Know your seaweed: fundamental knowledge needed to bring new species into cultivation

Abstract Driven by the expansion of the global Blue Economy, macroalgae are increasingly proposed for traditional food to critical solutions for bioremediation, industrial feedstocks, and ecological restoration. Scaling this sector requires a systematic approach to domesticating novel species and strains. This review provides a comprehensive framework and actionable roadmap to bring new macroalgal taxa into cultivation. Drawing on published literature and years of experience, this review evaluates the fundamental ecophysiological parameters, including light, temperature, photoperiod, salinity, and nutrients, necessary to regulate complex life-cycles and optimize nursery protocols. We further evaluate how next-generation tools such as multi-omics, genomic selection, microbial profiling, and hybrid species distribution models are shifting the industry towards precision aquaculture. To bridge the gap between laboratory scale protocols and commercial production, we address operational challenges, including biosecurity, germplasm biobanking, techno-economic constraints and processing with cascading biorefineries. These principles are contextualized through U.S. case studies spanning diverse biogeographic regions focusing on several economically relevant species: Saccharina angustissima (Maine), Saccharina latissima (North Atlantic and Alaska), Halymenia hawaiiana (Hawai’i), Caulerpa lentillifera (Hawai’i) and Gracilaria sp. (California). Finally, we emphasize the integration of stakeholder inputs and Traditional Ecological Knowledge to foster socio-ecologically resilient aquaculture frameworks and provide direction for future phycological research.