Canada’s three oceans – Atlantic, Pacific and Arctic – are changing and these changes are not an isolated concern to Canadians only. Oceans world-wide are changing. Several studies have identified early warning signs of significant ecological change in the oceans including: warmer ocean temperatures; declining extent and thickness of sea ice; high latitude waters becoming less salty, increasing acidity, as a result of carbon dioxide dissolving in the ocean; oxygen depletion in marine waters (i.e. hypoxia); changes to food webs; and declines in multiple commercial fish stocks, despite recovery efforts. These changes are in response to natural and human stressors, such as climate change, overfishing, aquaculture, pollution, nutrient loading, resource extraction, shipping and acidification. The direct, indirect and/or cumulative impacts of these stressors are a threat to ocean health and marine biodiversity. Diversity of ocean life from genes to species to ecosystems represents an irreplaceable natural heritage, crucial to our well-being and the sustainable use of ocean resources.
Ocean health is critical to ours and our planets health. Our oceans provide 95% of the liveable environment; host the greatest breadth of species diversity, between 500,000 and 10 million species; produce half the oxygen we breathe; produce food (e.g. fish, shellfish, kelp), and pharmaceutical and mineral resources; support diverse industries (e.g. fisheries, aquaculture, energy, transport); and regulate the climate. No matter how far from the coastline one lives, the oceans affects them. Realistically, we can’t stop using the oceans – we need the resources. Instead we need to find a way to use them more wisely and sustainably to maintain their health and ours. To achieve this, we need strategies for effective conservation and sustainable ocean use. These strategies require a strong science basis, yet our current knowledge of marine ecosystems is limited.