(b) The term “seasonal worker” refers to a migrant worker whose work by its character is dependent on seasonal conditions and is performed only during part of the year; (c) The term “seafarer”, which includes a fisherman, refers to a migrant worker employed on board a vessel registered in a State of which he or she is not a national; (d) The term “worker on an offshore installation” refers to a migrant worker employed on an offshore installation that is under the jurisdiction of a State of which he or she is not a national; (e) The term “itinerant worker” refers to a migrant worker who, having his or her habitual residence in one State, has to travel to another State or States for short periods, owing to the nature of his or her occupation; (f) The term “project-tied worker” refers to a migrant worker admitted to a State of employment for a defined period to work solely on a specific project being carried out in that State by his or her employer; (g) worker: The term “specified-employment worker” refers to a migrant (g) ii(i) Who has been sent by his or her employer for a restricted and defined period of time to a State of employment to undertake a specific assignment or duty; or (g) i(ii) Who engages for a restricted and defined period of time in work that requires professional, commercial, technical or other highly specialized skill; or (g) (iii) Who, upon the request of his or her employer in the State of employment, engages for a restricted and defined period of time in work whose nature is transitory or brief; and who is required to depart from the State of employment either at the expiration of his or her authorized period of stay, or earlier if he or she no longer undertakes that specific assignment or duty or engages in that work; 106