Warm waters factor into continued declining salmon returns: DFO

High water temperatures and low water levels are having a serious impact on Newfoundland and Labrador's Atlantic salmon population, as Fisheries and Oceans Canada reports more than 60 per cent of Newfoundland's salmon rivers remain in the critical zone.

"Once water levels drop, temperature can go up much faster. So then, you can have high temperature events," salmon stock assessment biologist Nick Kelly told reporters Friday.

"The number of young salmon over the next few years who are impacted by these low water levels or high temperatures, if they continue, could definitely reduce the number of salmon further, say five, six years from now."

DFO's 2025 salmon stock assessment shows a continued downward trend in salmon returns, and continuing historic lows felt since 2023.

Kelly said 62 per cent of assessed rivers in Newfoundland are in the critical zone. One of three rivers assessed in southern Labrador is also listed in the critical zone.

The other two assessed southern Labrador rivers are in the stable zone, while the one monitored river in northern Labrador is seeing positive returns and is listed in the healthy zone, Kelly said.

Limited snow melt in the fall led to low water levels in many of Newfoundland and Labrador's rivers this summer, paired with drought conditions in both July and August.

Kelly said those conditions caused mortality events in seven freshwater rivers, including in Middle Brook, Placentia Bay and Point Leamington among others.

While fatalities were low, one exception was a mortality event in Conne River.

Salmon returns have been devastated in the river in recent decades, since as many as 10,000 salmon returned each year during the 1980s.

"This year, out of about 585 fish, I believe, that returned to Conne, at least a hundred of them died," Kelly said.

"Within the same span of about a week or so in July, we had a lot of these mortality events on a bunch of different rivers on the island … River temperatures were up in the 20s, possibly high 20s. Which is definitely approaching, and possibly exceeding, the lethal limits for salmon."

Similar die offs were also reported at multiple salmon farms in Newfoundland this fall.

Kelly said salmon in the province also face continued threats surviving at sea. As less smolt head to sea each year, he said it could translate to even smaller returns in the future.