically, we have concentrated on larger, more visible species like big cats and whales,” Fraenkel noted. “Now, it is crucial that we shift our focus to include these vital aquatic species that play an essential role in our ecosystems.”
Why it Matters
The decline of migratory fish populations signifies a broader environmental crisis with far-reaching implications. These fish not only contribute to biodiversity but also support millions of livelihoods globally. Their loss could destabilise ecosystems and compromise food security for communities dependent on them. Immediate action is not just a matter of conservation; it is essential for maintaining the delicate balance of our planet’s freshwater resources and ensuring the well-being of countless individuals who rely on these species for their survival.
