Sightings of crayfish invader raise new fears for native wildlife

Sightings of a new invasive species of crayfish have prompted concerns over its potential spread in the UK, experts said today as a study was launched into the creature's impact on other wildlife.

Red swamp crayfish, a native of the south-eastern United States, have been spotted in the Regent’s Canal in central London, raising fears that they could spread across the country along waterways.

Ecologists are concerned that the red swamp crayfish could cause more harm to the native white-clawed crayfish, which have already been hit by the spread of the American signal crayfish, another invasive species which eats and competes with the indigenous crustacean.

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The white-clawed crayfish is now only commonly found in central, northern and Welsh waterways.

Red swamp crayfish have already become established in mainland Europe in recent years.

They have had a significant, negative impact on smaller indigenous crayfish and other wildlife and ecosystems.

The study, part of King’s College London geography department’s aquatic science research, aims to build up a comprehensive picture of the red swamp crayfish’s impact by catching and analysing crayfish species in the Regent’s Canal.

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The research has been welcomed by British Waterways, which manages the canal as part of a 2,200-mile network of waterways throughout the country.

British Waterways ecologist Leela O’Dea said: “It’s essential that we understand the extent to which invasive species are colonising the canals and rivers we manage across the UK.

“The inland waterways we care for provide a 2,200 mile-long linear wetland which is an essential habitat for thousands of fish, animals and birds.

“This study will inform the way we support these valuable ecosystems and help us ensure they continue to provide a wildlife haven across the country in years to come.”

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The King’s College London study is being led by undergraduate geography student Laura Cross, assisted by Dr Michael Chadwick.

She said: “With only a couple of sightings of the red swamp crayfish reported so far, and a lack of research into the effect of this invasive species in the UK, my dissertation is aimed at shedding some light on how the spread of invasive crayfish has altered the composition of the inland waterway network.

“I hope that my research project will improve our understanding of how different species of crayfish will interact, and emphasise the importance of tackling invasive species.”

Trapping for crayfish on British Waterway’s canals and rivers is normally strictly prohibited, and the organisation – along with the Environment Agency – stressed that the public should not remove crayfish from UK waterways without permission as it could further the spread of non-native species.