Recently, I had the opportunity to ice fish several small lakes having never been on them before. With map in hand, I narrowed down some depth changes and underwater features that from past experiences have yielded good days of angling and marked them for exploration. The result of these forays on to new water was several nice crappies in my bucket at the end of both trips. While a map may not give up the exact location of where the fish roam, without one you're always a step behind the school.
In this day and age of computerized Geographic Information System (GIS) maps and contour-tracing trolling motors, state agencies are able to make lake maps that break down the depths to mere inches. Once completed, many of these high-tech maps are available on state game and fish department websites.
Take for example the GIS maps compiled by the North Dakota Game and Fish Department (www.gf.nd.gov/lakedata.html). These maps display bottom contours in graduated shades of blue from white and periwinkle in the shallows to navy and dark blue in the depths; usually darkening in three- or five-foot increments. Add in aerial photos overlaid on the shorelines of the maps and an angler can pinpoint landmarks that correspond with desired areas to fish.
Even if the map isn't the most high-tech, as with the compilation of over 10,000 waters available at the Minnesota Department of Natural Resources Web site (www.dnr.state.mn.us/lakefind/index.html) through the "Lake Finder" resource, anglers still get a good idea of areas to target for their desired quarry. On top of that, the Lake Finder helps anglers narrow down more productive lakes by providing fish survey results, which chronicle the historical sampling data of each lake. Though some data sets are older, many lakes have been surveyed in the last decade, providing a reasonable estimate of fish populations. The resource also provides locations of access points, water clarity, and water level observations.
With this information in hand, anglers can get a quick overview of some likely places to start fishing. While certain spots will always remain hidden treasures, like the sunken boat on the large flat that holds walleye after walleye; many general areas are obvious just from viewing a contour map. Look for points and drop-offs where contour lines come close together, signaling a rapid change in depth. These areas are often good fishing, as fish can easily transfer from deep to shallow and back again.
Also look for those spots that stick out on the map. The hump or reef that rises into 20 feet out of a thirty-foot basin will always be a "must check" for many species of fish. Whether in the micro-contour setting, such as a boulder in stream current, or in the macro-contour setting such as a small reef on a wide expanse, these forms of structure in a generally featureless area are fish magnets and should be considered as some of the first places to check for many species.
With the printer-friendly quality of many agency maps, and high-resolution of many low-priced printers available, anglers can print out a number of maps and tuck them into fishing journals, plat books and gazetteers that they take on the water. From there, notes can be made as to the location of the most productive spots on the map in general areas of interest.
This winter, or anytime of year for that matter, take a few minutes before a fishing trip to examine the lake map. Whether it is a big body of water or a forty-acre lake, a map will get you pointed in the right direction for fishing success...in our outdoors.