The harvests of Gelidium are spread over a wide geographical area. Large quantities are harvested on the north coast of Spain, the middle to southern end of the coast of Portugal, and the west coast of Morocco. Smaller amounts are found on the Bay of Biscay coast in the southwest of France. Prior to the Second World War, the Gelidium of Japan was the main source of the world’s agar, but industrialization has led to depletion of the natural stocks, and today Japan harvests similar quantities to countries like Spain and Morocco. The Republic of Korea harvests commercial quantities for its local industry, in an area around the southern port of Pusan. In Mexico, Gelidium is harvested on the Pacific coast of Baja California. Warm-water species are collected from natural beds on the south coast of Java, Sumatra and many of the islands of Indonesia that lie between Java and Timor. Less significant contributors to the total harvest of Gelidium are Chile, China, France and South Africa.
For further details see McHugh (1991), and for an update on individual countries see Critchley and Ohno (1998).
Gracilaria is also distributed widely, with some species adapted to tropical countries like Indonesia, others to colder waters such as southern Chile and the Atlantic coast of Canada. Chileans pioneered the commercial cultivation of Gracilaria, using Gracilaria chilensis, native to its southern coast and containing a high quality agar. There are also large beds of wild Gracilaria in Chile, and it was the fear of depletion of these beds by overharvesting that led to the development of cultivation. Wild Gracilaria is also harvested in Argentina and Brazil, although the quantity is decreasing in Brazil because the quality does not compare well with the Chilean product.
China produces significant quantities of Gracilaria, mainly in the southern provinces of Guangxi and Hainan, where it is cultivated in ponds and estuaries; it is also cultivated in Taiwan Province of China. In Indonesia, wild seaweed is collected and some is cultivated in ponds. A more concerted effort appears to have been made in Viet Nam in recent years, with a variety of species being grown in lagoons and ponds in both the north and south. Beach-wash Gracilaria has been collected near Luderitz (Namibia) for a number of years, and, more recently, successful cultivation has been achieved in Luderitz Bay. Since the Second World War, wild seaweed has been collected from Saldanha Bay on the west coast of South Africa, but the yearly harvest has shown wide fluctuations. In southern Thailand, a source of income for women is the collection of free floating Gracilaria from tidal lakes and lagoons. Source: FAO