Consistent, efficient and successful methods for hatchery cultivation of Ecklonia

We’re working with The University of Waikato team members in refining the hatchery techniques needed to grow Ecklonia radiata – a foundational native kelp species with huge potential for Aotearoa’s regenerative ocean economy.

While twine seeding using lab-grown gametophytes is emerging as a preferred method in global kelp aquaculture, most research to date has focused on non-native commercial species in New Zealand.

That’s why we’ve been focused on closing the knowledge gap for Ecklonia – and we’re seeing promising results.

We conducted three separate experiments to identify optimal gametophyte culturing conditions to maximise growth or reproduction, and optimal seeding densities and seeding methods to maximise seedling density and attachment strength on seeding twine.

 Key findings?

·       Gametophyte growth was highest under red light at 20 µmol photons m-2 sec-1 and density of 0.025 g DW L-1

·       Reproduction can be successfully induced by placing gametophytes under white light at 20 µmol photons m-2 sec-1 and density of 0.005-0.05 g DW L-1

·       Spraying biomass onto spools was the best performing seeding method

·       There was no advantage to using binders or inducing reproduction in biomass prior to seeding onto twine

This study takes another important step towards developing consistent, efficient and successful methods for hatchery cultivation of Ecklonia. This enables tight control of stock cultures so they can be managed as long term reference cultures, or scaled up and induced to reproduce (form sporophytes/seeding) for seeding onto lines.

Optimising seeding methods and seeding densities will improve hatchery efficiency and success once lines are outplanted to a marine farm site. Read the full paper by Dr Marie Magnusson and Rebecca Lawton.