A new solution to reducing mangrove spread is being trialled in Tauranga Harbour this week.
Auckland-based company Fieldmaster designed the solution which is a purpose-built hovercraft fitted with a mangrove seedling mowing unit. It’s the first of its kind in New Zealand.
The hovercraft being trialled in Tauranga this morning. Watch the hovercraft in action here.
“Regional Council tendered out the design and build of a mechanical mangrove seedling control option that won’t leave deep tracks or significantly disturb other wildlife in the harbour,” says Bay of Plenty Regional Councillor and Regional Direction and Delivery Committee Chair, Paula Thompson.
“We’re already doing a lot of work with landowners in the catchment to reduce the sediment run-off that promotes mangrove growth. In the meantime, mangrove seedlings continue to pop up in areas that the local community have told us they want maintained as open water.
"They want to be able to keep swimming, boating and collecting kaimoana (seafood) in those spots.”
Paula says mowing efficacy has been refined following initial tests near Pahoia last year and a field trial in Athenree last month.
Fieldmaster are now putting the hovercraft through its paces in Waikareao Estuary this week, to check that final refinements are working well before Council take ownership of the machine.
“They’ll also be training some of our staff to operate it.”
Paula says results from intensive environmental monitoring carried out during hovercraft testing to date have found that the seedling mower operation had no significant adverse impacts on wildlife (including birds, crabs and titiko or mud snails) and it could operate within resource consent conditions.
“Tracking on the estuary bed was minimal; it left only light scuff marks that washed away soon after. Once the hovercraft is fully commissioned, there will be further environmental monitoring as it’s put into operation.”
Paula says the hovercraft is part of Regional Council’s commitment to helping Estuary Care Groups to hold the line on mangrove spread in consented areas.
“Volunteers have been using hoes to remove seedlings for the past ten years. It’s a back-breaking task so we agreed to explore mechanical options that will give them more time for restoration work like planting and pest control.
“This is part of our work to keep Te Awanui Tauranga Harbour healthy and accessible. If this week’s trials are successful, we’ll continue to work with Fieldmaster and Maritime NZ to get the hovercraft through the necessary certification processes before it can be put into operational use.”