Protecting Lyttleton Harbour from Mediterranean fanworm
01 December 2021
Biosecurity Business Pledge member Port of Lyttleton is an active Pledge member joining peer-to-peer learning sessions, sharing its lessons, and being active in the recent CE dialogue held in November 2021. Not only is the port working to help prevent biosecurity threats getting into New Zealand, but it is actively working with the local community and partners to mitigate biosecurity threats that are in its local region.
One example is the Port Company's dive team’s work to remove the marine pest, Mediterranean fanworm (Sabella spallanzanii), from the inner harbour.
The fanworm is a large worm with a long, leathery tube that is pale brown in colour. The tube is usually fixed to a hard surface and can grow up to 80cm. They have long tentacles at the top of the tube, which look like a spiral fan and are usually orange, purple or white.
The fanworm attaches to hard structures in sheltered marine environments, including pontoons, piles and vessels. They are easily spread by vessel movements and reproduce rapidly. It has been present in low numbers in the inner harbour for more than a decade and is a threat to native biodiversity and commercial marine farming operations.
Recent surveys show a rise in numbers and the likelihood of continued spread within and beyond the inner harbour. In particular the marina is one of six immediate high-risk locations under investigation in the harbour over at least the next three months.
The fanworm can multiply quickly especially going into the warmer months when vessel movements increase.
Port’s divers began the arduous task of removing the fanworm by hand at Te Ana Marina earlier this month.
This work is part of a wider response which will be led by Environment Canterbury and Biosecurity New Zealand which will survey and remove fanworm from other areas within the harbour.
Funding has been granted for the work from the Whaka Ora Healthy Harbour project to contract commercial dive services, and Lyttelton Port Company is contributing money and resources to the immediate response and the long-term plan.
Thanks for great work and demonstration to the Pledge commitments.
For more information about the Pledge and current members, take a look at our Biosecurity Business Pledge section.
This case study has been adapted from an article originally published by the Otago Daily Times, 24 November 2021.