Crappie fishing is as good as it gets in Mississippi's lakes and reservoirs. But for many anglers, good crappie fishing occurs only during the month surrounding the spawn when crappie are in predictable, shallow-water haunts. Serious crappie anglers ignore this "wisdom" and fish our waters year round. And they catch fish, too, as many articles in Mississippi Sportsman attest. It's a matter of knowing where to look.

A study by University of Missouri researchers sheds light on crappies' seasonal movement. Their results may help lead you to elusive summertime crappie in the Magnolia State.


Narrowing the search

Crappie move offshore in the summer. That's a lot of aquatic real estate to search for fish, but the hunt is compounded by water depth. Finding crappie becomes a three-dimensional game of hide and seek.

To the alert angler's advantage, lakes stratify in the summer. The thermocline - the zone of rapidly changing water temperature - separates the warm water above the thermocline from the cooler water below. In moderately to highly fertile lakes - the kind of lakes where crappie are usually abundant - the water below the thermocline lacks oxygen by early summer. The crappie are restricted to the water in and above the thermocline.

OK, but the thermocline may be 20 feet deep. That's still a lot of water to search for crappie. Here's where the University of Missouri research kicks in.

The researchers attached temperature-sensing radio transmitters to crappie, and tracked them throughout the summer in two Missouri impoundments. The water temperatures selected by crappie were integrated with lake temperature information to predict the temperatures selected under various water-temperature conditions.

In Little Dixie Lake, the crappie stayed in the warmest water available until the lake reached 75 degrees. The crappie selected the coolest water available when the average upper-water temperature climbed above 82 degrees.

In Rocky Fork Lake, the crappie occupied the warmest water until the average upper water temperature reached 82 degrees. As in Little Dixie Lake, the Rocky Fork crappie also selected the coolest water available, but not until the temperature climbed to 88 degrees.

The message to crappie anglers is simple: Crappie will move to deeper and cooler water sometime during the summer. This change in location may occur quite suddenly.


Unraveling the differences

While the crappie in both lakes made similar movements into deeper and cooler water in the summer, the temperature at which the transition occurred differed by 6 degrees. Rob Hayward, the University of Missouri fisheries professor involved in the study, offered that habitat differences between Little Dixie and Rocky Fork lakes may explain why the crappie moved to cooler water later in Rocky Fork.

Little Dixie has abundant standing timber in open water. After the spawn, crappie relocate to the standing timber. Their association with this vertical cover allows them to stay close to their preferred habitat and, at the same time, move up and down to find their thermal comfort zone.

Rocky Fork is deeper, the banks slope steeply into deeper water, and the lake lacks standing timber. After the spawn, the crappie remained near the narrow band of shallow-water vegetation. Without cover in deeper, cooler water, Hayward speculated that the crappie tolerated warmer water conditions longer before finally moving off cover to cooler water.

So the Missouri study adds even more information to the crappie anglers' strategy: Temperature and habitat affect summer crappie location, and summer habitat and when the crappie move there can differ in lakes with different mixes of habitat.


Do the science

By Hayward's own admission, this hypothesis needs to be tested in more lakes with habitat conditions similar to Little Dixie and Rocky Fork. Mississippi has lakes and reservoirs that closely match the Missouri impoundments. You be the scientist - collect your own data and determine the temperature at which crappie head for cooler water in your favorite lake.

You will need an underwater thermometer. Several underwater temperature meters are commercially available. Alternatively, purchase a temperature probe for your depth finder; one with 30 feet of cable will be sufficient to reach the thermocline in any Mississippi lake or reservoir.

At least once each day when you're out fishing, measure water temperatures from the surface down to the thermocline. Measure the water temperature at the depth where you are catching crappie, and use that temperature to locate crappie at other fishing spots. I think you will find the temperatures where you catch the fish are very consistent on any given day.

Repeating this throughout the summer will allow you to determine the temperature when the crappie seek cooler water and to predict crappie locations for years to come.