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downstream from the selected river mile starting point, the other 5 miles downstream (Figure B-1, Appendices). Intensive sampling began in the uppermost 0.5 mile section continuing for 24 hours. The second day, the intervening 4.5 mile section was surveyed by electrofishing starting at the lower boundary of the previous sample site and continuing downstream to the upstream point of the second 0.5 intensive section. From this point, the second 0.5 mile section was intensively sampled for 24 hours. Within each 0.5 mile intensively sampled reach, discrete habitat types were delineated (Figure B-2, Appendices) and fish collections conducted within them, rather than across several habitats. This permitted a delineation of habitat preferences for fish species with depths, velocities and sub-strates recorded for each subsample. Sampling was not only stratified spatially, but-also temporally by day and season. Days were sybdivided into three sampling periods and a midday period of sampling inactivity was reserved for equipment main- tenance, travel and personal activities of the crew (Figure B-3, Appendices). Daylight activities were devoted to netting, trapping, electrofishing and physical/ chemical measurements. Activities during darkness were devoted to tending nets, traps, electrofishing and some seining. Seasonal sampling conformed to river stage. Each year (when work was in progress) pre-runoff, runoff and post-runoff river stages were sampled in each of the six strata. The standardized sampling schedules and procedures were strictly adhered to; however, weather conditions, manpower shortages, and equip- ment failures dictated minor changes in schedules and sampling procedures at times. Schedules of the 1979, 1980 and 1981 standardized sampling are included in the Appendix (Tables Al-A3). Sample sites were precisely located on river maps and aerial photo- graphs. Sketches were made of each 0.5 mile intensively sampled reach illustrating the prevalence and juxtaposition of habitat categories (Table 1). Three cross-sectional depth profiles were recorded at each 0.5 mile intensive section using an electronic depth recorder. Depth profiles were recorded at each end of the 0.5 mile sample sections and at the mid-point of the section. Water quality measurements were taken at each intensive sample site. These included dissolved oxygen (DO), turbidity, air and water temperatures, salinity and conductivity. Such variable parameters as temperature and DO were taken between 1000 and 1400 hours for standardization. An effort was made to collect fish from every habitat present in a sample station. The habitat from which each fish was collected was