Bulgaria continues to replenish the 50,000 sturgeon stock of the Danube!

Bulgaria continues to replenish the 50,000 sturgeon herd of the Danube!

The next replenishment is expected in spring 2015, when another 40,000 fish will be released into the waters of the Danube.
November 2014 was already a significant month for the Danube sturgeon. 11,000 sterlet fry were released into the river in the area of ​​the Persina Nature Park, Bulgaria. The event was part of the plan to restore the 50,000 sturgeon herd, financed by the Operational Programme “Environment 2007-2013“, and is also part of the sturgeon protection program of the World Wildlife Fund (WWF).

The sterlets were transported in special water tanks, which were supplied with pure oxygen during the 4-hour road transport from the state of Montana, where they were brought to the point of Belene, on the banks of the Danube. Every hour, oxygen was measured by Professor Angel Cekov, who had been taking care of these sterlets since their birth. Thanks to this care, all the fish were delivered to their new home alive and healthy and are getting used to their new surroundings.

Each fish was tagged with a millimeter magnetic sensor. It helps track the migration of the herd and the spawning grounds. "This helps us protect the spawning grounds," says Stoyan Mihov, manager of WWF Bulgaria. Therefore, the young sterlets were released along the natural migration route of sturgeons, which is studied within the framework of the same WWF project to protect sturgeons. This means that they were released in conditions close to their natural birth conditions. Also, the pools in which they were raised were as similar as possible to the Danube environment.

In addition to the fact that the fish were tagged, they were also tested for the purity of their genetic code and origin from the Danube. Hybridization is a big problem for endangered species. "Sturgeon farms very often cross-breed for faster reproduction of fish and obtaining caviar. So you can see a North American sturgeon crossed with a Siberian one," said Mikhov.

"If we cross-breed sturgeons, it means we cannot protect the local species" - "and the survival of sturgeons is an indicator of the health of the river," says WWF manager in Bulgaria Vesselina Kavrakova.

Another reason to preserve the genetic purity of sturgeons is that they have existed for 200 million years - since the time of dinosaurs! "That is why sturgeons are often called "living fossils," says Mikhov.

However, sturgeons are now very vulnerable due to fishing and interference in their natural habitat. Unlike other sturgeons of the Danube, the sterlet (Acipenser ruthenus) is on the verge of extinction. Its relatives Beluga (Huso huso), Russian sturgeon (Acipenser gueldensteadti), Stellate sturgeon (Acipenser stellatus) are not so lucky - they have almost disappeared, while the Ship (Acipenser nudiventris) and the European sturgeon (Acipenser sturio) are on the verge of global extinction.

"It is very easy to destroy natural resources. It will take a lot of time, a lot of money and a lot of effort to restore what was lost," said Vesselina Kavrakova.
"The success of the first part of the restoration and conservation of the sturgeon stock gives hope that we can help nature restore balance. In addition, this was not the first initiative to replenish sturgeon in the Danube. Between 2006 and 2009, the Romanian Ministry of Environment released around 400,000 sterlet, beluga, stellate sturgeon and Russian sturgeon into the river. In addition, 90,000 were released in 2013 by the University of Galati as part of the European Fisheries Programme.