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

The Riverwatch project in Wester Ross is the latest initiative 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.

The rare molluscs live in the gravel beds of clean rivers and feed by filtering water and removing fine particles.

This helps 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.

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 had the potential to devastate fragile populations of mussels 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.

A total of 21 rivers across Britain are involved in the Pearls in Peril project, all of which are designated as Special Areas of Conservation (SACs).

In Scotland, these include the Rivers Dee, South Esk, Spey, Evelix, Naver, Borgie, Oykel, Fionaven, Abhainn Clais an Eas, Allt a'Mhuilinn, Ardvar & Loch a'Mhuilinn Woodlands, Inverpolly, Moidart, Kerry, Glen Beasdale, Ardnamurchan Burns, Rannoch Moor, North Harris, Moriston and Mingarry Burn on Mull.

In the 12th century Alexander I, King of Scots, was said to have the best pearl collection of any man living, but from the 16th century onwards there was commercialisation of the fishery and from the 19th century there signs of a growing shortage.

There is evidence that pearl mussels have become extinct from an average of two rivers every year in Scotland since 1970.

In 2011, pearl mussels joined giant pandas and Javan rhinos on a list of 365 of the world's most endangered species.

The following year 2012, several entire breeding colonies were stolen from remote areas of Harris.

So the 'Pearls in Peril' , a LIFE + NATURE project, was launched co-funded by 14 organisations across Scotland, England and Wales.

The project spans four years from 2012 to 2016.