The following post was written by Woodlore Aspirant Instructor Sarah Day.
Our wonderful waterways are now being accessed and enjoyed by more people than ever. The rivers teem with canoeists, kayakers and paddle boarders, as well as the traditional rowers and anglers. Most are aware to some degree of the risks of sharp (often man-made) debris in the river, fallen trees, and the hazard of the water itself – even that of Weil’s disease – but many are unfamiliar with the harm that their own actions can cause to the ecosystem and how they can avoid doing so.
I was paddling recently in the River Stour in Suffolk, near Langham. My partner spotted a jawbone (probably from a cow) on the river bed of the shallow section and picked it out to show me. It wasn’t the worn teeth and odd hole through the side that I noticed first though – it was the tiny, striped mollusc shell clinging to the bone.
I recognised it from the warning poster I’d seen at Alton Water the week before. It was almost certainly a zebra mussel; an invasive species of freshwater mussel, native to Russia, that probably came here originally in the ballast water of ships. It is small but prolific, and can totally clog up water treatment plants, kill native swan mussels, and cause lake beaches to become virtually unusable due to the swathes of sharp shell fragments.