New Report: Migratory Freshwater Fish Populations Down 81% Since 1970
Michelle Milliken
A recent report from a UN treaty showed that migratory species across the world are at risk, with about 1 in 5 threatened with extinction. The numbers were especially concerning for fish, and new research shines even more light on the dangers they’re facing.
The recently released Living Planet Index for migratory freshwater fish – a collaborative effort by groups including WWF, IUCN, The Nature Conservancy, and the World Fish Migration Foundation – has shown just how much habitat loss and degradation, overexploitation, pollution, and climate change are impacting freshwater fish. It found that, among 1,864 populations of 284 native migratory freshwater species, global populations fell 81% between 1970 and 2020. This is especially pronounced in Latin America and the Caribbean, where numbers were down 91%, and Europe, where the population fell 75%.
Herman Wanningen, founder of the World Fish Migration Foundation, says, “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. 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."
The authors say that, in addition to impacts on people who rely on freshwater fish for sustenance and their livelihoods, falling populations can also impact other species within the waterways and the health and resilience of the waterways themselves.
Unfortunately, the report found that about two-thirds (65%) of species included in the report have declined, jeopardizing their benefits. However, trends tended to be either very positive or very negative, with 31% of species showing an increase in their populations.
Factors that were found to be helpful included better management of fisheries, habitat restoration, dam removals, and further protections. Managed species were also found to do better than those without any management. Management may entail fishing restrictions, stocking, bycatch reductions, supplementary feeding, and no-take zones. These were most common in Europe, but also in North America, where populations only fell by 34%.
The report says that to get populations headed in the right direction, monitoring efforts should be strengthened, free-flowing rivers and swimways should be restored, existing threats should be addressed, and there needs to be international cooperation on conservation initiatives and commitments. The public and policymakers should also be encouraged to join the effort.
Michele Thieme, Freshwater Deputy Director at WWF-US, says, “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, 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 also notes that more information is needed to understand how populations are changing and why they are. In addition, there's limited data from Asia-Oceania and Africa. You read the whole report here.
