Native mussel numbers down almost 95% since 1960s, Thames survey finds

Scientists trying to replicate 1964 study say results reveal alarming deterioration in river's ecosystem

A survey of mussels has revealed an alarming deterioration in the River Thames ecosystem since the 1960s, according to a study.

Scientists attempting to replicate a 1964 survey of freshwater bivalves in a stretch of the Thames near Reading found striking results, as native mussel populations had crashed by almost 95%. One native species, the depressed river mussel, had vanished completely, and the remaining species were much smaller for their age, reflecting slower growth.