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<br />were easily distinguished in radiographs. Counts included number of vertebrae anterior <br />to abnormal vertebrae, number of abnormal vertebrae, and number of vertebrae <br />posterior to abnormal vertebrae. <br />Percent of compression of abnormal vertebrae was calculated by comparing <br />them to adjacent uninjured vertebrae. Average length of uninjured vertebrae was <br />obtained from two uncompressed, proximal vertebrae on each side anterior and <br />posterior to the abnormal vertebrae. <br />Capture histories of x-rayed fish were obtained from the Recovery Program <br />PIT-tag database to identify whether fish had multiple vertebral injuries from repeated <br />electrofishing captures and to examine growth of injured and uninjured fish that were <br />later recaptured. <br /> <br />RESULTS <br /> <br />Forty seven eolorado pikeminnow were caught by ISMP electrofishing from the <br />Colorado (n=21), White (n=13), and Yampa (n=13) rivers in May 1996. One of these <br />was a recaptured fish handled the day before. Total length averaged 554 mm (SD, <br />89.95) and ranged 355 to 774 mm (Figure 1). Length frequency was similar to that of <br />Colorado pikeminnow captured during ISMP in previous years (McAda et al. 1994a, <br />1994b, 1995, 1996). Conductivity ranged 175 to 400 ,uS/cm in the river and 350 to 480 <br />,uS/cm in flooded tributaries (Table 1). Secchi depth was 8 cm or less at several <br />locations. Electrofishing settings were pulsed-DC set at 30 or 60 Hz with output from <br />150-390 V and 4-15 amps. <br /> <br />8 <br />