How can you tell if a lake winterkilled?

[bowhunter79]

Hello All,
Wondering if there are any signs that a lake has winterkilled? I know it would not be winterkilled this year yet but from previous years. I was up a couple hours North of Edmonton and at a very little traveled smaller lake and we didn't catch or see anything. Didn't see any fish on the bottom or anything like that just wondering if it's worth going back and trying more spots.

Thanks
Steve

[npauls]

Dirty smelly water is the first sign of possible winterkill.

[fishman]

low o2 levels kill the plant life as they use up the o2 and then the plants die and turn the water brown color and it will smell to

[EZM]

Yeah ........ what those guys said ......... is right on.

A camera and a few punched holes might help - have a look for vegetation and signs of life in areas that should show some activity.

If the lake is small, has few springs and/or inflows/outflows and is shallow it's a good candidate for winter kill.

[HunterDave]

I'm pretty sure that it has more to do with the depth of the lake as opposed to the size of it. I seem to recall that a minimum depth of 30' is required for a good winter survival rate but I'm too lazy to look it up right now. It's been my experience that the best fishing is early into the season and it slows down as we get farther into winter. It could be due to a decrease in oxygen levels, I don't know. A couple of winters ago the ice fishing was very bad on numerous lakes in the area and that led people to believe that they had winter killed. I saw dead trout on the bottom with a camera. The next summer people were catching 3 lb trout in the same lakes so it obviously hadn't. The fish just seemed to disappear and be less active.

[BPman]

Originally Posted by fishman

low o2 levels kill the plant life as they use up the o2 and then the plants die and turn the water brown color and it will smell to

Not quite correct...
Reduced light levels and water temperatures of fall and winter reduce photosynthetic activity and the plants die. The decaying plants consume the dissolved oxygen to the point where the fish effectively suffocate.
It is too early for a winterkill this winter but if it happened last winter then the sulphurous smell would have dissipated last summer and dead fish rotted away by now. So there is no sure way to know what happened except you could contact local F&W to see what they know or fish it again and if skunked then scratch it off your list for a year or two
In general, shallow lakes with lots of vegetation are at a much higher risk of winterkill, or an over-night summer kill than are deeper lakes with less vegetation and trout are more vulnerable than most other species.

[TheLegend]

If you don't catch anything within 5 hours its winter killed.

[fishman]

Originally Posted by BPman

Not quite correct...
Reduced light levels and water temperatures of fall and winter reduce photosynthetic activity and the plants die. The decaying plants consume the dissolved oxygen to the point where the fish effectively suffocate.
It is too early for a winterkill this winter but if it happened last winter then the sulphurous smell would have dissipated last summer and dead fish rotted away by now. So there is no sure way to know what happened except you could contact local F&W to see what they know or fish it again and if skunked then scratch it off your list for a year or two
In general, shallow lakes with lots of vegetation are at a much higher risk of winterkill, or an over-night summer kill than are deeper lakes with less vegetation and trout are more vulnerable than most other species.

Sorry i was being lazy as i was typing on my phone i never explained it very well..........so photosynthesis is when the plant takes in co2 and h20 and light and releases............o2 and when the plant does the opposite it is called reverse photosynthesis....try to remember this from grade 8 science.......same thing happens in the summer at night just not as bad or as long that when it is dark the plants rob the o2 and release c02, hence there is no sunlight penterating the plants through the ice with snow cover in the water so the more depth of water usually you have more moluclues of 02 hence the plants dont rob all the 02 in the lake so the fish can live........i know that 02 needs a binder to grab onto where the c02 doesnt and the 02 with bind to the c02.........you get the point

[pikergolf]

Originally Posted by TheLegend

If you don't catch anything within 5 hours its winter killed.

This is the correct answer.

[GregT]

wwwmywildalberta.com has a list of dead lake as well as water with the potential for a winterkill. i dont know how accurate this is but its a start.

[hit_theice]

contact fish and wildlife they normally know if the lake winterkilled. also winterkills do not mean all the fish are dead in the lake if it was a partial winterkill. Lake Ilse and Nakamun often partial winterkill around here. one thing i noticed when this same thing happened to me on a useless trip was on the camera there was tonnes of activity. scuds, backswimmers all kinds of insect life going on. almost as if there was nothing in there to eat all the bugs over the summer.

[BPman]

Originally Posted by fishman

Sorry i was being lazy as i was typing on my phone i never explained it very well..........so photosynthesis is when the plant takes in co2 and h20 and light and releases............o2 and when the plant does the opposite it is called reverse photosynthesis....try to remember this from grade 8 science.......same thing happens in the summer at night just not as bad or as long that when it is dark the plants rob the o2 and release c02, hence there is no sunlight penterating the plants through the ice with snow cover in the water so the more depth of water usually you have more moluclues of 02 hence the plants dont rob all the 02 in the lake so the fish can live........i know that 02 needs a binder to grab onto where the c02 doesnt and the 02 with bind to the c02.........you get the point

That just about has it. The green chlorophyll molecules in the live plants are stimulated by sunlight to conduct the chemical reaction called photosynthesis whereby CO2 is absorbed and O2 is released into the water - the opposite of our respiration that takes in O2 and gives off CO2. In the summer, on warm nights, underwater plants may revert to the Dark Reaction or Hill Reaction that functions like our breathing - consuming O2 and giving off CO2. That situation can also kill fish in massive numbers and overnight.
Large deep lakes have a large volume of oxygen rich water so can compensate for O2 lost when shallow water (Littoral zone) plants die and decay.

[Don K]

If I don't pick up a fish in a few hours that lake is dead to me!! Lol