Alaskan salmon are decreasing in size thanks to climate change and competition, study says

By Paul Homewood

 

It is not only climate science which has become corrupted, but climate change has also corrupted many unrelated subjects as well.

This study on salmon, for instance, seems well researched, but cannot resist the urge (or maybe pressure) to put part of the blame on climate change, without as far as I can see any evidence whatsoever:

 

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Alaskan salmon are getting smaller due to climate change and competition, according to a new study.

The authors researched over six decades of data from the Alaska Department of Fish and Game — from 1957 to 2018 — on over 12.5 million fish.

The primary cause of the declining body size of salmon, according to the study, is that the fish are spending less time out in the open Pacific Ocean.

"We saw a strong and consistent pattern that the salmon are returning to the rivers younger than they did historically," Eric Palkovacs, a professor at UC Santa Cruz and a corresponding author of the study, said in a news release.

"It seems that the ocean is becoming a riskier place to be," he said.

The study looked at four species of salmon — Chinook, chum, coho and sockeye — throughout Alaska where residents have noticed a decrease in salmon size.

Besides spawning at younger ages, climate change and competition from the growing numbers of wild and hatchery salmon are also significant factors in salmon size reduction, according to the study.

"We know that climate drives changes in ocean productivity, and we see a consistent signal of climate factors associated with decreasing salmon size," Palkovacs said.

"Another consistent association is with the abundance of salmon in the ocean, especially pink salmon," Palkovacs said. "Their abundance in the North Pacific is at historic highs due in part to hatchery production in Alaska and Asia, and they compete with other salmon for food."

Krista Oke, an author of the study and a scientist at the University of Alaska, Fairbanks, said that the next thing the researchers want to analyze is what is causing the shift in the ocean itself.

https://edition.cnn.com/2020/08/20/us/alaskan-salmon-size-decreasing-trnd-scn/index.html

 

This is the Abstract:

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https://www.nature.com/articles/s41467-020-17726-z#article-info

So, we are told, declines in salmon size, primarily resulting from shifting age structure, are associated with climate .

Yet a full search of the detailed paper for mention of climate change only finds:

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In other words, there are lots of maybes and talk of modelling. Yet the results do not even provide evidence of any metabolic effects from temperature.

And the best that they can come up is that climate change might affect some species, but not others. Hardly a ringing endorsement for their little theory.

They have no clue at all of any mechanism which might explain why climate change could have had the effects seen, let alone proper statistical analysis to back it up. All we get is perhaps occurring through climate-mediated changes in food availability or quality.

But until proper, fact based evidence is provided of these changes and proof offered that they are caused by climate change, their assertions remain just an unproven theory. And unproven theories should not be used as the basis for a scientific paper.

As with most of these sort of nature studies, there are obvious and clear cut reasons for the decline in salmon, as the paper itself emphasises. Notably increased competition from both wild and hatchery salmon. There is simply no reason to invoke climate change, for which there is no evidence.

The clue however lies in the final paragraph of the article:

Krista Oke, an author of the study and a scientist at the University of Alaska, Fairbanks, said that the next thing the researchers want to analyze is what is causing the shift in the ocean itself.

In other words, we have no idea what is happening, but chuck us some more money and we’ll keep looking. And, as we know, talk of climate change is guaranteed to up the ante!

via NOT A LOT OF PEOPLE KNOW THAT

https://ift.tt/34mUKzf

August 22, 2020 at 08:12AM

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