Solution for caulerpa: Mechanical suction dredging technique

Big strides are being taken in the development of new dredging technology to control the invasive exotic caulerpa seaweed, said Biosecurity Minister Andrew Hoggard.

“A $10 million funding injection last year helped drive improvements to technology and getting new tools in the water. Today I’m happy to detail three exciting projects that have been funded,” said Hoggard.

“These new projects focus on methods that showed progress in an earlier phase of work.”

Northland Regional Council has been awarded the largest contract, with $6.2 million to progress its large-scale mechanical suction dredging technique.

“We know from the first phase of the accelerated program that this method can remove exotic caulerpa from sandy areas of the seafloor, and now we’re looking to increase its effectiveness,” said Hoggard.

“The project team is developing a new tool called a ‘submersible dredge planer’ which will operate remotely on the seafloor, rather than from a barge, and will remove caulerpa in a single pass.“

“The new system will include a dredge head, pumping arrangement, GPS positioning system, dredge spoil processing plant, and disposal system.”

The second project, receiving $2 million in funding, is to develop an ultra-violet light (UV-C) irradiation tool to kill the pest seaweed.

And the third project, with $1.9 million funding, is a special underwater treatment ‘chamber’ with a frame which covers the area of caulerpa being treated and has curtains to contain chlorine within the specific treatment area.