Monterey Bay Aquarium Research Institute
Marine Botany

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A number of red seaweeds, including Gelidium, are utilized for their natural gums. The phycocolloid agar is extracted from Gelidium and used for its gelling properties in a wide variety of products. Gelidium yields high quality agar with high gelling strength and low sulfate content. Agar is perhaps best known for its use in culturing bacteria and fungi. In recent years, it has been utilized for biomedical techniques such as gel electrophoresis. The form used for such processes is known as agarose and is more purified than most agar. Agar is also used in food prodution and transport: in canning foods, transporting cooked fish in gel, and as a clarifying agent in making beer, wine and coffee. It also has been used as a laxative. A little known use of agar is in finishing fabrics like silk to maintain sheen. Many more uses of agar exist.

Agar industries exist in at least 22 countries. Those where Gelidium is used in the production of agar include Japan, Korea, Taiwan, Indonesia, U.S.A., Mexico, Chile, Spain, France and South Africa. Though historically, Gelidium has been used widely in the agar industry, in recent years it has been falling out of favor because it grows more slowly and is less responsive to aquaculture conditions than other agarophytes such as Gracilaria. At present, aquaculture of Gelidium is only done on an experimental basis with limited success. The Gelidium used in industrial production of agar is all harvested from wild stocks. The harvesting is done with relatively low technological processes including collecting from drift after storms, collection in the intertidal at low tide, and collection in the subtidal using snorkeling and SCUBA diving in deeper waters. In Japan, dredging techniques are also used. Some regulation of the wild Gelidium stocks has been enacted in Japan by fisherman's collectives that recognized the need to manage the resource. However, in the future, as the need for agarose from Gelidium grows for specialized biomedical processes, it will probably be important to manage wild stocks of Gelidium to keep populations sustainable.

Finally, in countries such as Japan, China, Indonesia and Borneo, species of Gelidium are eaten. Seaweed may be enjoyed fresh or may be pickled or dried. Gelidium is also made into jellies which are eaten with other kinds of foods.

Gelidium frond


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© 1999 Sharon C. Komarow. All rights reserved.