Staggering collapse in migratory fish populations threatens health of millions and critical freshwater ecosystems

* 81% average decline in migratory fish populations since 1970 * Steepest falls in Latin America and the Caribbean, and Europe

Populations of migratory freshwater fish species continue to decline across the globe, risking the food security and livelihoods of millions of people, the survival of countless other species, and the health and resilience of rivers, lakes and wetlands. This news is supported by a global study published on 21 May by the World Fish Migration Foundation, ZSL, IUCN, The Nature Conservancy, Wetlands International and WWF.
Published ahead of World Fish Migration Day on May 25th, the new Living Planet Index (LPI) report on freshwater migratory fishes reveals a staggering 81% collapse in monitored population sizes on average between 1970 to 2020, including catastrophic declines of 91% in Latin America and the Caribbean and 75% in Europe. 

Habitat loss and degradation – including fragmentation of rivers by dams and conversion of wetlands for agriculture – account for half of the threats to migratory fishes, followed by over-exploitation. Increasing pollution and the impacts of climate change are also fueling the fall in freshwater migratory fish species, which have now been declining consistently for 30 years.

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.

Migratory freshwater fishes are vital to the food security and nutritional needs of hundreds of millions of people, particularly in vulnerable communities across Asia, Africa and Latin America. They also support the livelihoods of tens of millions, from 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,” said Michele Thieme, Vice-President Freshwater, WWF-US. “Prioritizing river protection, restoration, and connectivity is key to safeguarding these species, which provide food and livelihoods for millions of people around the world. Let's unite in this crucial endeavor, guided by science and shared commitment, to ensure abundance for generations to come."
The report is not all doom and gloom. Nearly one-third of monitored species have increased, suggesting that conservation efforts and improved management can have positive impacts. Some promising strategies include the improved management of fisheries, habitat restoration, dam removals, the creation of conservation sanctuaries, and legal protection.

For example, in Europe and the United States, thousands of dams, levees, weirs and other river barriers have been removed in recent decades, and momentum for such actions is growing. In 2023, Europe removed a record 487 barriers - a whopping 50% 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. 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. 

Stefanie Deinet who led the analysis from ZSL’s Institute of Zoology said: “Globally we’re seeing alarming declines in migratory freshwater fishes, and our analysis is a key towards understanding why. We’ve been able to paint the strongest picture to date of trends in these species, and although it still tells a bleak story, hidden within the data is a reason for hope. Almost one-third of monitored species populations have increased in size - highlighting the power of knowledge pooling, management and conservation action to identify possible strategies for restoring populations on a global scale.

While scaling up dam removals is a key solution to reversing the collapse in freshwater migratory fish populations, there are more. 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% of inland waters and restore 30% of degraded inland waters.

In particular, rising to the Freshwater Challenge’s goal of restoring 300,000 km of degraded rivers will contribute enormously to reversing the trend in migratory fish populations.

Along with protecting and restoring healthy rivers, 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.

There are many initiatives around the world supporting the recovery of migratory fish species and freshwater biodiversity in general. The Emergency Recovery Plan for Freshwater Biodiversity highlights a variety of measures that could transform the management and health of rivers, lakes and wetlands to improve the health of freshwater systems and biodiversity.

The Global Swimways Initiative identifies and prioritizes key river migration routes that are important for ecologically, culturally and economically important fish species. It highlights the collaborative efforts of international river basin authorities in addressing this critical issue. Since 2014, the WFMF has organized World Fish Migration Day every two years to raise awareness about migratory fish - the next is on May 25th with over 68 countries participating so far.

Chris Baker, director Wetlands International Europe adds: “Whilst this report further underlines the parlous state of Europe’s migratory fish and rivers there is some cause for hope. Grass roots action to reconnect our rivers and improve fish mobility is growing. Furthermore together with Wetlands International the Trans-European Swimways Network is helping to identify and prioritise the most important rivers and species for attention. To help this reach scale European governments must commit to and implement the Nature Restoration law to help accelerate the recovery of our rivers and migratory fish.

“This new study highlights the urgent need to protect, connect and restore freshwater systems for the benefit of both people and nature. The alarming findings of the report make clear that we are not doing enough today to support these fish and the places they call home. We must do better for migratory fish and for ourselves too. Only by working together – governments, other environmental NGOs, communities and Indigenous Peoples, and others around the world – can we bend this curve toward hope.”, continues Nicole Silk, TNC’s director of freshwater outcomes.

Find out more in the executive summary and full report.


About World Fish Migration Foundation (WFMF)
The World Fish Migration Foundation (WFMF) is a Dutch non-profit organisation dedicated to the protection, conservation, and restoration of migratory fish populations and their habitats. Their aim is to build an inspiring international dam removal movement to scale up obsolete river barriers removal and restore free-flowing rivers, for the benefit of nature and people.

Wetlands International Europe
Wetlands International Europe is the only network organization in Europe bringing together NGOs whose shared mission is to inspire and mobilize society to safeguard and restore wetlands.

The Nature Conservancy (TNC)
TNC, an environmental non-profit founded in 1951, impacts conservation in nearly 80 countries, has restored more than 4,900 miles (some 8,000 kilometers) of rivers, and has protected more than 125 million acres (51 million hectares) of land. 

Founded in 1826, ZSL is an international conservation charity, driven by science, working to restore wildlife in the UK and around the world; by protecting critical species, restoring ecosystems, helping people and wildlife live together and inspiring support for nature. Through our leading conservation zoos, London and Whipsnade, we bring people closer to nature and use our expertise to protect wildlife today, while inspiring a lifelong love of animals in the conservationists of tomorrow. Visit for more information.    

About WWF
WWF is one of the world’s largest and most respected independent conservation organizations, with over 5 million supporters and a global network active in over 100 countries. WWF’s mission is to stop the degradation of the earth’s natural environment and to build a future in which humans live in harmony with nature, by conserving the world’s biological diversity, ensuring that the use of renewable natural resources is sustainable, and promoting the reduction of pollution and wasteful consumption.

About IUCN 
The International Union for Conservation of Nature (IUCN) is a membership Union uniquely composed of both government and civil society organisations. It provides public, private and non-governmental organisations with the knowledge and tools that enable human progress, economic development and nature conservation to take place together.Created in 1948, IUCN is now the world’s largest and most diverse environmental network, harnessing the knowledge, resources and reach of more than 1,400 Member organisations and some 15,000 experts. It is a leading provider of conservation data, assessments and analysis. Its broad membership enables IUCN to fill the role of incubator and trusted repository of best practices, tools and international standards.



Fisherman on Luangwa river, Zambia

Fisherman on Luangwa river, Zambia

© James Suter , Black Bean Productions/WWF-US

White Sturgeon, Fraser river USA

White Sturgeon, Fraser river USA

© Zeb Hogan

Colonia Rio Weir, Spain

Colonia Rio Weir, Spain

© Catalan Water Agency

Salmon, Finland

Salmon, Finland

© Petteri Hautamaa/ WWF Finland