WWF-Ukraine joined regional and national partners in a large-scale ecological initiative — the release of endangered sturgeon species into the Danube River, within the Danube Biosphere Reserve
The waters of the Danube were stocked with 18,000 juvenile of sterlets (Acipenser ruthenus), each weighing up to 3 grams and 13,900 juvenile of Russian sturgeon (Acipenser gueldenstaedtii), each weighing up to 5 grams.
The event was organized on May 22nd, the International Day for Biodiversity, in cooperation with the Odesa Regional State Administration and the State Agency of Ukraine on the Development of Land Reclamation, Fishery and Food Program, with additional support from the TOV Odesa Sturgeon Breeding Complex, the Danube Biosphere Reserve, and the State Fishery Patrol. The release was held in accordance with the Sturgeon Action Plan for Ukraine (2021–2030), as part of the country’s commitments under the Bern and Bonn (CMS) Conventions, as well as the CITES Convention. It also continues a long-standing collaboration between regional authorities, scientific institutions, and international environmental organizations.
The fish have verified Danube genetic origin
The juvenile sterlets and Russian sturgeons were fertilized, incubated, and raised under controlled conditions at the TOV Odesa Sturgeon Breeding Complex.
Due to their small size (up to 5 grams), the fish are not yet subject to individual tagging or microchipping. However, this early developmental stage offers the highest chance of successful adaptation in the wild, as the young sturgeons better acclimate to natural conditions and begin developing instinctive behaviors from the outset. The sterlet (Acipenser ruthenus) is a freshwater sturgeon species that never migrates to the sea. Its presence serves as an indicator of clean and healthy river ecosystems. The Russian sturgeon (Acipenser gueldenstaedtii) is a larger migratory species that historically spawns in the Danube (and the other big rivers in Ukraine) and overwinters in the Black Sea.
Both species are listed in the Red Data Book of Ukraine and are protected internationally under CITES, the Bern Convention, and the Bonn (СMS) Convention.
Of the 26 sturgeon species that exist worldwide, six were historically found in Ukraine: beluga (Huso huso), sevruga (Acipenser stellatus), sterlet (Acipenser ruthenus), Russian sturgeon (Acipenser gueldenstaedtii), Atlantic sturgeon (Acipenser sturio), and ship sturgeon (Acipenser nudiventris). All six are listed in the Red Book of Ukraine. The latter two species are officially considered extinct within the country’s territory.
“This is the largest restocking effort we have carried out with our partners under wartime conditions. We are grateful to the Odesa Regional State Administration for their clear position and to WWF-Ukraine for their consistent support. These fish represent our biological future, and it is our duty to protect it. We are not just releasing fish — we are restoring balance in nature. Sturgeons are an umbrella species, meaning that by protecting them, we are protecting the entire riverine ecosystem. The Odesa region has historically been the native habitat of Danube sturgeons, and our goal is to make that a reality once again,” emphasized Viktor Katrechko, Director of the TOV Odesa Sturgeon Breeding Complex. “Our facility is a unique enterprise for Ukraine. We are the only fully operational broodstock hatchery with a closed sturgeon breeding cycle. Starting from reproduction through our established broodstock, we are able to raise fish from eggs to sexually mature individuals. This enables us to provide genetically pure and healthy juveniles for restocking and long-term monitoring. As a result, we are not only supporting natural populations but also helping to prevent the extinction of these remarkable species,” he added.
“Sturgeons are a symbol of the living heritage of the Danube — species that have survived millions of years, entire eras and empires, yet today find themselves on the brink of extinction. Their return to the wild is not only an effort to preserve biodiversity, but also a vital step toward restoring an ecosystem that has, for centuries, sustained life and provided resources for millions of people. What makes this even more valuable is that the Danube remains one of the last rivers in Europe where endangered sturgeons can still live and reproduce freely. We are deeply grateful to all the partners and participants in this initiative. The Danube deserves to remain alive, and sturgeons deserve to return to where they truly belong — the free, clean waters of this majestic river. Each restocking effort sends a clear message: we are not giving up. We are working, restoring, and protecting. And we want sturgeons to live not only in our memory — but in the reality of future generations,” explains Oksana Konovalenko, Freshwater Programme Manager at WWF-Ukraine.
“Restocking the Danube with sturgeons is part of a broader, long-term strategy that has been underway for many years. WWF-Ukraine has been actively involved in sturgeon conservation since 2016. During this time, our experts have helped identify key sturgeon habitats in Ukraine, secured their official protection, and strengthened efforts to combat illegal trade and poaching of sturgeon products,” adds Konovalenko.
It is worth noting that part of the funding for the sturgeon restocking was provided by Bob Kreiken, a volunteer and researcher from the Netherlands. He studies international biodiversity policy at Delft University of Technology. The Summer of 2024 he made a two-month-long expedition across Europe, along the Rhine by bicycle and over the Danube by kayak from the North to the Black Sea to raise awareness and €6.625 for the World Wide Fund for Nature to fund sturgeon conservation projects in Europe. The campaign Strong for Sturgeons reached over one million people across Europe through social media and news coverage.
“Ukraine is historically home to six species of sturgeons that inhabit its great rivers such as the Danube and the Dnipro. The Ukraine war is intricately related to the loss of sturgeons. Firstly, international scientific collaboration to conserve the sturgeon in the Black Sea basin has become much harder due to the war. To make the situation worse, the war has caused widespread destruction to nature, exemplified by the destruction of the Kakhovka dam which also destroyed the country's only sturgeon breeding facility: The only state sturgeon farm in Ukraine is completely flooded | WSCS. And amidst the decline in funding in Ukraine for nature conservation, and Russian disregard of environmental laws in the occupied territories, illegal poachers are able to increase their activities: Opinion: Submariners, Fish Poachers and Drug Dealers – the Many Fronts of the War for Ukraine. In war, what makes a nation becomes paramount. The destruction of natural heritage is as tragic as the destruction of cultural heritage because if you dare to see the connections, you understand they are the same. I hope that as part of the recovery of Ukraine, Europe steps in to ensure the full recovery of Ukrainian nature, which I believe will help people recover too,” shared Bob Kreiken.
