Lawton, RebeccaMagnusson, MarieLinzmeier, Juliet2026-02-022026-02-022025https://hdl.handle.net/10289/17909Seaweed is a versatile and renewable resource with applications ranging from food and medicine to biodegradable materials and beyond. While land crops have long been domesticated, ocean farming of macroalgae like Ecklonia radiata has only recently developed. This common New Zealand brown seaweed holds commercial promise, but localised species-specific cultivation methods are essential for success. This study aimed to optimise hatchery conditions for Ecklonia radiata by testing nutrient and light regimes. Two laboratory experiments assessed full-strength (20 mL PES L⁻¹) and double-strength treatments showed no significant differences, while the quarter-strength nutrients resulted in poor growth. High-intensity hatchery lighting (exceeding 100 μmol photons m⁻² s⁻¹ for extended periods) reduced sporophyte length and density, whereas 70% outplanting shade level yielded the best early growth. Based on these findings, it is recommended to use full-strength nutrient dosing (20 mL PES L⁻¹; 18.85 mg N L⁻¹, 0.81 mg P L⁻¹) once weekly, combined with gradually increasing light from 30 to 100 μmol photons m⁻² s⁻¹. During outplanting, light stress should be minimised, with deployment at 2-3 m depth during autumn months to promote establishment. These findings reinforce current hatchery protocols and support the scalable integration of Ecklonia radiata into New Zealand’s emerging seaweed industry.enAll items in Research Commons are provided for private study and research purposes and are protected by copyright with all rights reserved unless otherwise indicated.Thesis