 However, the biodiversity of Wadden Sea is smaller today than it once was; for birds, greater flamingos and Dalmatian pelicans used to be common as well, at least during the Holocene climatic optimum when the climate was warmer.Some regionally extinct species are still found here.Larger fish including rays, Atlantic salmon and brown trout are still present in several sections of the Wadden Sea, but others like European sea sturgeon only survive in the region through a reintroduction project.