Maritime traffic in ice-congested waters in Canada moves under the control of the Canadian Coast Guard or with its close support, the annual sea supply of Arctic establishments is carried out mainly by merchant ships chartered for the purpose, escorted by icebreakers and assisted by shallow-draft Northern supply vessels and locally based landing barges. A rapidly growing commercial traffic into the Gulf of St Lawrence in winter is provided with routing advice or icebreaker escort on an organized basis worked out in consultation with the commercial interests. These and other related operations have developed in recent years with meteorological and other scientific support provided by various agencies of the Government of Canada.