Made-in-Canada climate scorecard reveals unprecedented risks for marine life

For 20 years, captain Gail Atkinson fished out of Nova Scotia’s Cape Sable Island, just southwest of Canada’s lobster capital, Barrington Passage. Lobster Fishing Area 34, as it’s known, is among the richest lobster grounds in the world, accounting for more than 25 per cent of Canada’s total annual catch of the crustacean. But eight years ago, she went all-in on neighbouring Lobster Fishing Area 33, off Nova Scotia’s South Shore, after seeing that the area was producing better lobster catch than in previous years.

“District 33 was considered the poor man’s fishery because the lobster stocks weren’t great. District 34 was more lucrative,” Atkinson says.

Her gamble paid off. While Area 34 still performs as a top district, Fisheries and Oceans Canada (DFO) reports that in Area 33, lobster “landings since the early 1980s have been higher than the previous 30 years.”

“It used to be you’d have to scrape together your catch in 33, but I’ve noticed a big change. Lobsters in this area are following the cold water, moving up the eastern seaboard – that’s the theory, anyway,” Atkinson says.

Clearly, the lobsters are moving and changing, and the culprit is likely climate change.

The warming of the oceans, projected to continue over the 21st century, complicates life below and on the water’s surface. Scientists say these anthropogenic changes – a direct result of high greenhouse gas emissions – are disproportionately affecting high-value fished species such as lobster, shrimp and snow crab, compared with non-commercial ones.

Now, a made-in-Canada climate risk scorecard for marine species is laying the groundwork for climate-smart fisheries management. The aim is to help fisheries keep pace with how the negative consequences of climate change are affecting marine life – and, in turn, provide better support to fishers such as Atkinson.

“You can drill down into the scorecard and get more detailed information about exactly where species will be affected, what year it will be affected, and how climate risk is manifest for that species, which can help us make more informed management decisions,” says Daniel Boyce, a marine ecologist at Fisheries and Oceans Canada (DFO) and lead author of the climate risk scorecard for marine life, released in August in the journal Nature Climate Change.

Boyce says the scorecard can also help DFO, which is responsible for fisheries management across Canada, determine where to start, triaging which fish stocks are most vulnerable. Scientists can produce an overall climate change risk score for marine species, at all locations where they live, by considering a dozen indicators across three dimensions: sensitivity, exposure and adaptivity. “Sensitivity” examines how responsive a species is to climate changes, such as warming waters. “Exposure” considers how a species will fare under climate change induced scenarios, such as the loss of suitable thermal habitat or ecosystem disruptions. “Adaptivity” factors in how resilient a species is – for example, whether it can recover quickly from consequences of climate change.

It is vital that the fisheries themselves adapt quickly.

“Surface ocean temperature of the Northwest Atlantic has increased and is still warming,” says Frédéric Cyr, a research scientist at DFO. In recent decades, the global ocean has absorbed 90 per cent of Earth’s warming, with the first few metres of the ocean storing as much heat as the Earth’s entire atmosphere, Cyr says, referencing the work of the Intergovernmental Panel on Climate Change.

The scorecard provides an unprecedented picture of how marine life will fare in a warmer ocean.

Under the worst-case, high-emissions scenario, almost 90 per cent of 25,000 marine species globally would face high or critical risks, with species vulnerable across the majority (85 per cent) of their native distributions (meaning there would be nowhere for these species to seek refuge from the heat or other detrimental effects of climate change). But under a best-case scenario – low emissions consistent with the 2-degree warming limit in the Paris Agreement – climate risks would drop almost universally (98.2 per cent) for all marine species and ocean ecosystems.

Under a high-emissions scenario, harvested and commercially valuable species are disproportionately affected, with the risk of exposure to hazardous projected climate conditions three times higher than that for non-harvested species, reports a separate Canadian study by Boyce and colleagues. That preprint study, published in July, examined the climate vulnerability and risk for 2,000 species across three ecosystems and 90 fish stocks in the Northwest Atlantic Ocean, a documented global warming hotspot. Of those 90 fish stocks, 41 per cent were at high climate risk under high emissions, but that proportion dropped to 25 per cent under low-emissions mitigation.

“If we had a crystal ball and looked to the future, we expect that exploited species such as lobster will be far more at risk from climate change than non-exploited species,” Boyce says. “But in the same way, if we lower emissions, then we also find that the risk for these exploited species, especially the high-value ones, drops more significantly than for non-exploited species.”

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This is because under worst-case emissions projections, to which Boyce says the Earth is most closely tracking, cold-water species such as lobster are projected to lose much of their habitat. A 2017 modelling study found that under sustained ocean warming, lobster will continue shifting outside of their usual geographic range, migrating north, in search of cooler environments. This could explain why Atkinson is seeing lobster moving up the eastern seaboard.

“The parts of the ocean that are favorable for lobster growth and development from a temperature perspective, those are shrinking in the next 60 to 80 years. Projected changes to lobster are negative – it’ll lose habitat, it’ll become increasingly thermally stressed, and [the population] will likely shrink as a result,” Boyce says.

While that may seem like the distant future, fishers such as Atkinson are already trailing behind the lobster and tracking increasingly bad weather, another result of climate change.

“In winter, there are far more severe windstorms and winds with hurricane gusts than when I was a girl fishing with my father,” Atkinson says. “We’ve always had northwesterly gales and northeasterly snowstorms, but now there’s half a dozen storms a season with six-to-eight-metre seas forecasted.”

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Spring is when Atkinson, who has been a fisher for nearly 30 years, has observed the greatest changes. “The lobster activity in the spring is slower and the colder water is not warming up as quickly as it used to,” she says.

At present, two-thirds of Canadian fish stock assessments do not factor in climate change. Based on DFO’s own assessment conducted in 2021 (and released in 2022), out of 212, a little less than half (102) considered environmental and ecological data. Expectations are “that 65 per cent of the remaining 110 stocks could incorporate ecosystem knowledge in future assessments if resources and funding are made available,” the report says.

Oceana Canada, an independent charity, says the gap is greater. According to its fishery audit, released in November, DFO does not formally consider climate change data for 72 per cent of fish stocks, despite the availability of scientific evidence for 82 per cent of them. For critically depleted stocks, the situation is more dire: Only 3 of 33 consider climate change variables, the audit says.

“DFO has a long way to go to deliberately and methodically incorporate climate knowledge into decision-making for the sake of the future of our fisheries,” says Robert Rangeley, Oceana Canada’s science director.

To that end, Boyce and colleagues are incorporating the climate risk scorecard into DFO’s first-ever Climate Adaptation Framework for Fisheries. It will provide important information for fisheries management and infrastructure, such as wharf designs that withstand sea-level rise. Climate-smart planning, he hopes, will become the rule, rather than the exception.

“Rather than looking at stocks on an individual basis ... it should be a blanket policy to incorporate climate considerations into fish stock management across the board,” Boyce says.

This fits with DFO’s goal to shift away from single-species management to ecosystem-based management, which considers multiple species within a marine area, and looks at everything from the natural environment to human activity. The scorecard is also in line with the department’s precautionary approach: a policy that calls for greater caution in harvesting decisions – be it through quota cuts, gear restrictions or fisheries closures – when science is uncertain, especially for critically depleted species.

But the proof is in the planning, and currently, even when environmental and ecosystem factors are cited, they are not necessarily applied. Case in point: According to DFO’s own cod rebuilding plan, warming waters and reduced capelin prey are prime threats to a Northern cod comeback – but the plan neither applies added caution to cod or capelin harvesting decisions, nor does it mention “climate change.”

In Lunenburg, N.S., Atkinson says she’d welcome fisheries managers building climate variables into harvesting plans – but she also wants them to draw on the knowledge from people such as herself, who are witnessing the changes firsthand. She worries about what warmer ocean temperatures will mean for Canada’s most lucrative fishery.

“We are known for our cold-water hard-shell lobster. If the water warms, then what?” she says. “Lower quality lobster and a lower price.”

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