Kombu is the Japanese name for the dried seaweed that is derived from a mixture of Laminaria species. These include L. longissima, L. japonica, L. angustata, L. coriacea and L. ochotensis. These are all harvested from natural sources, mainly on the northern island of Hokkaido, with about 10 percent coming from the northern shores of Honshu. The first three of the above are the main components of the harvest. The plants grow on rocks and reefs in the sublittoral zone, from 2-15 m deep. They prefer calm water at temperatures between 3° and 20°C.