Authorities monitoring ‘worrying’ outbreak of crayfish plague in Co Cork

Total kill of crayfish population expected in the Blackwater River (Cork/Waterford) Special Area of Conservation

The white-clawed crayfish is a globally threatened species, with Ireland holding one of the largest surviving populations.

A first ever outbreak in Co Cork of the deadly crayfish plague has been recorded on the river Blackwater, with a causative agent detected in the river Awbeg and Spa Glen stream.

The “worrying situation” is being monitored by the National Parks and Wildlife Service, Inland Fisheries Ireland, the Marine Institute and independent ecologists.

Crayfish plague was discovered in Ireland in 2015 in Co Cavan. In response to further outbreaks, a National Crayfish Plague Surveillance Programme was established in 2018. This programme monitors the spread and persistence of crayfish plague throughout Ireland and the distribution of the white-clawed crayfish.

The white-clawed crayfish is a globally threatened species, with Ireland holding one of the largest surviving populations. The plague is devastating and causes 100 per cent mortality among infected white-clawed crayfish.

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A total kill of the crayfish population in the affected area is expected, which would have major consequences for ecology in the Blackwater River (Cork/Waterford) Special Area of Conservation.

There is no indication of how crayfish plague reached the area, but the disease can be transmitted in water or via contaminated equipment such as kayaks, waders or nets. It is completely harmless to people, pets, livestock and all other freshwater organisms.