Biosecurity New Zealand seeks public help

20 October 2005

Biosecurity New Zealand seeks public help to stop spread of sea squirt

Biosecurity New Zealand is asking for help from all marine users to prevent the spread of the invasive sea squirt, the clubbed tunicate, while expanding its search New Zealand-wide for the organism.

Senior Marine Advisor Brendan Gould says surveys undertaken over the past week have confirmed the sea squirt is present at locations ranging from Mahurangi in the north, through the Waitemata Harbour, on Waiheke Island, and down to Kaiaua in the Firth of Thames.

And a search yesterday by divers found the clubbed tunicate established in Lyttelton Port.

“We now have good reason to believe that the organism has been in New Zealand for some years may have spread to a number of areas, even though our investigations show it is not in great numbers in individual locations where it’s been found,” Mr Gould says.

Brendan Gould says Biosecurity New Zealand is looking at whether future control of vessel movements from affected areas will be practical and effective. Current assessment, however, indicates such measures will be impractical to manage on a large scale.

“Our focus now is rapidly checking for the clubbed tunicate’s presence at high-risk sites. These include ports, marinas and aquaculture locations such as mussel and oyster farms. We will be asking port operators and the aquaculture industry to help us by checking their operations for the presence of the sea squirt and reporting suspected finds to Biosecurity New Zealand.

“Overseas evidence suggests that the clubbed tunicate is particularly attracted to man-made structures and that natural ecosystems tend to be less affected. But we still have a lot of research to do on its impacts in New Zealand which will take some time.”

Mr Gould says work is now focusing on how to reduce the risk of the clubbed tunicate spreading to high risk locations, and where it’s already present, what the options are to control or manage it. Unfortunately, overseas work where it exists has not identified any sustainable ways of controlling or eradicating it where it has established.

While Biosecurity New Zealand pieces together a wider picture of the organism’s presence throughout New Zealand, the agency is seeking public vigilance, particularly from marine users.

“It’s really important that boaties come on board with the effort to curb its spread. Marine users must now take responsibility for keeping their vessel hulls and equipment clean and free of fouling,” Mr Gould says.

The aquaculture industry is also keen to emphasise the need for good boat hygiene. Graeme Coates of the NZ Marine Farming Association says his members in the top of the South Island have a lot at stake with this situation. “We would like other boaties to make sure their vessels are well cleaned and that they don’t spread this pest into areas of marine farming.”

Biosecurity New Zealand says where people are preparing to move to another region, they should ensure their vessel is clean. “We’re asking people to check their hull before setting sail and where it is heavily fouled, to clean it where it is,” Mr Gould says.

It is known that regular cleaning and the use of anti-fouling treatment will greatly help
contain the spread of the clubbed tunicate. The organism prefers a dirty boat to hang
onto and if hulls and equipment are clean, the sea squirt is unlikely to be transferred.

Biosecurity New Zealand is also asking those same water-users, divers and people generally using the ports and harbours to keep an eye out for the clubbed tunicate. If they see anything suspicious, contact the Biosecurity New Zealand toll free number: 0800 80 99 66 or visit: www.biosecurity.govt.nz/pests-diseases/animals/seasquirt

Work is ongoing today to ensure that all yachts leaving the Waitemata Harbour this weekend on the HSBC Coastal Classic yacht race to the Bay of Islands are clean before they leave.

And work is underway on information for boaties that gives tips on what to look out for, what to do if the clubbed tunicate is found, and how to maintain hulls.

ENDS

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