The "Inter-Agency 3-Alpha Code" was developed by the Coordinating Working Party on Fishery Statistics(CWP) to establish a common system to exchange data among the members and facilitate the reporting of fishery statistics from national correspondents. Once a 3-alpha identifier has been assigned to a species item it is not changed and thus it is a permanent reference to a species item. Codes for species items which have been cancelled, often because recognized as synonym of a valid species, are not reused but are considered as 'dead codes'.