The Thermocline and How It Effects Fishing

Temps July 22 Stabilizing

Temps July 22 Stabilizing

You may have noted in the previous post that I am a little concerned about a major shift in temperature layering of the water with the recent wind and cold front. Fish Do Not Think! They are totally motivated by two things right now – FOOD and Comfortable water! (spawning is the other “key trigger” but that factor does not apply in this situation)

Many lakes will develop a thermocline during the hot summer. A thermocline develops when layers of water seperate into several layers and the lowest level of water in the lakes is full of rotted decaying matter which also depletes of oxygen.

Because this bottom layer of water is depleted of oxygen bait fish cannot survive below the thermocline. This concentrates baifish and predator fish above the oxygen depleted zone and brings them together in tighter feeding zones for fishing.

You might mark fish on your fish finder but you may fail to get them to strike if they are not in their “feeding zone”! Most species of fish have a preferred temperature of water that they will actively feed in. Find this area of temperature with fish present and you will greatly increase your chances of catching fish.

Fish are cold blooded. In water too cold, fish will be dormant, sluggish and will not feed. In water too warm, they will be seeking a more comfortable environment. So, an understanding of how different temperatures of water break up will help.

On larger bodies of water masses of water temperature are much larger and in a constant state of change. The location of these large masses of temperature are highly affected by the changes in weather conditions. These large masses of warm and cold water also have a moderating layer that is known as a “temperature break”and we often refer to that obvious line as the thermocline. The area of, and immediately around, the temperature break is the most active “feeding zone” and generally offers a kind of invisible wall that concentrates the baitfish and in turn the predator fish.

Let’s hope we haven’t been affected too badly with this recent upset. If the baitfish break up and spread out, our target fish will spread out also and fishing will get tougher.

Filed under: Fishing Tips

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