Living Planet Index

LPI for Migratory Freshwater Fishes

Migratory fishes that spend all or parts of their life cycle in freshwater are highly threatened (IUCN 2023; Darwall & Freyhof 2015). The Convention on Migratory Species (CMS), which focuses on species that migrate across borders, highlighted in a recent report that 97% of CMS-listed fishes are threatened with extinction (UNEP-WCMC 2024). One of the largest issues leading to declines is the loss of free-flowing rivers and blockage of migration routes (Grill et al. 2019; Belletti et al. 2020; Thieme et al. 2023; Keijzer et al. 2024), impairing movement and reducing the ability of fishes to complete their lifecycle (Winemiller et al. 2016).

The LPI for migratory freshwater fishes was developed to monitor trends fish that live in freshwater habitats either partly or exclusively, which are often impacted by these changes in habitats. This index is suitable as a complementary indicator for Goal A in the post-2020 global biodiversity framework as it can show trends in species populations impacted by reduced or improved connectivity of freshwater habitats.

Using an improved species selection method and data set compared to the last report (Deinet et al. 2020), the latest index show a 81% decline between 1970 and 2020 (Deinet et al. 2024; Figure 1).

Figure 1. Index of abundance of 1,864 monitored populations of 284 species of migratory freshwater fishes, showing a decline of −81% between 1970 and 2020. The white line shows the Living Planet Index values, and the shaded areas represent the bootstrapped 95% confidence interval (−63% to −91%).

The declines are widespread across regions – ranging from −28% in Asia-Oceania to −91% in Latin America and Caribbean (Figure 2).

Figure 2. Index of abundance for monitored migratory freshwater fishes between 1970 and 2020 in North America (−34%; 623 populations of 48 species), Latin America and Caribbean (−91% since 1975; 533 populations of 84 species), Europe (−75%; 390 populations of 45 species) and Asia-Oceania (−28%; 218 populations of 102 species). The bold lines show the Living Planet Index values, and the shaded areas represent the bootstrapped 95% confidence intervals.

Using information on local threats affecting 328 populations of 146 species, we found that habitat loss, degradation and change accounted for around half of the threats to these populations (Figure 3a). This was followed by overexploitation and invasive species and disease. At the regional level, habitat-related threats were the largest threat category in almost all regions, adding to more than 50% of all the threats in Africa, Asia and Europe (Figure 3b).

Figure 3. The distribution of threats for monitored migratory freshwater fishes a) globally and b) for different regions. Threat information was available for 328 populations of 146 species, totalling 581 recorded threats. The numbers in the bars (brackets) correspond to the number of times a threat was listed.

Further Information

• IUCN (2023) The IUCN Red List of Threatened Species. Version 2023-1.
• Darwall WRT, Freyhof J (2015) Lost fishes, who is counting? The extent of the threat to freshwater fish biodiversity. In: Conservation of Freshwater Fishes. Closs, GP, Krkosek, M, & Olden, JD, editors. Cambridge University Press pp. 1–36.
• UNEP-WCMC (2024) State of the World’s Migratory Species. UNEP-WCMC, Cambridge, UK
• Grill G, et al. (2019) Mapping the world’s free-flowing rivers. Nature 569:215–221
• Belletti B, et al. (2020) More than one million barriers fragment Europe’s rivers. Nature 588:436–441
• Thieme M, et al. (2023) Measures to safeguard and restore river connectivity. Environmental Reviews er-2023-0019
• Keijzer T, et al. (2024) Threats of dams to the persistence of the world’s freshwater fishes. Global Change Biology 30:e17166
• Winemiller KO, et al. (2016) Balancing hydropower and biodiversity in the Amazon, Congo, and Mekong. Science 351:128–129
• Deinet, S., et al. (2020) The Living Planet Index (LPI) for migratory freshwater fish - Technical Report. World Fish Migration Foundation, The Netherlands. Download report
• Deinet, S. et al. (2024) The Living Planet Index (LPI) for migratory freshwater fish 2024 update - Technical Report. World Fish Migration Foundation, The Netherlands. Download report

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