A joint investigation has been launched into the mysterious deaths of thousands of juvenile Pacific oysters in the North Island.
The industry organisation, the Oyster Association, will work with the Ministry of Agriculture and Forestry to look into the significant increase in mortality rates.
Aquaculture New Zealand says the unusually high number of deaths is occurring in farms from Bay of Plenty in the east, and from north of Kawhia in the west, since mid-November.
It says that typical mortality rates for the juvenile oysters, or spat, are usually between 5% and 10%, but on some farms it is between 30% to 80%.
The main impact will be reduced numbers of spat needed to stock oyster farms for next year's harvest.
MAF response manager Richard Norman says the investigation is still in its early days and it would be premature to speculate on the cause. Aquatic disease specialists have taken about 250 samples for analysis.
Mr Norman says all of the organisations involved understand the urgency of the situation and the need to identify the problem and fix it.
The Food Safety Authority says there is no evidence to suggest any concerns about food safety, either in oysters consumed domestically, or exported overseas.
No problems with other oysters have been detected, including Bluff oysters.
