Water users urged to enhance biosecurity

Date published: 28 September 2023

Commercial and recreational water users in Co Tyrone are being urged to enhance their biosecurity measures after tests have confirmed an outbreak of Crayfish plague in the Upper Ballinderry River catchment.

The public are asked to report any sightings of non-native invasive species such as American signal crayfish on: https://www2.habitas.org.uk/records/ISI

A number of dead native white-clawed crayfish (Austropotamobius pallipes) were discovered during routine freshwater invertebrate monitoring surveys along the stretch of the Upper Ballinderry River at Ardtrea Bridge between Cookstown and Coagh earlier this month.

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

“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,” said Rose.

“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.

If you come across dead crayfish in the area, the advice from NIEA is to report but not touch any dead fish.

“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,” added Rose.

Notes to editors: 

  1. The disease is thought to have been introduced to GB by the spread of non-indigenous, plague-carrying crayfish species like the American signal crayfish. Introduction into new watercourses in Northern Ireland is likely to have occurred when spores have been carried in on equipment that has not been properly cleaned after visiting an infected area, as to date no non-native crayfish have been detected here in NI.
  2. Check, Clean, Dry website: www.invasivespeciesni.co.uk/what-can-i-do/check-clean-dry/
  3. Follow DAERA on Twitter at and Facebook.
  4. All media queries should be directed to the DAERA Press Office: pressoffice.group@daera-ni.gov.uk or telephone: 028 9052 4619.
  5. The Executive Information Service operates an out of hours’ service for media enquiries only between 1800hrs and 0800hrs Monday to Friday and at weekends and public holidays. The duty press officer can be contacted on 028 9037 8110.

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