
The River Exe is home to culturally iconic and protected native diadromous migratory fish species, including Atlantic salmon, European eel, three lamprey species, and brown/sea trout. The River Exe also holds populations of other fish species, some of which have become integral to the ecology of upper reaches.
The City of Exeter was built on the site of the Roman fortress “Isca Dumnoniorum”, a name describing the flowing water of the River Exe. It is believed the name originally meant “full of fish” indicating the River Exe was once well known for its abundant fish populations.
Click on the Read The River Exe Project Blog button to discover more about the River Exe, its history and our work with partners to keep it healthy and flowing freely for a long time to comes.
Why do weirs pose a problem for fish migration?
Fish and weirs have co-existed for hundreds of years, right? True. However, times have changed.
In the past 50 years migratory fish populations have declined globally by an average of 76%, with a decline in Europe of 93%.
Climate change is causing more extreme drought and flood events, affecting river flows and limiting the flow windows that enable passage.
Cumulative impacts by multiple weirs magnify effects, can significantly reduce fish reaching the most productive habitat at the top of the catchment, and also have complex impacts on population genetics.
For further information on how weirs impact fish populations, please contact our project officer Phil Turnbull via [email protected] or Devon River & Fisheries Manager Adrian Dowding via [email protected]

By opening up free migration in the River Exe, we are contributing to international efforts to protect and enhance the integrity of North Atlantic diadromous fish species. Only by coordinated effort can we build a future for our shared international resources.
Weirs of the River Exe
Fish migration traffic jams
To help visualise the fish traffic jams occurring in the river, Strategic Exe Weirs has categorised various structures by impact on fish migration according to the following traffic light system:
Red
Weirs causing significant delays to upstream & downstream migration
Amber
Weirs causing notable delays OR a current active project under S.E.W.
Green
Sites allowing free movement of multiple native fish species.
It is the goal of Strategic Exe Weirs to progress all noted sites to Green light status by delivering bespoke solutions for each project site.
For further information on live sites, please visit the Strategic Exe Weirs blog.
Our Interactive Map
Click on the map below for more information on the selected project site.
How can fish migration be improved at a weir?
WRT work together with partners and project stakeholders to produce bespoke solutions that work for everyone involved.
Bespoke options may include:
Removal of a weir if appropriate
Nature-like option, in-river or bypass
Technical fish pass (e.g. Larinier fishway)
Fish passage easement (e.g. pre-barrages)
To learn more about bespoke fish passage solutions, including successful projects delivered by WRT and project partners, please get in touch.
Each project site is subject to a standardised options appraisal process that includes all stakeholders from the beginning of a project, ensuring a workable and effective solution can be developed and delivered.
Support Strategic Exe Weirs
By supporting our Strategic Exe Weirs project, you will be supporting the free movements of native fish species in the River Exe.