Wild Atlantic salmon in Newfoundland and Labrador have seen a second year of increasingly low returns, with most of the province’s rivers being classified by the Department of Fisheries and Oceans (DFO) as being in critical condition.
While salmon stocks are usually assessed biannually, low river returns in 2023 triggered an unscheduled stock assessment for 2024. Atlantic salmon born in Newfoundland spend between two to five years in their home river before going out to sea, while Labrador salmon take around three to seven years due to colder temperatures.
Normally, these salmon spend one year at sea before returning to spawn. The rate of returns in many N.L. rivers have seen a major decrease, some of which were down by more than 50 per cent.
“This year, we’re seeing a higher magnitude of declines on more of our assessed rivers, but especially on the west coast where returns were much lower than normal,” said Nick Kelly, DFO stock assessment biologist. “At-sea survival of salmon smolts, which left the rivers in 2022 to return in 2023 as adults, is below average, with less than three per cent of smolts surviving to return last year on the rivers that we had estimates for.”
Of the 15 rivers assessed in Newfoundland, four were deemed by DFO scientists to be in the healthy zone and one was in the cautious zone. In Labrador, one of the four assessed rivers was considered healthy.
Some rivers fared worse than others. Muddy Bay Brook in Southern Labrador, for example, saw only 42 salmon returns in 2023, dropping the rivers stock status from well into the healthy zone in 2022 to critical condition by 2023. The Torrent River on the Northern Peninsula suffered a similar fate, with salmon returns dropping from over 7,000 salmon in 2022 to just under 1,200 in 2023.
The main factor that played into these diminished rivers was the survival rate of salmon at sea, which is mostly spurred by increasing marine temperatures. In the past three years, ocean surface temperatures have been the hottest on record in the region, with 2022 being the warmest. Many rivers across the province also saw temperatures in excess of 25°C, which can have potentially lethal impacts on both juvenile and adult salmon.
Kelly said a variety of factors play into the declining salmon population in the province.
“These include changing conditions with the marine environment such as changing water temperatures, changes in the zooplankton community, predation, sea ice and others,” said Kelly.
“On the south coast of Newfoundland, aquaculture is another potential factor that could be impacting marine survival, of which we’ve seen extensive scientific literature in other regions of the world.”
The future of salmon stocks in Newfoundland and Labrador is hard to predict, according to Kelly.
“Just think about the fish that spawned last summer. Their eggs will hatch this spring, and they’re not going to leave the river for another three years on average and come back. So, it is hard to forecast down the road, because you’re talking 6–7 years in the future. There’s so much uncertainty that could impact that between now and then,” said Kelly. “We’ve tried to forecast it like two decades ago, and there was also high uncertainty in trying to do it.”
