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1 <br /> <br />MODDE AND IRVING <br />547 <br />515 <br />483 <br />450 <br />418 <br />386 <br />L <br />N <br />O <br />Y <br />N <br />fY <br />547 <br />515 <br />483 <br />450 <br />418 <br />386 <br />547 <br />515 <br />483 <br />450 <br />418 <br />386 <br />547 <br />515 <br />483 <br />450 <br />418 <br />386 <br />547 <br />515 <br />483 <br />450 <br />418 <br />386 <br />547 <br />515 <br />483 <br />450 <br />418 <br />386 <br />321 <br />94 95 94 95 <br />FIGURE 2.-Seasonal movement patterns of six male razorback suckers in the middle Green River between April <br />1993 and June 1995. Horizontal lines represent the Escalante spawning area (RK 442-501) and the Yampa River <br />spawning site (RK 555). <br />te). Fish 177D1B returned to Split Mountain Can- <br />yon in October and 180B26 returned sometime <br />before March. In late July 1993, approximately 2 <br />months after implantation, the transmitter from <br />one adult razorback sucker was found in a shallow <br />inlet near Stewart Lake. The fish was presumed to <br />be dead. <br />Fish implanted with transmitters either ex- <br />pressed milt or were heavily tuberculated at cap- <br />ture, suggesting they were probably involved or <br />preparing for spawning activity at the time of cap- <br />ture. We assumed that these fish engaged in spawn- <br />ing activity in 1994 and 1995 when they returned <br />to identified spawning sites in the spring, although, <br />because of high flows and turbidity, it was not <br />possible to confirm actual spawning. <br />Maximum downstream movement of the six fish <br />implanted with transmitters ranged between 0.0 <br />and 112.7 km (Table 1). Most movement occurred <br />just before, or following, congregations at spawn- <br />ing locations (Figure 2 and as reported by Tyus <br />and Karp 1990). During both years of study, mean <br />downstream movement exceeded upstream dis- <br />tance traveled, although two fish in 1993 and one <br />in 1994 moved further upstream than downstream. <br />Maximum downstream movement averaged 33.1 <br />(SD = 21.8) and 61.8 km (SD = 43.8) during <br />1943-1994 and 1994-1995, respectively (Table 1; <br />Figure 2), In 1993-1994, two fish underwent ex- <br />tensive downstream movements (55.5 and 68.0 <br />km) compared with three fish between 1994-1995 <br />(93.3, 99.0, and 112.7 km). In 1994, two of the <br />six transmitter-implanted fish moved to a different <br />spawning area than the one they were captured at <br />the previous year. Fish 180B2C was collected on <br />the Yampa River spawning bar in 1993 but moved <br />94 95 <br />94 95 <br />94 95 <br />94 95 <br />