Posted on 25 April 2020
While highly endangered, sturgeons are excellent indicators of the ecological status of the Danube, especially concerning the function of the river as an ecological corridor.
23 April 2020
- Three hundred juvenile Russian sturgeons (Acipenser gueldenstaedtii
) were released into the Danube River at Isaccea, Romania with the aim to save and strengthen two highly endangered Danube sturgeon populations using state-of-the-art conservational methods. The event follows other stocking activities which took place last year, one in Isaccea and another in Baja (Hungary)
, which were organised by the MEASURES Project (Managing and Restoring Aquatic Ecological Corridors for Migratory Fish Species in the Danube River Basin) in cooperation with WWF.
“The fish were released after being previously individually tagged with PIT (Passive Integrated Transponder) microchips. Taking into account that commercial fishing of sturgeon is prohibited in Romania, we consider that sturgeons have a high chance of safely reaching the sea to grow and to return to the Danube for reproduction
,” said Marian Tudor, Danube Delta National Institute for Research and Development.
The 1-year-old sturgeons were raised in fish ponds at a fish farm in Tulcea County. During the last few months, the sturgeons have lived in ponds filled with river water specific to the place where they will be released. This is essential for migratory species because they must get used to the water in which they will return for breeding.
The Russian Sturgeon (Acipenser gueldenstaedtii
) is also known as the "Danube Sturgeon" because it was once the most common species of sturgeon in the river. The decline of the species was mainly caused by the construction of dams
(Iron Gates I and II) which blocked the access of sturgeons to the breeding areas in the Lower Danube. This species of sturgeon can reach 2.35 m in length and can weigh over 100 kg. Sturgeons are on the IUCN Red List of Critically Endangered Species, and considered to be the most endangered group of species on the planet.
This month, a Ministerial Order
was published in The Official Journal of Romania
referring to endangered Black Sea marine species and measures for their protection and conservation. The list includes the Russian Sturgeon, along with the Starry Sturgeon (Acipenser stellatus
), the European Sea Sturgeon (Acipenser sturio
) and the Beluga Sturgeon (Huso Huso
). The list is to be transmitted to the Permanent Secretariat of the Black Sea (part of the Black Sea Convention
), in order to be included in the Black Sea Red Data Book, which is updated every 5 years on the basis of scientific evidence.
"This is why it is essential to be able to track, in case of capture, the sturgeons released in the Danube which all have an implanted tag. Recapture data is very important because it provides information about the success of the stocking effort, the state of the wild population, the state of the natural environment and, last but not least, in the case of migratory species, information about the existence and functionality of ecological corridors
. " - Cristina Munteanu, Project Manager, WWF-Romania
Sturgeon and other migratory fish species represent the historical, economic and natural heritage of the Danube. Furthermore, they are indicators of the ecological status of the river’s watercourses, especially concerning the function of the river as an ecological corridor. The fragmentation of rivers by transversal structures like hydropower dams or flood protection measures poses a threat to natural fish populations if they are no longer able reach important habitats like spawning grounds, feeding grounds and wintering habitats. Transnational management and restoration actions to re-establish these corridors as migration routes, as well as stocking with indigenous species, are essential until we have achieved a self-sustaining population again.
For more info, please contact:
Danube Delta National Institute for Research and Development (DDNI),
Tulcea, Romania, firstname.lastname@example.org
About the project
(01.06.2018-31.05.2021) includes 10 countries along the Danube (Germany, Austria, Slovakia, Slovenia, Hungary, Croatia, Serbia, Romania and Bulgaria). The project partners have joined forces to conserve endangered migratory fish species in the Danube River Basin (DRB). During the three year project, MEASURES will map and identify key habitats by developing and testing a methodology for migratory fish habitat mapping, develop a harmonised strategy for restoring ecological corridors, and support inclusion in future management plans. The project will also compile an online database - the ‘MEASURES Information System’ – that will facilitate the access of experts, decision-makers and the general public to the relevant information available.
WWF is engaged in sturgeon protection measures in most Danube countries, most recently through the Life for Danube Sturgeons Project.
Sturgeons used to be present in almost all European rivers, but today seven out of the eight species of sturgeon on the European continent are threatened with extinction. Sturgeons have survived the dinosaurs, but now teeter on the brink of extinction. The Black Sea Region is crucial to the survival of these species in Europe. The Danube and the Rioni River in Georgia are the only two rivers remaining in Europe where migrating sturgeons reproduce naturally. The main reasons are overfishing and loss of habitat through dams that block migration routes or in-river constructions, facilitating navigation. These are often detrimental to the feeding and spawning habitats, necessary for sturgeon survival. Within the EU the only river with naturally reproducing sturgeon populations remains the Danube. Crucial but no longer reproductive stocks are left in the Po River in Italy and the Gironde in France. Restocking activities take place in Bulgaria, Hungary, Romania, France, Germany, Poland, Austria and the Netherlands. Our priority is to identify and protect the critical habitats of the remaining four sturgeon species (Huso huso
, Acipenser stellatus
, A. ruthenus
, A. gueldenstaedtii
) in the Lower Danube and north-western Black Sea, as well as to reduce pressure on their remaining populations by addressing poaching and ensuring protection.