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<br />ISMP Collections: <br /> <br />All data summarized and submitted, <br /> <br />Colorado River, Colorado, Fall 1993: <br /> <br />A total of 37 fall young-of-the-year collections for Colorado River Miles <br />183.2 to 135.2 were preserved during 20 to 22 September 1993. The <br />collections contain 8,041 fish (an average of 217 specimens per <br />coll ect ion) representi ng 15 species. Cypri nids account for 92% and <br />catostomids 7% of all fish preserved, About 86% of the fish are <br />nonnative. Fathead minnow, sand shiner and red shiner account for 56%, <br />14%, and 13% of the fish, respectively, The most abundant of the four <br />native species are the Gila chubs which account for 7% of all fish taken <br />but 48% of the natives. A total 'of 558 chubs (17-61 mm TL) were found <br />in 34 collections. Based on fin ray counts, most of the chubs are <br />probably roundtall chub; a few might be humpback chub. A couple <br />specimens have very extreme fin meristics (one with 14 dorsal fin rays, <br />one with 12 anal fi n rays, and another with 6 anal fi n rays). No <br />Colorado squawfish or .obvious. razorback suckers were identified. There <br />is a relatively slim possibility that some of the fish identified as <br />flannelmouth sucker might actually be razorback sucker, but such is not <br />morphologically obvious. Native bluehead and flannelmouth suckers <br />represent 82% of the catostomids. Among the non-cypriniform species, the <br />western mosquitofish is most abundant and represents about 1% of all fish <br />collected. <br /> <br />Colorado River, Utah, Fall 1993: <br /> <br />A total of 76 fall monitoring or young-of-the-year co 11 ect ions for <br />Colorado River Miles 107.8 to 3,2 were preserved during 21 to 24 <br />September 1993, The coll ect ions contain 26,924 preserved fi sh <br />representing 16 species and (an average of 402 specimens per collection). <br />About 98.9% of the fish are nonnative, Fathead minnow, red shiner and <br />sand shiner respectively account for 41%, 40%, and 17% of the fish. The <br />most abundant of the five native species is bluehead sucker which <br />accounts for 0,5% of all fish taken but 46% of the natives, Based on fin <br />ray counts, most of the chubs are probably roundtail chub; a few might be <br />humpback chub. A total of 60 chubs (17-61 mm TL) were found in 27 <br />collections throughout the monitored reach, but most (77%) were taken <br />above River Mile 55, A total of 65 Colorado squawfish (15-37 mm TL) were <br />found in 19 collections all below River Mile 85, but mostly (89%) below <br />River Mile 50. The largest concentration of Colorado squawfish (33 in <br />one collection, 3 in another) was taken at River Mile 16.5. <br /> <br />Green River, Utah, Fall 1993: <br /> <br />A total of 5 fall monitoring or young-of-the-year collections were <br />preserved for Green River Miles 99.3 to 1.3 taken during 21 to 24 <br />September 1993. The collections contain 4,511 preserved fish <br />representing 7 species and (an average of 902 specimens per collection). <br />Cyprinids account for all but three specimens preserved; the three <br />exceptions are bluehead sucker, Over 99% of the fish are nonnative, Red <br />shiner, sand shiner, and fathead minnow account for 66%, 30%, and 4% of <br />the fish, respectively. Native species include Colorado squawfish, <br /> <br />3 <br />