SCIENTISTS at the Marine Institute have identified the disease responsible for the deaths of hundreds of fish at the Lough and Belvelly Lake.
Officials at the institute confirmed that the virus detected in the fish is carp edema virus (CEV), genotype 1.
However, they have been unable to identify the source of the infection and have pleaded with anglers and the public to remain vigilant to avoid future contamination.
More than 750 fish were removed from the Lough since the beginning of May, with a further 200 removed from Belvelly Lake.
In response to the issues, angling was suspended on a number of waterways in a bid to discover the source of the disease and to prevent further cross-contamination.
To date, all fish tested from the Lough and Belvelly have tested positive for CEV. Testing is still ongoing, including DNA sequencing.
Molecular tests for Koi Herpesvirus Disease (KHV) were negative for all fish sampled. Additional molecular tests for cyprinid herpesvirus are also in progress.
The gills and skin of the sampled fish revealed an extremely high level of infestation of parasites and fungal infection, according to a statement issued by the Marine Institute.
Virological screening for Spring Viraemia of Carp is still ongoing with no virus observed to date. Bacteriological tests have revealed no growth of bacteria.
"While we've identified the presence of CEV (known to cause koi sleepy disease) in all the samples tested to date at the Marine Institute, we are still carrying out further tests for confirmation of the cause of the carp mortalities at The Lough and Belvelly lake," explained Dr. Neil Ruane, from the Marine Institute's Fish Health Unit.
Dr. Jeff Fisher, Director of Marine Environment and Food Safety Service at the Marine Institute added, "Though the ultimate cause of the introduction of the disease agent into the loughs cannot be determined from current information, the loss of significant numbers of carp in these two lakes highlights the need for vigilance among anglers and other recreational users of Irish waters in the cleaning of their equipment and gear thoroughly after use, and also for the need for fishery owners and members of the public to be aware of the potential risk of transferring fish that may carry disease into the wild, and to never release ornamental fish into lakes or rivers.
"We're continuing to work closely with Inland Fisheries Ireland and Cork City Council and the Cork Carp Anglers Club to determine the cause of this fish kill, contain the incident, and identify appropriate biosecurity measures for the future."