Kia ora koutou

I’m writing to advise that exotic caulerpa has been confirmed at two new locations in the Hauraki Gulf – the Mokohinau Islands and Rakino Island.

These new detections are disappointing but not unexpected, given the ability for exotic caulerpa to be moved over long distances on vessels and marine equipment.

We’re now working with partners and those people most closely associated with the new affected areas to determine the most appropriate response to this discovery.

The immediate focus is undertaking some rapid, targeted surveillance to better understand what we are dealing with and whether removal of the exotic caulerpa is feasible.

The new population at Mokohinau Island was brought to our attention by scientists working in the area who submitted photos of suspected caulerpa.

The Rakino Island incursion was found by Auckland Council staff carrying out surveillance for exotic caulerpa and who sent us photos.

NIWA’s Marine Invasives Taxonomic Service scientists have confirmed exotic caulerpa from the images. Analysis of samples will be required to formally identify the actual species at the new locations.

The Mokohinau Islands are administered by the Department of Conservation and are uninhabited but a destination for boating, fishing and diving.

The exotic caulerpa was found at a depth of approximately 23 metres in the Edith Passage just east of Motupapa and Hokoromea Islands.

Rakino Island, near Motutapu and Waiheke Islands, has a small number of residents, and is also a marine recreational area. Approximately one square metre of exotic caulerpa was found in Woody Bay at a depth of about seven metres.

Exotic caulerpa is currently found at five other upper North Island locations – Aotea Great Barrier Island, Ahuahu Great Mercury Island, Waiheke Island, Kawau Island and Te Rāwhiti Inlet in Northland.

We’ll continue to keep you posted as our response to exotic caulerpa continues.

Ngā mihi

John Walsh