While surveying for otters along a riverbank, we uncovered shells of the critically endangered mollusc, freshwater pearl mussel (Margaritifera margaritifera).
Photograph of freshwater pearl mussel by Frazer MacFarlane
In Scotland, we are lucky to host some of the world’s most crucial populations, however suitable rivers supporting pearl mussels are in decline. Threats include illegal pearl fishing, habitat damage and loss, leading to poor water quality.
Pearl mussels are protected under law, making it an offence to disturb, injure, take or kill freshwater pearl mussels as well as sell/advertise sale, or possess freshwater pearl mussels or pearls collected after 1998.
Photograph freshwater pearl mussel under water by Frazer MacFarlane
How these shells arrived on the riverbank can be hypothesized; they may have become dislodged during spate or carried downstream and predated by otters or birds. The condition of the shells suggests they washed up naturally.
Though the word pearl does refer to the shiny white spheres located inside shells, it also means of great rarity and worth, which pearl mussels are to our natural heritage.
You can help protect pearl mussels by reporting to authorities suspicious activity on rivers, suspected pearl fishing, shell piles as evidence of potential fishing, or if concerned works are causing damage to rivers and banks.
Contact us if you would like more information on pearl mussels or concerned work may affect populations.