Fishing with Rod Discussion Forum
Fishing in British Columbia => General Discussion => Topic started by: RalphH on March 22, 2023, 10:23:54 PM
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If anyone has been following release of lake oxygen levels this winter it looks like we are about to realize what is perhaps a record year for winter kill in many popular lakes in the interior including lakes like Roche and Salmon. I got an email from Salmon Lake Resort today. Oxygen levels in the lake were measured at 0.6ppm just below the ice and 0.00 at the bottom of the lake under a 20 inch thickness of ice. Ideal oxygen levels are 2.0ppm or higher. The expectation is that no trout have survived the winter. Douglas Lake Ranch is actively trying to obtain 'catchable' size fish for many of their privately stocked lakes which means they likely expect this scenario in most of the lakes on the ranch. For many lakes the transition from an uncharacteristically warm fall to ice over was so sudden the lakes had not gone through turnover leaving a large amount of living plant biomass to die and rot under the ice robbing the water of dissolved oxygen.. If you are making plans for a spring trip be sure to check lakes you want to visit have not suffered a significant winter kill.
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It won't be pretty. Region 3 lakes that people hope to fish by Christmas were frozen over by mid November. The shallower lakes close to Kamloops have been suffering from whitening since early February with visibility measured in inches rather than feet. Larger lakes, in the shallows you can see the dead materials floating in the shallows. The amount of bacteria and fungi consuming this matter must be insane and the ice is still thicker than it was this time last year.
In deeper lakes the fish are down at the 60'-80' level, and some even deeper. A lot of the larger lakes have huge shallow shoals with only a small deeper area, such as Salmon lake, mentioned and even then at just over 30' it's probably not enough.
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I read a recent quote from legendary retired fisheries biologist Brian Chan who is arguably the leading authority on interior lake fly fishing and probally the best Stillwater angler in all of B.C saying its the lowest oxygen levels on the lakes around the Kamloops area he has ever seen in 40 yrs.
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If anyone has been following release of lake oxygen levels this winter it looks like we are about to realize what is perhaps a record year for winter kill
Where would find this kind of info? Winter kill info seems to be a bit of a guarded secret, which I sort of understand as one would not want to make claims about winterkills (or lack of) that turn out to be incorrect. Measured O2 levels shouldnt really be a secret as it's just a measured quantified value. It would be interesting to compare with previous year's readings as well
I've been to two winterkilled lakes, and didnt find out about either until well after the fact. The first time was a partial kill, but still managed to get into a few, including my largest of the trip, so just because there's some winterkill doesn't mean it's not worth checking out, especially if it keeps everyone else away.
The other time was apparently a complete kill and unsurprisingly got skunked; not even a single object on the sounder.
For many lakes the transition from an uncharacteristically warm fall to ice over was so sudden the lakes had not gone through turnover leaving a large amount of living plant biomass to die and rot under the ice robbing the water of dissolved oxygen..
I've not really considered what mechanisms might make winterkill worse one some years vs another, other than length of ice-over. I wonder if the aerated lakes have fared any better.
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I have seen it on a few Facebook pages. The Province does measure oxygen levels at a sample of lakes (by no means all) - Roche is one and has had very low samples.I don't know if that info is publicly released but word does get out. Douglas Lake hired a biologist to measure the levels on Salmon and as I has reserved some time on the lake this spring I was copied on a letter. Send me a PM and I can copy you. I can't tell you more.
I'd also suggest you check before visiting a lake that is prone to winter kill. It sounds like that a lot of lakes will kill this winter. Salmon had a winter kill in 2018/19 but seldom does winter kill. Summer kill is a common issue there though usually not all fish die. Roche had a kill some years back. You can check with the F&W regional office closest to whatever lake you intend to visit or by calling the nearest tackle shop.
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A buddy of mine said someone on flybc yesterday posted a bunch of potential winterkill numbers for a bunch of interior lakes. I’m not on flybc so I can’t confirm.
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here is the list from Flybc.ca
(https://forum.flybc.ca/uploads/monthly_2023_03/589354641_PotentialWinterkillMar2023.JPG.e3c5734fee83f03fe89c47e75153daf6.JPG)
here is an alternate list from Flybc.ca :D
(https://gallery.flybc.ca/i.php?/upload/2023/03/28/20230328095242-17cd86f5-xl.jpg)
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here's an update from FFSBC on what lakes have experienced winter kill, which have not and others without a report as yet:
https://www.gofishbc.com/Blog/Science-and-Research/Winterkill-Update-Spring-2023.aspx
right now it sounds like there has been partial kills on some lakes that are on the list as having WK.
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here's an update from FFSBC on what lakes have experienced winter kill, which have not and others without a report as yet:
https://www.gofishbc.com/Blog/Science-and-Research/Winterkill-Update-Spring-2023.aspx
right now it sounds like there has been partial kills on some lakes that are on the list as having WK.
Ill be at Marquart this weekend so I'll post about my findings!
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20 years ago winter kill was always a big concern, When planning trips to the interior you never know what to expect. Going out in the spring you were always hoping that there was no winter kill or that the lake was not turning over.
may long was always a crap shoot for lakes turning over
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in my experience, interior lake fishing in the first half of May is very iffy. Overall in any time of year, finding decent fishing is 50/50 at any time, particularly when it comes to Pennasks. Very moody fish.
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in my experience, interior lake fishing in the first half of May is very iffy. Overall in any time of year, finding decent fishing is 50/50 at any time, particularly when it comes to Pennasks. Very moody fish.
I hope luck is on my side then, it would suck to end up unsuccessful especially when travelling so far, words cant explain my eagerness to catch some bigger trout.
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I hope luck is on my side then, it would suck to end up unsuccessful especially when travelling so far, words cant explain my eagerness to catch some bigger trout.
Marquart isn't a big fish lake, lots of little ones. Lundbom has been on a downward swing the past 2 years as well but still bigger than Marquart
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lots of images on social media of Roche and the fish kill there. Reports are it's almost a complete wipe out.
going to be an interesting season of people moving about to new waters to fish with their old stand byes basically dead.
Not good
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lots of images on social media of Roche and the fish kill there. Reports are it's almost a complete wipe out.
going to be an interesting season of people moving about to new waters to fish with their old stand byes basically dead.
Not good
It is hard to believe all fish died. but will know after a few weeks.
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Marquart isn't a big fish lake, lots of little ones. Lundbom has been on a downward swing the past 2 years as well but still bigger than Marquart
maybe so, but keep in mind that to me a 3-4 lb trout is a big trout
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maybe so, but keep in mind that to me a 3-4 lb trout is a big trout
Hahaha. 3-4lb trout is big trout for everybody. Most people think their catch is 3-4lb when it is actually half to one pound fish. their 24 inches fish is actually 14 inches.
In kamloops area, a trout reach 3lb will be usually at least 20 inches long. Bring a tape or scale if you like.
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a close estimate is the length x (girth squared)/900 (or 800 in some formula)
so an 18 fish with a 10 inch girth would be (18* 100)/900 = 2lbs
there are many on line calculators you can use and i am sure an app can be found
example: https://www.fishswami.com/fish_weight_calculator
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Hahaha. 3-4lb trout is big trout for everybody. Most people think their catch is 3-4lb when it is actually half to one pound fish. their 24 inches fish is actually 14 inches.
In kamloops area, a trout reach 3lb will be usually at least 20 inches long. Bring a tape or scale if you like.
yea I always have a yellow paper tape measure and a scale, I will know if its three pounds if it is similar to the pinks i was catching my first salmon season. I agree that so many people over exaggerate how big their catch is. I find it amusing the things people lie about ;D
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a close estimate is the length x (girth squared)/900 (or 800 in some formula)
so an 18 fish with a 10 inch girth would be (18* 100)/900 = 2lbs
there are many on line calculators you can use and i am sure an app can be found
example: https://www.fishswami.com/fish_weight_calculator
maybe I will make an official mathematical formula as my 4th year engineering capstone project ;D
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Winterkill is normal, natural, and not unexpected, occurrence in the artificial fishery that we have created for ourselves.
While the Kamloops trout is native to some lakes in the region, the provincial fisheries/hatchery program has stocked trout into lakes where they didn't exist prior, has propagated various strains of trout outside their normal range, has genetically modified fish to maximize growth, uses artificial means to support fish populations, and builds structures to create/sustain fish-supporting bodies of water.
It's an artificial fishery that wouldn't exist without tax dollars and license fees.
Low dissolved oxygen in interior lakes is normal, natural, not unexpected, and has been happening for many hundreds of years. It just becomes a tragedy when it shatters the hopes and dreams of thousands of stillwater anglers and represents a loss of hundreds of thousands (millions?) of dollars worth of hatchery stock.
The province has created a world class fishery that is a significant economic driver. This isn't meant to be a criticism of that. But let's face it...it's a largely artificial fishery propped up by millions of dollars of annual investment and winterkill is a natural occurrence that impacts an unnatural process.
Caveat: a bit of a troll post, but I believe most of it :)
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You are quite right there is little natural about most of the popular Interior locales but our south coast fishery is also pretty much an artificial fishery. Plus the fish are subject to a long list of hazards both natural and human created. Many more of the stocked fish in interior lakes grow to a good size while these days we known something like 2% of hatchery salmonids do. That's a pretty limited payback.
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I'm not sure I've ever witnessed such an intense heatwave (as the one we are about to start) within a few days after iceoff.
My question is does anyone know if this will speed up turnover or does it make it worse. I would say it should speed it up but I'm not sure.
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https://northernwoodlands.org/outside_story/article/lakes-spring-back-to-life
The density of water changes with temperature. We know that 212°F is the boiling point for water, and 32°F is freezing. A third significant number regarding water chemistry is 39°F – the temperature of maximum water density.
In the fall, a lake cools until it reaches a uniform 39°F. As the lake continues to cool it becomes stratified – the heavy, 39°F water stays on the bottom, while the water near the top is chilled by the below freezing air temperatures. Ice, less dense than water, forms when the lake’s surface temperature reaches 32°F. The ice acts as a barrier to wind, which prevents the lake water from mixing; it also inhibits the lake’s exchange with oxygen in the atmosphere. Once a lake is frozen, the depletion of oxygen by the lake organisms begins.
Just when the lake’s oxygen supply is nearly exhausted, spring arrives and the ice cover slowly melts, exposing the surface to warmer temperatures and vigorous vernal winds. The lake’s surface water begins exchanging gases with the air. When the surface water warms to 39°F, it sinks, pushing through the deeper water and infusing it with oxygen. This process creates a powerful convection current that continues to churn until all the lake water is an even 39°F, top to bottom, and the water has reached its oxygen saturation point (approximately 12 parts per million).
so if the top layer of water is less than 39 degrees a number of hot days may it speed up.