An invasive non-native mollusc species has been discovered in a Lincolnshire River – posing a potential threat to our native fresh and brackish water ecosystems. The findings are published in the latest issue of the Journal of Conchology out today.
The 4-5cm Gulf wedge clam (Rangia cuneata), is native to the Gulf of Mexico and had never been recorded in Britain until now. The discovery was made by expert Dr Martin Willing, Conservation Officer for the Conchological Society, whilst undertaking monitoring of a rare mussel in the River Witham for Buglife and Natural England. The species was discovered in large numbers in South Forty Foot Drains which lead into the River Witham in Boston, Lincolnshire.
Dr Martin Willing said “Based on the size of the clam shells we think the Lincolnshire population was probably established at least 5-6 years ago. Interestingly these species are usually found in brackish (slightly salty) water but on this occasion they were in freshwater.”
Dr Sarah Henshall, Buglife’s Lead Ecologist said “This discovery comes within a month of Buglife publishing an eight prong strategy for freshwater invertebrates, one of which is improving biosecurity, eradication and mitigation measures because of the extreme vulnerability of freshwater species and habitats to damage from invasive non-native species.
These species could pose a potential threat to our native fresh and brackish water ecosystems. Gulf wedge clams grow quickly and once established can become the dominant species, crowding out native species and potentially changing the structure of the ecosystem and environment. In addition they may cause potentially adverse economic impacts, such as problems with water pipes”
There is an urgent need to establish the full extent of Gulf wedge clam presence in Lincolnshire. Experts will use scientific techniques to more accurately assess the origin and date of arrival of this non-native species. The Environment Agency with the help of the Conchological Society, National Museum of Wales and Buglife will monitor the spread of this species.
David Heaver, Natural England Invertebrate Specialist said “It is important to understand the impact of these invasive species on our native fauna. The River Witham is home to one of our rarest and most vulnerable mussels – the Witham orb mussel”