Active management of marine pests in the Wellington Region
Greater Wellington Regional Council and Top of the South Marine Biosecurity Partnership (TOS) conducted the second regional marine pest survey on moored vessels at Chaffers Marina, Clyde Quay, Evan’s Bay Marina, Seaview Marina, and Mana Marina from 24 to 28 November 2025.
Wellington Harbour - Photo / Top of the South Marine Biosecurity Partnership
The purpose of the survey was to determine the level of marine growth on vessel hulls and niche areas, such as rudders and propellors where pests can remain hidden from view. The survey found a number of pest species including three species known to already be established in the region: wakame seaweed (Undaria pinnatifida), the lightbulb sea squirt (Clavelina lepadiformis), and the carpet sea squirt (Didemnum vexillum). Species previously recorded from the region and found again during the survey included the clubbed tunicate (Steyela clava) and Mediterranean fanworm (Sabella spallanzanii) found on a vessel in Wellington Harbour.
The Mediterranean fanworm is an ‘Unwanted’ and ‘Notifiable’ organism under the Biosecurity Act 1993 and is not known to be established in the Wellington Region. All Mediterranean Fanworm found during the survey were removed by specialist divers.
These survey results highlight the need for boat owners and marina operators to be proactive with regular vessel biofouling management to prevent the introduction and spread of marine pests. management includes professionally cleaning and antifouling in-water vessels regularly and looking out for, and reporting, marine pests. If you think you may have seen or found a marine pest, please report it to Biosecurity NZ by calling 0800 80 99 66 or by completing a report form at report.mpi.govt.nz.
For more information about Top of the South Marine Biosecurity Partnership please visit the TOS website.
Photos: Mediterranean fanworm found in November surveys. Learn more about how to identify Mediterranean fanworm at our Marine Pest ID Guide