Every 3000th pearl mussel contains a natural pearl, the reason for its famousness and to some part for its decline. But even more dangerous are the changes in structure and quality of streams. The pearl mussel inhabits clear streams on acid subsoils. The exploitation of the pearl reserves and the regulation and pollution of streams have almost led to extinction. The populations in the border region Germany/Czech Republic/Austria count among the biggest ones in Central Europe.
Images: 1 BN Archive, 2,3 Josef Limberger