Sampling, Mapping and Adding Value to Marine Invasive Seaweeds of the Iberian Peninsula

Non-indigenous species (NIS) can be defined as species that colonized new geographical areas where they were not present previously. Their increasing appearance has been causing considerable ecological and economic problems globally. Under this scope, biological invasion and invaders’ success has been an important topic during the last decades. Hundreds of marine NIS have been introduced around the world and seaweeds (marine macroalgae) are a significant part of them. Studies conducted worldwide in the last decade have been reporting around 250 species of introduced seaweeds. The northeast part of the Atlantic is especially known to be home to many introduced species and more than 100 introduced species of seaweeds are reported in Europe. This thesis will go through the processes of seaweeds invasion, from their introduction stage and their introduction vectors, to their invasive success, focusing on the main NIS of seaweeds that can be currently found at the northwest of the Iberian Peninsula. Particularly, six NIS of seaweeds (Sargassum muticum, Grateloupia turuturu, Asparagopsis armata (including Falkenbergia rufolanosa stage), Undaria pinnatifida, Codium fragile subsp. fragile and Colpomenia peregrina) were previously selected and sampled – based on DAFOR (Dominant, Abundant, Frequent, Occasional or Rare) cover ranges scale – along intertidal sites located within the northwest of the Iberian Peninsula. As a result of the sampling, the distribution of those seaweeds has been updated for the area, producing a hotspot map of their presence and relative abundance. Furthermore, the environmental management of NIS was addressed, as well as their potential uses such as biofertilizers, bioactivities, feed and food, aiming to show how these species, which are jeopardizing the ecosystem, can be an excellent environmental resource of bioactive compounds with high industrial potential and high socio-economic revenue.