A climate scorecard provides a picture of how marine life will fare as oceans become warmer, which is projected to continue over the 21st century
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.