Freshwater pearl mussel project
This project is funded by Local Nature Partnerships in partnership with Parc Cenedlaethol Eryri and Welsh Government.
Learn more about freshwater pearl mussels and why they are so unique.
the project goals.
Improve fish and pearl mussel habitats by adding spawning materials, completing the riparian buffer zone, and protecting riverbank biodiversity.
Partner with local groups and schools to raise awareness about Afon Eden's SAC/SSSI species through training on river surveys, biosecurity, pearl mussels, and otter holt building.
Improve access by replacing stiles with footpath access and gates to enhance public access while protecting the environment.
Educate the general public with guided walks and install information panels to highlight the conservation efforts and key species benefiting from the project.
The Afon Eden, a Special Area of Conservation and Site of Special Scientific Interest, is home to one of the UK’s most endangered species, the freshwater pearl mussel (Margaritifera margaritifera). These mussels, are crucial for maintaining river health, filtering water and supporting biodiversity. However, their populations have dramatically declined due to habitat loss, pollution, and changes in river flow. The mussels’ survival is tightly linked to salmon and trout populations, another declining species. Work is taking place to restore habitat and create a thriving Afon Eden.
protecting our endangered species
Over the years the Afon Eden has faced several issues that threaten its ecological health and the habitat of the freshwater pearl mussel.
Habitat and Spawning Ground Loss: There is a shortage of suitable habitats and clean, gravel-rich spawning grounds for species like salmon, otters, and freshwater pearl mussels. Land use changes and environmental degradation further reduce these critical areas, hindering wildlife reproduction and survival.
Climate Change: The river is increasingly impacted by droughts and flooding, which disrupt natural flows and degrade habitats, affecting species that rely on stable river conditions.
Livestock Issues: Livestock accessing the river causes poaching and water quality issues, leading to erosion and nutrient pollution.
Sewage Pollution: Untreated or poorly treated sewage entering the river contributes to nutrient enrichment, degrading water quality and further harming sensitive species and habitats.
Invasive Species: Invasive plants like pondweed outcompete native species, disrupting the river's ecological balance and affecting biodiversity.
Sedimentation: High sediment runoff from agricultural ditches and erosion reduces water quality and smothers vital habitats.
Riparian Buffer Zones: The absence of riparian buffer zones allowed pollutants, including sewage and agricultural runoff, to enter the river more easily, exacerbating water quality issues and habitat loss.
issues facing freshwater pearl mussels
community
The success of our freshwater pearl mussel conservation project was made possible through the active involvement of the community. Local residents, educators, and students played a vital role in restoring habitats, monitoring water quality, and gathering data on wildlife. Throughout the project, we passed on traditional heritage skills such as dry stone walling, built otter holts to support riverside wildlife, and encouraged hands-on learning that deepened connections to the local environment. Thanks to this collaborative approach, the community not only helped protect this endangered species but also became champions of their river’s long-term health.
education
As part of this project, the North Wales Rivers Trust worked closely with local schools to deliver educational workshops and site visits focused on the critically endangered freshwater pearl mussel and the importance of protecting our freshwater ecosystems.
We collaborated with a local school to help students learn about the life cycle of the freshwater pearl mussel through the creation of a storybook. This engaging project deepened their understanding of this endangered species, encouraged creative thinking, and strengthened their connection to the local environment. The storybook has now been published and is available to purchase.
In addition to the storybook, pupils also had the chance to take part in site visits, where they built bug houses and took part in invertebrate sampling activities.
Through these initiatives, we empowered the next generation to play an active role in protecting their local waterways and the rich biodiversity they support.
MABLI, MABON & THE FRESHWATER PEARL MUSSEL | THE SECRET LIFE OF ERYRI SERIES
Dive into the heart of Eryri with Mabon the salmon and Mabli the otter as they uncover the hidden wonders of their river home. Meeting Mair, the wise freshwater pearl mussel, they learn of her vital role in keeping the waters clean and the ecosystem thriving.
Through playful rhymes and vibrant illustrations, this tale celebrates friendship, discovery, and the unseen heroes of our natural world. Inspiring young readers to cherish and protect the environment.
“This project has been invaluable for enhancing local ecosystems and biodiversity. By improving habitats along the Afon Eden, we’ve not only helped the freshwater pearl mussels but also fostered healthier conditions for all riverine species.”
— Dr Liam Whitmore , Lead River Habitat Officer
Project timeline
phase one
reintroducing gravels and boulders
To improve the riverbed's natural structure, we reintroduced over 60 boulders and added 100 tonnes of river-washed gravels. These actions are designed to create viable spawning habitats for local fish species, supporting the overall health of the ecosystem.
Livestock management
We have implemented fencing measures to exclude cattle and sheep from a 2.5-kilometer stretch of the riverbank. Additionally, we installed solar-powered pumps, hard standing areas, and troughs, providing alternative drinking sources for livestock and further protecting the river from potential contamination.
Riparian buffer zone
We have established a 10-meter wide riparian corridor that is already enhancing habitat diversity. This initiative includes the planting of over 1,000 native trees along the corridor, which will play a crucial role in stabilising riverbanks, improving biodiversity, and providing essential shade for the Afon Eden as temperatures rise.
Working with ysgol bro hedd wyn
We have collaborated with students to create an educational storybook that explains the life cycle of the freshwater pearl mussel. Additionally, we conducted site visits where pupils built bug houses and participated in an invertebrate survey, enhancing their hands-on learning experience.
Phase 2
Tree planting
Our tree planting initiative, which includes the pollarding of established willow trees, is set to create bank stabilisation and improve wet woodland habitat. These trees will provide nutrients for invertebrates and cover for fish, contributing to a balanced ecosystem in the face of climate change.
Community monitoring
Extensive surveying of the site has been conducted including both aquatic and terrestrial invertebrates, habitat, peat and monthly water quality testing.
Establishing a wildlife walk
Our new wildlife walk has been designed to allow visitors to explore this beautiful site and appreciate the increasing biodiversity. This scenic trail offers an opportunity to witness firsthand the restoration efforts that are revitalizing the ecosystem and fostering a thriving environment for wildlife.
