76 — Mediterranean fanworm, Sabella spallanzanii

Mediterranean fanworm, Sabella spallanzanii,
Tamaki Drive, Auckland, Sept. 2015.

The Mediterranean fanworm, Sabella spallanzanii (Gmelin, 1791) is a recent invader to New Zealand waters, and another species thought to have turned up via the hulls of ships. It was first detected at the port of Lyttelton in May 2008 and from there it spread to Auckland's Waitemata Harbour and has also been recorded from Northland. It seems most likely that this fanworm was introduced from southern Australia, where it has been an invasive species since the 1980's.

Mediterranean fanworm, Sabella spallanzanii,
Tamaki Drive, Auckland, Sept. 2015.

Mediterranean fanworm, Sabella spallanzanii,
Tamaki Drive, Auckland, Sept. 2015.

Mediterranean fanworms are now widespread in the Waitemata Harbour and are a common sight at and below low tide along Tamaki Drive. Their abundance is a concern due to the unforeseen effects large numbers of these worms could have on the benthic ecosystem, especially when it comes to nutrient cycling.

They can form clumps, which in turn form a canopy of feeding fans; excluding food from any filter-feeders below them. It is thought that these canopies of fanworms could out compete native species.

Mediterranean fanworm, Sabella spallanzanii,
Tamaki Drive, Auckland, Sept. 2015.

The fanworm itself lives in a long tube, which can (when not encrusted) look like a dark plastic cable reaching up to 40cm in length. The tubes attach to anything hard (rocks, shells, wharf pilings, ship and boat hulls) and look weirdly unnatural, like pieces of electric cabling.









More info:

Background information on the Mediterranean fanworm Sabella spallanzanii to support regional response decisions.

http://www.biosecurity.govt.nz/files/pests/mediterranean-fanworm/mediterranean-fanworm-factsheet.pdf

http://www.environmentguide.org.nz/issues/marine/marine-biosecurity/im:2097/