The data examined in this study were obtained from John Pitlo, Iowa Department of Natural Resources, through Barry Drazkowski, Environmental Management Technical Center, U.S. Fish and Wildlife Service. The data represent partial results of the radio tracking of 24 largemouth bass in Pool 12 of the Upper Mississippi River between 1986 and 1990. In this work, the data are divided into five time segments, winter, prespawn, spawn, summer and fall, with each period marked with an appropriate chronological reference period. A major focus of this project has been to develop a flexible workplan and a thoroughly documented file structure and nomenclature. To accomplish these goals and to provide for maximum flexibility, time was divided into semi-monthly segments and then combined to generate seasonal periods. Field data for each fish was coded into EPPL7 and geo-referenced to Pool 12 coordinates. Following this, data for individual fish were tracked as they were combined and overlaid on a 1975 land use/land cover habitat classification model provided by the EMTC. Next, data for all fish were combined for each season to obtain a composite picture of bass movement and habitat utilization in Pool 12. As a last step, the EPPL7 GIS was queried to provide a summary of river habitat usage per period by individual fish and by all fish combined. Results from the study show that during the winter period 63% of the fish locations were in open water. 18% were found in the vegetation combination of lotus, duckweed and coontail. The spawn period showed 45% of the locations in open water. Almost 55% of the sightings were found in vegetation, with coontail heading the list with 17%. During the fall period, vegetation occupied 46% of the locations and open water 53%. Coontail occurred in 14% of the locations. These results show that bass prefer open water during the overwintering period. Other results show that fish moved up to 9 miles to overwintering areas, but this was not evident with all of the fish.