Seasonal patterns of growth, alginate content and block structure of the alien invader <i>Sargassum muticum</i> (Fucales, Ochrophyta) from the Atlantic coast of Morocco

Abstract In the present study, alginate yield and composition were investigated during seasonal life cycle of alien brown alga Sargassum muticum harvested from Atlantic coast Morocco. Alginate ranged 11.14% in winter to 25.62% spring/early summer, coinciding with maximum vegetative growth. Monthly monitoring block structure showed that highest mannuronate (M)/guluronate (G) ratio was recorded development S. , before sexual maturity resumption growth, giving flexibility alga. The unusually high molar monad fractions (F G ) dyad GG guluronic acid late summer/early autumn appeared be related stiffness senescent thalli. Rheological characterisation exhibited pseudoplastic behaviour, apparent viscosities measured when blocks dominated structure. This study suggests could exploited as an alginophyte for commercial applications. best harvest time is May-June, which corresponds yield, thallus largely completed reproduction, ensuring sustainable exploitation species.