Projet Life Intégré Marha. Exploration du lien entre l'activité de pêche et le stock modélisé de Laminaria digitata et Laminaria hyperborea de la Région Bretagne. Bilan d’activités de l’Ifremer pour le volet côtier

Within the framework of the Life Marha programme, in collaboration with the ANR IDEALG, research was conducted on Breton subtidal reefs, focusing in particular on Laminaria digitata and Laminaria hyperborea, whose distribution and stock assessment are essential for sustainable management. The study is structured around three complementary components: The first provides an objective mapping of Breton infralittoral seabeds based on six major abiotic variables, enabling the identification of homogeneous ecological units and improving the representation of these habitats and optimizing their sampling. The second develops predictive biomass models based on 16 years of data and morphobathymetric, hydrodynamic, and biogeochemical variables. It highlights distinct ecological niches for the two species and delivers a quantitative estimate of standing biomass. Finally, the third component analyzes the relationship between potential biomass and the activity of kelp harvesters in Finistère (SIH data 2013–2020), emphasizing fishers’ ability to target productive areas and providing scientific support for quota adjustments.