Vegetative Propagation of Pyropia to Advance the West Coast Nori Industry

Project Number
Project Date Range
Funding Agency
National Oceanic and Atmospheric Administration (NOAA)
Focus Area(s)
Sustainable Fisheries and Aquaculture

The global production and harvest of seaweeds is now a $7 billion industry and is expected to grow to $22.1 billion by 2024. In California, however, where demand has skyrocketed, in-state production of edible seaweeds is low; the market is dominated by seaweed products that are imported from Asia. While some wild seaweeds are commercially harvested in the U.S., the targeted species have suffered due to recent environmental changes, leading to inconsistent availability. Regulations limiting the harvests of these species are also highly restrictive.

This project developed new propagation techniques for edible seaweed species which will allow for year-round production in land-based aquaculture tanks. In partnership with Intertidal Seaweed, a commercial seaweed harvest and production business in northern California, the researchers developed innovative, effective and simplified vegetative propagation protocols for Nori.

Though COVID-19 restrictions delayed the project’s launch, in late 2021 the team developed and tested a protocol that yields Pyropia perforata monospores, which can be used to produce new seaweeds: young growing blades are cleaned with distilled water, then homogenized with a miniature electro-mechanical blade to generate clone cuttings. These monospores are activated and will propatage new gametophytic growths on culture rope if cultured with 100 mg L-1 GeO2, which appears to prevent overgrowth and contamination. This suggests there is a scalable method of seaweed propagation that is more suitable to California regulations than the methods currently used in China. Growth of new fronds stopped at four months, but resumed when inoculated rope cultures were transferred to floating platforms in outdoor grow tanks, in natural sunlight and temperature conditions. This validated the full lifecycle potential of this method, though growth was small, so further investigation and refinements are needed. Further studies revealed that this method works for P. perforata, but not for another native kelp species, Pyropia abbottiae.

Continuing research in this area will generate a new business, improving the economic and environmental viability of the California seaweed industry.

Principal Investigators
Daniel Swezey
University of California, Davis