Laminaria hyperborea reaches 3.5 m long. Stiff thick stipe with digitate frond olive-brown to dark brown. Forms the famous kelp forests on rocks from 0 to 30 m, from Norway to Brittany. Key habitat sheltering very rich biodiversity of invertebrates, fish and epiphytes. Lifespan 15 years. Fished for alginate extraction. Spectacular spring growth. Sensitive to warming that threatens its southern range. Exceptional immersive diving in dense forest.
