With a wide range of tidal stream strengths and depths, there is a remarkable marine fauna within Strangford Lough and it is one of the most diverse sea loughs in the UK. The communities’ present range from the very rich high-energy communities near the mouth, which depend on rapid tidal streams, to communities in extreme shelter where fine mud support burrowing brittlestars, the Dublin Bay prawn Nephrops norvegicus, and a rich community associated with horse mussels Modiolus modiolus.