Towards a healthy Danube

Fish migration at the Iron Gates

Posted on 18 November 2013


The Danube is the largest European river in which several sturgeon species are still present. This is an extraordinary situation. The Danube river basin countries are committed to improve the connectivity of the river for migratory fish, under them the sturgeon. This to reach spawning, feeding and nursery areas.

The Iron Gates I and II dams between Romania and Serbia form a major ecological barrier for sturgeon and other characteristic migratory Danube fish species. The dam complexes consist of weirs, ship locks and hydropower stations. The Iron gates are the first impassable obstacles in the Danube from the black sea and located at ca. 850 km distance from the estuary in the Black sea.

Restoration of river connectivity at these sites would reopen a reach of more than 800 km upstream This will provide suitable habitat and spawning grounds along the Danube and its tributaries to several migratory fish species.

Dutch  - Romanian partnership
The project team consists of fish migration experts of ARCADIS, LINKit consult, Wanningen Water consult, Fish Flow Innovations and the Romanian Danube Delta National Institute (DDNI). ARCADIS is the leading partner of the consortium, the project is partially financed by the Dutch government under the Partners for Water Programme.

Involved stakeholders
The following supporting stakeholders are involved: International Commission fort the protection of the Danube River (ICPDR); Ministry of Foreign affairs Romania; ministry of Environment and Climate Change  Romania; Ministry of Agriculture; Forestry and Water Management Romania; National Administration Apele Române; National Agency for Fisheries and Aquaculture Romania; Hidroelectrica Romania; Derdap Hydro Power Plant – Serbia, Ministry of Agriculture, Forestry and Water Management – Serbia; Embassy of the Kingdom of the Netherlands in Romania and WWF


Extend the possibilities for different sturgeon species and other migratory fish to migrate 800 km further upstream in the Danube river system. Project result will be a report providing a continuation of the 2011 FAO study*.


The following activities are carried out and reported:

  • Tagging and monitoring of sturgeons in order to determine the correct location for a fish passage at the Iron gates II;
  • Preliminary design of a fish way at Iron gates I and II for upstream fish migration, including a cost estimate.
  • Preliminary study to downstream fish migration possibilities;



A better ecological status for the Danube river gives the whole ecosystem a boost. The water quality will improve and all kind of fish and bird species will benefit from the improvement. Mainly the sturgeon.
For the different sturgeon species it will mean that it has better circumstances to maintain its populations in the Danube river.
The international Dutch – Romanian partnership will set an example for other large fish migration barriers in Europe and the rest of the world.
Innovative technology will be integrated and tested in the Danube river.

Technologies used

Fish passages for sturgeons at large hydro power stations. This technology is highly innovative in the world and is very limited available.

For downstream migration of migratory fish, FishFlow Innovations develops and builds innovative fish migration facilities and protection systems. Their fish friendly products have been developed with particular attention for the natural preference and behaviour of fish.  Fish friendly hydro power turbines that enable passage without injury or mortality are used in the project.

Project location

Project partners

  • Arcadis Nederland B.V.
  • Linkit consult