The red seaweed Asparagopsis armata is a target species for aquaculture due to its efficacy as an anti-methanogenic ruminant feed additive. However, limited knowledge regarding its reproductive biology and methods for closed-life cycle cultivation has delayed adoption of this method in aquaculture. This thesis therefore aimed to address these knowledge gaps by investigating (1) reproductive phenology, (2) techniques for inducing life-cycle transitions, (3) nursery requirements, and (4) internal mechanisms regulating reproductive processes in A. armata. A comparative analysis of A. armata reproductive phenology in New Zealand from 2021 to 2022, compared to 1978 to 1981, identified potential climate-driven shifts in phenology. Specifically, the occurrence period of gametophytes was shorter, and cystocarp production and viable carpospore release were delayed in comparison to 1978–1981. Discoloration, low reproductive output, and low survival rates in 2022 were likely caused by heat stress. These findings will help guide aquaculture practises and advance our understanding of climate change effects on seaweed reproductive phenology through future comparative studies. Mass production and release of tetraspores in domesticated A. armata tetrasporophytes was demonstrated through a 14-day exposure to a reduced critical photoperiod of 8 h L:16 h D. Increasing the temperature from 15 to 18 °C resulted in a marked increase in tetraspore release, whereas exposure to 11 and 13 °C, along with lower light intensities and nutrient concentrations, did not initiate tetrasporogenesis. These results highlight the importance of temperature, among other environmental factors, in controlling reproductive output. A distinct bimodal pattern in tetraspore release was observed, and tetrasporogenesis could be re-induced in the same biomass by adjusting key environmental parameters. These findings collectively offer precise control over tetrasporogenesis, facilitating commercial hatchery production. Key parameters for enhancing the growth and development of juvenile gametophytes of A. armata were identified, notably moderate temperature and water flow, which resulted in substantial biomass productivity increases. Gametophytes developed more rapidly under a 12h L:12h D photoperiod, while growth was enhanced under lower irradiances. Additionally, lowering nutrient concentrations resulted in cleaner cultures without compromising growth. These results elucidate the influence of environmental factors during the early life stages of A. armata, providing essential insights to enable large-scale nursery operations. Finally, an analysis of metabolomic and transcriptomic dynamics during induction of tetrasporogenesis identified marked changes in gene expression. While metabolomic changes were less prominent, accumulation of several metabolites occurred. Multiple pathways and genes, such as those related to polyamine and steroid hormone production, environmental signalling, and carbon metabolism, were upregulated during induction. These results demonstrate a dynamic biochemical and molecular response, particularly in the early stages of initiating tetrasporogenesis, laying the groundwork for identifying candidate genes and metabolites that regulate this process. In summary, this thesis significantly advances the science and knowledge required for the successful cultivation of A. armata by creating foundations to (1) guide the selection of cultivation techniques, (2) develop climate-resilient management strategies, (3) enable the implementation of streamlined commercial hatcheries and nurseries, and (4) direct future research aimed at deciphering the fundamental internal mechanisms of reproductive transitions in seaweed.