Concise review of the kelp genus Eisenia Areschoug

Eisenia (order Laminariales) is a genus of warm-tolerant kelps found in the Northern and Southern Hemispheres of the East Pacific, as well as in the North West Pacific, where species form beds in rocky bottoms along the sea coast from the intertidal and subtidal zones. There are seven recognized species in the genus, including the endemic and vulnerable E. galapagensis. Despite some remarkable morphological variations, Eisenia species are characterized by two twisted stipe-like parts arising from the main stipe. Genetic data have recently contributed to the understanding of Eisenia systematics; however, additional studies on E. desmarestioides, E. cokeri, and E. gracilis are needed. Aside from economic benefits, Eisenia farming has various other essential benefits, such as resource sustainability and ecosystem benefits, which are especially important in climate change scenarios. Spore-based cultivation has been reported only for E. arborea, E. bicyclis, and E. nipponica (formerly known as E. arborea sensu Arasaki). This kelp is widely consumed in Korea and Japan and utilized as a raw material for alginate production and feed for abalone cultures. Because of its nutritional composition and mineral concentration, Eisenia is also a potential food source outside Asia. Moreover, various pharmacological applications of Eisenia have been reported, particularly those related to antioxidant, antidiabetic, and anti-inflammatory properties. Phlorotannins (brown algal polyphenols) derived from E. bicyclis are linked to these bioactivities. In this work, we present a comprehensive synthesis of the current state of knowledge on Eisenia, offering insights into its taxonomy, distribution, ecology, cultivation, and various applications.