Several rivers in west Scotland have been proposed as Special Areas of Conservation for their outstanding populations of freshwater pearl mussel and three are included in the Life in UK rivers project.
Less than 100 years ago freshwater pearl mussels used to be an abundant species in many European rivers, including Great Britain and Ireland. Today the situation is quite different and the freshwater pearl mussel is now regarded as globally threatened. The decline has been especially marked on the continent and in England and Wales, while Scotland is now considered a European stronghold for the freshwater pearl mussel. Even so, freshwater pearl mussels are extinct or about to become extinct in two thirds of the Scottish rivers that were occupied by this species 100 years ago.
Several reasons have been suggested for the observed decline in freshwater pearl mussel populations, all of which relate to changes resulting from human activity, particularly those which have taken place over the last 50-100 years. Mortality due to pearl fishing has been a major cause of decline across the range of the pearl mussel, leading to total extinction in many rivers. In 1998 the freshwater pearl mussel was given full protection in UK under the Wildlife and Countryside Act, making it illegal to take or kill any freshwater pearl mussels. The protection also includes pearl fishing using special tongs.
Other major reasons for the decline include agricultural and industrial pollution, loss of habitat due to river engineering and declining populations of salmon and trout. Freshwater pearl mussels need healthy salmonid populations to complete their life cycle. Mussel larvae (glochidia) are parasitic on the gills of salmon and trout and only those larval mussels which find such a host will survive.
Most of the remaining viable freshwater pearl mussel populations in Scotland are found in rivers in the Scottish Highlands. Situated in remote areas with scattered settlements, limited industry, agriculture and forestry activities these rivers have not been as affected by habitat destruction and deterioration in water quality as those in more populated and developed areas.
To ensure that these rivers will provide good habitat and sustainable freshwater pearl mussel populations in the future, a management plan has been developed for each river, taking the needs of the freshwater pearl mussel into consideration. Catchment wide issues and activities that may impact on the mussel population are addressed and initiatives that may benefit the sustainability of populations will be implemented. Key stakeholder groups, including owners and occupiers, freshwater pearl mussels experts, fisheries groups, local authorities and public bodies were closely involved in the development of the management plans.
River Kerry
River Borgie
River Moidart
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