Huge collapse in migratory fish populations
A new study has revealed a staggering 81 per cent collapse in worldwide migratory fish populations in the 50 years since 1970
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The recently published Living Planet Index (LPI) report on freshwater migratory fishes reveals an average 81 per cent collapse in monitored population migratory fish populations, including salmon, trout, eel, and sturgeon, between 1970 to 2020. The situation in Latin America and the Caribbean is especially marked where populations have fallen by 91 per cent.
The reasons are, as so often, habitat loss and degradation of freshwater habitats, including the fragmentation of rivers by dams and other barriers and the conversion of wetlands for agriculture. Other key reasons for the declines include over-exploitation, increasing pollution and the worsening impacts of climate change.
‘The catastrophic decline in migratory fish populations is a deafening wake-up call for the world. We must act now to save these keystone species and their rivers,’ said Herman Wanningen, founder of the World Fish Migration Foundation. ‘Migratory fish are central to the cultures of many Indigenous Peoples, nourish millions of people across the globe, and sustain a vast web of species and ecosystems. We cannot continue to let them slip silently away.’ In addition to providing sustenance for millions migratory freshwater fish also support livelihoods, including local fisheries to the global trade in migratory fish and fish-byproducts, and the multi-billion dollar recreational fishing industry.
‘In the face of declining migratory freshwater fish populations, urgent collective action is imperative. Prioritizing river protection, restoration, and connectivity is key to safeguarding these species’, said Michele Thieme, Deputy Director, Freshwater at WWF-US. She continued with a call to arms, ‘Let’s unite in this crucial endeavour, guided by science and shared commitment, to ensure abundance for generations to come’.
The report, which was produced by the World Fish Migration Foundation, ZSL, IUCN, The Nature Conservancy (TNC), Wetlands International and WWF, is not all doom and gloom. Nearly one-third of monitored species have increased, suggesting that conservation efforts and improved management can and are having positive impacts. Some promising strategies include the improved and/or species-focused management of fisheries, habitat restoration, dam removals, the creation of conservation sanctuaries, and legal protection.
An example of conservation actions that have helped migratory fish populations increase comes from Europe and the United States where thousands of dams, levees, weirs and other river barriers have been removed in recent decades. In 2023 alone, Europe removed a record 487 barriers – a 50 per cent increase over the previous high reported in 2022. Meanwhile, in the United States, the largest dam removals in history are currently underway along the Klamath River in California and Oregon. Dam removals can be cost-effective, job-producing solutions that help reverse the disturbing trend of biodiversity loss in freshwater systems as well as solutions that improve river health and resilience for people, too.
A WWF statement said that while scaling up dam removals is a key solution to reversing the collapse in freshwater migratory fish populations, more action can be taken. Decision makers across the globe must urgently accelerate efforts to protect and restore free-flowing rivers through basin-wide planning, investing in sustainable renewable alternatives to the thousands of new hydropower dams that are planned across the world as well as other measures that contribute to the ambitious goals in the Kunming-Montreal Global Biodiversity Framework to protect 30 per cent of inland waters and restore 30 per cent of degraded inland waters.
Along with protecting and restoring healthy rivers, WWF says that there is an urgent need to strengthen monitoring efforts; better understand fish species’ life-history, movement and behaviour; expand international cooperation, such as adding more freshwater migratory fish species to the Convention on Migratory Species (CMS); and promote greater public and political engagement.
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