Green and brown Kappaphycus alvarezii strains obtained from commercial seaweed farms in Bohol, Philippines were brought to Tosa City, Kochi Prefecture, Japan in in 1992. Yearly field cultivation trials during warmer months were undertaken in the subtropical waters of Tosa Bay by the Pacific Ocean until a farming protocol was established in 2015. Only the green Kappaphycus alvarezii survived. The seaweed biomass was out-planted in Tosa Bay in spring when surface seawater temperature (SST) was 23oC. Seedlings were tied 20 cm apart on lines 0.50 cm to 1 m from the surface to floating cages (10m X 10m). Seaweed growth increased as SST increased 24-25oC in June, doubling its weight in a week in August when temperature was 28-29oC. This slowed when the SST increased to 32oC, stabilizing in September (28oC), and continuing to grow well until 23oC in November. One or two smaller harvests were made before September with the third and largest harvest in November for a total annual yield of 2t fresh seaweed from and initial 20 kg seed stock. Seed stock for the next planting season was selected from the best of the last harvest and this was maintained in covered tanks with seawater maintained at 23oC, under natural light, within a land-based hatchery.
Harvests were mainly marketed for human food, some as frozen seaweed or in dried powder form. The most important market (~30% of fresh harvest) that has sustained this boutique-type of Kappaphycus farming operation was its use in gourmet, Italian and French cuisine in Japan with the fresh, harvested seaweeds shipped to their kitchens. The profitable production of smaller, controlled volumes of good quality, fresh Kappaphycus by boutique type operations, as demonstrated in Tosa Bay, may provide an option to the large commercial operations that are presently practiced for the carrageenan market.