Country diary: pearl mussels settle down for a ripe old age

River Torridge, Devon: From drifting hitchhiker to sedentary filter-feeder, these rare shellfish lead a precarious existence - but they can reach the age of 80Hidden from sight within the meandering lower reaches of the Torridge, one of Britain's most endangered species is clinging on to life, holding fast among the rocks in the ever-changing flow.By a secluded wooded section of the bank, the two of us pulled on waders before edging into the current. My expert guide, Izzy Moser of the Devon Wildlife Trust, went first, using a bathyscope - a glass-bottomed funnel - to view the stony riverbed; I followed, carefully matching her footfalls as we slowly made our way downstream. Continue reading...