Work has started on a project to remove protection boulders from an Angus riverbank to boost freshwater pearl mussels and salmon populations.
As part of a £3.5 million UK project, The Pearls in Peril Project (PIP) will see 873 metres of boulder bank protection removed from sections of the River South Esk and its White Water tributary in Glen Clova and Glen Doll. Work was expected to start on Monday (July 6).
The South Esk is a site of European importance as a Special Area of Conservation for its pearl mussels and salmon. And it is high priority site due to an increase in illegal exploitation reported in the area.
The bank protection was installed in the 1990s to limit riverbank erosion and channel movement. This reduced river habitat quality for freshwater pearl mussels, salmon and trout.
The boulders’ removal will make the riverbank more accessible for water voles around one of the restoration sites.
This new population was only found last summer by PIP survey staff – the first record of these rare mammals for this part of Glen Clova.
PIP has also been working to increase awareness of illegal pearl fishing and launched a Riverwatch Scheme for the River South Esk at Montrose Basin Visitor Centre on July 7.
Freshwater pearl mussels are rare molluscs that live in the gravel beds of clean rivers. They feed by filtering water and removing fine particles. This helps keep our rivers clean and benefits other species like salmon and trout. The mussels are critically endangered and Scotland is one of their few sole strongholds. Mussel larvae spend the first few months of their lives attached to the gills of young salmon and trout, so healthy fish populations are vital to their lifecycle.
Freshwater pearl mussels have historically been fished for the pearls they can produce.
However, they very rarely contain pearls and they are fully protected under law – it a crime to kill, injure, take or disturb them. During the works there may be minor disruption to footpaths and tracks. Signs and alternative routes will be in place.