The Transition From Spring To Summer

Areas where thermoclines intercept structure can be important spots for crappies in natural lakes during summer. Because of the lake’s low oxygen content, crappies can only descend beneath the thermocline for very short periods of time. This serves to concentrate fish just above the zone of rapid temperature change. Rockpiles, humps, reefs, brushpiles, fallen trees—and anything else crappies can use for cover—that extend above the thermocline become key areas, if the thermocline is shallower than 40 feet.

A rock- or brushpile on an otherwise featureless flat in 20- to 25-foot depths can become a prime summer haunt for crappies in natural lakes as well as reservoirs, especially when found in close proximity to diverse forms of shallow cover and structure crappies tend to use, like weedlines on points and shallow humps in areas with large shallow flats near an archipelago of islands or series of main-lake points. The best “deep” cover in natural lakes is rarely far from an extensive and diverse weedline or rocky shoreline with added cover (fallen trees, etc.) and rarely far from some example of confined open water.

Deep rockpiles, rock flats, and reefs can provide plenty of crayfish, insect larvae, and other forms of invertebrates for crappies to prey upon when baitfish numbers decline or recede temporarily to open water. One reason we refer so often to rockpiles is the documented preference crappies have for transition zones, where some soft substrates surround areas of rock or gravel. Just as areas where diverse soils and bottom types coming together can provide a greater mix of plant and invertebrate life, so, too, can the meeting of hard and soft bottom in deeper areas provide a wider variety of forage options. Transitions from soft to hard bottom can, in fact, be key areas for most species of fish living in natural lakes for the same reasons. Such areas consistently draw more baitfish over the course of time.

The intersection of the thermocline with these types of structure or cover can serve to concentrate crappies at a certain depth level, making them easier to locate vertically, in some cases. The “deep” bite on a rockpile or hump is often hottest during mid-morning and afternoon hours, and often dematerializes as the sun approaches the horizon later in the day. As light levels decrease, crappies tend to rise and suspend off nearby weedlines, fallen trees, rows of docks, and other forms of shallower cover. By sunset, they might move right into the weedline or fallen trees and concentrate along outside edges and branches, with some fish cruising over and among the wood or weeds.

As described in the segment on weedlines, this pattern often reverses at dawn, with crappies moving out to suspend off the breaks or over their deep cover before settling back down to rockpiles, humps, and deep reefs sometime around mid-morning.