Following a report from a shellfish farmer of unusual mortalities in farmed Pacific oyster (Magallana [syn. Crassostrea] gigas) at a farm site in the River Exe in Devon, a Fish Health Inspector from the Centre for Environment, Fisheries and Aquaculture Science (Cefas) visited the affected site in the Exe. Samples taken from the affected site were confirmed as positive for oyster herpesvirus-1 microvariant (OsHV-1 µvar), and a new containment area covering the tidal waters and coastal zone around the River Exe has been declared. This has also incorporated The River Teign containment area previous controlled by CD22/2015.
In accordance with The Aquatic Animal Health Regulations (England and Wales) 2009, movements of shellfish out of the containment area covering the River Exe and River Teign (including surrounding coastline), have been restricted, following the confirmation of oyster herpesvirus-1 microvariant (OsHV-1 µvar).
Cefas acting on behalf of Defra has issued a Confirmed Designation prohibiting the movement of Pacific oysters from the containment area and applied the following additional control measures:
- You must apply to the Fish Health Inspectorate for permission if you wish to move any Pacific oysters out of the Confirmed Designation area, including movements into purification centres (depuration plants).
- You must notify the Fish Health Inspectorate of any increased or unexpected mortality observed in shellfish stocks.
In addition, England continues to have OsHV-1µVar control areas in Essex, Kent and Suffolk; Butley Creek; and Poole Harbour.
There are no implications for human health.
Any suspicion of the presence of OsHV-1µVar in Pacific oysters should be immediately reported to:
Fish Health Inspectorate
