2nd Underwater exotic Seaweed survey completed
Caulerpa brachypus and Caulerpa parvifolia are invasive exotic seaweeds which are the subject of rahui and a Controlled Area Notice (CAN) for our neighbours Aotea Great Barrier Island and Ahuahu Great Mercury Island. It is possible that in Aotea’s case, the seaweed arrived up to two years ago now becoming widespread in three bays facing Waiheke.
In a further step towards its goal of forming a Waiheke specific response to *exotic Caulerpa , Waiheke Marine Project conducted the second of two planned ‘proof of concept’ underwater surveys in March. Using a Remote Operated Vehicle (ROV) with video capability operated by Logan Marine, this survey focused more on the Onetangi bay area.
As with the first ROV survey in Oneroa bay this was made possible by support from the Hauraki Gulf Forum and occurred during a rare weather window. Fortunately, no exotic Caulerpa was discovered during the day with the resulting video footage being analyzed to understand any learnings for sharing with wider agencies.
In early April, Craig Thorburn and Ngāti Paoa Ki Waiheke attended the Ecofest - Pestival day held at Piritahi Marae to present the project's activity and raise awareness of Exotic Caulerpas threat to Waiheke. As the presentation took place on one motu, fellow Steering Group member Grant Crawford was viewing first hand the impact over at Aotea-Great Barrier, with Okupu beach covered in a carpet of exotic weed washed up by Cyclone Gabrielle.
Grant observed `There were giant bags totalling at least 50 tonnes packed by the team at Moturairehe marae visible on the foreshore and as I crossed Blind bay the seafloor mat was continuously visible in 3 or 4 metres of water - we couldn’t find the edges”.
Other regions are working to raise the visibility of this threat as well. A Marine Biosecurity Seminar Series has been organised by the Top of the North Marine Biosecurity Partnership and the Top of the South Marine Biosecurity Partnership. On 24th May at 10am an online Marine Biosecurity Seminar is taking place with panelists from Aquaculture NZ, Waiheke Marine Project and Kelly Tarlton Marine Wildlife Trust, Yachting New Zealand, Northland Regional Council and the NZ Marina Operators Association. The public is invited to attend and can register here
On the 1st of May we learned that the Controlled Area Notice (CAN) for Aotea Great Barrier and Ahuahu Great Mercury Island was temporarily extended by 6 months on 27th April and at the time of writing MPI/Biosecurity response to WMP’s proposal for Waiheke Island was expected at any time.