Kelps are one of the most economically and ecologically important groups of seaweeds in the world. Most kelps are confined to cold temperate regions, and northern Spain is the southern distribution limit of many species in Europe. As the supply from wild harvest cannot meet increasing current and future demands, methods to successfully cultivate kelp species are needed. This review integrates key points about mariculture of kelp species from different cultivation trials conducted along the Atlantic coast of southern Europe, and more specifically about Undaria pinnatifida (wakame) and Saccharina latissima (sugar kombu) along the northern Spanish coast. It focuses on the following topics: (1) effects of hydrodynamic conditions on culture grounds in coastal bays in order to identify optimal locations for culture of both kelp species; (2) suitability of different raft culture systems in sheltered and more exposed environments; (3) identification of the most suitable time frame for the mariculture of both kelps and its relationship with environmental factors; and (4) different methods for open-sea cultivation of S. latissima based on practices traditionally employed in Asian Saccharina farming. Finally, (5) this paper discusses the development of mariculture of the introduced kelp, U. pinnatifida, in relation to the native kelp, S. latissima, both from economic and environmental perspectives. Overall, the information reported here contributes to the knowledge necessary for the successful mariculture of these and other kelps on a commercial basis in this and other areas of Europe.
