Warning Issued Over Water Safety Amid Crayfish Plague Outbreak

The Department of Agriculture, Environment and Rural Affairs (DAERA) has issued a warning to both commercial and recreational water users to "enhance their biosecurity measures" after tests confirmed an outbreak of Crayfish plague in the Upper Ballinderry River catchment in County L'Derry.

Earlier this month, during routine freshwater invertebrate monitoring surveys a number of dead native white-clawed crayfish were discovered along the stretch of the Upper Ballinderry River at Ardtrea Bridge between Cookstown and Coagh.

NIEA's invasive species specialist, Rose Muir, said tests have confirmed the crayfish kill was caused by an outbreak of Crayfish plague, which is a type of water mould.

She continued: "Such outbreaks are characterised by significant mortalities of native crayfish without any apparent effect on other aquatic organisms. The disease is harmless to people, pets, livestock and all other freshwater organisms.

"This organism has the potential to severely damage the crayfish population and removes a key species from the eco system which can affect other species who rely on it, thereby causing an ecological imbalance in the river.

"We are urging all water users in this area to take extra precautions and observe the 'Check, Clean, Dry' biosecurity protocols after leaving the river or before returning to it again."

The advice is to:

• Check your equipment and clothing for living organisms. Pay particular attention to areas that are damp or hard to inspect.

• Clean and wash all equipment, footwear and clothes thoroughly. If you do come across any organisms, leave them at the water body where you found them.

• Dry all equipment and clothing – some species can live for many days in moist conditions. Make sure you don't transfer water elsewhere.

This is only the second confirmed outbreak in Northern Ireland with the last one on River Blackwater in 2018.

Rose added: "The disease tends to move upstream, but at this location it is already quite high up the catchment, so there may be mortalities further downstream. Our field staff will be checking for, and collecting, dead crayfish to establish the extent of the outbreak.

"In the meantime, we would ask anyone who finds infected crayfish to provide details of the location, images and any other details to the Invasive Non-Native Species Team at invasivespecies@daera-ni.gov.uk or Tel: 028 9056 9558. Non-native invasive species such as American signal crayfish should be reported at National Museums NI website."