Deadly crayfish plague detected in Cork river for first time
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A deadly disease with a 100% kill rate among crayfish has been detected in Cork for the first time, with authorities now scrambling to contain the outbreak.
If the crayfish plague continues to spread, there is a high probability the white-clawed crayfish will become extinct from most rivers in Ireland, the National Parks and Wildlife Service (NPWS) warned.
The so-called crayfish plague was first recorded in Cavan in 2015, before spreading to other rivers and decimating the species. It has now been detected in the Blackwater River in Cork, the NPWS confirmed.
The disease, which is harmless to people and animals, kills all white-clawed crayfish that are infected, threatening an already precarious existence among such species across the world.
Ireland is one of the last remaining outposts for the white-clawed crayfish in the world.
"Given the experience of outbreaks elsewhere, a total kill of the crayfish population is expected which will have major consequences for the ecology of the Blackwater, Awbeg, and the whole of Munster Blackwater catchment," the Department of Local Government and Heritage said.
Fishers, kayakers, and others have been urged to take extra care around the Blackwater catchment area in order to contain the disease as much as possible.
The NPWS and Inland Fisheries Ireland (IFI) jointly asked people to use the "check, clean, and dry" protocol.
This involves "cleaning everything that has been in contact with the water using hot water above 45C, or a high-pressure spray if possible". This is followed by "a drying period where all equipment and wet gear is dry for at least 48 hours, should be adopted as standard practice in all freshwaters".
Disinfect everything if complete drying is not possible, the NPWS and IFI said.
White-clawed crayfish are the only such freshwater species in Ireland and are protected under Irish law and the EU Habitats Directive.
In 2015, research from the Royal Society's biological journal found 32% of global crayfish species were classified as "at risk of extinction", disproportionately higher than most other species on both land and water.
Invasive species are responsible for much of the crayfish populations whittling away in Europe, where up to 80% of the white-clawed species have disappeared.
The department said crayfish plague is caused by a fungus-like organism of North American origin but which now occurs throughout Europe.
It normally grows on the outer shell of crayfish and, as North American crayfish are generally immune to it, they can prevent any infection reaching their body tissues, the department said.
"However, when the water mould infects white-clawed and other European crayfish, it rapidly, and fatally, spreads into the body tissues. Infected animals become distressed and behave abnormally and may survive several weeks before dying," it warned.