Biosecurity advice issued to Co Tyrone river users after confirmed outbreak of Crayfish plague

The public have been asked to report any sightings of non-native invasive species such as American signal crayfish. Credit: DAERA

Water users in Co Tyrone are being asked to enhance their biosecurity measures following a confirmed outbreak of Crayfish plague in Upper Ballinderry River.

It comes after a number of crayfish were found to have died during routine freshwater testing.

The Northern Ireland Environment Agency (NIEA) said Crayfish plague is a "type of water mould".

It added that the disease is "harmless to people, pets, livestock and all other freshwater organisms".

In a statement, the Department for the Environment (DEARA) outlined that a "number of dead native white-clawed crayfish were discovered during routing freshwater invertebrate monitoring".

Known as Austropotamobius pallipes, they were found 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).

“Such outbreaks are characterised by significant mortalities of native crayfish without any apparent effect on other aquatic organisms," she explained.

"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.

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 uk or Tel: 028 9056 9558.

"Non-native invasive species such as American signal crayfish should be reported at records/ISI,” added Rose.

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