The ocean shelf off Labrador has hit record high temperatures this summer, according to the federal Department of Fisheries and Oceans.
St. John’s-based DFO research scientist Frederic Cyr told CBC News the summer of 2023 has been “pretty incredible” for the world ocean.
“The entire North Atlantic reached record high temperatures,” said Cyr — although it’s still generally colder than the rest of the ocean, he added.
Cyr said the shelf reached up to 15 C off central and southern Labrador. And while northern Labrador by the Torngat Mountains had a close to average summer, nearer Nain, the July average was roughly three degrees above normal, and one to two degrees warmer on average in August, Cyr said.
South of Makkovik, July was four degrees above normal and August was three degrees warmer than normal, Cyr said.
“In some bays it can be much warmer, but I’m talking about the size of the shelf. It’s much colder than elsewhere, but it’s still much warmer than a normal year,” Cyr said. Ocean warming has several effects, he said. It can mean changing habitats, forcing some species to move farther north in search of cooler temperatures.
And the warmer the water, the less oxygen it is likely to hold, he said, so species that need more oxygen may need to move. Warming water also means there’s a bigger difference between the temperature of the top layer of the ocean and the lower layers, Cyr said.
“The ocean is layered as a cake, basically,” Cyr said. “The warmer the surface water is, the more let’s say stratified, so the more difference there is in between these layers.
“That can impact the amount of oxygen going down into the ocean and nutrients moving around the ocean, impacting the food chain.”
NunatuKavut monitoring thousands of striped bass moving in
In southern Labrador, there are concerns about how a fish species moving in will affect the food chain. The NunatuKavut community council and DFO are monitoring striped bass populations.
Striped bass are a large fish that are found along the Atlantic coast, typically as far north as the Gulf of St. Lawrence, said Kristen Milbury, an aquatic biologist with the NunatuKavut community council.
Before 2017, Milbury said, a few rare ones were sometimes found off the Labrador coast, but since then they’ve been showing up in the tens of thousands. The council is collecting sightings and information from people to keep an eye on the bass population and its impact on the local food supply.
“It’s good for us to sort of stay on top of it and keep monitoring these species in the event that they do stick around and we do start to see some other changes as a result,” Milbury said.
“But that’s to be expected. I mean, climate change is causing lots of species to move northward.… So this might just be another result of that.”
In 2019, NunatuKavut studied bass stomach samples and saw they were eating the small forage fish people rely on, including smelts, capelin and herring, as well as small juvenile fish, including cod, trout and salmon.
“Predominantly they’re eating those sort of small forage fish, which is alarming to people because, of course, those are the bottom of the food chain species,” Milbury said.
This summer researchers attached trackers to some striped bass to try to determine if the fish are staying in Labrador waters over the winter. Anyone can report striped bass sightings to the local NunatuKavut office or fill in an online survey on the community council’s website.
Cyr hopes to do more research on the temperatures at different depths. The North Atlantic is a unique place, he said, and one year can have no effect on the next.
“We’re really at the Arctic gateway,” said Cyr. “It’s a very dynamical region, a lot of changes from one year to the next. So the fact that it’s warm this year doesn’t mean that it’s going to be warm next year. It can be completely different.”
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