Saturday , October 23 2021

Researcher about the situation of B.C. salmon in a lump of warm water – Terrace Standard


Anomalies or new norms, researchers carefully track the persistent clumps of warm water in the northeast Pacific Ocean and what they mean for salmon.

In the last two months, the high pressure ridge that developed in the beach area of ​​B.C produced a warm and long summer. The storm season is late, and the water is two to three degrees warmer.

Richard Dewey, associate director of science at Ocean Networks Canada, and the University of Victoria, has carefully tracked around 2,000 kilometers of warm areas that made their first appearance in the fall of 2013 and became much more visible in the spring of 2014 – when researchers created the term "lump".

"The program woke us up what happened here. Atmospheric flow, storms, and jets are united and we get weaker winds above the gorge and therefore we don't mix cold water and everything stays warm, "Dewey said.

Now they pay attention. In 2017, oceanographers began to see warm masses disappearing in depth, but this year returned in the northeast Pacific and in the Bering Sea.

"Maybe this is the tendency. Maybe this is how climate change will reflect itself in our backyard, but we don't know that yet, "Dewey said.

Ocean Networks Canada has instruments along the base and near the ocean coast. They did not take the 2014 lumps on their sensors until months later, so the researchers continued to observe satellite data and maps of sea surface temperature for the Gulf of Alaska.

Impact on salmon

Ocean heating also affects the temperature of fresh water.

Sue Grant leads the Salmon Program of the Canadian State of Fisheries and Oceans (DFO). Its role is to integrate what we know about salmon and their ecosystems. Marine researchers and freshwater researchers see the relationship between clots and heating in rivers and rivers.

"The clump itself is an oceanographic phenomenon but it is caused by coupling with the atmosphere and that also results in clean water," Grant said.

Salmon is anadromous, with fresh water and marine life, and they experience warmer temperatures in both habitats. Grant said the effects of the 2014 and 2015 warm clots varied across salmon stocks at B.C. and the Yukon region.

"Responses vary, although some of our shares in the south and some in our north are not going well this year. We saw lower than average survivors in salmon stocks in Fraser Watershed last year in various species and we saw below the average survivors this year at Fraser. There are other examples in the north, "he said.

Grant uses a marathon analogy to describe what 3-5 degrees Celsius does above the season done for salmon.

If he runs a marathon in 50 degrees Celsius he may not survive because 50-60 degrees Celsius is outside the optimal temperature range. Salmon have an optimal temperature range too, and when they try to migrate upstream during the summer, they can have a negative influence on their migration.

Water temperatures that are warmer than average also have an impact on nutrient levels.

When ecosystems shift in 2014-2015, the surface layer of the Gulf of Alaska is weaker in nutrition. Ocean Networks Canada sees that cold-water species that require nutrient-rich environments are not very common, while warm-water species that can adapt to low-nutrient conditions tend to dominate.

"When salmon are out there at bay and along the coast eat under such conditions, they return in 2016-17, slightly smaller than usual," Dewey said.

"The amount I see says this warm condition can produce smaller fish sizes so that it has some impact as well."

Both Grant and Dewey said they were paying attention, but it was too early to make a projection and what it meant to be a warm lump of 2018 for salmon.

They can, however, take data from recent years – the salmon response to warming in fresh water and marine ecosystems – and watch to see if there are patterns and what can mean for the future of salmon stocks.

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