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braided channels are common. Above Marble Creek the valley narrows, gradient increases further, braids and meanders cease, pools become infrequent, and riffles predominate. Temperature varies little between the fastwater and slackwater (Davis 1961). Fish abundant in the St. Joe River fastwater include largescale suckers (Catostomus macrocheilus), bridgelip suckers (Catostomus colum- bianus), mountain whitefish (Prosopium williamsoni)', cutthroat trout (Salmo clarki), redside shiners (Richardsonius balteatus), dace (Rhinichthys sp.), and sculpin (Cottus sp. Northern squawfish range as far upriver as Bluff Creek at river mile 87, but are most abundant below Marble Creek (Reid 1971). SPAWNING BIOLOGY Methods Fieldwork was conducted between June 10, 1980, and August 10, 1981, but was concentrated during June and July of both years. Trammel, trap, and experimental gill nets were set nightly in different areas of the St. Joe, St. Maries, and Clearwater Rivers in the late spring and early summer of 1980, during the period that literature information indicated spawning should be in progress. Capture success and general condition of fish taken in each areas were compared to determine which areas were used by spawming squawfish. Swimmers equipped with faceplates and snorkels then examined these areas to locate spawning sites. Spawning behavior was observed and described qualitatively by the snorkelers. In 1981, fieldwork on spawning biology began on June 2 and was restricted to the St. Joe River. Transects were established at 4 sites where fish had been observed spawning in 1980. Counts of fish made by two snorkelers independently swimming standardized routes were averaged to give an index of fish abundance of each site. Counts were made only during days and hours when lighting and turbidity resulted in Secchi depth measurements of at least 5 meters. Counts were repeated at two-day intervals if conditions allowed. Fish behavior and appearence were also noted at the time of each count. Throughout the spawning period, river temperature (midmorning) and level were determined at one- or two-day intervals with a hand-held thermometer and a fixed, calibrated staff. During the period of peak spawning activity, areas where spawning had been observed the previous year were checked by snorkelers. Each spawning site located was outlined with painted rocks placed on the stream bottom and then mapped from a baseline established with a cali- brated line along one bank. Calibrated transect lines (at least four per site) were extended across the river perpendicular to the baseline at measured intervals. Baseline length and transect number and spacing were chosen to give accurate and complete coverage of each site and its immediate surroundings. Velocity profiles, depths, and substrate com- positions were determined at stations along each transect line, and the presence or absence of spawning or holding fish was noted. The number 49