Rewilding the Danube River

Last October, specialists released 700 Russian sturgeon into the Danube River in Isaccea, Romania. It’s something of a rescue mission for a species that has survived since the time of the dinosaurs. Sturgeon populations are in jeopardy: They are illegally fished for caviar, and dams shrink vital stretches of their habitat. The restocking project is part of a Danube-wide effort known as MEASURES, which, in partnership with WWF, works to revive wild sturgeon in the region and reduce the obstacles that stand in their way—while including the community in sturgeon conservation.

SHRINKING SPACE Wild sturgeon once thrived across Europe. Today, the last wild sturgeon populations still reproducing naturally in Europe are found only in the free-flowing Lower Danube, which courses through Ukraine, Romania, Bulgaria, and Serbia.

AT RISK Hydropower dams have erased important spawning and feeding areas, cutting off fish migration paths. Of the six sturgeon species native to this stretch of the Danube River, two are extinct and four (such as the baby Russian sturgeon pictured) face high risk of extinction.

COMFORT ZONES In the MEASURES restocking project, the young fish are raised in ponds filled with river water from the location of their future release. This allows the migratory fish to adapt to the freshwater into which they will be released and to which they will return to breed. Researchers attach yellow tags to the fish for later identification.

DATA TO THE RESCUE As the tagged fish migrate out to the sea and then back to the river, records of their journeys will provide important data for researchers working to restore healthy populations.