The four-year project will centre on 21 of Britain’s key conservation sites, focusing on the protection of remaining mussel populations which face extinction in many rivers.
Scottish Natural Heritage (SNH) said the sites in Scotland, England and Wales are designated as special areas of conservation under the European Habitats Directive and are deemed to be the most important for the survival of pearl mussels.
Central to the project will be a crackdown on wildlife crime, with riverwatch schemes involving police and fishery owners helping to prevent the illegal persecution of the mollusc.
Dr Iain Sime of SNH said: “The freshwater pearl mussel has suffered a catastrophic decline across its former range.
“It is important and we need to care because it is an excellent indicator of good water quality, and we all need good quality drinking water.
“As part of the project we are aiming to restore river channels and plant trees along more than 70km of riverbanks to help provide the habitats which the pearl mussels need to flourish.”