New controls in place to prevent spread of oyster disease Bonamia ostreae in New Zealand waters

New rules to protect flat oysters from the disease-causing parasite Bonamia ostreae have begun being applied to recreational fishers and boaters in some New Zealand waters from Friday, September 1.

Bonamia ostreae is in the Marlborough Sounds and Big Glory Bay at Rakiura, Stewart Island. It infects and eventually kills flat oysters (commonly known as Bluff oysters or tio). It is, however, not a food safety risk and fresh good quality Bluff oysters are safe to eat.

Biosecurity New Zealand deputy director-general Stuart Anderson says a new Controlled Area Notice (CAN), which came into force from September 1, places conditions on movements of vessels and shellfish in the upper South Island, Big Glory Bay, the Chatham Islands and the lower South Island.

Under the CAN, areas where Bonamia ostreae is known to be present are designated as contained zones, and areas that are free of Bonamia ostreae and where there are significant populations of flat oysters are protected zones. The rules cover the movement of shellfish into and out of these zones, and fouling (visible sea life including shellfish, algae or weed) of boats and gear in these zones.

The contained zones are in the upper South Island and Big Glory Bay in Rakiura Stewart Island. The protected zones are the lower South Island and Chatham Islands.

The rules:

• Flat oysters must not be moved into or out of the Big Glory Bay contained zone.
• All shellfish or shellfish waste (including shells) collected in a contained zone cannot be put in the sea outside the zone.
• Vessels and gear must not be moved into or out of a contained zone unless they are visibly clear of fouling, unless a permit is obtained.
• Shellfish or shellfish waste from outside a protected zone must not be put in the sea inside the protected zone.
• Gear must not be moved into protected zones unless it is visibly free of fouling.

Mr Anderson says clubs, marinas, charter operators and local businesses in affected areas have been spoken to as part of raising awareness of the revised rules and what they need to do to prevent the spread of Bonamia ostreae.

Details of the rules, including conditions that apply to marine farm operators and information on applying for special permits, can be found at here.