understanding and improving water quality in UK rivers
The Census used professional monitoring of invertebrates to understand more about the subtle pollutants 'stressing out' our fish.
Although this project has now concluded, we wanted to carry on species-level monitoring across the UK. To achieve this we have packaged the Riverfly Census method up for volunteer groups.
Why Survey Riverflies?
Insects (which make up 97% of all animal species) have declined 59% since 1970
This is hugely problematic for wild salmon & trout, who need need healthy water environments to thrive.
But why are aquatic insects so important?
Foundation of life
Small but all-sustaining, insects are food for our wild fish, birds and mammals. Without invertebrates, the food web would collapse.
Long-term health indicators
As nymphs, insects are constantly exposed to the water, sometimes for years. A water sample would only give you river health information for a single point in time.
Every invertebrate is unique, thriving in a specific
We frequently talk about missing flylife and lack of fish compared to the 'good old days', but anecdotal evidence like this has little weight in environmental decision making.
The Riverfly Census was our way of collecting much needed high-resolution, scientifically robust data about water quality in our rivers.
The Census Process
Across English and Welsh rivers, we have professionally sampled and analysed invertebrate life to understand the the water quality issues that need tackling
We use this professional, scientific evidence to campaign for improved protection of our wild waters.
The Riverfly Census has
Multiple sample sites were
Kick sweep sampling was completed in spring and autumn to EA guidelines, at all sample sites.
Sampling and species-level identification were carried out independently by professional external consultants, Aquascience Consultancy Ltd.
Species presence/absence data
The data was then evaluated
MAKE A STAND
The data was compiled, and is
Scroll down to our map to view the local reports and for the link to download the national report.
How do we sample?
Here’s how we use insect samples to find out what’s going on:
A 3-minute kick sweep sample is taken at a river site making sure to survey all the different habitat types.
The sample is pickled using a special alcohol. This preserves the insects so that counting and identification can be done at a laboratory.
The sample is sorted into groups by an expert and the insects are identified to species level using a microscope.
The list of species present is put into a unique scientific calculator. This gives a value for how much the site is being impacted by five key stressors.
What Did We Find?
The Riverfly Census has produced two main outputs:
A national baseline
Watch this space, we are working hard to generate a national summary of our findings, using the data to drive national policy improvements and influence more robust baselines.
Click below to read our national conclusions & policy recommendations:
Evidence to drive local improvement
In progress, we are currently compiling local information and delivering our results to relevant policy makers and stakeholders. See our map below and keep an eye on our news for release of local reports.
Use the map below to find our local Riverfly Census reports: