The phrase "increased tanker" means there are more large ships specifically designed for carrying and transporting large amounts of liquids, such as oil. Full definition
Some opponents may also exaggerate the potential for a public health catastrophe resulting from a spill in Vancouver harbour, as well as the effect of increased tanker traffic on the health of struggling Salish Sea orca populations. (critical-angle.net)
Liberals: Trudeau has promised a Liberal government would reject the Enbridge Northern Gateway project approval because of threat increased tanker traffic poses to the ocean economy and clear opposition from First Nations and B.C. residents. (rabble.ca)
The expansion, involving almost 1,000 km of new and mostly underground pipeline, will triple capacity to 890,000 barrels per day — and significantly increase tanker traffic through the shallows of the Georgia Straight, off southern B.C. (canadianlawyermag.com)