With pearl mussel population numbers now dropping in one of its last remaining strongholds, the North East of England, solitary freshwater pearl mussels are being forced to live their lives in empty beds. If the species fails to revive its love life in the North of England, it will almost certainly become extinct south of the border.
Now the Environment Agency is playing matchmaker by relocating some of the last remaining pearl mussels from the North Tyne to its Kielder fish hatchery in Northumbria. In the more confined space of the hatchery, Agency fisheries officers will help the mussels socialise in more intimate surroundings.
Pearl mussels are one of England’s oldest river inhabitants and should be found in numbers, packed together in dense beds and reproducing through a sort of ‘group sex’ – males release sperm into water which is then filtered by the females. A long lived species, pearl mussels can live up to the age of 100 and can be sexually active from around age 12 to 100, their numbers have nevertheless declined massively since their abundance in Britain in Roman times was reportedly one of the factors that led Julius Caesar to invade.
Environment Agency expert Anne Lewis, said, “If the pearl mussels fail to revive its love life then the entire species will be extinct south of the Scottish border. We have relocated 40 pearl mussels to Kielder Hatchery and so far they are thriving.
“But we need to see the pearl mussels reproduce. So far, their sex-lives seems all but a distant memory and as yet, we have had no results. We are constantly learning more about the pearl mussel though and we hope it won’t be long before the species is showing signs of recovering.”
In healthy populations, many thousand pearl mussels are found together in beds. They have a long life-span, become sexually mature at about 20 years-old and live for over 100 years. But individuals have become so thinly dispersed in the wild that fertilisation has now become a near-impossibility.
The Pearl Mussel is extremely sensitive to water quality and habitat conditions. Illegal dredging and increased sedimentation have taken their toll on the species. Although an internationally protected species, the illegal practice of pearl fishing has been cited as one factor in reducing the mussel population density, with the resulting decimation leading on to current breeding problems.
