2022 will be a historic year for the annual River Severn shad run. The twaite shad is an iridescent, silvery fish related to herring. It is on the International Union for Conservation of Nature (IUCN) Red List of Threatened Species as endangered in the UK. Shad live most of their lives out at sea but every spring journey upriver to spawn in freshwater. However, for nearly 180 years, the shad’s epic River Severn spawning migration has been curtailed by navigation weirs built across the river in early Victoria times.
For 35 generations of shad (and 7 generations of humans) these weirs have stopped the shad from reaching their historic spawning grounds in gravel beds further upriver. But following the completion of the last of 4 large fish passes by Unlocking the Severn early this January, the River Severn has been unlocked for shad once again!
Unlocking the Severn are seeking volunteers to join their team of citizen scientist volunteers at Tewkesbury in Gloucestershire. At upper Lode, alongside the Severn Ham meadows, there is a smaller weir that shad can pass over, using a notch at the riverbank. This is where volunteer citizen scientists count the fish, collecting important real-time data about each year’s shad run.
Upper Lode Weir, Tewkesbury. Unlocking the Severn.
Shad passing over the white monitoring boards. Nina Constable Media.
Attending individually (or with a friend or family members), the volunteers watch the notch for observations of 2o minutes (sometimes doing more than more observation per visit), counting any shad they see pass upstream. It is very exciting if you are lucky to see a lot of shad moving and the activity is quietly meditative for the rest of the time. The counting location is a short walk from town, alongside beautiful meadows that are designated a site of special scientific interest (SSSI) for rare ground-nesting birds and plant life.
The volunteers’ count data is used to estimate migrating shad numbers which provides an important comparison between years. Overtime, access to quality spawning grounds will restore this fish’s fortunes so that future generations of fish will start to thrive and the Severn Shad run can become prolific once again!
No previous experience is necessary, although all volunteers must attend a training session with us before they begin.
Would you like to get involved?
If you are interested to find out more, please visit us at Tewkesbury Town Hall gardens on Saturday 16 April, or register your interest using the form below and select Shad Migration Monitoring.