Clean boat hulls key to keeping invasive fanworm out of region

A recent survey conducted by Greater Wellington and Top of the South Marine Biosecurity Partnership found and removed a small number of Mediterranean fanworms attached to hulls of boats in marinas around the Wellington region.

Mediterranean fanworms are marine pests, not currently established in the Wellington and Marlborough regions. They can spread quickly after spawning and outcompete native organisms for space and food. None of the fanworms found were reproductively mature and were successfully removed by divers. 

Wellington Harbour Master Grant Nalder says the fanworms were isolated to vessels that travelled from Auckland in early 2024.

“A subsample of vessels were inspected during this survey and there is the possibility that fanworm may exist on vessels not inspected, especially those that have travelled from Auckland,” says Mr Nalder.

“We ask anyone bringing a boat into the region to ensure that their hulls are thoroughly inspected to prevent the introduction of marine pests. Boaties can learn more about helping our moana at Clean below? Good to go.”

“Outside of fanworms, a concerning number of the surveyed boats were found with high levels of fouling. Keeping a vessel hull clean is a normal part of boat upkeep, prolonging their useful life, helping them move well and importantly to avoid shifting around invasive fouling species.”

Greater Wellington senior environmental scientist Dr Megan Melidonis says Wellington is not the only region at risk from the fanworms.

“By carrying out surveillance for these pests we are protecting not only our region but also the Marlborough region, which supports an economically significant aquaculture industry,’ says Dr Melidonis.

“This survey also highlights the benefits of Greater Wellington’s partnership with Top of the South and the importance of developing a new marine biosecurity programme which supports consistent marine biosecurity surveying and pathway management.” 

Top of the South Marine Biosecurity Partnership Chairperson Richard Frizzell says it's important for boaties to be aware of the marine biosecurity rules in the Top of the South to avoid the risk of being turned away from their destination.

“Vessel hulls must be clean and must not exceed ‘light fouling’ when entering the Marlborough, Nelson, or Tasman regions.  Our dive teams will be back out inspecting vessels throughout the Top of the South regions over the coming weeks,” says Mr Frizzell.

If you come across a suspect marine animal or marine plant, report it as soon as possible to MPI by calling the Biosecurity New Zealand Exotic Disease and Pest Hotline 0800 80 99 66 or log it online. Remember to take photos and record the location of the organism.