Danube Sturgeon Conservation

On 26 November 2025, the ICPDR reported an encounter in the Croatian Drava: a single ship sturgeon, caught and released. The fish belonged to one of six sturgeon species native to the Danube. Its return to the water was a welcome moment, but a single confirmed record cannot establish a stable population.

The Danube historically supported beluga, Russian sturgeon, stellate sturgeon, sterlet, ship sturgeon and European sturgeon. Today, recovery programmes focus on beluga (Huso huso), Russian sturgeon (Acipenser gueldenstaedtii) and stellate sturgeon (Acipenser stellatus), all Critically Endangered in the 2022 IUCN update, and sterlet (Acipenser ruthenus), Endangered in that update. Their protection brings together fishing restrictions, habitat work, captive breeding and enforcement against illegal trade.

What survives, and what has been lost

European sturgeon remains locally extinct, according to the ICPDR. The ship sturgeon recorded in the Drava offers a different picture: a confirmed individual, with the population’s future still unresolved.

Local survival and global extinction risk answer different questions. A species can disappear from one river while surviving elsewhere; its global threat category does not tell researchers how many fish remain in the Danube. That requires population monitoring, beyond recording occasional sightings or releases.

The Danube is one of Europe’s most important remaining sturgeon systems. It is not the EU’s only wild sturgeon river: European sturgeon also survive in France’s Gironde system. That distinction gives local losses their proper context. The wider sturgeon conservation guide explains how species recovery differs from recovery within a particular region.

Why recovery needs a connected river

The Iron Gates dams cut the route between the lower and middle Danube. For migratory fish, including sturgeons, that means losing access to the Drava, Sava and Tisza, a major obstacle identified by the ICPDR. Protecting fish below the dams cannot, by itself, restore access to the upstream spawning and nursery habitats that a connected river would make available.

Poaching removes fish despite protective rules. Bycatch is the unintended capture of fish during fishing for other species. Both can kill animals conservation programmes are trying to retain. Habitat degradation, pollution and fish kills add further pressures, according to the ICPDR. A fishing ban tackles only part of that damage.

Recovery therefore depends on places working together: breeding areas, the routes between them and the habitats where young fish grow. The guide to dams, pollution and habitat loss explains the mechanisms. Across the Danube, the practical challenge is to protect those connections across borders, rather than safeguard isolated stretches of water.

Fishing protection, country by country

National fishing law and international wildlife trade controls do different jobs. The table concerns wild fish, not permission to market farmed caviar. Scientific capture and conservation work may still need specific authorisation where ordinary fishing is prohibited.

Romania also prohibits specialised sturgeon-catching equipment, including the hook lines known locally as carmace. Bulgaria’s permanent measure replaces its previous fixed-term approach; it does not signal that wild stocks have recovered. To establish whether a particular product is lawful, examine its origin and trade documentation separately from the fishing rules.

Europe’s framework and the Iron Gates

The EU Habitats Directive provides legislation, the EU Strategy for the Danube Region supports regional coordination, and LIFE funding supports projects. According to the Bern Convention, the European Commission endorsed the Pan European Action Plan for Sturgeons under the Habitats Directive.

The Bern Convention’s Standing Committee adopted Recommendation 199 in 2018 to support the Pan-European Action Plan for Sturgeons. The plan guides coordinated action alongside national and river-basin plans, rather than replacing them. Further recommendations in December 2024 addressed habitat assessment, population monitoring and conservation outside the wild, translating broad commitments into methods countries can use.

The International Commission for the Protection of the Danube River, or ICPDR, coordinates work across the basin. Its We Pass initiative examined fish migration at the Iron Gates. We Pass 2 followed, commissioned in 2021 to develop a feasibility study and preliminary designs. These are planning stages; an operating fish passage remains a different milestone.

Following fish, breeding fish, protecting fish

LIFE Sterlet, led by BOKU University, focused on restoring sterlet in the Austrian Danube. Its successor, LIFE-Boat 4 Sturgeon, runs from 2022 to 2030 and focuses on four native sturgeon species.

Protection also has to follow fish beyond the riverbank, into restaurants, retailers and supply chains.

Austria’s Federal Agency for Water Management describes the project’s distributed broodstock, with breeding adults held at different sites, and a cryogenic gene bank preserving reproductive material at very low temperatures. Together, these form part of its conservation breeding work.

The project brings BOKU, viadonau, WWF teams and other partners into conservation breeding and standardised monitoring. Tagging and recapture help researchers distinguish stocked animals from other fish and assess what happens after release. The ultimate test is a population that sustains itself, rather than the number of fish leaving a hatchery.

In Serbia, the MonStur in the Danube project reported telemetry installations near Bogojevo and Ljubičevac in December 2025. The work involved the University of Belgrade’s Institute for Multidisciplinary Research and BOKU. By following tagged fish remotely, telemetry lets researchers investigate their movements. The guide to restocking benefits and risks explains the biological safeguards behind releases.

Protection also has to follow fish beyond the riverbank, into restaurants, retailers and supply chains. The LIFE-linked WWF project on reducing Danube sturgeon poaching brought together conservation organisations, authorities and the Leibniz Institute for Zoo and Wildlife Research. Its market investigations exposed transactions to forensic examination, bringing an otherwise hidden problem into view.

What the market evidence reveals

Laboratory analysis can uncover what a label conceals. Ludwig and colleagues’ 2023 study examined 149 samples of sturgeon meat and caviar from Bulgaria, Romania, Serbia and Ukraine, using genetic and isotope analyses. Genetics helps establish identity; isotope evidence helps distinguish production histories.

The authors identified 31 samples, 21% of the total, as illegally wild-caught. They also identified 17 sold in breach of CITES or EU rules, and 47 cases of consumer deception. These findings concern the samples investigated, rather than a representative share of every product sold across Europe, and the categories should not automatically be added together as separate products. WWF’s earlier 2021 report used 145 tested samples and reported 27 of wild origin.

A separate WWF analysis recorded 395 sturgeon-related illegal incidents reported for Bulgaria, Romania and Ukraine between 2016 and 2023, drawing largely on enforcement authorities’ data. That count captures detected cases, leaving the full extent of offending unknown. The guide to sturgeon poaching explores the enforcement challenges, including why even an apparently orderly supply chain still needs independent checks.