Crayfish plague confirmed as signs erected in Limerick

Plague threatens to wipe out species in Ireland

Maria Flannery


Maria Flannery


Crayfish plague confirmed as signs erected in Limerick

Signs have been erected in Askeaton and along the Deel

THE large kill of crayfish in County Limerick’s River Deel is the result of crayfish plague, it has been confirmed following laboratory analysis.

Limerick City and County Council has erected signs along the river, which runs through Askeaton and Rathkeale, asking for the public’s help in curbing the plague.

Samples were tested at the Marine Institute Fish Health Unit, confirming the presence of the plague which is threatening to wipe out the white-clawed variety in Ireland.

“Thousands” of dead crayfish were detected a number of weeks ago in Rathkeale, and river users have been urged to follow strict guidelines to prevent the spread of the plague.

There is concern that the disease will reach the main Shannon. While “it is not feasible to close off rivers”, the Department of Arts, Heritage and the Gaeltacht is requesting a voluntary ban on moving boats and fishing gear to other catchments.

“There is no known risk to humans or pets,” said a department spokesperson.

The Department and Inland Fisheries Ireland is urging all river users, where crayfish may occur,  to implement strict cleaning and drying of their equipment once they leave the river and before using it again.

“This is especially important as it is known that the crayfish plague organism can be carried on wet equipment to new sites. Containment of the outbreak is essential to prevent spread to other as yet unaffected populations in Ireland,” said the spokesperson.

“Anyone using the river is being urged to observe the Check, Clean and Dry protocol. All wet gear including keep nets and storage bags should be checked for any silt or mud, plant material or animals.

“It then should be thoroughly cleaned and finally dried. Disinfectant or hot water over 40C should be used to clean all equipment,  followed by a 48 hour drying period. This should be adopted as standard practice in all freshwaters.

“Drying is especially important, including removing of any water from inside a boat and disposing of it on grass,” warned the department spokesperson.

People are also being asked to alert the authorities of any mass mortalities of crayfish and sightings of unusual crayfish, for example those with red claws or of a large size.

The white-clawed crayfish is a globally threatened species and Ireland holds one of the largest surviving populations.

Throughout its European range, this species has been decimated by the impact of crayfish plague. Until 2015, Ireland was considered free of the disease.

“If crayfish plague becomes established, there is a high probability that the white-clawed crayfish will be eliminated from much of the island,” said the spokesperson.