Young fish survival rates boosted by River Dee improvement works
Juvenile fish have been seen passing through a notch at Chester weir only days after improvement works were completed to help fish migration in the River Dee.
In partnership with the Environment Agency, the aim of the work was to improve downstream passage for young salmon and sea trout as part of the multi-million-pound LIFE Dee River project, led by Natural Resources Wales (NRW).
Located at the tidal limit of the Dee, Chester weir is 150 metres in length and 3 metres high. An existing canoe and fish gate was in place in the weir crest that had not functioned for over 20 years.
Prior to the work, young fish were often delayed on their downstream journey by the weir, particularly at low flows in the spring when there was not enough water to help them pass over the structure.
Unable to swim over such a large man-made barrier, fish would congregate above the weir and were more vulnerable to predation from birds and larger fish.
Work to dismantle the existing gate and surrounding structure was carried out during low tides by experienced local contractors, using a pontoon to transport materials across the river.
A new, specially fabricated stainless-steel gate was installed which is operated by a winch on the bank, allowing it to be opened and closed easily at key periods throughout the year.
Gethin Morris, Senior River Restoration Officer for the LIFE Dee River project, said:
“It’s fantastic to see that fish are already finding their way through the notch, showing the immediate benefits of carrying out this work.
“River connectivity and improving access at structures such as Chester weir, is vital for the upstream and downstream migration of fish and will have a direct impact on spawning success.
“This important work will provide a safe route downstream for juvenile fish, reducing delays at the weir and increasing their chance of survival, which is crucial in our efforts to help reverse the global decline in fish populations.”
Rebecca Marsh, Environment Agency Fisheries Team Leader, said:
“We are delighted to see such positive results following the improvement works on Chester weir. It is vital that fish can migrate through rivers to help support their breeding populations and provide access to sustainable habitats.
“The Environment Agency is committed to working with others including the LIFE Dee River project to improve the ecology of rivers and protect the local wildlife.”
The recent works at Chester weir feed into the project’s larger programme of works throughout the entire Dee catchment, which is more than 1,800 km².
Issues such as habitat loss, poor spawning grounds, pollution and man-made barriers are all being addressed by the project, and positive results are already being seen.
With freshwater populations in rapid decline, dropping by an average of 83% since 1970 according to the 2022 Living Planet Report, the LIFE Dee River project is fighting to ensure the River Dee and the ecosystem it sustains will be there for the enjoyment of generations to come.
The project is funded by the EU LIFE programme, Welsh Government, Environment Agency, Eryri National Park Authority, Dŵr Cymru/Welsh Water, and will run until December 2024.
Here is a video of the juvenile fish passing through a notch at Chester weir.