Study area
The Celtic Sea is a shelf ecosystem (range depth 57-340m) located in Northwestern Europe. It is characterized by a gradient of sediments from shallow sand to mud habitats. It harbors a larger species richness than the surrounding area due to its position at the biogeographical border between warm water Lusitanian species and cold water Boreal ones (ICES 2018a). For decades, the Celtic Sea has been an important fishing ground for European countries and fishing has been shaping its ecosystem (Hernvann & Gascuel 2020). Importance of fishing driving the ecosystems have decreased after 2009 (Mérillet et al. 2020) but remains high, around 4000 thousand tons landed per years over 2000-2015 (Hernvann & Gascuel 2020).