Undaria eradicated from Fiordland inlet
A Fiordland inlet has been declared free of the invasive marine pest undaria, five years after it was discovered.
Environment Southland marine team leader Kathryn McLachlan said declaring Taiari/Chalky Inlet free of undaria was proof that local elimination was possible.
Undaria is a brown seaweed that was first discovered in New Zealand in 1987 and has since spread along the coasts of the North, South and Stewart Island.
It grows rapidly and excludes many native coastal species such as pink kelp, which pāua depended on, according to Te Ara, The Encyclopedia of NZ.
It was found in Chalky in 2019 on lines next to the Stella ship wreck in North Port, Taiari/Chalky Inlet.
Environment Southland, Biosecurity New Zealand and Department of Conservation staff launched an elimination project to remove the pest using divers.
A technical advisory group said there would need to be five years of no mature plants before the site could be declared free of undaria. This was the first incursion in Fiordland to be declared undaria-free, and diving work was continuing to remove undaria from Tamatea/Dusky Sound and Te Puaitaha/Breaksea Sound.
The work was time consuming and resource intensive, but worthwhile, McLachlan said.
Environment Southland also encouraged the public to ensure they did not further the spread. “We want people to take steps not to transport undaria when moving within and leaving the Dusky complex and to follow the Fiordland Marine Regional Pathway Management Plan rules to keep a clean hull, clean gear and maintain residual seawater standards.
“We’re also asking people to remain on the lookout in other areas and to alert us if they see any undaria in sites outside of the Dusky/Breaksea complex.”
New sites can be reported to Environment Southland through a dedicated website. Members of the public should leave it in place and not try to remove it.
Reports should include GPS location, photographs, a description of where it was found (how deep, whether it was on natural substrate and an artificial structure) and how much was there.
In September 2020, undaria was also identified on cray pots at Broad Bay, Rakiura Stewart Island.
With no new growth in the past four years, this site is on-track to be declared undaria-free next year.