Move to prevent further spread of Asian seaweed in Fiordland

[New Zealand] A Controlled Area notice has been issued for an area of Breaksea Sound in Fiordland to prevent further spread of the Asian seaweed Undaria pinnatifida (Undaria).

Environment Southland biosecurity manager Richard Bowman said the notice issued for Breaksea Sound will not prevent access to the area, but will put restrictions in place for mooring, equipment and anchoring.

Undaria is common around NZ ports. It was first identified in Fiordland in 2010 and a multi-agency eradication response has been underway since. In 2017, a survey found Undaria to be widespread in the Beach Harbour and John Islands area of Breaksea Sound.

“We know the damage a marine pest such as Undaria could do to the ecology and economy of this area, so we need to consider every option. Fiordland is an incredibly precious and unique area, it is a national treasure and needs to be protected.”

Research suggests that the risk of Undaria being carried out of the area will be highest when vessels or equipment are inactive for prolonged periods prior to moving to a new location.

“Undaria has a growth rate of 1-3cm per day, so if vessels sit idle for extended periods of time within an area harbouring Undaria, there is a high likelihood of it attaching itself and being moved outside the area when the vessel moves. With the current tools available, reducing its spread is the best option at this stage.

“Our goal is to reduce the potential environmental impacts by slowing down its spread as best we can. We are continuing to explore all options and we will meet with our partners and University of Otago marine scientists in the New Year to explore the possibility of an intensive control programme for Undaria.

The introduction of the Fiordland Marine Pathway Plan in April 2017 was a major step in reducing the transport of marine pests like Undaria into the Fiordland marine area.

“As Undaria has demonstrated, once a pest gets in, they are extremely difficult and expensive to eradicate, so the plan puts in place measures which will reduce the chance of something like this happening again,” Richard said.

Fiordland Marine Guardians chair Dr Rebecca McLeod said the Guardians felt it was imperative to push for a Controlled Area at the site of the Undaria infestation in Breaksea Sound.

“We welcome this decision from Environment Southland. Having a Controlled Area will significantly reduce the risk of people transporting Undaria to other areas in Fiordland on their boats and gear and provide valuable time to consider how else we can act to manage this incursion. With the exception of Undaria in Breaksea Sound, Fiordland is one of the last coastal marine areas of New Zealand that remains free of invasive species. We argue that this status is worth fighting for.”

The restrictions within the Controlled Area are:

1. Vessels may occupy the Controlled Area on a mooring for a maximum duration of 48 hours.

2. Anchoring in the Controlled Area is prohibited.

3. No marine gear or equipment, including lobster pots, mooring lines and any other equipment to establish new moorings, may be transported out of the Controlled Area.

4. Dive gear used within the Controlled Area must be treated or dried prior to use outside of the Controlled Area, using one of the following methods:

a. Dishwashing detergent 5% solution soak for one minute;

b. Bleach 2% solution for one minute; or

c. Hot water >60oC for one minute.

5. All on-board residual seawater collected in the Controlled Area must be treated as above or discarded within the Controlled Area.


View original article at: Move to prevent further spread of Asian seaweed in Fiordland





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