Freshwater mussels serve as biological filters, food for wildlife, monitors of water quality, and the basis of a $50 million industry.  America’s Ohio River Basin is home to the largest and most diverse group of freshwater mussels in the world. This video reviews the natural history of freshwater mussels, focusing on their environmental, aesthetic, scientific, and commercial values. It also investigates their decline towards extinction, due to pollution, dam construction, and other human activities. Efforts to preserve, protect, and restore native mussel species are explored.