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Auckland beaches under threat from marine pest

Published: 29 September 2017

Auckland’s marine environment is under serious threat from a destructive Australian pest.

The Australian droplet tunicate (Eudistoma elongatum) grows in clusters of slimy white tubes. It can quickly smother entire beaches and foreshores, and damage or destroy marine farms.

The snot-like pest has been spotted in three parts of Auckland:  Mahurangi Harbour, Sandspit and Oakura Bay on Waiheke Island. It grows on sand, mud, and seagrass beds, and can latch onto hard surfaces like rocks and shells.

It also attaches to artificial surfaces like wharves, pontoons and the underside of moored boats. Boats berthed at marinas and those anchored to buoys are at greatest risk of having the pest make their hull their home, particularly if they are not being taken out for cleaning regularly.

Australian droplet tunicate is difficult to get rid of once established, as the tubes grow back and spread from broken pieces, and have a free-swimming larval stage.

Auckland Council Marine Biosecurity Advisor Samantha Happy says the pest’s arrival in Auckland is worrying.

“This pest will change our beautiful foreshores forever, and is nearly impossible to control once established,” she says.

“Preventing the pest spreading is something every kiwi, especially sea farers and boat owners, needs to be part of, so we can keep our treasured marine playground pest-free for future generations.”

“It’s especially important for boaties to play their part in by checking their hulls.”

How you can help stop the spread of Australian droplet tunicate

Here are some useful actions everyone can take to stop the spread:

  • If you have a bio-fouled hull, check and get it cleaned before travelling 
  • plan ahead for summer and book in with boat maintenance facilities in advance
  • if your boat is heavily bio fouled, haul it out and clean it appropriately – cleaning in-water will only spread any pests
  • keep antifoul fresh
  • find out more about other region’s rules at the Marine Pests website.

If you see Eudistoma elongatum or any other marine pest outside of established sites, note the location, take a photo or sample if you can, and report it to the Ministry for Primary Industries hotline on 0800 80 99 66.

Contact the Auckland Council Biosecurity team on 09 301 0101 or biosecurity@aucklandcouncil.govt.nz for advice.

Serious threat to marine farming industry

Waiheke-based oyster farmer Nat Upchurch says marine pests can cause serious damage to the marine farming industry.

“As a marine farmer you’re on the frontline when it comes to facing new pests,” he says.

“It’s absolutely a priority to deal with this and stop the spread before it gets more serious.”

“In the past we’ve been hit hard by new organisms that have had a massive impact on the business and my work. We need everyone to take action to stop it getting to that stage.”