Why do Crappies school up in deep water and when?

[united jigsticker]

The thermocline represents the seperation of the denser water against the lighter water.

In the summertime you won't find any fish below the thermocline level due to cold temperatures and lack of oxygen.

In the fall, as the surface water cools and increases in density, the columns of water switch places. This is called "turnover". Once turnover is complete, temperatures and oxygen is similiar at all depth levels.

Fish move deep in the fall of the year because lower water temperaures and decreased sunlight cause the weeds to die off and decay. This produces carbon dioxide and forces the fish and their prey away.

On lakes with clearer water, the weeds in fall will stay green longer and continue to produce oxygen because the water doesn't shield out as much of the days available rays. Also, clearer water doesn't absorbe cold as quickly, and the water stays slightly warmer longer.

The fish folow prey and oxygen, as the prey follow their prey and oxygen as well.

In the wintertime, thickening ice, decaying weeds, and the lack of atmospheric absorbtion forces the fish and their prey to reside in the deep basins of the lake where oxygen levels and temperature are more stable.

In the spring when melting begins, runoff provides oxygen in its own form. Also, as the snow melts and ice thins, water claritys increase along with increased pourosity of the ice and sunlight is once again allowed to penetrate to the shallow weeds, and photosynthesis can begin again.

The fish and their prey once again may begin to move closer to the weeds and shallow flat areas.

This is my best explanation. Scott Steil and MJ5 can do a heck of a job assisting me with this and provide perhaps a more thourough explanation in absence of anything I may have missed.

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Fish On! WHOA Bessy!

[Guest]

Well put United Jigsticker,

In some cases the water temperature is even warmer the deeper you go in the winter. The water closer to the ice can be colder. That also draws the fish deeper. As the season progresses you will see fish suspended even higher and even in some cases a foot or so below the ice.

You can typically find crappies suspended over deeper water once the light penetration and weeds die off. After a week or so of early ice fishing you will see a change in fishing patterns. Your average fishing depths will increase and fish will begin to hug the bottom. Once fish become accustom to the turnover and change in temp, metablism, etc, then they will begin to suspend and chase food throughout the water column.

Weather patterns can also cause crappies to move deep. If you're fishing crappies over a mid depth weed bed, say 15 feet, and a cold front comes through, it's not uncommon to find fish hugging the bottom of a 35 foot hole the next day. And visa versa when the weather warms dramatically. If you're catching crappies over a 25 foot holes and the temp rises from 15 to 55 degrees over night (as we've been experiencing lately), you might be catching fish in 10 feet the next day. A lot of factors come into play here though.

One main point to remember is that every lake is different. Because one thing works in one lake doesn't nessecarily mean that it'll work on a neighboring lake. Punch a lot of holes and keeping moving until you find a productive pattern.

Good Fishin, Matt.

Fishing Reports from MJ5 and Fishing Minnesota...
http://frida.blc.edu/~mjohnson/mj5.html

[Guest]

I'm just wondering why crappies school up in the deepest water possible? I thought it was due to the thermocline, but I've seen many of these school over a 20' depth range. If it was thermocline, it seems they would be all at the same depth? Why do they do this? If it is strictly for food, why are baitfish or other food sources attracted to these areas?

What time of year generally can you find them schooled in deep water? just winter and late summer or all summer and all winter? I realize they are in shallow spawning in the spring, but do they gradually work out to deeper water spending the majority of summer in more modest depth ranges or do they go from the spawning beds out deep again right away? Is there any transition from Summer to fall to winter as far as where to locate crappies or do they stay deep from late summer through the winter in general? Thanks!

[CrappieJohn]

Addict...It may help to look at these fish as having two periods in thier calendar year, those being vertical and horizontal periods. The vertical period starts in the early fall right after the turnover and lasts until late spring just prior to the spawn. During this time the fish' travels are up and down primarily with SOME movement into shallower waters as the weather and water temperature dictates. After the spawn, with constantly warming waters, they become very horizontal creatures in the water column; their food source has changed dramitically to preferring minnows and larger insects and water-borne crustaceons and invertibrates and the thermocline has also come into play. This period will last until the fall turnover. Hope this helps. Crapster

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Sure life happens- why wait

[united jigsticker]

Tom,

Long time my friend.

When did you change your name to John?

How's the bite been down there as of late?

united jigsticker

[Swimmer]

The following of zooplankton movement may explain why you find Crappies in varying parts of the water column. Species of large bodied zooplankton such as Daphnia (Cladocerans) and Copapods and may move up and down the water column at different times of day. Their movements up to the surface and then back down again are typically diurnal (twice a day) mainly because they are following their prey phytoplankton (algae). Crappies feed heavily on zooplankton at many times of the year and given that the Crappie's depth of field is not so great when it comes to zooplankton, they tend to follow the migration quite closely. In one SD lake study, the percentage of zooplankton in a White Crappie's stomach contents was 59%, while it was 39% in a Black Crappie.