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275 <br />Order <br />Stream order was determined by methods originally developed by Horton <br />(1945) and later modified by Strahler (1952, 1957). <br />FISH COLLECTION <br />The low concentration of total dissolved solids (60 p/m) in stream waters <br />meant that more reliable fish population samples could be obtained with explo- <br />sives than by using electrical fish collecting equipment. A total of 2.75 miles <br />of stream were sampled at 291 stations, using 4 miles of explosive prima cord. <br />A 0.125- or 0.225-inch mesh net was stretched across the stream to block <br />fish from moving out of the sampling area prior to the explosion. The net <br />and the effectiveness of prima cord assured an unbiased collection of 100 per- <br />cent of the fish population within each sample area. All collected fish were <br />identified and measured from tip of snout to end of longest lobe of the caudal <br />fin. <br />COMPUTER ANALYSIS <br />The CUMDIS (cumulative distribution) statistical program (package 52) was <br />used to generate cumulative frequencies, means, and standard errors about pre- <br />determined variables. All confidence limits were calculated by using t values <br />at the 95 percent level. The STAPTPAC/LIBRARYA unit at Utah State University <br />was used to run an inverted matrix multivariate analysis. <br />FINDINGS <br />Only selected data appear in this report. If the reader wishes to review <br />complete information concerning the relationships between aquatic variables, <br />the relationship between aquatic variables and fish populations, and multi- <br />variable control of fish populations, the author can provide a report titled <br />"Geomorphic and aquatic conditions influencing salmonids and stream classifi- <br />cation--with application to ecosystem classification." The work was supported <br />by the Forest Service SEAM (Surface Environment and Mining) Program. <br />Effect of Channel Materials on Fish Populations <br />Many authors have demonstrated that excessive fine sediment is detrimental <br />to aquatic life (for example, Cordone and Kelly 1961, Phillips and Campbell