An endangered species found in our catchment
The freshwater pearl mussel is a species of bivalve found in clean, fast flowing streams in northern Europe and the north east of North America. The North Tyne River is the only place they can be found in the whole of the Tyne catchment and one of two places with a population in England.
Different areas have different subspecies of the freshwater pearl mussel and some subspecies are more endangered than others. They are usually found embedded in sand and gravel at the bottom of streams half a meter to two meters in depth. Freshwater pearl mussels have elongated shells that are yellowish brown when the mussels are young, and increasingly darker brown as they age. As their name suggests, freshwater pearl mussels can produce pearls and the interiors of their shells are iridescent white mother of pearl.
Freshwater pearl mussels are at risk from a variety of factors. They are sensitive to various forms of pollution, and need clean water to survive. They also need river beds with clean sand and gravel; if the river bed is composed of too much fine silt, they will suffocate.
Freshwater pearl mussel larvae are carried upstream by hanging onto the gills of salmonoid fish, so a healthy population of these fish is necessary to sustain a population of mussels.
The freshwater pearl mussel is endangered globally and critically endangered in Europe, and is already extinct in some countries. In the UK, most freshwater pearl mussels are found in Scotland, with a small minority in Wales and the north of England.
Freshwater pearl mussels are found in the lower Rede and the North Tyne downstream of the confluence with the Rede. The population is unfortunately in decline but projects are underway to attempt to reverse this.