Mediterranean fanworm found in Pilot Bay

25 September 2013

Bay of Plenty Regional Council has confirmed that a single specimen of the invasive aquatic pest Mediterranean fanworm (Sabella spallanzanii) has been found at Pilot Bay in Tauranga Harbour.

“It’s extremely disappointing that this unwanted organism has appeared in Bay of Plenty waters,” said Warwick Murray, General Manager Natural Resource Operations.

“It’s most likely the organism was brought here on the hull of a boat. Boat owners must remember to regularly clean their boat hull, keep their anti-fouling paint in good order, and ensure the hull is clean before they travel to a new region.”

“At this stage only a single specimen has been found in Tauranga Harbour, and we will immediately survey the Harbour to establish if there are more,” he said.

On 13 September, a University of Waikato diver found a single Mediterranean fanworm growing from a rock near the bathing sheds at Pilot Bay. The Ministry for Primary Industries confirmed it’s Sabella spallanzanii.

The Council is now developing a delimiting survey to ascertain the scale of the problem, with help from MPI and the University of Waikato, and plans to start this survey next week.

Mediterranean fanworm can grow in dense, thick mats that compete with native plants and animals for nutrients and space. It can interfere with boat equipment and aquaculture, and affect recreational activities like diving by changing the underwater character. Once well established, it’s very hard, or even impossible, to eradicate.

Along with Auckland Harbour, Mediterranean fanworm is also found in Lyttleton and Whangarei Harbours, and was discovered on two barges in Coromandel Harbour earlier this year.

For more on the Mediterranean fanworm, visit www.mpi.govt.nz or read the factsheet here.

Questions and Answers
How did Mediterranean fanworm get to Tauranga Harbour?
The pest may have been brought here on the hull of a boat from an area where Mediterranean fanworm is well established.

This is an unfortunate reminder of the overwhelming importance of boat owners regularly checking and cleaning their boat hulls, using anti-fouling paint on the hulls, and checking especially carefully before they take their boat to a new region.

Why is it an issue?
Tauranga Harbour is a taonga, a treasure, for the Bay of Plenty. We treasure the native flora and fauna that live in the Harbour, and we want them to thrive.

Mediterranean fanworm can grow in dense, thick mats that compete with native plants and animals for nutrients and space. It can interfere with boat equipment and aquaculture, and affect recreational activities like diving by changing the underwater character. Once well established, it’s very hard, or even impossible, to eradicate.

So it’s vital that we act as quickly as possible to establish its spread and prevent further spreading if possible.

It seems to be a ‘random finding’. Does the Council monitor pest plants and animals in the Harbour?
Tauranga Harbour is part of a formal surveillance programme carried out by NIWA on behalf of MPI. The last survey was completed earlier this year and found no evidence of Mediterranean fanworm. We believe this is a new incursion.

We encourage anyone who thinks they have found a pest plant to take a sample and report it straightaway to the Ministry for Primary Industries.

How will I recognise Mediterranean fanworm?
It has a brownish/grey tube of up to 40 centimetres in length. At the top of this tube is a single white fan, banded with pale orange or brown. It often grows in clumps, although the specimen found recently was growing alone.

The Mediterranean fanworm does look like some native New Zealand fanworms, but is larger.

What should I do if I think I’ve found one?
• Take a photo, or even better a sample. Seal the sample in a plastic bag with a small amount of seawater, and chill – don’t freeze.
• Note the exact location and date where you found it.
• Contact MPI on the pest diseases hotline, 0800 80 99 66.

What will you do if the survey in Tauranga Harbour finds lots of Mediterranean fanworm?
We don’t know what actions will be appropriate until we have the results of the survey. We need to get that information first.

Where else in New Zealand is Mediterranean Fanworm found?
The organism is established in Lyttleton, Auckland, and Whangarei Harbours

For more information on Mediterranean Fanworm, please visit www.mpi.govt.nz

ENDS

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