Wildlife gold discovered in Colliters Brook
A critically endangered visitor has swum 6,000km to visit Long Ashton...
Gold…
It’s unusual to start a blog on biodiversity with an explanation of gold (but it is a timely introduction especially with the reports of President Trump’s insatiable appetite for the metal!). Trump’s not alone. Gold has been a precious commodity for thousands of years with small amounts found in Spanish caves dating to approx. 40,000 BCE with the first known evidence of gold craftsmanship dating back to the 5th millennium BCE. But from medieval times, the extraction process has led to massive ecological devastation so it was much more exciting for someone to discover an increasingly rare species - wildlife gold - in Long Ashton
Wildlife gold…
That someone is Owen Newman, one of the LANCE Trust trustees from its earliest days. As a Long Ashton river-fly monitor he has been involved in monitoring a site monthly from August 2024 and submitting invaluable data to a national programme monitoring the health of the UK’s watercourses and co-ordinated in Avon by the Bristol Avon Rivers Trust (BART).
“There I was, on the 7th June 2026, in my wellies. An old man standing in Colliters Brook on the boundary between North Somerset and Bristol City carrying out my river-fly survey in my usual site when, as I lifted my riverfly net out of the water, I was absolutely transfixed by something small, robust and streamlined in the bottom of my net. I realised it was a dark 15cm long elver gliding around among the bits of vegetative detritus, freshwater shrimps and various riverfly larvae that form my usual haul.
An elver is a young eel and, as I took it gently out of the net to pop it in a tray of water to photograph this incredibly rare find, I realised I hadn’t held an eel for around 60 years. That last time was when I stopped fishing in the Cambridgeshire Great Ouse. And I hadn’t seen a live eel since November 1983 when I filmed eels at night being caught in an elaborate trap alongside the River Avon near Salisbury. The full grown, nearly one-metre long eels were destined for the London eel pie trade. Since then, the European eel population has fallen by 95% and the species is listed as ‘critically endangered’ on the IUCN Red List of Threatened Species in the UK – that means it's at an extremely high risk of extinction in the wild and the report from the IUCN’s ‘Eel Specialist Group’ makes grim reading indeed.
Eels are now one of the most endangered species in the UK and, as far as I know, no-one else has reported finding a young eel around here for many years. So this one was a treasure indeed.
It had taken me about thirty minutes to get from my home in Long Ashton to my regular monitoring site on Colliters Brook but this amazing elver in my net had started life as an egg laid in the Sargasso Sea in the Bermuda Triangle before setting off on a mind-blowing journey and constantly changing lifestyle.
First, it had travelled about 6,000kms, drifting on the Gulf Stream for 1 or 2 years as a transparent, willow leaf-shaped ‘leptophalus’, feeding on plankton and rapidly growing but facing constant danger from predators, oil spills, habitat degradation and pollution.
Following generations of eels that have travelled the same route for millennia, it arrived in the Severn Estuary and transitioned into a ‘glass eel’.
In time, this glass eel entered the Avon at Avonmouth at which point, it may have already transitioned into its next phase – an ‘elver’.
Swimming upstream and passing under the Clifton Suspension Bridge, the elver would have abruptly turned right and somehow managed to navigate through the morass of brown mud that lines the Avon plus the relatively new tunnels, gratings and concrete culverts around Riverside Garden Centre and the industrial area that hold the waters of Colliters Brook in check before emerging into the relative safety of a small stretch of the ‘real’ Colliters Brook.
As a freshwater species, the elver feeds nocturnally in the brook on insects, worms and small fish slowly changing into its present dark colour. If it was a female and, if she is very lucky, she will live for another 20 years changing colour yet again with her belly turning yellow, unsurprisingly, becoming called a ‘yellow eel’. But she’s not finished yet. Turning silver and becoming a ‘silver eel’ she will migrate all the way back to the Sargasso Sea. As a saltwater fish, she will then feed on small saltwater fish, crustaceans and molluscs before eventually breeding and dying.
Every eel has an incredible story and watching this elver - full of life and vitality - left me with both sadness and anger. Anger that the species is facing rapid decline within my lifetime, for I know this elver faces a very uncertain future.
In 2012, a 15-year study of European eels in the Bristol Channel found that the eel population was probably just 1% of its numbers in 1980. Since then, there will have been further declines with increasing development and pollution.
But I also had hope for the few, like this one, that have been so determined to circumvent many obstacles in order to reach an area like Colliters Brook. There are an increasing number of organisations, such as the Somerset Eel Recovery Project, striving for their protection. And, with Bristol City Council signing The River Avon Charter it includes the promise "to promote the existence and flourishing of diverse species and unique habitats”. Let’s hope North Somerset Council follows its lead.
However, this elver also faces the adverse impacts of the impending Taylor Wimpey development in and around Woodspring Golf Course, with the development boundary just over 500 metres upstream.
Very recently, I’ve sadly discovered that their ecologists missed the presence of eels - one of the most endangered species in the UK - in one of their watercourses. So I’m doing my best to rectify this by highlighting the species’ presence with North Somerset Council, Bristol City Council, the Environment Agency, Avon Wildlife Trust and Bristol Avon Rivers Trust in the hope that Taylor Wimpey will properly mitigate the potential damage from the development to ‘our’ eels.
It has also reinforced my determination to carry on riverfly monitoring at this site and hope that others from Long Ashton will join in… for who knows what they will find.”
What is Riverfly Monitoring?
The Bristol Avon Rivers Trust (BART) works to protect and improve our rivers for the benefit of people and wildlife. As part of this work, BART coordinates Riverfly Monitoring across the Bristol Avon Catchment, helping local volunteers play an active role in looking after the waterways on their doorstep.
The Bristol Avon Catchment is a unique and beautiful network of rivers and streams, with the Bristol Avon at its heart. Stretching 75 miles from its source in Wiltshire to its confluence with the River Severn, the River Avon and its tributaries are the lifeblood of the area: in Long Ashton we have Colliters Brook and the Land Yeo.
In Long Ashton since 2024, the LANCE Trust and local volunteers have joined the effort, monitoring our watercourses and contributing valuable data about their health.
Years ago a large eel was found in the pond near Birdwell School probably just before it headed back to the Sargasso Sea, so who knows what our water courses hold. Next time, it could be you that finds wildlife gold out there.
Supporting the riverfly project in Long Ashton
A small group of volunteers with the Trust has been monitoring six sites on the Land Yeo, the Ashton/Longmoor Brook and Colliters Brook for a couple of years, but we are always looking for more riverfly monitoring volunteers to help collect data. Please get in touch and we will pair you up with an experienced monitor to learn the ropes. To get more of a feel for what we’ve been up to, read our blog: What’s in Long Ashton’s streams?
Getting a local Riverfly monitoring group up and running requires more than willing volunteers. Monitors need proper training as well as specialist sampling and identification equipment. We are therefore extremely grateful to Long Ashton Parish Council for providing an essential grant a couple of years ago to support the initial training of our volunteers and purchase the equipment the Trust needed to get started.
Their support has enabled the Trust’s local volunteers to become part of a much wider network of citizen scientists keeping watch over the health of our rivers and streams.
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