Conservation of threatened freshwater pearl mussel populations: river management, mussel translocation and conflict resolution

Abstract

River engineering work has historically been responsible for the decline and extinction of a number of endangered freshwater pearl mussel [ Margaritifera margaritifera (L.)] populations and potentially remains a significant threat. The impact of different types of river engineering work on a number of Scottish M. margaritifera populations is examined and discussed. M. margaritifera is now fully protected under law in most countries and guidance is urgently needed so that river managers can integrate ecological and socio-economic factors when considering the impact of proposed activities on M. margaritifera populations. To safeguard the remaining important populations, a simple conflict resolution framework is suggested for the appraisal of proposed developments in rivers with pearl mussel populations. Operations likely to harm mussels and permanently damage their river bed habitat should not proceed. In exceptional circumstances (outlined), the translocation of small numbers of adult mussels may possibly be considered as a potential management tool, but mussel translocation has been little used and should be considered experimental and last resort.