The development of barrages and marinas is a major threat to any sizeable estuary in Wales. Marinas can be found in many locations and there is both a marina and a barrage in Cardiff Bay that flooded the estuarine habitats and wader and wildfowl feeding grounds where the Taff and Ely rivers enter the Bristol Channel. Developments of these kind also pose a threat to migrating fish, several of which are considered to be threatened European species, such as Atlantic salmon (Salmon salar), allis shad (Alosa alosa), twaite shad (Alosa fallax), sea lamprey (Petramyzon marinus) and river lamprey (Lampetra fluviatilis).
