Incurable herpes behind big oyster die-off in New Zealand

An incurable herpes-like virus is behind the widespread deaths of juvenile Pacific oysters in upper North Island marine farms, Ministry of Agriculture and Forestry (MAF) has confirmed. That is going to have a huge financial impact, with farmers bracing for a huge drop in crop numbers and an impact on their sales next year. The NZ$30 million oyster farming industry disclosed last week that it had been experiencing big losses of juvenile oysters over November and early December.

Marine pathologists at MAF used molecular tests and DNA sequencing to show the presence of ostreid herpes virus-1 (OsHV-1) in samples from affected oyster farms, and MAF response manager Richard Norman said it was possible the die-off had been due to a range of factors, triggered by unusually warm water temperatures. Elevated water temperatures may be potentiating or kicking off the effect in the small oysters that are affected," he said.

Ostreid herpes viruses are known to affect not only oysters but also clams, scallops, and other molluscs, according to French Research Institute for Exploitation of the Sea pathology lab director Tristan Renault. He has suggested in Europe that global warming could be an explanation of the appearance of this particular type of the virus. Read more...

This blog is written by Martin Little The Aquaculturists, published and supported by the International Aquafeed Magazine from Perendale Publishers.