UPDATE: The Department of Agriculture and Rural Development (DARD) has confirmed an outbreak of Ostreid Herpes Virus, OsHV1-µvar, on one site in Carlingford Lough following a sample of dead Pacific Oysters (the Crassostrea Gigas type) showing positive results yesterday evening when tested by the Agri- Food and Biosciences Institute in Dundonald, Co Down. The latest information indicated there have been no reported mortalities in any other site on either side of the Lough.
OsHV1-µvar originated in France and has been detected in Ireland since 2009 causing significant mortalities from time to time in Pacific oysters. The north of Ireland had a limited number of outbreaks but the virus has been widely detected in Lough Foyle, Carlingford Lough, Killough Bay and Strangford Lough in Northern Ireland.
Research to date has not identified any method to combat the mortalities, which appear to be linked to rising water temperatures. The virus appears to lie latent until water temperatures reach 15 to 16 degrees at which stage the oysters begin to die very quickly. Temperatures have risen to 20 degrees in recent days, which has significantly reduced dissolved oxygen levels in shallow areas where oysters are grown.
“Such temperatures are not unusually warm, but combined with the presence of the virus, and calm weather which inhibits oxygen mixing into the water column, conditions have resulted in oyster mortalities,” DARD explained in a statement to AgriLand this morning.
DARD has also confirmed that there are no measures available for compensation or restocking through its department or under European funding.
“We has assisted industry through the European Fisheries Fund for a project taken forward by the Cross-Border Aquaculture Initiative Team, in conjunction with Pacific oyster farmers. The disease control project aims to compile baseline data for the Pacific oyster industry and investigate possible farming techniques to try to limit risk of spread of this virsus,” it said.
“DARD is sympathetic to producers affected by any disease outbreak and Fish Health Inspectorate are always available to offer advice and assistance. DARD is committed to maintaining our high fish health status and operates comprehensive disease control measures,” it added.
The Pacific oyster industry in Northern Ireland produced 136.68 tonnes in 2011 and was valued at approximately £545,600 sterling. The shellfish industry as a whole was estimated to value approximately £6.2m sterling (includes mussels, oysters and scallops).
Invertebrate viruses are not known to affect humans and the Northern Ireland Food Standards Agency is not aware of any reports of human illness associated with this virus.
Speaking to AgriLand this afternoon, South Down SDLP MLA Seán Rogers has spoken out in support of the horrendous circumstances that some local oyster farmers find themselves in.
“I was shocked to hear and see first-hand the devastation to oyster farming on the Northern side of Carlingford Lough. One farmer has lost 80 per cent of his stock in just two days, which is essentially three years of hard work in often very difficult conditions, gone. It is assumed that these losses are linked to the unusually high water temperatures of late in Carlingford Lough. Last night’s average was 19 degrees. The Department of Agriculture has confirmed that the OsHV Virus is present in Carlingford Lough but it appears to flourish in warmer water. Tests into the losses are ongoing at present.
The MLA is raising concerns that possible more farms will be become infected and has called for greater and immediate resources into research to combat the issue.
“We could potentially be looking at the total decimation of oyster farming as we know it in Carlingford Lough. This is a very serious situation. These farmers need assistance and they need it fast in order to begin re-building their livelihoods. I have made urgent representations to the Minister in support of these farmers.”
