Image of Ecklonia radiata lifecycle/NIWA.

Seeding twine type affects hatchery and at-sea success, but has rarely been examined for any seaweed species. Seeding density can also influence hatchery outcomes, affecting zoospore settlement, gametophyte growth, and sporophyte formation. Although spore density effects for Ecklonia radiata have been studied in petri dishes, applied research directly on twine remains lacking.

To address these key knowledge gaps, we conducted experiments to identify the optimal seeding twine type, twine diameter, and spore seeding density for Ecklonia radiata.

Greenwave Aotearoa Project Lead Rebecca Barclay-Cameron says 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. The initiative, co-funded by the Ministry for Primary Industries’ Sustainable Food and Fibre Futures Fund and EnviroStrat, aimed to pave the way for a new seaweed farming industry in New Zealand.

We’ve been talking with seaweed researchers and entrepreneurs in New Zealand and globally to explore the viability of blue carbon methodology for seaweed production. In the absence of a verified method or market anywhere in the world to monetise blue carbon and nutrient credits from seaweed, we are looking at the potential of establishing a fund as a bespoke ‘environmental subsidy’ for future GreenWave Aotearoa farmers. The goal of the fund would be to provide financial support for regenerative ocean farmers to scale their practices, while incentivising climate impact, water quality and biodiversity data reporting.

We’ve been testing techniques to help protect seedlings and increase survival during outplanting. We’re also starting to introduce automation in the outplanting process. We replaced the manual winding of the seeding twine onto grow ropes with a purpose built outplanting machine developed by the University of Waikato aquaculture team in collaboration with the School of Engineering which has reduced the number of people required to outplant.

We’re continually testing new methods to increase the efficiency of the hatchery process. A key advancement has been the development of methods to successfully maintain broodstock in tanks and induce formation of reproductive tissue on demand.