Researchers identified 150 asprete fish in Romania’s Vâlsan River during annual scientific monitoring conducted from September 22 to 25, down from 181 specimens in 2025. Of this year’s total, 114 fish (or 76%), were found along a single 450-meter stretch representing less than 5% of the approximately 10 km in which the species was detected.
The asprete (Romanichthys valsanicola), Europe’s rarest freshwater fish, survives only in the Vâlsan River in Romania’s Argeș county and nowhere else in the world. The 2026 survey found the species at nine of the 21 monitoring stations examined by researchers from the Centura Verde/Green Belt Foundation’s Aspretele Trăiește/Asprete Lives conservation programme and its partners.
According to the foundation, the core population is trapped between a concrete barrier upstream that the fish cannot cross and the Brădetu wastewater treatment plant downstream. The plant allegedly operates outside the required parameters and chronically pollutes the river, creating what conservationists describe as a chemical barrier that restricts fish movement and affects survival downstream.
Pollution of the Vâlsan River caused by the Brădetu wastewater treatment plant, August 30, 2026. Credit: Green Belt Foundation
The monitoring figures showed that the number of specimens identified in the 450 m core area remained virtually unchanged, at 114 this year compared with 113 in 2025. Downstream from the treatment plant, however, the number fell from 68 to 36, accounting for almost the entire year-on-year decline.
“The figures now clearly show the connection between the distribution of the asprete and the continued poisoning of the Vâlsan River by the treatment plant, which has failed to operate within the required parameters for many years,” conservationist Alex Găvan, president of the Green Belt Foundation and founder of the Asprete Lives programme, said.
He also called on the Romanian state to ensure the ecological flow required to maintain the river ecosystem downstream from the Vâlsan dam and the Dobroneagu water intake.
“Without the ecological flow calculated by the National Institute of Hydrology and Water Management, the asprete has no chance,” Alex Găvan stated. “We have a fish that is unique in the world, while the river and the community of the Vâlsan Valley need healing. Beyond preserving a species and an extremely valuable ecosystem, we are talking about an urgent public health issue.”
The asprete requires fast-flowing, well-oxygenated water. Lower flows reduce the available habitat and the dilution of wastewater, while warm, dry conditions cause the remaining water to heat more rapidly and retain less oxygen.
Asprete photographed in the Vâlsan River on September 23, 2026. Credit: Alex Găvan/Green Belt Foundation
The foundation said the ecological flow is frequently not maintained downstream from the dam and water intake. Plus, the absence of sewerage systems in the Brăduleț and Mușătești communes adds further pressure on the river.
Because most identified specimens are concentrated in such a short section, conservationists warn that a single severe pollution incident, flood, or extended period of low flow could threaten the species with extinction.
“For the asprete, together with the people of the Vâlsan Valley, the authorities and our partners, the choice is simple: either we save it now, or we lose it forever,” Alex Găvan said.
The foundation is working to remove three artificial barriers in the Brădetu area, including the concrete structure preventing the fish from moving upstream. The project, carried out through the Open Rivers programme, would reconnect approximately 12.8 km of river habitat.
Meanwhile, nearly EUR 500,000 was allocated through Romania’s 2026 state budget to restore the Brădetu treatment plant to the required operating standards following discussions between the foundation and public authorities.
Another proposed measure concerns the mandatory ecological flow. Values calculated in 2024 by the National Institute of Hydrology and Water Management, through a study commissioned by the foundation, could be incorporated into the water-management permits for the Vâlsan dam and Dobroneagu intake.
In another move, on September 22, the foundation also submitted a five-year conservation project for funding under the European Union’s LIFE programme. The LIFE ASPRETE proposal is backed by Romania’s Environment Ministry and the Presidential Administration’s Climate and Sustainability Department.
If approved by the European Commission, the project would involve the University of Natural Resources and Life Sciences in Vienna, the Hungarian University of Agriculture and Life Sciences, and the Dutch Sensing Clues foundation, alongside scientific advisers from France, Germany, and Romania.
The project would combine annual monitoring with habitat restoration, controlled restocking, and the preparation of a national action plan for the species. It also proposes the creation of an Asprete Sanctuary for research and captive breeding, intended as permanent conservation infrastructure.
The sanctuary would be built on approximately 1.5 hectares in the village of Galeșu, Brăduleț commune, within the Vâlsan Valley Natura 2000 site. The Green Belt Foundation has acquired the land for this purpose.
“If Romania loses the asprete, the entire world loses the asprete. We are talking about a species that exists almost entirely between two points on the map just a few minutes’ walk apart. That is why what happens along 450 meters of river in a village in Argeș is not a local issue. It is a responsibility Romania has toward the entire planet, and the outcome is being decided now, not ten years from now,” Alex Găvan told Romania-insider.com.
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Discovered in 1956, the asprete is endemic to Romania and classified as critically endangered on the International Union for Conservation of Nature’s Red List. It historically inhabited the Argeș River and Râul Doamnei as well, but now survives only in the Vâlsan, within an area protected by the Natura 2000 network and the Vâlsan Valley Nature Reserve.
Before the Asprete Lives programme was launched in 2019, official Environment Ministry data estimated the remaining population at only 10 to 15 specimens. Incidental surveys identified 12 fish in 2020 and ten in 2021.
Then, standardized annual monitoring across 21 stations began in 2022. Researchers identified 57 specimens that year, 153 in 2023, 97 in 2024, 181 in 2025, and 150 in 2026.
The species’ documented range covered approximately 16 km between Brădetu and Vâlsănești from 2022 to 2024. It was detected across only around 9.5 km in 2025, while this year’s survey extended the known range by approximately 600 meters downstream, although it remains well below the earlier 16 km area.
The 2026 monitoring was conducted by 12 researchers: Mircea Mărginean and Răzvan Andrei Pop of Fauna & Flora; Andrei Togor and Marcus Drimbea of Aqua Crisius; Nagy András Attila and Szilágyi Bálint of Babeș-Bolyai University; Ilie Telcean of the University of Oradea; and Călin Lațiu, Alex Uiuiu, George Muntean, Tudor Păpuc, and Raul Savin of the Applied Ichthyology Laboratory at the University of Agricultural Sciences and Veterinary Medicine in Cluj-Napoca. Fauna & Flora country director Iain Trewby and Green Belt Foundation representatives Adrian Dăscălescu and Nicoleta Dobrotchi also participated.
Asprete monitoring field team in Mușătești, Argeș county, on September 23, 2026. Credit: Green Belt Foundation
The Green Belt Foundation, formerly the Alex Găvan Foundation, has run the Asprete Lives programme since 2019.
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