Some conservationists say they are concerned that Nova Scotia's prolonged drought could cause long-term damage to salmon stocks.
Atlantic salmon return from their ocean feeding grounds to the rivers where they were born each fall in search of an ideal spawning area. Nose spawning season in October and November, ccritically low water level are threatening how this important step in their life cycle will end.
“I'm very concerned about how this generation of salmon will survive,” says Amy Weston, managing director of the Nova Scotia Salmon Association.
Female salmon lay and incubate their eggs in a nest or gravel bed known as a redd. Weston said the fish are picky about where to build their nest and require favorable water temperatures and water flow, two factors impacted by the dry conditions.
Salmon prefer cold, oxygen-rich water, and the warmer the water becomes, the less oxygen it contains. Low water levels also mean reduced habitat for fish and make it difficult for them to move, making them more vulnerable to predators.
While recent rains have helped replenish some of the major watersheds where salmon spawn, Weston worries that if the drought continues, it could lead to other problems during the winter.
“When we have shallow water and if we have a cold winter, ice will form in the river. And if it's too shallow, it will form and freeze to the bottom of the river,” she said. “It then picks up the gravel as it breaks down and you risk losing those red spots.”
Fish in the province were already under increasing stress due to low water level and sudden increase in water temperature. On the St. Marys River, one of Nova Scotia's largest and most significant salmon rivers, the effects of the drought were particularly severe.
“The feeder streams that keep the main branch flowing are completely dry. Gone, there's nothing in them,” said Scott Beaver, president of the St. Mary's River Association.
He said the lack of flow had left small trout and minnows trapped in shrinking pools of warm water, making them easy prey for natural predators. Low water levels can also hinder the migration of adult salmon and expose them to predation.
Beaver said at one point during the drought he feared “we might lose the 2025 spawning season altogether.”
But he said rains in late October likely gave the fish a reprieve and gave hope to people working to ensure the species' survival.
However, both Beaver and Weston said long-term solutions are needed to restore natural buffers, such as riparian forests, that will provide shade and help keep rivers cool.
As extreme weather becomes more common due to climate change, it's important that communities commit to caring for fish habitat, Weston said.
“We need to make our rivers as resilient as possible to climate change,” she said. “There is a lot we can do to improve the situation and make habitats more sustainable for both fish and people.”
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