Mapping the global mass flow of seaweed: Cultivation to industry application

The global flows of cultivated seaweed were estimated for the year 2019 using a combination of literature review, assumptions, and simple conservation of mass calculations. Red seaweeds were found to be the largest contributors to the hydrocolloids industry, for both food and non‐food applications. Carrageenan‐containing species were found to be the largest contributors to both food (62%) and non‐food (55%) hydrocolloids and are the primary source for water gels, which make up 27% of non‐food hydrocolloids, followed by pet food (16%), toothpaste (6%), and others (6%). Carrageenan also accounts for almost all meat products, which make up 35% of the food hydrocolloid industry, and dairy products, which make up 26%. Agar‐containing seaweeds are used in confections (10% of food hydrocolloids), baking (9%), and other (2%) and make up 15% of non‐food hydrocolloids. Porphyra (nori) is cultivated for direct consumption and makes up 23% of direct food consumption. Cultivated brown seaweeds were found to comprise Laminaria/Saccharina for alginate production (30%), Laminaria/Saccharina for direct consumption (44%), and Undaria for direct consumption (16%). About half of the alginates produced make up 18% of food hydrocolloids, and the other half is used in non‐food hydrocolloids comprising technical grades (28% of non‐food) and animal feed (3%). The results are discussed in the context of emerging markets for seaweed and the potential for seaweeds as a substitute for staple foods, and the environmental impact of seaweed farming is explored through a review of life cycle assessment studies.