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Exotic caulerpa detection in Fantail Bay, Coromandel Peninsula

Small patches of exotic caulerpa have been discovered in Fantail Bay on the north-western coast, near the top of the Coromandel Peninsula.

It’s disappointing to find exotic caulerpa in another new area but it is not unexpected given it can be moved by people over long distances on vessels and marine equipment. The locations we’re finding caulerpa are typically in bays where vessels anchor.

Fantail Bay is a remote location with a Department of Conservation campground and is popular with divers and fishers.

Divers carrying out reef restoration work in the area found a number of small 10x10cm patches at a depth of 8-10 metres. NIWA taxonomists were able to confirm the find as exotic caulerpa from photographs.

Biosecurity New Zealand will work with partners and people associated with the area to determine the most appropriate actions following this discovery.  

Exotic caulerpa is currently found at seven other upper North Island locations - Aotea Great Barrier Island, Ahuahu Great Mercury Island, Waiheke Island, Kawau Island, Rakino Island, the Mokohinau Islands and Te Rāwhiti Inlet in Northland.

Out at sea? See weed? Bag it. Bin it.

The new detection at Fantail Bay, along with discoveries last month at the Mokohinau Islands and Rakino Island, serves as a reminder to boaties and fishers that they need to help avoid spreading this invasive seaweed.

While we know it can spread naturally, particularly from large areas of infestation, we also know that being caught up on vessels and equipment is the main way it is moved over distances.

If you’re out boating, before you move locations – when you pull up anchor or fishing gear, check it for any attached seaweed. If you find seaweed, remove it, securely contain it in a bag or other container and dispose of it in bins back on shore.

Also – if you think you’ve seen exotic caulerpa, let us know. Record the location, take a photo if possible, and call us on 0800 80 99 66, or report it online at