Scottish Natural Heritage and Heriot-Watt University have been working in collaboration to investigate the genetic connectivity of selected horse mussel beds in three marine regions in Scottish waters (West Coast; North-east and Orkney; and the Shetland Isles). The horse mussel beds sampled were found to have moderate to high levels of genetic connectivity and beds within marine protected areas (MPAs) were generally well connected to nearby populations outside protected areas, at both local and regional scales. Horse mussel bed populations from semi-enclosed water bodies (e.g. sea lochs and firths) appear to act as a source of larvae rather than a sink from adjacent populations.
The larvae of benthic marine species are subject to dynamic ocean currents and complex processes which drive connectivity patterns across Scotland's diverse coastal geography. This study greatly improves our understanding of the genetic connectivity of this Priority Marine Feature in Scotland, however, further work is required to investigate how horse mussels are related in other regions in Scotland as well as further afield. The results of this work will contribute towards MPA management advice and the implications of climate change on populations viability, and decision making for MPAs that contain or are in proximity to horse mussel beds.