Process; 2019-2028


EUSDR Priority Area(s): PA 4 Water Quality, PA 6 Biodiversity, Landscapes and Air & Soil Quality
Submitted by: PA 4


EUSDR PA 4 in cooperation with EUSDR PA 6 is very active on increasing the knowledge base on migratory fish species, including sturgeon – the Danube endemic fish species, and is looking for possibilities of re-establishing their migration routes. PA 4 supports international projects like the MEASURES project to restore ecological corridors for migratory fish or We Pass I and II projects to enable fish migration at the Iron Gates, and presented a brochure “Promoting Measures to Enable Fish Migration in the Danube River Basin” summarising the current knowledge. PA 4 carried out a study on effects of noise and waves on fish species and a fish migration restoration document, and prepared an animated film about sterlets. PA 4 will also promote hydro-morphological measures to achieve good ecological status of waters needed for fish migration.




PA 4 Action Plan, Action 5 objectives:

  • raising broad public awareness for the Danube sturgeons as flagship species for the Danube River basin and for the ecosystems and biodiversity of the Danube River basin as a whole;
  • fostering sturgeon conservation activities including protection of habitats, restoration of fish migration routes and ex-situ conservation measures;
  • closing knowledge gaps concerning monitoring of pressures and planning of measures for fish migration in coordination with PA 6.

There are two major barriers on the Danube River for migratory fish species – Iron Gates in Romania/Serbia and Gabčíkovo Water Structure/Dunakiliti in Slovakia/Hungary. Construction of fish passes in Iron Gates can serve as information base for construction of other fish passes in Danube River (e.g. Gabčíkovo, and upper Danube ones). Migratory Fish Flagship Process will make an effort to facilitate removing the fish barriers on the Danube River.


Need and (expected) impact


In 2021, PA 4 prepared the brochure “Promoting Measures to Enable Fish Migration in the Danube River Basin”. In 2022, PA 4 organised a fish migration working meeting, which provided the platform for discussions about the behaviour of migratory fish species and technical solutions of fish pass designs e.g. the Iron Gates and Gabčíkovo Water Structure. In addition, PA 4 finalised the fish migration restoration document that takes into account the suggestions from the meeting. The document provides a database of relevant information on migratory fish restoration (e.g. methodologies, the investigation on behaviour of fish species, an overview of ichtyocenoses in Middle and Upper Danube), and estimates alternative technical solutions of fish pass design for specific migratory fish at the Gabčíkovo Water Structure. The document serves as the actual knowledge base for designing and constructing fish passes in the Danube River.


Macro-regional dimension


Migratory fish species (e.g. sturgeons) can spawn only in the river without barriers and borders, so this process will affect all countries on the Danube River. Therefore, conservation measures will be effective only in case they are applied at macro-regional level. Moreover, countries and operators of Iron Gates and Gabčíkovo Water Structure should closely cooperate for creating the most feasible solution for fish passes.


Stakeholders involved


ICPDR; PA 6 – Danube Sturgeon Task Force (DSTF); related projects leaders, related hydropower operators (e.g. Water Construction, Slovakia, Hidroelectrica, Romania), experts on migratory fish protection in the Danube Region, experts in the field technical design of fish passes, PA 4 SG members, etc.

Regular cooperation with the mentioned organisations, ensured by trilateral and SG meetings, joint events.


Budget and Funding


The process has already been partly financed by implementation of the PA 4 relevant projects related to sturgeons. The transnational projects were financed by European Commission and Interreg Danube Transnational Programme.

The new financing should be allocated for sturgeon conservation measures projects and processes (e.g. negotiations, meetings, conferences, workshops and public awareness raising campaigns).


Further information




Andrea Vranovská, Priority Area 4 team member, Water Research Institute, Bratislava, Slovakia (