Recorded natural predation of freshwater pearl mussels Margaritifera margaritifera (L.) in Scotland

The endangered freshwater pearl mussel M. margaritifera (L.) has been the subject of much research and the causes for its decline are well known. However, in contrast to other unionids, little or nothing has been published about the natural predators of M. margaritifera. This paper draws together observations of natural predation events from over 300 detailed licensed river surveys in Scotland between 1996 and 2007. M. margaritifera has few known natural predators and the evidence presented suggests that that natural predation does not cause significant mortalities in any of the Scottish rivers surveyed.