In short, small lakes are vulnerable to both Mother Nature and fishing pressure. The sheer massiveness of big lakes, on the other hand, offers protection from both winterkill, and to a certain degree, fishing pressure. In fact, depth is at least as important in creating a top-notch crappie fishery as is the total surface area. Deep water is vital to growing and sustaining trophy crappies. Deep holes, particularly in wintertime, sustain stable water temperatures and ample forage.
Crappies respond to deep holes based on food location and climatic conditions.
Also, a wicked high-pressure system, occurring in this same piece of water, might drive fish down to or near the bottom and render them inactive. Either way, a high percentage of crappies in big lakes spend most of the cold-water period in deep water. Another reason why deep water is important to crappie proliferation is the refuge it provides. Deep water allows crappies to feed and lounge away from ambush zones, i.e. the weed beds and rock piles found in shallower water. Here, northern pike, muskies, bass and walleyes prey on panfish.