Removing invasive seaweed Caulerpa at Aotea by suction dredging

MPI is trialing suction dredging methods to remove the invasive seaweed Caulerpa from the seafloor at Aotea Great Barrier Island.

The operations are due to begin this week and run for two weeks.

After the removal some areas will also have chlorine applied and contained with mats, to test if the suction alone works, or if further treatment is needed, and how effective this is.

Professor Chris Hepburn, Director, Aquaculture and Fisheries Programme, University of Otago, said: “This trial is important and well overdue. We need tools to deal with Caulerpa – a species with the potential to profoundly change some of our most important coastal ecosystems. The proposed trial will be challenging but we need tools and strategies to control Caulerpa.”

“Quick action to control and eliminate exotic marine species when they are first detected is a real hole in marine biosecurity in New Zealand. I hope this event and this research will help us develop plans and tools that promote action before more expansive and expensive operations are required.”

“You don’t get a second chance at these things.”

Dr Ian Davidson, Team Leader – Invasion Ecology and Management, Cawthron Institute, added: “The Aotea suction dredge trial is an important step in marine invasion management for exotic Caulerpa. We need to understand if we can have an impact on the trajectory of this invasive seaweed.”

“This is a positive step toward developing effective tools and methods to reduce its footprint or stop it from establishing in additional locations. Using the best information available about the site, we have designed a robust approach to answer key questions about efficacy, efficiency, logistics, and non-target impacts.”

“These are all key elements that will inform a broader plan to tackle this invasion.”