This project aims to investigate the potential of using waste scallop shells to mitigate acidification in watercourses. Scallop shells contain 95% calcium carbonate, which can help increase pH in watercourses and improve water quality. This project is partly based on a successful American study which used clam shells.
700 tonnes of clean scallop shells are being purchased from a local seafood processing company. A portion of the shells will be placed directly instream into selected watercourses to dissolve over time and potentially increase the pH. The remainder of the shells will be crushed and placed along forestry tracks where road drainage during floods may wash the calcium into surrounding watercourses.
The River Bladnoch in SW Scotland was designated SAC status in 2005 for Atlantic salmon however some areas of the catchment are highly impacted by acidification. Atlantic salmon and brown trout cannot reproduce and reside in highly acidified watercourses as the low pH prevents salmonid eggs from hatching. It is vital to find natural and cost-effective solutions to mitigating the impacts of acidification on salmonids within Scotland as well as the rest of the UK.
This project is investigative and experimental and results will be used to guide repeat or similar projects in the future. The project will be heavily monitored to ensure there is a good understanding of the impacts the scallop shells have on watercourses.
Pictured below is Scotland's First Minister, John Swinney MSP, being briefed by Jamie Ribbens of the Galloway Fisheries Trust on the project during the 2025 Fisheries Management Conference held near Perth. It's great to see members from the Scottish Government engaging with projects like this that the Wild Fisheries Fund support.
