Asparagopsis taxiformis (limu kohu) is a native red seaweed of ecological and cultural significance in Hawaiʻi, that has been of growing interest in both restorative aquaculture and sustainable cultivation. However, hatchery methods for Hawaiian strains remain underdeveloped, limiting progress in reliable seedstock production and large-scale restoration efforts.
This work focuses on developing early-stage hatchery protocols to optimize the growth and culture performance of Hawaiian A. taxiformis gametophytes under controlled laboratory conditions. Preliminary experiments examined the combined effects of nutrient dosing, nutrient ratios, and light intensity (Photosynthetically Active Radiation, or “PAR”) on daily growth rate and thallus health. Although no statistically significant differences were observed in initial plate culture trials (two-way ANOVA, p = 0.819 for PAR and p = 0.243 for nutrient treatments), results provided valuable insight into gametophyte tolerance across light and nutrient gradients at this stage. The highest daily growth rate (4.80%) occurred under moderate light (PAR = 5) with low-nutrient media (N1, &fraq12;-strength). Further flask scale trials indicated that lower phosphorus-to-nitrogen ratios, below those typically used in standard algae formulations for nutrient supplementation (ie. F/2 etc.), supported higher growth rates, while over-supplementation relative to biomass density decreased nutrient use efficiency. Optimal growth occurred when cultures exhibited nutrient uptake of approximately 80–100%, suggesting that balanced, rather than excess, nutrient conditions promote stable and sustained development.
Together, these findings represent key steps toward establishing scalable hatchery protocols for Hawaiian A. taxiformis gametophytes, providing a foundation for both commercial cultivation and restorative aquaculture applications.