25/08/2026
Fish Pass Drop-ins will start again in September (although you won’t spot a Shad!) as too will our Diglis Island and Fish Pass tours. Keep an eye on our Events listings at canalrivertrust.org.uk/diglis for our Autumn dates being released soon.
Our fish in focus this week is sometimes described as a "silver ghost" because of how rare sightings are. 👻
The twaite shad is a member of the herring family, but like salmon, they spend most of their time in the sea and migrate to freshwater rivers to spawn in the spring.
This is known as anadromy, and the twaite shad's spring migratory pattern has led to another of its nicknames: the "May fish."
Like true lovemakers, the twaite shad spawns after dark - they swim in tight circles, splashing noisily while releasing eggs and s***m, an act often heard before it's seen.
As spawning is such an energy sapping activity, many fish die afterwards. That being said, the UK's survival rate is higher than lots of places in Europe.
Centuries ago, the twaite shad was abundant in the River Severn and regarded so highly that it was served in King Henry III's court and exported across Europe. The way we might look forward to the arrival of swallows today, the same used to be true of this fish.
The construction of weirs and dams in the 19th century caused a massive decline in twaite shad populations, as they were prevented from reaching their spawning grounds.
Many projects are now reopening these routes, like Diglis Fish Pass, allowing fish to swim around large weirs. Completed in 2021, the pass at Diglis is one of four on the River Severn we built as part of our Unlocking the Severn project, in partnership with Severn Rivers Trust, Environment Agency and Natural England.
2026 saw a massive jump from 2025 in the numbers of twaite shad moving up the fish pass, and we hope this only increases in the future. Thanks to this project and ongoing work from our teams, we can help nature thrive. 📈
Due to their rarity, it's imperative (both ethically and legally) that if you do accidentally catch one, you return it to the water immediately.
