The UK’s largest fish pass has opened at Holme Sluices on the River Trent in Nottinghamshire, helping salmon to reach spawning tributaries including the Derbyshire Dove and Derwent. 

The pass, built by the Environment Agency at an eye-watering cost of more than £10 million, will also help migrating eels, trout and other species to get past the sluices, which protect Nottingham from flooding. It is 200m long, 6m deep and 6.5m wide, split into 20 chambers, and will open and close based on the river level.  

Simon Ward, EA fisheries technical specialist, explained that “different species need varying flow rates depending on their anatomy and swimming ability. We had to increase the level of modelling we did … to make sure the flows through the fish pass were suitable for all fish.” 

He added, “The improvements to the spawning will increase manyfold because we can get fish past Nottingham very quickly. If the fish have more energy when they reach the spawning grounds, they can produce more eggs and the spawning will be more efficient, more productive.” 

The pass will have a public viewing platform and information boards.