Invasive Caulerpa Arrives On Our Shores

By John Freer

News this week that the highly invasive Exotic Caulerpa has been found on the Coromandel Peninsula coastline comes with a claim that it is the most serious marine pest invasion yet to occur in New Zealand.

That observation comes from Professor Emeritus, Barry Shaw, of Massey University, who last month released a report on the seaweed pest as impacting Aotea Great Barrier Island.

The report was undertaken for the Aotea Great Barrier Environment Trust of which Barry is deputy chairman – a copy is posted below.

“We are on the brink of losing control of Exotic Caulerpa if more urgent action is not taken. I have a property on Aotea Great Barrier Island and have been following the Caulerpa infestation since it was first reported back in June 2021.

“Because so little has been done to control the spread on Aotea, boats anchoring there are now picking up Caulerpa and spreading it on anchors and other gear to new sites around the Hauraki Gulf – with the most recent ones being Fantail Bay, Rakino and now sadly the Mokohinau Islands,” said Barry.

This week following confirmation of the Fantail Bay infestation, Waikato Regional Councillor Warren Maher, expressed his concerns on the potential damage the seaweed could impact on both the regions commercial and recreational fishing sectors.

An avid recreational fisherman and diver, Warren said he had witnessed the damage first hand where the seaweed had grown over and completed covered scallops and other shellfish.

While some areas around the Hauraki Gulf have programmes in place to attempt to halt the Caulerpa spread, Warren this confirmed there is nothing in place for the Coromandel Peninsula.

He said work was being undertaken by the regional council to detect outbreaks, but there is no eradication plan.

The Fantail Bay discovery was made by an Auckland University marine research team.

Today the Hauraki Gulf Forum met and there was considerable discussion on the Caulerpa situation, Forum co-chair and Hauraki District Mayor, Toby Adams, recently advised CFM of his concerns on the pest spread and the need for significant injections of funding to control it.

The forum heard that there are real concerns about more infestations being discovered around the Coromandel Peninsula and the need to keep lobbying for more financial investment to bring the invasion under control.

Open the link below to hear an interview with Cr Warren Maher.

The Anatomy of Invasion_Caulerpa on Aotea Great Barrier Island v10