Federal report reveals complex changes taking place in our oceans

Every four years, the Department of Fisheries and Oceans produces a report summarizing the current state of Canada's Atlantic, Pacific and Arctic Oceans. This year's publication is all about changing seas.

The report, Canada's Oceans Now, 2020, is a general overview of the state of the oceans that line our east, west and north coasts, giving us by far the longest coastline in the world at almost a quarter of a million kilometres. Even though the geographical range is huge, all three oceans are connected and interact with each other, affecting all life in the water and on the land.

The report charts a long list of changes in the oceans, such as warming, especially in the Arctic which is warming twice as fast as the global average. It also details ice loss, sea level rise, ocean acidification, habitat degradation, and shifting distribution of species and transformation of food webs manifesting differently in different regions. 

One example is how the loss of sea ice in the Arctic is allowing orcas, or killer whales, to move north and enter Hudson Bay. Native narwhals and bowheads are changing their behaviour and locations to avoid them.

Warmer ocean temperatures caused by climate change are allowing many species to move northward, so a record number of salmon are appearing along the northern coasts of Yukon and Northwest Territories while those along the southern Pacific coast are in decline. 

Differences in sea level rise

One interesting observation is how sea level rise will affect each coast differently. Oceans around the world have risen 21-24 centimetres since 1880 threatening low lying coastlines. But the effect in Canada is different for each ocean.

Along the West Coast, tectonic forces caused by the collision of the North American plate with the Juan de Fuca plate are pushing Vancouver Island upwards faster than sea level is rising, so levels are going down.

The same is true in some parts of the Arctic, such as Hudson Bay, where the land is rising from the retreat of the massive ice sheet since the last ice age.

However, that same retreating ice sheet around Halifax along the East Coast is causing the land there to move downward, so rising sea level will become more apparent there. 

The changes to the ocean chemistry and circulation cited in this report are at every level, from the bottom of the food chain to the top predators, and they are happening more quickly today than in the past.

Mitigating marine change

Change is not new to the marine environment, it has been a hallmark of the Earth's oceans for billions of years.

Temperatures have risen and fallen along with the cycles of ice ages, there have been mass extinctions, such as the Permian extinction more than 250 million years ago where the oceans were virtually sterilized as an estimated 95 per cent of marine life was wiped out.

But despite these dramatic changes, life managed to return, often in a different form from that which came before.

Today, a new threat comes from human activity in the form of climate change, fishing and agricultural, urban and sewage runoff from the land. Those can all be managed to lessen our impact. 

Protecting marine areas

The oceans can also repair themselves if we just leave them alone.

Another recent report, co-authored by University of British Columbia's William Cheung and Juliano Palacios-Abrantes, as well as Dalhousie University's Boris Worm, says that by increasing the number of marine protected areas around the world would have the triple benefit of increasing biodiversity, boosting marine fisheries and securing marine carbon stocks held in the sediment and by plants. 

That report's 26 authors map out a "blueprint" governments can use to safeguard 80 per cent of global habitats for endangered marine species. 

Some priority areas they identified within Canadian jurisdiction that include locations such as the Fundian Channel south of Nova Scotia, the Southern Grand Banks and the Central Coast of British Columbia.

Canada, along with other countries around the world, has committed to protecting at least 30 per cent of our marine and coastal areas by 2030. As of August 2019, Canada had protected 10 per cent of its marine areas.

Focused attention on the world's oceans

The United Nations has declared the years 2021-2030 as the Decade of Ocean Science for Sustainable Development.

It is an effort to, "reverse the cycle of decline in ocean health and gather ocean stakeholders worldwide behind a common framework that will ensure ocean science can fully support countries in creating improved conditions for sustainable development of the Ocean."

We as individuals can also help the oceans by learning more about them and taking time to appreciate our extensive ocean coastlines.

The Canadian Ocean Literacy Coalition is a good place to start where you can join with other Canadians to take action to preserve our oceans for future generations.