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Jack&7
02-22-2010, 06:43 PM
Hey all of you fish biologists (certified or otherwise ;))

I am really curious how lakes stratify in the winter and at what temperature zone fish are most comfortable.

I read an excellent post from someone (???) describing the importance of the thermocline and how that can produce the big fish.

Can anyone enlighten me on this?

Sundancefisher...looking your way!:cool:

Jack&7
02-23-2010, 07:07 AM
Wow!

12 hours and nobody has an answer for me? I thought I would have all kinds of opinions, info and other stuff by now!

It seems everyone is more interested in threads about who can post on the forum or ask for rides!;)

What happened to the people that want to talk about fishing?:huh:

WayneChristie
02-23-2010, 07:09 AM
I dont know the info you are looking for, but I would be very interested in learning the same thing, I seem to need some help these last few weeks :D

tacklerunner
02-23-2010, 09:34 AM
Wow!

12 hours and nobody has an answer for me? I thought I would have all kinds of opinions, info and other stuff by now!

It seems everyone is more interested in threads about who can post on the forum or ask for rides!;)

What happened to the people that want to talk about fishing?:huh:

Wow I was just thinking the exact same thing and then I saw you got 2 posts. Got excited, :cool: opened it and it's just you and Wayne.:( Now it's the you and Wayne and me. :cry:

nicemustang
02-23-2010, 10:14 AM
I don't have much to say....except from what limited knowledge I have from books...

Winter water temp is mostly isothermal. This is because the sunlight doesn't have a chance to heat the water on the top layer of the lake. Isothermal is known and constant temp, so the water in a lake in the winter is mostly constant. This happens after fall turnover. Then ice up freeze the lake in time so to speak until the sun heats the lake again when the water will stratify in the spring.

Thermocline is important in the summer months for sure. Thermocline is the area of water that separates the less dense water on top, with the dense cold water below. Typically bait fish and other life lives in the thermocline. Walleye for example rarely go below the thermocline in deep lake because of the lack of oxygen. Lakers cruise the thermocline and actively hold in its depth, rising or falling to feed on the bait fish.

So that's how I understand it. Hope this helps somewhat.

DarkAisling
02-23-2010, 10:44 AM
What happened to the people that want to talk about fishing?:huh:

:lol: Everyone has an opinion, but you asked a question that actually requires a good knowledge base to answer ;)

And with that I'll say "I don't know what the answer to your question is." I do look forward to the replies though: so I can learn something too.

some guy
02-23-2010, 12:36 PM
A very brief summary.
Water is most dense at 4 Celcius. At this temperature it will sink to the bottom and force the warmer water up. Water is less dense at 0 C so it stays on top and eventually freezes.
The thermocline is a layer of water that seperates the cold water from the warm water. Apparently most fish are most comfortable feeding at the top or just above the top of the thermocline.

ice
02-23-2010, 01:04 PM
an Accurate Description of a thermocline... is where the water temp drops between 1 and 7 degrees cooler. in a 5 foot range.
All i know. is That whitefish like to be below the thermocline. And the big pike like to sit above the thermocline waiting for the whitefish to come up, to feed.

And for a second part iv been told that in deeper lakes the thermocline switches in the winter. making the top water cooler and the deeper water warmer. thats why you'll see bigger pike along with whitefish in the shallower water during the winter.
but in many cases this may not be true.
just my 2 cents

ice
02-23-2010, 01:17 PM
I don't have much to say....except from what limited knowledge I have from books...

Winter water temp is mostly isothermal. This is because the sunlight doesn't have a chance to heat the water on the top layer of the lake. Isothermal is known and constant temp, so the water in a lake in the winter is mostly constant. This happens after fall turnover. Then ice up freeze the lake in time so to speak until the sun heats the lake again when the water will stratify in the spring.

Thermocline is important in the summer months for sure. Thermocline is the area of water that separates the less dense water on top, with the dense cold water below. Typically bait fish and other life lives in the thermocline. Walleye for example rarely go below the thermocline in deep lake because of the lack of oxygen. Lakers cruise the thermocline and actively hold in its depth, rising or falling to feed on the bait fish.

So that's how I understand it. Hope this helps somewhat.

i see some truth to this and some false.
As i have jigged off the bottom at 60 - 70 feet. and pulled up some monster walleyes.

ice
02-23-2010, 01:24 PM
Also you have to realize that fish are fish. and they react in a strange manner. There is no one to say if they like the deep or shallow water, cooler hotter. big or not.
Or even with that fish calendar.
im a firm beliver that you can entice a pike to take your lure on any given day. You may not catch a "LOT" but if you know your stuff you will catch one.
you tell me what pike is going to pass up a meal they only have to inhale. even on the inactive days, Pressure changes. its the same with the eye's the perch family are in schools.
if you can find them. you can catch them. If you know the right tactics. Im not too experienced with anything else but Mariah, wich is my winter trophy. whites also in the winter. So its kind of hard to belive what these "Experts Say" its all statistics. Skill, And Luck. imho
if you have the knowledge on where to go. then chances are. you'll catch fish.

tacklerunner
02-23-2010, 03:04 PM
Good info. I learned something.

WayneChristie
02-23-2010, 05:51 PM
thanks for the info :)

jrs
02-23-2010, 07:15 PM
In the winter in many Albertan lakes oxygen concentrations can impact fish use more than temperature. Especially in shallow eutrophic lakes (very productive, generally shallow and weedy). Often all the weeds and debris at the bottom begin decomposing meaning there will be no oxygen left. Often as you move up the water column oxygen will increase. I know of a lake by Lethbridge where, a few years ago the pike were all hanging out about 2 feet below the ice for the latter part of winter. Ice out that year corresponded with a large windstorm which caused a sudden turnover killing all the fish. Kind of saw it coming (very very productive lake) but it did make the pike tough to catch with normal techniques during the last few weeks of the season (like fishing near bottom). The atlas of Alberta lakes has some pretty good information about different things that impact fish distribution. I'd recommend you read through.
http://sunsite.ualberta.ca/Projects/Alberta-Lakes/foreword.php

In regards to the thermocline, it can be important in the winter as oxygen can be extremely depleted below it in lakes that don't completely turn over every year. Also a factor in summer but then again temperature isn't as variable during the winter so oxygen would be the driving force influencing fish.

WayneChristie
02-23-2010, 07:19 PM
thanks JRS , giving me some ideas now.

ice
02-23-2010, 08:17 PM
In the winter in many Albertan lakes oxygen concentrations can impact fish use more than temperature. Especially in shallow eutrophic lakes (very productive, generally shallow and weedy). Often all the weeds and debris at the bottom begin decomposing meaning there will be no oxygen left. Often as you move up the water column oxygen will increase. I know of a lake by Lethbridge where, a few years ago the pike were all hanging out about 2 feet below the ice for the latter part of winter. Ice out that year corresponded with a large windstorm which caused a sudden turnover killing all the fish. Kind of saw it coming (very very productive lake) but it did make the pike tough to catch with normal techniques during the last few weeks of the season (like fishing near bottom). The atlas of Alberta lakes has some pretty good information about different things that impact fish distribution. I'd recommend you read through.
http://sunsite.ualberta.ca/Projects/Alberta-Lakes/foreword.php

In regards to the thermocline, it can be important in the winter as oxygen can be extremely depleted below it in lakes that don't completely turn over every year. Also a factor in summer but then again temperature isn't as variable during the winter so oxygen would be the driving force influencing fish.
wow i dont see how a windstorm could create such a catastrophe but damn.

And in the winter. Yeah its is based on oxygen thats where fish will be.
But in what i said its the exact same thing. The whitefish dont needd a ton of oxygen. so in the summer there under the thermocline. but in the winter when the oxygen becomes even more depleated/ they start rising into the shallower water. also there is a feeding aspect along with spawning.

Soiler
02-23-2010, 08:23 PM
As i understand it, the fish like to hang out around the edges of the thermocline as the tempature is where they're most comfortable. In early ice fishing the lake will get cold enough for the thermocline to flip from what its at in the summer. The warmer water is at the bottom & colder on top! The O2 levels affect where the fish hangout later in the ice fishing season but not sure that the O2 affects the thermocline!! But i'm just spouting what i got out of a Walleye fishing book!!

ice
02-23-2010, 08:31 PM
As i understand it, the fish like to hang out around the edges of the thermocline as the tempature is where they're most comfortable. In early ice fishing the lake will get cold enough for the thermocline to flip from what its at in the summer. The warmer water is at the bottom & colder on top! The O2 levels affect where the fish hangout later in the ice fishing season but not sure that the O2 affects the thermocline!! But i'm just spouting what i got out of a Walleye fishing book!!

Thermocline
a transition layer between deep and surface water

The thermocline is the transition layer between the mixed layer at the surface and the deep water layer. The definitions of these layers are based on temperature.
The mixed layer is near the surface where the temperature is roughly that of surface water. In the thermocline, the temperature decreases rapidly from the mixed layer temperature to the much colder deep water temperature.

The mixed layer and the deep water layer are relatively uniform in temperature, while the thermocline represents the transition zone between the two.

Not many fish find it comfortable to be near the thermocline. except for the witefish. wich like to be well below. the thermocline. other fish species mainly like the warm water. with the ecption being some of the bigger pike. because like i said. they like to cruise the top of the thermocline for whites..

In the winter the thermocline has no effect on fish. it is the oxygen. You wont find anything lurking in the deep water. thats for sure.

goldscud
02-23-2010, 08:39 PM
Big wind at ice out can bring all the oxygen depleted water up to the surface as the water cycles due to a current from the waves. The fish get stuck in water that has now mixed with the low oxygen water. They can run low on oxygen pretty quickly resulting in death.

ice
02-23-2010, 08:44 PM
Big wind at ice out can bring all the oxygen depleted water up to the surface as the water cycles due to a current from the waves. The fish get stuck in water that has now mixed with the low oxygen water. They can run low on oxygen pretty quickly resulting in death.

makes sence Thanks:)

ice
02-23-2010, 08:51 PM
Most alberta lakes dont have a thermocline.
Just the really deep stuff more then 100 feet like cold.
Mind you a thermocline can run in 20 - 60 feet easy..
you also have to realize. that it is the colder water that holds the oxygen its best. and thats why many lakes summer kill. is because they are shallow. resulting in warmer water tempuratures.

ice
02-23-2010, 09:14 PM
there are so many factors plaing on how all the fish behave. thats its idiotic. to even try to explaine accuratly how they react to thetrue alberta conditions.
And it lays at rest, Nobody really knows.

nicemustang
02-23-2010, 09:22 PM
i see some truth to this and some false.
As i have jigged off the bottom at 60 - 70 feet. and pulled up some monster walleyes.

First of all, I didn't say they never go that deep. But they rarely do due to the oxygen levels.

Second, pulling up walleye from those depths are a super extreme case.

Third, unless you are pulling that eye up very very slow (5+ mins), there is no way it's going to survive. In fact I have read an arcticle somewhere that 50% of walleye caught at 35 + FOW have a high chance of death. They can't release their air in the sac very easily. I know this first hand because I've done this by accident on a few occasions.

ice
02-23-2010, 09:33 PM
First of all, I didn't say they never go that deep. But they rarely do due to the oxygen levels.

Second, pulling up walleye from those depths are a super extreme case.

Third, unless you are pulling that eye up very very slow (5+ mins), there is no way it's going to survive. In fact I have read an arcticle somewhere that 50% of walleye caught at 35 + FOW have a high chance of death. They can't release their air in the sac very easily. I know this first hand because I've done this by accident on a few occasions.

And im not saying that it wasnt a rare extreme case.
All im saying is thati tapped into a rare reserve.. second there was no way of me telling if the fish survived at all. as i was fishing for keeps. especially walleye at that size. good 6 -7 pounders.
And in the nature of this thread. Theres no real hard evidence. there was a thermocline present.
Im just sharing past exeriences thats all:)

ice
02-23-2010, 09:35 PM
ad also. oxygen levels can rise. in deapper waters due to frigid tempuratures. But it fluxuates from lake to lake. where another could have sever depleted amounts.

ice
02-23-2010, 09:41 PM
also. i wasnt jigging for eyes at the time i tapped into them. i was jigging for whites.