Labrador's Arctic char vulnerable to climate change, says new study
Southernmost fish might not be able to adapt to warming world
A new study paints a troubling portrait of potential climate change impacts on Arctic char in Labrador, amid calls for more research to better understand what the future holds for the species that occupies a place of immense value in Canada's North.
The study, published recently in the journal Nature Climate Change, is the result of years of field and laboratory work by a team of Canadian scientists. The researchers spent several summers sampling migratory Arctic char — the variant of the fish that moves from fresh to saltwater and back again — in rivers across the region, from its northern reaches in the Torngat Mountains all the way south to the tip of Newfoundland's Northern Peninsula.
The study then analyzed the fish's genetic data and, combined with climate modelling from 2050, concluded the southernmost fish are the most vulnerable and "may be unable to adapt to pervasive warming in the Arctic."
"What we think we're seeing with this data is that we can expect there to be declines in this region for decades to come, essentially. That we expect that we will be losing those migratory [southern] populations," said Kara Layton, a study co-author and an associate professor at Aberdeen University in Scotland.
Predicting that the char will shift northward falls in line with already known science, said Layton.
"We have seen this already in things, like plants and birds and that, so we know these sorts of trends, and this loss of the southern range contraction is happening elsewhere," she said.
Scientific research on Labrador's Arctic char stocks is fairly thin, with study co-author Ian Bradbury saying the new work has helped map out the char's DNA and fill in some blanks about population, past and present. But overall, there's no solid understanding of just how many fish are out there.
"We've started to scratch the surface in understanding which populations are going to be vulnerable, of Arctic char in Labrador. But I still think there's a lot of unknowns in terms of understanding how many individuals we have there and what the magnitude of these changes that are coming actually will be," said Bradbury, a research scientist with the Department of Fisheries and Oceans in St. John's.
Labrador is predicted to warm much more than the island portion of the province, according to provincial climate data that shows Nain could be 7.3 C warmer in winter by 2050.
With the new Arctic char knowledge assembled and published, Bradbury said it gives both scientists and communities information to help direct work around the species in a rapidly changing world.
"It's something that I think really does further stress the need to mitigate climate change impacts, and it does give us something that we can start to monitor, so that we can start to prepare for these changes as they occur," he said.
'Crying' for more science: harvesters
Arctic char is a highly prized traditional food in Inuit communities, such as the five within Nunatisavut territory on Labrador's north coast. The only commercial fishery for Arctic char in Newfoundland and Labrador is based in that region, where the Torngat Fish Producers Co-operative holds the distinction of operating the province's northernmost fish plant, in Nain.
The head of the co-op said he doesn't get any comfort from the study's findings that his region's char could fare better than its southern counterparts. While Keith Watts welcomes the new research, he said far more of it needs to be done.
"We've been crying and asking for more science from DFO, because it is their responsibility, for quite some time — decades," said Watts, the co-op's general manager.
Watts said the co-op's annual harvest is well below the DFO-set quota, taking only up to 40 per cent of what's allowed. People in Nunatsiavut can also fish their own Arctic char through the Inuit domestic harvest program, but as Watts said that amount is also largely untracked, he's concerned about increasing commercial fishing in the face of so many unknowns.
"We're not comfortable with the fact that there's not enough science on the abundance of the species. We don't want to put it into jeopardy," he said.
From a business standpoint, the co-op's small catch doesn't make the Arctic char fishery viable, Watts said. The co-op offsets those losses from more lucrative species, as well as subsidies from the Nunatsiavut government, to ensure people can buy the fish either in Nain or the co-op's storefront in Happy Valley-Goose Bay.
"Arctic char is very important to Nunatsiavut people and always has been, and always will be. Because of the decline of other things, such as caribou, and food insecurity in the north coast, Arctic char is very important," said Watts.
Labrador: 'at the forefront of climate change'
That cultural importance is not only cultural, but also ecological. Labrador's Arctic char live throughout the entire region's coast, which means they've adapted to very different temperature conditions, that Layton and Bradbury said can vary by as much as 10 C from its southern to northern edges, or what they call a "steep environmental gradient."
That range in latitude, in a rapidly warming world, means an uncertain future for Labrador.
"It's a region that I really think is going to be at the forefront of climate change impacts," said Bradbury.
As such impacts happen, the char could act as a bellwether for Labrador's larger biodiversity, and better understanding how Arctic char have evolved to their current surroundings by looking at their DNA could help.
"We know that its a really, really important species, and one that can tell us a lot, I think, about climate impacts more broadly," said Bradbury.
As Watts and the co-op call for more science to be done, there is more research in the works. The Torngat Wildlife, Plants and Fisheries Secretariat is setting up a char-counting fence in the Fraser River, which empties into Nain Bay. Watts said the work was delayed for a year due to the pandemic.
Bradbury said he'll continue the study's work, with more genetic sampling of char to come in summers ahead, in the hopes of refining their predictions and figuring out how many fish the future holds.
"I think the only way we're actually going to start to get at that is through continued monitoring, and being in Labrador, and using some of these new approaches to start quantifying changes as we see them," he said.