Endangered native mussels are staging a comeback after scientists intervened to safeguard their future.
Numbers have been in decline in Britain for many years due to a dangerously low reproductive rate.
River pollution, dredging and poaching are thought to have had a catastrophic effect on the breeding habits of the freshwater molluscs, which can boast a royal association dating back to the time of Elizabeth I.
However an Environment Agency programme has seen 70 pearl mussels taken from Welsh rivers explode in to a population of 70,000 at the Mawddach hatchery in Wales.
While millions of larvae were fertilised 12 months ago nobody knew how many would become juveniles. Now the agency hopes it will be able to introduce tens of thousands of mussels back into Welsh rivers by the end of the decade.