Greenwave Aotearoa has marked the conclusion of a three-year native seaweed pilot in the Hauraki Gulf.
Greenwave Aotearoa has marked the conclusion of a three-year native seaweed pilot in the Hauraki Gulf.
The pioneering Greenwave Aotearoa project has concluded its successful three-year pilot to trial native seaweed cultivation in the Hauraki Gulf and can ultimately answer the question — how do you grow it?
The initiative, co-funded by the Ministry for Primary Industries’ Sustainable Food and Fibre FuturesFund and EnviroStrat, aimed to pave the way for a new seaweed farming industry in New Zealand.
EnviroStrat project manager Rebecca Barclay-Cameron said the pilot proved that the brown kelp Ecklonia radiata can be farmed and that there was more success in areas that are multitrophic — where two or more species are grown together — in this case mussels.
“Greenwave Aotearoa’s regenerative ocean farming pilot has laid the foundation for a new aquaculture industry, demonstrating that seaweed aquaculture is not only feasible but holds significant promise for New Zealand’s economic and environmental future.”
In the final year, the pilot successfully added the native red seaweed Gigartina atropurpurea at trial sites near mussel farms off the Coromandel coast.
The project involved growing fertile seedlings on twine around ropes, marking New Zealand’s first commercial planting of this native species.
“Our journey has been a learning curve in every sense,” Barclay-Cameron said.
“Over the past few years, we’ve fine-tuned our methods, adapted to shifting environmental conditions, and tackled regulatory hurdles to establish a viable seaweed farming business.
“It’s been so rewarding to witness the team adapting to the challenges of growing native seaweeds that have never been commercially farmed before.”
The pilot’s main focus was on the keystone species of native New Zealand brown kelp Ecklonia radiate.
Seedlings grown in Tauranga and Coromandel-based hatcheries were planted in consented aquaculture zones off Ponui Island and south of Coromandel town in the Firth of Thames.
Team members from the University of Waikato, Premium Seas and EnviroStrat worked closely and tried various sites beyond the original scope of the project in a bid to test the impact of different environmental and biophysical conditions on growth and productivity.
While the pilot concluded with numerous successes, it also faced challenges, including marine pest species grazing on young seedlings and a marine heatwave which led to new scientific insights on seaweed growth in different marine temperatures.
Researchers from the University of Waikato, led by Dr Marie Magnusson and Dr Rebecca Lawton, contributed to the trial’s scientific design, bringing expert oversight to the growing and harvesting processes.
The growth of Ecklonia radiata was challenged from the beginning by a late start because of supply chain issues driven by Covid-19.
The marine heatwave and marine pests — biofouling — also inhibited any impressive growth in the sites that were consented for the trial.
“Ultimately I think it comes down to picking a great site and focusing on what you can control,” the University of Waikato’s Peter Randrup said.
“Ocean farming is like land farming. Nature is complex and different regions suit different crops.
