Thermocline & pre-fall patterns

[jb_adams]

I spent a lot of time on the lake this weekend.  I caught "0" fish (par for the course).  I tried several bait tactics all in natural colors because this lake is a clear water lake with heavy pressure, windy, lots of boating activity, and rising water due to heavy rains.  The water is starting to smell early this year because our water supply is from the lake.  That means the thermocline is expanding.  What I observed out of two days of fishing at the end of a large cold front and flooding rains for about a week is the following:

- surface temp 80-84 degrees avg.

- fish suspended off main lake in 30-40ft at the throat of large coves or on shelves near deep water

- fish only feed on selective opportunities and over 30-40ft depths

- I think the fish stay suspended in the upper end of the thermocline in 60-70 degree temp water to stay comfortable and feed when they feel like it

- I think they launch themselves like rockets at baitfish above and then swim back to their supsended water temp. layer

- slow presentation in shad patterns is a must so conventional baits won't work

My question is, when the thermocline is expanding an the "lake turnover" is in the beginning stages, is it hard to catch fish during this time of year?  Is it after the lake has turned that the fall fishing season begins?  I guess our lake is in a "pre-fall transition stage" currently.

[Shad_Master]

I fished a small lake this weekend -- air temps were in the low 60's when we got there and water temps were in the mid 70's.  We immediately noticed that there was a serious scum on the water with lots of bubbling action.  After about an hour we began to notice big chunks of "yuk" floating in the water.  However, we found lots of fish along the shore anywhere from right on the bank out to about 30-40 feet in depts of 0' to 14'.  After about two hours the scum had all dissapeared and there was no more "yuck" floating around.  My guess is that the lake tried to "turn over" but the water heated up enough to stop it before it was done.

We caught fish, but they were very selective about where they were holding -- stacked up on one brush pile and none on another about 30 feet away at the same depth.  I think you are right that the "turn over" signals the beginning of fall patterns.  However, I'm not sure how soon after the fish get active again.

[Walkingboss]

I fish in New Hampshire and water temps have been generally in the mid-70's.  I don't know much about turnover specifics, but I'd have to think that up here a lake wouldn't begin to turn-over until temps got solidly into the mid 60's.  At any rate the smallmouth have already began bunching up under baitballs (especially smelt) and hanging 3-10' above the bottom in 35-45' of water.  The largemouth are jammed tight to cover as shallow as can be.  I pitched a jig-n-pig on a large stump in 2' of water yesterday and pulled three 3+ lb. bass off the shoreline side.  They were literally laying on top of one another.

I have 3 tourny's left this year and the pigs have got to be ripe for the pickin'.  I'm pretty good getting at the smallmouth, but if ya'll have any advice on northern tier fall patterns for largemouth, I'm all ears.

[jb_adams]

My conditions are quite different.  The only "gunk" floating on top is due to heavy rains for over a week and stuff is washing into the feeder creeks (bark, leaves, dirt, etc)  This makes a nice hiding spot for bass but the water temp is too warm and the light penetration is still pretty intense as well as too little oxygen in the feeder creeks because of all the rain and silt.  The main lake channels are full of oxygen due to the wind.

The lake here hasn't turned over yet.  It's starting to turn over but this is usually a 2-3 week period and the smell in the water supply has gotten better as well as the water temp is back up even with all the rain.  I think the lake will fully turn over the course of the month and by early October, it will be turned.

Then the feeder creeks will become bass havens.....I hope.

So, back to the original question....does the lake turning process cause bass to become in active or active?  When the thermocline expands, the fish scatter throughout the thermocline right?

[roadwarrior]

The lake "turns over"  when the cold, deeper water becomes warmer than the surface water. Warm water rises, cold water sinks. That is NOT happening right now. Generally, the colder water (below the thermocline) contains less dissolved oxygen. If this is in fact the case on your lake, it is VERY unlikely that you will find fish below the thermocline.

During the period when the lake does turn over, fishing is tough (impossible). However, if there is water release, fishing below the dam can be awesome. "Turnover" is usually associated with a shad kill (oxygen depletion). Predator fish lose all inabition when this occurs.

[jb_adams]

I know what turning-over means.  I also know that the water temp below the thermocline will not have fish in it.  It's too cold for them and they prefer warmer water within their comfort zone if it's available.  I was just curious if the fish are less prone to eat during the turning process.  I have seen fish jumping and chasing shad over the last few days so I know they are feeding a little but very selectivley.

The lake here does this every spring and fall so it's a common occurance with the algae in the water, not so much the shad.  I think shad may die from the lack of oxygen but I haven't seen a large amount of dead shad.

They had a report on the news last week about the "fishy" water and they had a local botanist explain the phenomena and how the algae effects the water smell.  About 1 part per 2-million is detectable by the human nose of this particular type of algae.  So one Folders coffee can full of this algae in Beaver Lake can be detected by the human nose.

Thanks for the info.  I guess I'll keep on fishing when I can and see what else I can learn through obervation and trial.  Eventually, I'll learn the "ins and outs" of this lake and learn to catch fish consistantly.