Fish cribs, man-made magnets for crappie, walleye and bass,
revealed by Humminbird Down Imaging
Dr. Jason Halfen
Professional Walleye Angler
Navigation:
In lakes and impoundments that lack significant natural cover (weedbeds, rocks, timber, etc), and even in some bodies of water that possess these structural features, artificial fish cribs often serve as key locations for fish activity. Serving as both a local foundation for the food chain (providing a surface for baitfish-attracting algae and microorganisms to grow) and a source of cover for baitfish and young gamefish, cribs attract anglers in search of crappies, bass, walleye, and other gamefish that find the cribs to be reliable sources of food and protection. Artificial cribs made of plastic or wood are easily identified by sonar, and Humminbird's Down Imaging and Side Imaging technologies provide outstanding, high-resolution views of these artificial fish-attracting structures.
Navigation:
The impoundment where most of my guide trips occur, Lake Wissota in Chippewa Falls Wisconsin, contains a large number of log fish cribs, installed annually by the Chippewa Rod and Gun Club. Cribs are assembled on the ice during the hard water months, and sink into place as the ice recedes in the spring. The cribs are between 6' and 8' square, and between 5' and 6' high. They are filled with brush to provide cover for the baitfish that attract gamefish and panfish to the vicinity of the cribs. The Chippewa Rod and Gun Club has installed hundreds of cribs since their project began, and more cribs are due to be sunk this winter. Here is a picture of a set of newly-built fish cribs, awaiting the spring thaw that will send them to the bottom of the Yellow River that feeds Lake Wissota.
The 3-way split screen view that is available with Down Imaging is an information-packed, high-resolution way to visualize the water column beneath the boat, as well as off to the sides by incorporating the Side Imaging view. This 3-way split screen view shows the boat's progression from a shallow, hard bottom flat through a deeper area and then back up into shallow water. A large number of cribs are found within the deeper portions of this area, and are known summertime crappie producers. The right-side Side Imaging view also clearly shows the transition from hard, sandy substrate (bright bottom) to softer muck (darker bottom) found in the deeper portions of the reservoir.
I'll close this article with a few more split screen views containing both Down and Side Images of cribs. The image on the left shows a group of cribs that are associated with a fast, sandy shoreline drop off to deeper, softer basin. The right hand image shows a large collection of deep water cribs that are near a transiton from hard to soft bottom, and associated with an man-made rock "reef" (the bright white opbect in the upper right Side Image. If your favorite lake or reservoir has an active crib program, a Humminbird fishing system equipped with Down and Side Imaging will help you identify, locate, and mark the GPS positions of any crib that is within the sonar range of your unit (up to 480 feet from side to side!). This will make you a more efficient and productive angler, as you'll spend more of your time catching fish, rather than looking for the structure that might concentrate them.
We'll start our discussion of cribs by looking at some isolated cribs in relatively deep water. The bottom in this area is relatively hard (primarily rock) and has some scattered timber than has been washed downriver over the years. This first image shows a pair of cribs (one visible and one absent in the lower, 2D sonar view) bracketing a rock hump. A transition from hard packed sand bottom (to the left of the hump) to gravel and small rock (to the right of the prominent crib) is also apparent. The level of detail revealed by Down Imaging is simply astounding; individual horizontal logs are clearly visible in the prominent crib. Note that this level of detail is completely absent in the traditional 2D view (collected with dual-beam, 200kHz/83kHz sonar). The prominent crib to the right of the rock hump could easily be mistaken for a brushpile or perhaps even a tightly packed school of fish. Down Imaging eliminates any doubt in the angler's mind: this object is most certainly a fish crib. Similar conclusions can be reached by examining the split screen images below, which reveal highly detailed pictures of other deep water fish cribs.
Here is a large collection of cribs in a Down Imaging -2D (200 kHz/83kHz) split view. A few scattered fish riding above the cribs are noted in the 2D view.
Here is a pair of cribs sitting in about 20 feet of water, with a small school of fish loosely associated with the cribs (white returns to the left of the cribs, around 10 feet deep).
