Open this photo in gallery: Fishing boats tied up in Bay de Verde, Newfoundland, on Feb. 1, after tariffs were announced by the U.S. on Canadian exports.Greg Locke/Reuters Domestic exporters will wake up to a grim new reality on Tuesday as U.S. President Donald Trump launches a trade war with Canada and Mexico by imposing 25 per cent tariffs on most imported goods, while hitting the energy sector with a 10 per cent levy. Mr. Trump’s decision to impose across-the-board tariffs this week will affect businesses ranging from B.C. lumber companies to Alberta oil producers, prairie farmers and potash miners,…