How deep is too deep?

[gasman707]

I've fished the same lake the last two Sunday's with fair results for nothern. It's small but is very deep.It's 22 acres but only 1% is under 3ft and 65% is 20ft and over max depth is 52ft and the widest area is about 400ft. The problem is any time we set the minnows below 20ft or deeper they dont live very long the 15 to just below the ice range are still very alive 8hrs later. We get almost all of our flags with in 20ft of shore (6ft from shore averages 15ft deep).  I cant find any panfish, perch, or crappies though I catch them there in summer any ideas? If minnows die below 20ft wouldn't other fish as well?

[hollis]

My guess that their isn't enough oxygen after a certain depth there. I once proved (w/o and O2 meter) to our local lake association that our lake had no O2 in fairly shallow water when #1 my sonar with a quad head scan of 90 degrees wouldn't find ANY fish in mid summer after 8-10 feet, and #2  I lowered several healthy pan fish down in a cage about 12 feet and they died faster that if they were thrown up on a bank. (If thrown up on a bank they would get a little O2 until their gills dried out. It was incredible how fast they expired. Our lake was over fertilized by too many septics leaching phosphorus into the water table from houses around the lake (something the property owners didn't want to hear,..just dump more copper sulfate in the water more often...) causing algae blooms and when so much algae died their decay pushed out O2 and then the problem at night when no sun, the levels would go way down to dangerous levels before the morning  esp if the water was warm/hot.
In winter this can also happen with a lot of the surface covered with ice and no air contact. Small bodies of water have more of a problem. Some ponds have winter kills so bad that even rough fish can't make it. I would guess that this is happening to some extent to your lake. In the deeper water you would see this first.

[Pomoxis]

Sounds like what hollis says is right. Winterkill is somewhat common in ponds. The water is isolated from the influx of new oxygen from the air because of the ice layer, and the oxygen depletes due to the oxygen consuming action of the bacteria of decay. But I have never thought about whether it happens only at deeper depths during a winterkill. Summer oxygen depletion can happen in the layer below the thermocline because it is isolated from the air.

Now that I am thinking about it, it sort of makes sense that the deeper layers would lose oxygen during a winter kill, especially in a deep water like you are describing. But you would need to have a large amount of bacterial activity, maybe caused by some large amount of biological pollution like hollis said. The bio activity would give off heat and keep the bottom at 39.2degF and the presence of ice would prevent vertical circulation caused by wind, thereby creating a layer effect like the thermocline in summer.

Yes it can happen. The fish will seek out the water with good oxygen. When you force a baitfish to deeper, oxygen poor water, it will die. Stay in the 20ft or less water. Try for those "missing" fish species in shallow water, maybe shallower than you expect. 

You were talking about ICE fishing, weren't you?

[hali-man]

Try for those "missing" fish species in shallow water, maybe shallower than you expect.
You were talking about ICE fishing, weren't you?

It's also very likely that fish are suspending if in fact the deeper zones are depleted of oxygen.
Try different depths over the deep water, especially for the crappie.

[gasman707]

Thanks for the replys. That is probally whats happening but was unsure. I also notice when ever you drill a hole no matter where on the lake by the time you clean it out it is loaded by the hundreds  of what I believe to be fresh water shrimp. They are about the size of a pen point and swim backwards atleast to the naked eye very hard to see.

[Hood]

get a vex and search....when your done searching...search more...put the time in and you'll find em

[AirManCam]

I dont know about you guys but with the whole o2 content thing, I've pulled lakers from 170 or so feet...and I've caught quite a few big pike out of 40 feet of water..Usually where its a hump, on the hump from deep to shallower

[bayonne]

some lakes are not good ice fishing lakes in nj we have a res. loaded with fish and bait during summer thiers no ox. below 10 ft i almost always do poorly ice fishing open warter i nock them dead but mostly at dawn and dusk thiers big pike and even hard to get them thru the ice

[crappieslayer22]

depends on how well the water is oxgenated but for some lakes around here i gust so i could let out my hole spool