More than 700 Mediterranean fanworm have been discovered in Tauranga Harbour in the last week.

Bay of Plenty Regional Council staff believe they’ve removed 99 per cent of the new infestation, but will be working hard with the Tauranga Moana community to ensure the remaining one percent is also eradicated.

The fanworm was discovered on the harbour’s seafloor, south of the container wharf, late last week. It’s a disappointing blow for the Regional Council’s biosecurity team who have been running a successful surveillance and eradication programme since the first fanworm was found in the harbour in 2013.

Bay of Plenty Regional Council Senior Projects Officer, Hamish Lass says illegal cleaning of an infested boat hull nearby was most likely the cause.

“It's important to contain and dispose of any fouling that is cleaned off a boat properly because allowing it to sink to the sea bottom or drift away will only aid the spread of marine pests.

“Once well established, fanworm is very hard to eradicate so it’s up to every boat owner to regularly have their boat hull correctly cleaned and ensure that anti-fouling paint is fresh.

“We removed nearly 99 per cent of the infestation within just a few days of the discovery, but given the size of the fanworms found, it is likely that some may have reached maturity and have spawned since becoming established.

"We are therefore asking all Tauranga harbour users to remain on the lookout for Mediterranean fanworm, particularly in the upcoming summer months.”

For suspected finds please call MPI on 0800 80 99 66.