The Métropole Rouen Normandie (France) has installed artificial nurseries with the help of Ecocéan, who has installed “Biohuts” in several European ports already. Rouen has chosen to install these to help rehabilitate the ecosystem and ecological functions in the marina basin. Due to the artificialization of the marina, native species (eel, trout, pike, etc) have disappeared from the basin. There is almost no vegetation or shelter in which young fish can hide from predators, leading to a degraded ecosystem. This 20.000-euro project will be monitored over the next few years to see how the “Biohuts” help restore the ecosystem.