More than 1,000 tonnes of invasive pennywort removed from River Great Ouse

Environment Agency crews have been hard at work along the River Great Ouse in Ely removing tons of floating pennywort from the rivers and watercourses.

Maintenance teams are more than half way through a six-week programme, removing the invasive non-native species to try to stop it spreading further along the Ouse and the River Cam.

Using floating weed harvesters and lifters, the teams have removed more than 1,000 tonnes of wet cut invasive weed, while another team followed up behind, hand removing and spraying the smaller pieces of weed.

Floating Pennywort is normally found in tropical aquaria and garden ponds. It is, however, being found more and more in rivers across the country.

It forms very dense mats of vegetation which can grow rapidly - up to 20cm per day - out from the riverbanks.

These mats have the potential to cause serious problems for fish and anglers by suffocating fish and preventing access to the water.

The plant also obstructs movements of animals and boats, restricting navigation and recreational use of watercourses.

Darren Trumper, Environment Agency team leader said: “Floating Pennywort

has become a major problem for us all in the River Cam and Ely Ouse.

“Some of the Floating Pennywort mats we are removing from the riverbanks along the Ely Ouse are 22 metres long and 10 metres wide, and can be a depth size of about 30mm. In one location the teams removed a mat weighing 1.7 tonnes.

“The rivers and its tributaries in our area provide the perfect breeding ground for Floating Pennywort which has formed dense mats.

“These block out oxygen and light in what was very good aquatic habitats for fish, and native plants. It also deprives birds and creatures from feeding from the waters.”

Native to North America, Floating Pennywort is a fast growing invasive species of freshwater plant. It is widespread and well established in the south and east of England and appears to be spreading rapidly north and westwards.