A species on the brink – Freshwater Pearl Mussel
They can live for over a century, they have one of the most bizarre life-cycles of any species you’re likely to find and they’re one of the reasons why the Romans invaded Britain. What’s more is that their future is in our hands. The freshwater pearl mussel might not have the glamour of some other iconic ‘Scottish’ species like the golden eagle or red squirrel, but they’re incredibly important. Scotland holds around half of the world’s population of this fascinating creature and they are currently balancing on a knife-edge.
Populations are found in some of the rivers flowing into Loch Ness.
Freshwater pearl mussels are very slow-growing and live at the bottom of clean, generally fast-flowing rivers. These animals, which spend the early part of their life harmlessly attached to the gills of trout and salmon before settling onto a suitable substrate are now extinct across most of their former range. Highland rivers are a stronghold for the species.
As their name suggests, they very occasionally bear a pearl, and this has in many ways led to their downfall. The taking of mussels by ‘pearl-fishers’ has been the main reason for the massive declines in these populations, but they have also been affected by pollution and river-engineering works.
The freshwater pearl mussel was given full legal protection in 1998 but unfortunately illegal activity still continues. Every year we still come across significant ‘kills’ where piles of hundreds of empty shells mark the scene of a few hours illegal fishing, where a whole population of this globally threatened species can be wiped out in a couple of hours.
These threats to the species have meant that the freshwater pearl mussel is a UK Wildlife Crime priority. This means that the Police work closely with Scottish Natural Heritage, anglers, bailiffs, river users and a wide-range of other organisations to help tackle these crimes by improving awareness, collection of intelligence and better enforcement to safeguard the species.
However, whilst the police and other organisations do their best to help tackle wildlife crime in this way they can’t do it alone, and the help of the public can be absolutely crucial. Pearl fishing is often carried out in remote locations, or very early in the morning when there is less chance of being detected, and often during the summer when daylight hours are long and the rivers are low. Fishing is often carried out by wading out into rivers and using glass-bottomed buckets to find the mussels and a cleft stick to recover them. If anyone sees or suspects that pearl fishing is taking place we urge people to report it to their local police station and Wildlife Crime Officer as soon as possible.
At the same time there are numerous projects aimed at active conservation of the species, including a recent £3.5 million project funded by the European Commission’s LIFE+ fund and secured by Scottish National Heritage and 14 other organisations. The project will improve habitats for the species, encourage simple and effective positive management of rivers where they are present, improve awareness and understanding of the species as well as helping address wildlife crime issues.
So it’s not all doom and gloom for this remarkable species, and everybody has a role in ensuring it’s survival – let’s hope that we can bring the freshwater pearl mussel back from the brink.
If you would like more information on the species visit SNH’s website at http://www.snh.gov.uk/about-scotlands-nature/species/invertebrates/freshwater-invertebrates/freshwater-pearl-mussel/