Challenges to the future domestication of seaweeds as cultivated species: understanding their physiological processes for large-scale production

A detailed understanding of physiological and reproductive processes in seaweeds has repeatedly proven to be an essential pre-requisite in the successful development of a sustainable industry. The prime example of this was the classical discovery of the “conchocelis”- phase of Pyropia (Porphyra) by Kathleen Mary Drew-Baker in 1949. Such elegant research proved to be pivotal to the development of a globally important “nori” industry which transitioned from the simple provision of the enhanced surface area of the substrata for spore settlement to the sophisticated, mechanized and computerized operations in modern hatcheries supplied by seedling banks of selected species and their cultivars. All of the pre-requisite knowledge was acquired through intensive applied research. However, not all solutions need to be high-tech; problems caused by epiphytes and contaminants have been achieved by exposing Pyropia nets periodically and was found to be effective. This protocol was achieved based on fundamental observations by farmers which were then complemented and refined by laboratory trials. Techniques must be adapted for site-specific differences, as abiotic factors such as water current and movement, surface seawater temperature, light regime and photoperiod, nutrients dispersion and water quality are interrelated, either positively or negatively, influencing seaweed productivity and the end-use of the biomass. Unfortunately, positive techniques that have been shown in vitro/silica can prove to be impractical once attempted at large-scale cultivation and/or the return on investment is not justified by the commercial value of the resultant seaweed biomass. This chapter presents a summary of how the judicious application of knowledge based on the ecophysiological processes of common seaweed species from tropical and cold-waters can assist the future development and scale-up of the global seaweed industry