Wild salmon in two rivers along the west coast have displayed symptoms of a potentially deadly disease prompting the authorities to issue a warning against taking the possibly infected fish from the water.
In recent days Inland Fisheries Ireland (IFI) has received reports that individual fresh-run wild salmon have been found in the River Leannan in Donegal and the River Corrib in Galway displaying suspected signs of red skin disease (RSD).
Low incidences of the disease were first documented in 2019 in several European salmon stocks and in the past few weeks suspected cases have again been reported in small numbers of returning salmon in Denmark, Norway and Scotland.
In Ireland last year suspected incidences of RSD were reported in 56 salmon from 17 rivers throughout the country. The majority of these reports were in June and July with only single incidences reported prior to and after this time.
Salmon affected by RSD have a characteristic red-spotted rash on their underbelly and may appear lethargic or moribund. The rash can either be localised or extend along some or most of the length of the fish.
As the disease progresses, skin lesions, signs of bleeding and skin ulcers can develop primarily along the belly area and extend to the head and tail. Secondary fungal infection can further develop which may ultimately result in death of the salmon.
IFI staff are working with the Fish Health Unit in the Marine Institute and international colleagues to monitor and respond to the situation while working within the constraints imposed by Covid-19 restrictions.
As part of its monitoring programme, anglers and fishery owners are asked to report any cases of salmon with signs of RSD to IFI to help determine the occurrence of the disease nationally.
Anglers who capture such salmon are advised to follow normal biosecurity procedures and disinfect tackle, waders and equipment. Until the cause of the disease has been determined and the risk of spreading the disease established, affected salmon should not be removed from the water.
"We are asking anglers and fishery owners to remain vigilant and report any catches of salmon with signs of this disease to us as soon as possible within the constraints imposed by the Covid-19," said Dr Paddy Gargan, senior research officer at IFI.
Anglers are asked to forward any reports of salmon with signs of RSD along with photographs and an estimate of fish weight to firstname.lastname@example.org or by calling IFI’s 24 hour confidential hotline number on 1890 34 74 24.