Working for the freshwater pearl mussel in Lahemaa National Park

From 29/06/2015 to 01/07/2015 we were working in Lahemaa National Park for the benefit of the freshwater pearl mussel (Margaritifera margaritifera).
Volunteer conservation holiday leaders were Eva-Maria and Pille from Estonia, but in the group we also had four international people from India, Hong kong and Bangladesh. The native distribution of this species is Holarctic.

Freshwater pearl mussels can be found only in one river in Estonia. (Photo by Pille Pirn)

In Estonia they only live in one river in Lahemaa NP Freshwater pearl mussel is endangered worldwide. This species needs clean and sediment free water. They also need a good population of salmons, who are host organism for the larva. Clean gravel and sand is essential, particularly for juvenile freshwater pearl mussels, for if the stream or river bottom becomes clogged with silt, they cannot obtain oxygen and will die. The freshwater pearl oyster is a filter animal that feeds on particles carried by currents.

Removing branches from a beaver dam. (Photo by Pille Pirn)

During this talgud we removed some abandoned beaver dams, because they accumulate sediment and prevent the fish from crossing it. In Estonia there are too many beavers at the moment and it starts to affect other species. We only took the necessary branches for the water flow, respecting the rest, because the dams are very important refuge places for a lot of aquatic animals, including young fish and some birds use it as a resting place.

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