Site selection for kelp (Laminaria japonica Aresch)

Abstract

The important commercial seaweed Laminaria japonica was introduced into China in the late 1920s from Hokkaido, Japan. Although commercial production of kelp harvested from its natural habitat has been carried out in Japan for over a century, mariculture of this algae on a very large commercial scale was realized in China in the 1950s. Between the 1950s and the 1980s kelp production in China increased from about 60 to over 250,000 dry weight metric tons annually, making China the largest producer of Laminaria. The success of the kelp cultivation industry has mainly depended on the adoption of three important techniques: (1) the floating raft method of cultivation in which young sporophytes are attached to culture ropes which are fastened to long floating rafts in suitable coastal waters, (2) low temperature cultivation of summer seedlings in which Laminaria sporelings are cultivated over the summer months in cooled water whose temperature is kept below 10° C, and (c) application of ni trogen fertilizer in the open sea. The chief extracts from Laminaria are algin, iodine and mannitol, products widely used in textile, printing, medical and food manufacturing industries. Laminaria is also used to manufacture a variety of products for human consumption and for making various kinds of health foods. The techniques of raft culture and seedling-rearing used for Laminaria production may also be used for cultivating other species of seaweeds, such as Undaria, Gelidium and Eucheuma, as well as for mariculture of scallops, abalone and mussels. Though Laminaria is a cold water species, these growing techniques may be adapted for growing commercial seaweeds in countries located in warmer climates. This manual was specially prepared for the “Training and Demonstration Course on Laminaria Sefarming,” an activity under the UNDP/FAO/NACA Regional Seafarming Development Project (RAS/86/024).