Catchment News

Crayfish Plague Outbreak – Clodiagh (Tullamore) River, County Offaly

There has been an outbreak crayfish plague outbreak near Clonaslee, County Offaly in the Clodiagh (Tullamore) River. Anyone who enters our rivers or lakes should always Clean, Check and Dry all their equipment to protect this native species. Crayfish plague kills 100% of native crayfish infected.

Water users (recreational users, anglers, scientific assessment/ sampling etc) in this catchment should ensure all biosecurity measures are put in place to prevent spread of disease and invasive species. 

All agencies involved in managing and protecting the rivers in Ireland should encourage and ensure users of the river to Check, Clean and Dry their equipment before using it and again when leaving a river.  The crayfish plague disease can be carried on wet equipment, so all necessary measures must be put in place to prevent the spread to unaffected populations in other rivers. 

• CHECK – all equipment and remove of any plant and animal matter before leaving a site and again before entering a new site
• CLEAN – Disinfect equipment with an approved disinfectant, see advice below from the National Biodiversity Data Centre
• DRY – Ensure equipment is allowed to dry before entering a new site and any residual water is drained from boats etc before leaving a site

Crayfish plague is a disease that decimates our native crayfish populations causing 100% mortality.  The White-clawed crayfish is native to Ireland and is commonly found in many lakes, rivers and streams.  It is an important part of the river ecosystem as it is a grazer of plants and is food for the otter.  The White-clawed crayfish is a protected species, however crayfish plague is an Invasive Species and is a huge threat to this native population due to its devastating impact. 

Please circulate this information to any water users in your organisation to ensure they are implementing the biosecurity measures outlined here.

What can you do?

• Check, Clean and allow all equipment to thoroughly DRY-out then dry for further 48 hours
• If drying out equipment is not feasible equipment should be:
  • Power Steam washed at a suitably high temperature (at least above 65 degrees)– use of mobile steam power washers or use of nearby power washers at Service stations as an alternative
  • Disinfect everything using an approved disinfectant such as Milton (follow product label), Virkon Aquatic (3mg/L), Proxitane (30mg/L) or an iodine-based product for 15 minutes. Items difficult to soak can be sprayed or wiped down with disinfectant
  • Engine coolant water or residual water in boats/kayaks should be drained and where possible flushed out with disinfectant
• Become familiar with the identification of the native and non-native crayfish: view crayfish identification tips
• Immediately report all suspected sightings of non-native crayfish or dead native White-clawed Crayfish through the online form with location coordinates and your contact details. If possible, please supply a photo of the crayfish showing the underside of the claws to aid in verifying the sighting
• Follow the Crayfish Reporting and Sampling Protocol document updated July 2019
• Do not release any non-native crayfish into Ireland’s waters, it is illegal to do so
• Please circulate this species alert as widely as possible

Learn more:

Crayfish plague – Biodiversity Ireland

White-clawed Crayfish Austropotamobius pallipes | National Parks & Wildlife Service (npws.ie)