AFTER DARK THERMOCLINE CLUTTER

Discussion in 'Fish Finder Review and Study' started by Quint, Aug 9, 2009.

  1. Quint

    Quint New Member

    Messages:
    293
    State:
    N.C.
    After dark when there is a thermocline present, why does all the clutter show up above it? Not a problem during the day or when a thermocline is not present? Thanks
     
  2. gottofish

    gottofish New Member

    Messages:
    10
    State:
    Missouri
    Great question. I've noted the difference as well. Maybe.....just maybe, it's the convection of the surface water cooling and sinking and the deeper warmer water rising causing turblence as it falls and rises respectively. I certainly see more clutter after sun down. Just a guess.
     

  3. Quint

    Quint New Member

    Messages:
    293
    State:
    N.C.
    I have also thought about the same scenario! But why does this only happen at night when the thermocline is present? When it rains or a cold front hits during the day when a thermocline is present the heavy clutter does not engulf the water column above the thermocline like it does at night? And surface temp changes do not cause clutter issues during either day or night when the thermocline is not present? The clutter makes it very hard to mark fish at night when a thermocline is present! You have to turn the sensitivity down to see any thing other than clutter above the thermocline, below is the clear dead sea! Where you were marking fish before dark striper, shad, white perch, and cats seem to disappear? Do they move? Maybe but I know they aren't extinct! LOL And this is not just my boat or my unit have seen this issue on every combo I've fished with. Would like to know why, and also more about reading and operating a sonar under the night time/thermocline condition! THANKS
     
  4. jerry9497

    jerry9497 New Member

    Messages:
    512
    State:
    Tobaccoville NC
    I've noticed more clutter at night recently, I only want to see a few feet from the bottom of thermocline down. so it dosent bother me, I have float rigs out for anything above thermocline. The thermocline is there 24/7 what happens during any one day has little effect on it. above it has higher oxygen in the water so maybe trash and thus bait suspends more easily I dont know. a thermocline is the warmer water "floating" above the denser less oxygen cold water. It is present in anything less than a moderate flowing river. When winter comes and the surface of the lake water becomes colder than the water at the bottom of lake the lake will "turnover" a thermocline will begin to form when temps stabilize or begin to warm.
     
  5. jim

    jim New Member

    Messages:
    2,579
    State:
    Jacksonville NC
    there is a theory that the plankton that have risen durring the day to meet the sunwarmed water are now dropping down in the water column causing the clutter or the surface water is now cooling causing a bounce effect off the surface.Lots of theorys not sure what the answer is.Quint go to the Lowrance website ,they have some excellent tutorials on sonar operation and you can even play with emulators of their sonars.:big_smile:
     
  6. metalman

    metalman Well-Known Member

    Messages:
    3,456
    State:
    IN
    Name:
    Winston
    I do believe Jim is close to it here. I have read similar things although they always seem to be published by biologogists and so are never written from a fisherman's point of reference. I don't recall having read anything in sonar tutorials that addresses it...W
     
  7. ShilohRed

    ShilohRed New Member

    Messages:
    4,339
    State:
    West Tn
    Yes I think Jim is also right on this. As I have seen it lots of times when the theromcline is there.
    Pete
     
  8. jim

    jim New Member

    Messages:
    2,579
    State:
    Jacksonville NC
    lowrance defines clutter as being caused by many things including air bubbles from wind and wave action which makes sense because things usally calm down at night after all those boat wakes etc .they also say algae and plankton cause it.Just turn the sensitivity down a little.
     
  9. Quint

    Quint New Member

    Messages:
    293
    State:
    N.C.
    One of my fishing partners has also told me about the plankton theroy. And do belive it to be the best theory but it seems that know-one really knows! I can tell you this you do have to turn the sensitivity down its the judgement of what your looking at that getts me. And as soon as the sun comes up so does the clear view of fishable water. And you start marking fish once again like cowboys do cattle? Here when the thermocline shows up Mid-Late June - Mid-Late Sep you rarelly see a fish below the thermocline. But you better belive it stays clear all ninght long. lol
     
  10. Quint

    Quint New Member

    Messages:
    293
    State:
    N.C.
    Sat. early a.m. to mid afternoon. The thermocline was heavy before light not marking any fish below it, moderate clutter above! After light the upper clutter dissapated and a irratic thermocline very fait was present. After light marking fish down deep well below the thermocline as marked erlerier before light? But when I put a bait deep it would die, and no bites? Up above the pre dawn mark of around 23 ft the bite was on! #'s of 10- 20 lb fish and a 32 lb blue with only being able to get 4 rods out at the time. Untill the dead air, heat and boat traffic all seem to kick into gear at the same time! Got a few more short bites and had a 20? boat side that cut the line? I thought a bad place in the line due to X# of causes but my dad said he thought the hook cut the line? Sure glad it was not THE ONE! 80 lb leader and 40 lb main line, the main line was the WEAK link! I guess they were pulling water? and a slight mix was happening? Hope to C one soon!
     
    Last edited: Aug 17, 2009