The rivers Dee and Don are known for their historic spring run of Atlantic salmon, but environmental pressures have caused salmon numbers to fall. Patchy monitoring also made it hard to know where conservation investment would do the most good.

With funding from bp, NatureMetrics and the River Dee Trust carried out eDNA monitoring across the whole catchment. Community volunteers and bp staff collected the samples. Combining eDNA with hydrological data, the project produced fine-scale salmon maps, pinpointed invasive species and identified biodiversity hotspots. This gave the Trust a clear guide for river restoration, and gave bp credible data to support its nature commitments and TNFD disclosures.

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The rivers Dee and Don once supported strong Atlantic salmon populations. Climate change, pollution and habitat loss have driven numbers down.

Traditional monitoring couldn’t provide the large-scale, multi-species data needed, and existing records were fragmented. That made it hard to target conservation investment with confidence.

The partners needed:

• Robust biodiversity data across the whole catchment, not just at isolated sample points
• A way to find the habitats that matter most for salmon and other species
• A scalable, auditable approach that bp could use to back up its nature commitments to investors and regulators
• A way to involve local communities, building shared stewardship of the river for the long term

NatureMetrics worked with bp and the River Dee Trust to design and deliver an eDNA sampling programme across the River Dee and Don catchment.

• Community-led sampling: we trained community volunteers, River Dee Trust staff and bp employees to collect water samples at strategic locations using NatureMetrics sampling kits.
• Targeted analysis: we focused on Atlantic salmon, invasive Pacific pink salmon and freshwater invertebrates, which act as indicators of water quality.
• Validated processing: samples were analysed using NatureMetrics’ validated bioinformatics pipeline.
• Connected data: we combined the eDNA results with hydrological models and the Trust’s existing river monitoring data. This extended the insights beyond the individual sample sites.

Combining eDNA with hydrological and river monitoring data made it possible to:

• Map Atlantic salmon across the catchment: fine-scale maps of salmon eDNA concentrations showed areas of unusually high or low abundance.
• Identify biodiversity hotspots: we mapped hotspots based on overall species diversity and the presence of species of conservation concern.
• Pinpoint invasive species: invasive Pacific pink salmon were detected and their locations precisely identified.
• Find areas of environmental stress: invertebrate eDNA was linked to pollutants and habitat quality, showing where the river is under pressure.

Complete results were delivered in weeks, not the months that conventional surveys would have needed.

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A clear guide for restoration
The River Dee Trust can now prioritise habitats, tackle threats and restore biodiversity where it matters most for Atlantic salmon.

Earlier action on invasive species and pollution
Knowing where pink salmon are, and where sensitive invertebrates show stress from sewage or industrial effluent, means problems can be dealt with at the source.

Credible data for nature commitments
The project gives bp a verifiable biodiversity baseline. This supports its nature commitments, TNFD disclosures and lender requirements, and shows credible nature stewardship to stakeholders.

A model that can be repeated
The community participation model creates a scalable framework for future monitoring. Repeating it year on year will track how restoration, invasive species control and pollution measures are working.

Room to do more
The same approach can monitor other species of conservation concern, such as European eel and lamprey. It can also find hotspots for fish and freshwater insects.

Open data for science
The eDNA data is shared with GBIF (The Global Biodiversity Information Facility), making it available to researchers worldwide.

Read the project press release here.

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