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20 October 2005
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
"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:
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
For further information, please contact: Lesley Patston, Senior
Communications Adviser, Ph. 027 205-1418 Or Phillip Barclay, Senior
Communications Adviser, Ph. 027 229-9145
Further information about the clubbed tunicate is also available on the
Biosecurity New Zealand website: