Biosecurity NZ divers look for sea squirt in Northland

Biosecurity New Zealand has widened its net in the hunt for the insidious sea squirt, a plant-like animal which poses a huge risk to marine farming in New Zealand.

The sea squirt (clubbed tunicate) has so far been found in parts of Auckland's Hauraki Gulf and in Lyttelton port - but this week Biosecurity NZ is extending surveillance, with divers searching Northland waters.

Senior marine adviser Brendan Gould said the agency needed to know if there were any other infected locations around the country to help plan further action.

"Surveying so far indicates the organism has been in the country for some years and may have spread to areas outside the Hauraki Gulf and Lyttelton," he said.

The National Institute for Water and Atmospheric Research, which is carrying a national surveillance programme, is focusing on sites considered to be at high risk due to their proximity to known infestations, or because of their high volume of marine traffic.

Biosecurity NZ is also asking members of the public, especially marine users, to keep an eye out for the sea squirt and report any suspected finds to its free 0800 number (0800 80-99-66).

Mr Gould said Biosecurity NZ was looking at a range of control measures, including wrapping infected structures with plastic, injecting acetic acid into the wrap and dipping equipment in acetic acid.

Meanwhile, marine users could help prevent the spread of the creature, he said.

"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."

Preliminary start dates and locations for initial surveillance are:

* Whangarei: Basin Marina, Marsden Pt port over next week (starting today).
* Akaroa - November 2.
* Lyttelton - November 3.
* Greymouth - November 9.

There will be surveillance scheduled in the near future for the following areas identified as high-risk due to proximity to known infestations or vessel movements.

These are: Bay of Islands (Opua), Mangawhai Harbour, Tutukaka, Nelson port, Wellington port, Bluff, Greymouth, Dunedin port, Napier port, New Plymouth, Whakatane port, Whitianga Marina and Tauranga port.

- NZPA