Hydrodynamic Stressing and the Response of Endangered Freshwater Pearl Mussels to Turbulent Flows

Whilst there is encouragement to be taken from the fact that Scotland remains a stronghold for M. margaritifera populations, a trend of continued population decline persists. Our understanding of the hydraulic characteristics associated with successful M. margaritifera proliferation in the wild is poor. Additionally, evidence to suggest how M. margaritifera respond to variation in the associated parameters, is limited. The primary motif of this research project is to address the knowledge gap. Initial experimental analysis sought to establish a non-invasive method of quantifying acute mussel stress; using behavioural response indicators, coupled with measures of physiological condition. Results from this work have provided a foundation for investigating mussels as biosensors to remotely track alterations in chemical, hydraulic, and geomorphological parameters. Further research has investigated the response of live mussels to alterations in flow depth, with consideration of riverbed geomorphology, in both a laboratory flume and regulated river. Current experimental work in a laboratory flume is utilising remote sensor technology to understand the impact of flow velocity on mussel behaviour; examining how flow velocity may impact habitat selection, and how a mussel’s behaviour may in turn affect the surrounding hydrodynamics. The results emanating from this research will be novel and will ultimately provide urgently needed empirical data to drive future conservation strategies implemented by government (SNH, SEPA) and utilized by the hydroelectric industry (SSE).