 The site is also a marine protected area as it includes intertidal areas and contains marine components.The Beddmanarch–Cymyran site comprises the area of coastal salt-marshes, mud-flats and shallow coastal water lying between Holy Island and the mainland of Anglesey.This includes the Cymyran Strait (sometimes called the Holy Island Strait), the tidal reaches of the Afon Alaw to the east and extends northwards to Porth Penrhyn-Mawr.