Canada is an ocean nation. Our motto, A Mari Usque Ad Mare, means “from sea to sea.” Eight of ten provinces and all three territories — home to 86% of the Canadian population — are adjacent to salt water. Our coastline is more than 200,000 kilometres long, said to be the longest in the world. Our oceans cover some seven million square kilometres, seven-tenths the size of our landmass. We are an ocean nation. But we are failing our oceans. This report, Sustaining Canadian Marine Biodiversity, was prepared by an expert panel convened by the Royal Society of Canada. Its task was to assess the state of Canadian marine biodiversity and look for ways to sustain it. As well, it was asked to review whether Canada is meeting its national and international commitments to sustain marine biodiversity — that is, whether it has done enough to provide healthy, safe and prosperous oceans for the benefit of Canadians today and in the future.