In a Storied River, Fish Are Dying in Droves as Climate Change Scorches Canada (NY Times)-Very disturbing info

Other factors enter the equation when both air and water temps continue to rise. I am personally, very uncomfortable fishing in bright sun (no breeze) temps of mid 70s degrees or higher and will quit fishing even during the most significant hatch.

At what temperatures do warm water species like bass begin to quit feeding and even die off? A little blackle research turned up the following:

When bass fishing optimum feeding temps (60 - 80) are exceeded in late-spring or early summer, growth rates drop off sharply. When temperatures get excessively hot (mid 90s), fish will lose weight. Bass will die when water temperatures get into the triple digits if they cannot find a cooler refuge.

Remember the Atlantic Ocean reached 101 degrees earlier this year!

Point being that the warming trend is not showing any signs of diminishing and all fish have a threshold.
 
SSPey said:
Far as I can tell, this is both the start and the end of this topic. None of the 34 papers citing this work by Crockford take further steps to clarify the historic use or distribution of bluefin in the NE Pacific and I couldn’t locate any others. That’s unfortunate and Crockford is apparently mired in other controversies. It’s a cool topic.
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It's certainly interesting. My critical brain is sending up red flags that as ocean conditions off the Washington Coast improve for bluefin tuna, what reason would there be for them to be less common than the archaeological record (according to this study) suggests they are. The most reasonable answer I can think of is high exploitation rates of that species throughout the Pacific.
 
Consider that our bodies warm to something less than 104 degrees to fight off an infection, and it puts a 101 degree ocean into perspective. Nothing can survive for long at those temperatures... at least nothing good....

I have no idea what we're in for, but it's gonna be different from what we're used to. That much is certain.
 
Mossback said:
Lol
Why would I go there ?
Maybe to fish for salmon, sure...
No, I will let the Tarpon come to me. I'll just be waiting in the shade of my palm tree eating a pineapple from the back yard.
:)
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I just figured there was a reason you weren’t already living in Tarpon country. You could be eating a pineapple under a palm tree in Florida.
 
No Floriduh for me...
Looking further south.
;)
 
Otter said:
I don’t think investigators are immediately dismissing any possible cause(s). Since this is my home river, I’m trying to keep current on more news about this terrible loss. Here’s a recent article in the Vancouver Sun (BC):
vancouversun.com

Calls to close Cowichan River to fishing as 'dead zone' forms

The Cowichan’s decline “is the death of 1,000 cuts.”
vancouversun.com vancouversun.com

I checked river water temperature records online for this time period, and noted it was about 21 to 23 C. Pretty high for coldwater fish.

High water temps have a double whammy effect on fish. The higher the water temp, the less oxygen it holds. And high water temps also increase fish’s metabolism; meaning fish have a higher demand for oxygen, but there’s less oxygen in the water.

Another cause of low dissolved oxygen is organic pollution, which uses up oxygen as it decomposes. We’re talking here about the minimally-treated sewage discharged from the town into the upper river.

They are also considering possible toxins dumped into the river. The river is overcrowded with people swimming, camping, and boating in summer, especially in yet another recent record drought. Maybe somebody did something really bad.

Since this situation is of interest to American PNW anglers, and even as far away as New York City, I’ll post any news that I find.
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As promised, here is the (expected) news on the cause of this unprecedented fish kill:

Prolonged drought and sustained heat.

The federal Dept. of Fisheries and Oceans has examined samples of dead salmon and trout, and say that lesions found on the fish are associated with “stressful environmental conditions,” including low oxygen and high pH levels in the water. “This can potentially be caused by the decay of algal growth, which appears to be more prevalent than usual this year.”

News article here:
www.timescolonist.com

Prolonged drought, low flows behind mass fish kill on Cowichan River, says DFO

Samples of the dead salmon and trout fry discovered by swimmers below Skutz Falls in late July showed lesions associated with stressful environmental conditions
www.timescolonist.com www.timescolonist.com

Another news article has a photo of how much algae is growing on normally fairly clean bottom substrate:
 
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