Crayfish plague discovered at River Blackwater in Tyrone

by Gráinne Connolly

Water users, both recreational and commercial are being urged to take precautions when visiting the River Blackwater catchment in Co.Tyrone. 

The warning comes after some dead native white-clawed crayfish were discovered there during routine field surveys. 

The Department of Agriculture, Environment and Rural Affairs (DAERA) then tested the fish for the presence of 'Crayfish Plague' and results confirmed that all three samples tested positive.

According to DAERA, "Crayfish Plague is a type of water mould and outbreaks are characterised by mass mortalities of native crayfish without any apparent effect on other aquatic organisms." 

Based on previous incidences across Ireland, this organism has the potential to severely damage the crayfish population, which would cause an ecological imbalance in the river.

A spokesperson for DAERA said: 

“If you think you may have found some infected crayfish please enter the location, images and any other details on the CEDaR Online Recording website(external link opens in a new window / tab).

“Crayfish plague tends to move upstream, but at this location it is already high up the catchment, so there may be mortalities further downstream.

"All field staff will be asked to check the area for any further dead crayfish and will be instructed to collect them if they do and send for further testing until we establish the extent of the outbreak.”

Anyone using the river or any others in the catchment are being urged to observe the "Check, Clean, Dry” and “Stop the spread” biosecurity protocols after leaving the river or before returning to it again.

DAERA’s advice is:

• 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