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<br />Study Timetable and Direction <br /> <br />This evaluation was originally developed and scheduled for three years. <br />The first two years (FY98 and FY99) were planned for field collections and FY2000 <br />for preparing the final report. Study direction was changed in August 1998 when <br />the RIP Management Committee discontinued all field work previously scheduled for <br />the spring, summer, and fall of 1999 (March through September). The only field <br />work scheduled for FY99 was conducted during October 1998. Analyses of the field <br />data and preparation of the final report was accomplished in FY99 instead of <br />FY2000. To accomplish the necessary objectives for a 2-year field evaluation, <br />the field methodology and study design was initially developed for 2 years of <br />field work, not 1 year. Consequently, less information was collected because one <br />year of field work was canceled, and therefore, study objectives were not <br />sufficiently addressed and some of the end products were not met. <br /> <br />STUDY AREA <br /> <br />This evaluation included the Upper Colorado River from RM 187.6 immediately <br />downstream from the Price-Stubb Dam (RM 188.3) to Lorna (RM 152.6) and the Lower <br />Gunnison River--RM 3.0.0.7. Fish collections with electrofishing were conducted <br />exclusively in a 4.6-mile section of the Colorado River from RM 187.6 to RM <br />183.0. Telemetry from boats was conducted from Colorado River RM 185.5 to RM <br />152.6 and the lower 2.3 miles of the Gunnison River (Figure 2). <br /> <br />METHODOLOGY <br /> <br />Field efforts for this evaluation relied on two separate techniques, mark <br />and recapture and telemetry, both appl ied independently to determi ne if sub. adult <br />and adult fish would use the passageway to pass over the GVIC Diversion Dam. The <br />first method involved collecting native and nonnative fish with electrofishing <br />and marking them from the first 2 miles of river immediately downstream of the <br />di vers i on dam. Although the passage structure was constructed to provi de passage <br />primarily for Colorado pi kemi nnow, surrogate native and nonnative fishes were <br />also marked and tagged because Colorado pikeminnow numbers inhabiting the study <br />area were low and determining if and when pikeminnow would use the fish passage <br />at this site might take considerable time. <br /> <br />Sub-adult and adult fish of the most common large-sized, native fishes <br />(flannelmouth sucker, bluehead sucker, and roundtail chub) were initially <br />inserted with a PIT tag and released. After the administrative decision was made <br />in mid-August to discontinue field work for the following year, use of PIT tags <br />was discontinued and it was decided that a short-term mark (i .e., fin clip) would <br />suffice for the remainder of the study. Therefore, between 3 April and 27 April <br />and between 17 July and 20 August, all native fishes captured were PIT tagged. <br />Between 24 and 28 August, all native fishes were fin clipped. Other common sub- <br />adult and adult nonnative fishes such as common carp and white sucker that were <br />captured were marked with an external, individual, serially-numbered Floy@ <br />"spaghetti" tag in the dorsal musculature. Rainbow trout, brown trout, and <br />sucker hybri ds (whi te sucker X fl anne 1 mouth sucker, whi te sucker X b 1 uehead <br />sucker, and bluehead sucker X flannelmouth sucker) were all marked by clipping <br /> <br />4 <br />