Local people will be in the front line in the fight against the illegal fishing of the threatened freshwater pearl mussels in the Highlands.

The rare molluscs live in the gravel beds of clean rivers and feed by filtering water and removing fine particles. Thishelps keep Scotland's rivers clean and benefits species such as salmon and trout. However conservationists say they are critically endangered, and Scotland is one of their remaining strongholds.

The Riverwatch project is the latest initiative in Wester Ross to protect the species along the west coast and will launch in Gairloch tomorrow.

Riverwatch volunteers are being invited to attend the launch, which will feature a walk along a local river to discuss pearl mussel ecology, followed by training in identification and reporting of pearl mussel crime.

The new work comes in response to reports of recent illegal pearl fishing in the West Sutherland area.

Natalie Young, Riverwatcher from the Pearls in Peril LIFE project, said: "Wester Ross has some globally important populations of pearl mussels and it is essential that these mussels are protected from pearl fishing. This is especially important in response to the spate of pearl fishing incidents reported in the Lochinver area last year.

"Freshwater pearl mussel populations on the West coast are extremely vulnerable to pollution and illegal fishing. The Riverwatch scheme aims to raise awareness of the threat to pearl mussels from illegal exploitation and to train volunteer Riverwatchers how to spot and report pearl mussel crime.

"Freshwater pearl mussels have historically been fished for the pearls they may produce. However, they very rarely contain pearls and they are fully protected under law - it is a crime to kill, injure, take or disturb freshwater pearl mussels."

Chief Inspector Colin Gough, Police Scotland Area Commander South Highland, said: "Illegal pearl fishing has the potential to devastate the fragile populations we have here in the Highlands. Freshwater pearl mussels are protected by law and are a very important part of a river's habitat therefore it is vital we encourage members of the public to report any suspicious activity. "

He said Police Scotland would continue to work in close partnership with the Pearls in Peril LIFE+ project by supporting their river patrols, and investigating any reports of this type of crime.