Keeping Mediterranean fanworm out
Marlborough remains relatively free of Mediterranean fanworm, despite the invasive marine pest being found here.
Council’s Senior Biosecurity Officer Hayden Nott told June’s Environment Committee there was a large risk to the aquaculture industry if populations became established.
“The first fanworm was found here in 2014 and there have been a number of small incursions since,” he said.
Council’s Biosecurity team is working closely with Marlborough Sounds Marinas to identify high-risk vessels – those that have travelled north of Tauranga or to Lyttleton Harbour in the past 12 months – and carry out inspections to help prevent fanworm establishing itself here.
Marlborough Sounds Marinas require all high-risk vessels to provide evidence of antifouling within the past six months or a lift and wash within the last month before a berth is allocated.
The biosecurity team coordinates the fanworm dive surveillance programme and during the 2024/25 season diving contractors inspected more than 2,200 vessel hulls in Marlborough with six found to have fanworm. A further nine fanworm were found on the seabed and structures within the Waikawa area
Continued dive surveillance has shown that the pests found were in a confined area and there was no evidence they were breeding or spreading.
Mediterranean fanworm poses significant ecological and economic threats, particularly to Marlborough’s aquaculture industry as it can rapidly colonise in suitable environments. Boat owners play a crucial role in this by keeping their boat hulls clean.
Dense colonies have the ability to impact aquaculture production, increase maintenance costs for boaties and affect marine biodiversity.
Although some fanworm were found on vessels, there was a high level of compliance with the regional pest management plan rules, Mr Nott said.
Council is part of a Top of the South partnership which carries out summer surveillance programmes throughout Nelson, Tasman, Marlborough and Wellington to help with education and awareness about marine pests.
