Ecklonia radiata is the dominant kelp species in southern Australian and in New Zealand coastal waters and Ecklonia maxima is the dominant kelp species in South African waters. Neither species is harvested in any great quantity at present but both species have very long stipes and are sources of good quality alginates.

In Australia Kennelly (1987a,b) has shown how the recovery of a kelp forest after the removal of mature plants was dependent on the season at which the mature plants were removed. If plants were removed in the winter months, normal settlement and recruitment of juvenile plants occurred and a new canopy cover was established rapidly. If plants were removed in the spring, summer and autumn, however, the cleared area was initially settled by a dense turf of red algae which inhibited the settlement of gametophytes or the development of young sporophytes in the winter months.

In South Africa a great deal of research has been undertaken into the energetics and population dynamics of the species which forms part of the food web for the commercially important rock lobster fishery. As a result of this 20-year-long, ongoing, work, it is unlikely that Ecklonia harvesting will be allowed due to the key role the kelp has been shown to play in the primary productivity of the coastal ecosystem (R. Anderson, pers. comm.). The stipes of drift-line Ecklonia are still collected from the beaches, air-dried, baled and sold on the world market for alginate production (H.T. Powell, pers. comm.).

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