IUCN Red List 2025: Europe’s freshwater fish in crisis—nearly 60% under pressure

Europe’s rivers and lakes are among the most heavily altered ecosystems in the world. Hardly any body of water remains unaffected—many have been regulated, dammed, or fundamentally transformed by human use.

The updated IUCN Red List (2025)—the most comprehensive assessment of European freshwater fish in 15 years—makes the consequences of this trend visible: More than 40% of Europe’s freshwater fish species are threatened. In addition, numerous species have already gone extinct.

Many of Europe’s freshwater fish species are endemic. That means they are restricted to this region worldwide—they occur nowhere else. They often live only in individual river systems, lakes, or very small habitats. When such a population disappears, this means not only a regional loss, but the global extinction of the entire species. The decline of European freshwater fish is therefore far more than a local problem: it leads directly to a permanent loss of global biodiversity.

The European Red List of freshwater fish was prepared by more than 135 experts from over 30 countries and constitutes a scientifically robust assessment of extinction risk.

Nearly half of all fish species threatened

The new IUCN Red List 2025 covers a total of 558 assessed freshwater fish species in Europe. 77 species were assessed for the first time, mainly as a result of taxonomic revisions.

The central finding:

• 42.1% (approx. 222 species) of European freshwater fish species are considered threatened—that is, Vulnerable (VU), Endangered (EN), or Critically Endangered (CR)
  In the last European assessment from 2011, this share was still 37%—an increase of 5.1 %.
• In addition, 17.5% (approx. 94 species) are considered Near Threatened (NT). These species are on the verge of moving into a threatened category.
  In 2011, this share was only 4.2%—so it has more than quadrupled.

If threatened and near threatened species are combined, 58.9% of all European freshwater fish species are under increased conservation pressure. That corresponds to about 316 species. If species that are already extinct (EX) or extinct in the wild (EW) are also taken into account, more than 60% in total of species are affected.

Breakdown of threat categories

For species that still exist (excluding those already extinct), the following distribution emerges:

• 8.6% (46 species) are Critically Endangered (CR)—a decline compared with 2011 (12%), though mainly due to reassessments
• 18.8% (101 species) are Endangered (EN)—a marked increase (2011: 9.9%)
• 14% (75 species) are Vulnerable (VU)—slightly down (2011: 15.1%)

The share of Endangered species (EN) has nearly doubled, while at the same time significantly more species are moving into the category Near Threatened (NT). This suggests that many species are gradually shifting toward higher threat levels.

Extinct freshwater fish species in Europe

The current IUCN Red List lists 20 species of European freshwater fish that have gone extinct since the year 1500. Many of these species disappeared decades or even centuries ago, but some have only now been officially confirmed as Extinct.

• 20 species are considered globally extinct (EX)—including well-known Central European species such as the Lake Constance whitefish, the Fera and the Lake Geneva whitefish
• 1 species is regionally extinct (RE)—Aral barbel (Luciobarbus brachycephalus)
• 1 species is considered Extinct in the Wild (EW)—Racovitza’s rudd (Scardinius racovitzai) from Lake Peta in Romania. The species survives only in human care, including at Tiergarten Schönbrunn in Vienna, Zoo Plzeň (Czech Republic), and in breeding programs in Romania and Bulgaria.

New classifications since 2011

Since the last European assessment (2011), nine species have now been newly confirmed as Extinct (EX). These are not, however, recently occurred extinction events. Rather, new data and targeted follow-up surveys show that these species had already disappeared earlier, but for a long time were still listed as Critically Endangered (CR) or under Data Deficient (DD).

The fish species newly classified as Extinct:

• Orkney char (Salvelinus inframundus)—described in 1909 from Hoy Island, the second-largest of Scotland’s Orkney Islands; last record in its natural habitat probably in 1912
• May trout (Salmo schiefermuelleri)—endemic to the Danube catchment (Attersee, Traunsee, Fuschlersee), Austria; last confirmed sighting in the late 19th century
• Ören whitefish (Coregonus trybomi)—a salmonid from Lake Ören in Sweden; last seen in the 1950s
• Swiss whitefish (Coregonus zugensis)—an endemic salmonid in Lake Zug in Switzerland; not documented since the beginning of the 20th century
• Starnberg whitefish (Coregonus renke)—probably already extinct by the end of the 19th century in Lake Starnberg in Germany
• Chiemsee whitefish (Coregonus hoferi)—an endemic salmonid from Lake Chiemsee in Germany; disappeared in the second half of the 20th century
• Jándula chub (Squalius palaciosi)—a cyprinid endemic to Spain; not documented since the late 1990s
• Volga shad (Alosa volgensis)—an anadromous migratory fish from the Caspian Sea and the Volga (formerly also the Terek and Ural); last sighting in 2016 or earlier
• Thracian shad (Alosa vistonica)—a clupeid endemic to Lake Vistonida in Greece; last seen in 1995

This development shows a typical pattern: many freshwater fish species disappear unnoticed and without immediate scientific documentation. Only decades later, when targeted searches remain unsuccessful and historical data are evaluated, is their extinction officially confirmed. The Red List therefore not only reflects current losses, but also makes long-overlooked extinction processes visible.

Freshwater fish species on the brink of extinction

Some European freshwater fish are classified as Critically Endangered (CR), but with the additional note Possibly Extinct (PE or Possibly Extinct in the Wild, PEW). This means there have been no confirmed records for years or decades, but complete extinction cannot be demonstrated with absolute certainty.

These critical cases now include:

• Struga trout (Salmo balcanicus) – CR(PE)
  The species is endemic to Lake Ohrid (Albania). The last secure record dates from the 1960s. Since then, targeted follow-up surveys have been lacking. Because of its similarity to other trout species in the lake, however, it may have remained unnoticed, for example within commercial fisheries.
• Epirote minnow (Pelasgus epiroticus) – CR(PE)
  This small cyprinid is endemic to Lake Pamvotida in Greece. No specimens have been recorded since 2003. Eutrophication, dam construction, and the discharge of untreated wastewater have severely degraded the lake’s water quality.
• Ammersee kilch (Coregonus bavaricus) – CR(PE)
  The species from Lake Ammersee in Bavaria is probably extinct, because only three individuals were documented between 1951 and 2003. The main reasons for the decline are eutrophication of the lake, hydrological changes in the catchment area (for example straightening of the Ammer), and overfishing, especially of juveniles.
• Atlantic sturgeon (Acipenser oxyrinchus) – PEW
  The species probably no longer survives in natural populations in the Baltic Sea, but may persist through reintroduction projects or remnant stocks in controlled programs. Outside Europe, the Atlantic sturgeon still lives along the North American Atlantic coast—from Canada to the Gulf of Mexico—with reproducing populations in several river systems.

These examples show how difficult it is to determine the extinction of freshwater fish with certainty. Many species live in hard-to-access habitats, are rare, or are confused with similar species. As a result, they can remain undetected for years even when their populations have already collapsed. The status Possibly Extinct (PE) therefore marks a critical threshold: the species may already have disappeared or may survive only in last, undetected remnant populations.

No longer extinct: 3 rediscoveries

Alongside the many losses, there are also a few positive developments: some species that were long considered missing or even extinct have been recorded again and are no longer considered Extinct (EX):

• Lake Constance deepwater char (Salvelinus profundus)
  It had been considered missing for decades and was rediscovered in 2016 after there had been no record for more than 40 years. Today, the species is classified as Endangered (EN).
• Ukliva dace (Telestes ukliva)
  This species from the Cetina river system in Croatia was rediscovered in 1997 after previously being considered missing. In the current Red List it is listed as Endangered (EN).
• Danube delta gudgeon (Romanogobio antipai)
  This gudgeon from the lower Danube region (Romania, Bulgaria, Ukraine) was recorded again in 2016. Today it is considered Vulnerable (VU).

Even species that have not been observed for decades can in rare cases still exist. What matters here is targeted research: only intensive field surveys can detect such remnant populations and thereby make it possible to initiate conservation measures at all.

At the same time, these cases also make one thing clear: the absence of records does not automatically mean that a species is extinct, but it makes protection considerably more difficult.

Real improvements are rare

The authors of the IUCN Red List 2025 make clear that many of the observed changes in threat categories do not reflect real improvements.

Of 224 species with changed assessments:

• 113 species were assigned to a higher threat category
• 84 species were downgraded to a lower category

At first glance, this could create the impression that a substantial share of populations has recovered. But that impression is misleading, because less than 5% of these changes are based on actual developments in nature.

Most of the adjustments are due to other factors: improved distribution data for a species, more precise estimates of population sizes, and taxonomic revisions (for example splitting or lumping species). In other words, many species were not “saved,” but merely recorded more precisely and better understood. The development of the data situation also points to this: whereas 27 species were still classified as Data Deficient (DD) in 2011, the current Red List lists only 6.

If one looks exclusively at real changes in populations, the picture is considerably more sobering:

• Only 3 species show a real improvement
  including the sheefish (Stenodus leucichthys), which was downlisted from Extinct in the Wild (EW) to Near Threatened (NT)
• At the same time, 8 species have demonstrably deteriorated further.

Even in the few cases of improvement, these are often not classic recovery stories, but rather the result of new findings about already existing populations.

The Red List is becoming more precise, but the condition of species is hardly improving. The apparent progress is therefore largely a statistical effect. In reality, genuine recovery remains the exception.

Especially affected: migratory fish, karst systems, and isolated or temporary waters

Migratory species are particularly strongly affected. Around 39% of migratory freshwater fish show declining populations, whereas for non-migratory species it is only about 14%. This difference illustrates how heavily fragmented rivers are today: dams, weirs, and other barriers interrupt migration corridors that are crucial for reproduction and foraging. Species such as the Atlantic sturgeon or the allis shad (Alosa alosa) depend on moving between sea and river to reach their spawning grounds. When these routes are blocked, populations often collapse within just a few generations or disappear entirely.

Certain habitats also stand out because of especially high threat rates. In karst systems, which are characterized by underground watercourses, caves, and isolated springs, more than 90% of fish species are threatened. These habitats often harbor highly specialized, endemic species with extremely small ranges, such as various goby or minnow species in the Balkans. Even minor changes—for example through water abstraction, pollution, or construction measures—can lead here to the collapse of entire populations.

The situation is similarly critical in freshwater springs as well as temporarily flowing rivers and streams, in which around 54% of species are considered threatened. These often small and isolated ecosystems react particularly sensitively to changes in the water balance. Many of them lie in the Mediterranean region, where increasing water scarcity, intensive use, and advancing climate change further intensify existing pressures. Longer dry periods, falling water levels, and rising temperatures place additional pressure on species such as the Ukliva dace and other regionally endemic cyprinids.

The main threats to Europe’s freshwater fish

The new Red List makes clear that the decline of many species is no coincidence. The causes are known and affect a large share of European waters at the same time.

1. River engineering and water management

The greatest threat comes from interventions in river systems. Around 69% of species are affected by dams, water abstraction, and other forms of water management, with a further almost 50% affected by additional changes such as channel straightening or canalization.

Across large parts of Europe, rivers are now heavily fragmented. Dams and weirs block migration routes, alter natural flow patterns, and prevent fish from reaching their spawning grounds. At the same time, important habitats are lost, including floodplains, inundation areas, and structurally diverse bank zones.

2. Pollution

Pollution is also widespread. Up to two thirds of all species are affected by pollution, especially from agricultural inputs, wastewater, and industrial emissions.

Nutrients from agriculture lead to eutrophication of waters and thus to oxygen depletion. In addition, there are pesticides, heavy metals, microplastics, and increasingly also new pollutants such as pharmaceuticals or endocrine-disrupting substances.

3. Invasive species

Another major factor is the spread of non-native species. More than half of Europe’s freshwater fish are affected by this. Introduced species compete with native fish for food and habitat or directly displace them. In some regions, such as the Mediterranean, invasive species are now as common as the original fauna.

4. Climate change

Climate change is also worsening the situation. Rising water temperatures, changing precipitation patterns, and more frequent droughts put many species under pressure. In particular, specialized fish that depend on specific temperature ranges or stable water levels react especially sensitively.

5. Overexploitation

The use of waters themselves also plays a role. Fisheries, water abstraction, and other forms of use can directly reduce populations or further impair habitats.

What matters is that these threats very rarely act in isolation. Rather, they interact and reinforce one another. This interplay is what makes freshwater fish conservation so difficult, because several causes would have to be addressed simultaneously in order to save species. The result is that many populations have so far recovered only minimally despite the known causes.

One of the most species-rich vertebrate groups

Freshwater fish are among the most species-rich vertebrate groups on Earth and are considered important indicators of the condition of entire ecosystems. Their decline is therefore not an isolated phenomenon, but a clear warning signal of the advancing loss of ecological stability.

Europe’s rivers, lakes, and wetlands are among the continent’s most valuable habitats, yet also among its most threatened. The new Red List of freshwater fish therefore comes at a decisive moment: the protection of inland waters is increasingly moving into focus, and the need for robust data is growing.

The findings provide a solid basis for planning conservation and restoration measures more effectively. In this respect, the IUCN Red List complements existing assessments: while the Water Framework Directive captures the condition of entire water bodies, the Red List highlights the situation of individual species. Only this combination shows where action is needed and which measures can actually be effective.

Without consistent and coordinated measures—especially to protect habitats, reduce pollution, control invasive species, and limit climate change—a substantial portion of this biodiversity is at risk of being lost irreversibly within just a few decades.

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Sources

• European Commission, Directorate-General for Environment, Ford, M., Adams, C., Amaral, S., Artaev, O., et al. (2026). European Red List of freshwater fishes: Measuring the pulse of European biodiversity. Publications Office of the European Union. https://doi.org/10.2779/880135
• International Union for Conservation of Nature. (2026, 13 April). Almost half of European freshwater fishes at risk of extinction, new IUCN Red List reveals. https://iucn.org/press-release/202604/almost-half-european-freshwater-fishes-risk-extinction-new-iucn-red-list