Estonia’s endangered freshwater pearl mussel colony to receive new specimens 27.09

According to Kunnar Klaas, head of RMK Põlula Fish Rearing Department, the population of freshwater pearl mussels in Estonia has fallen under 10,000 specimens; a critical point for the survival of the species.

“The mussels are still reproducing, but the newborns are unable to survive due to the polluted state of their environment, leading to a lack of population renewal,” says Klaas. “The population of freshwater pearl mussels is aging and dying. What they need is the restoration of their habitats.”

The RMK and University of Tartu are partaking in a joint project between Finland, Sweden and Estonia called LIFE Revives; the goal of the project is to revive and restore natural habitats of freshwater pearl mussels.

Klaas notes that it’s possible to improve the situation of the freshwater mussels fairly quickly. “During the restoration of the mussel habitats, young freshwater mussels are being raised in RMK Põlula Fish Rearing Centre and in the river in a controller environment,” says Klaas. From the lab, 5000 one-millimetre long mussels will be relocated to into the river into special nests or boxes in which they will be maintained in the future as well. The river will also undergo restoration work through the addition of sediment-traps, rocks and current-guides.

In order to give the mussels a chance at survival, it’s important to restore the river’s hydrological regimes, water quality and to guarantee a stable current. In order to achieve this, the RMK will map out all drainage systems and structures that could potentially harm the mussels. These will be removed, if possible.

The University of Tartu will monitor mussel habitats and ensure the success of the restoration works. A baseline study will map out the riverbed using sonar or by hand in the shallow parts of the river. Open riverbanks will be studied through drones. The data gathered here will be used to find local restoration points with the highest chance for undergoing a successful restoration.

The project is led by the University of Jväskylaä. Similarly to Estonia, the project is also aimed at restoring habitats, basins and buffer zones in Finland and Sweden. Restorations are carried out in 32 Northern and Western Finnish rivers and in 36 Northern Swedish rivers. Altogether, around 1.5 million young freshwater pearl mussels will be raised and released into the wild. In 12 of the rivers, specialised living facilities – so called kindergartens – will be created for young mussels.

The LIFE project will last for six years and has a budget of 15.9 million euros, with 9.5 million euros having been granted by the European Commission. The Estonian budget is 2 million euros, 1.2 of which will be allocated to the restoration of wetlands, 400,000 to monitoring and 400,000 to raising young mussels. In addition to the European Commission, the Ministry for the Environment and RMK fund Estonian activities, both with 334,000 euros.

Põlula Fish Rearing Centre begun raising mussels last year. This spring, 400 freshwater pearl mussels have been released back into their native habitats.

Further information:
Kaupo Kohv
Head of RMK’s Nature Protection Department
+372 5349 7924
kaupo.kohv@rmk.ee

Marko Kohv
Researcher of Applied Geology for the Geology Department of the University of Tartu
+372 5666 3752
marko.kohv@ut.ee

Kunnar Klaas
Head of the RMK Põlula Fish Rearing Department
+372 527 8245
kunnar.klaas@rmk.ee