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<br />lHJ3uS7 <br /> <br />reproductive output. If proper environmental conditions are provided strong year classes are <br />expected. <br /> <br />Mean catch rates (fish per net) and mean body condition in the upper reach are also provided here <br />to indicate year-to-year trends: <br /> <br />Year Catch rate (Fish/net) Condition (Fish 500-599 <br /> mm TL) <br />1991 0.324 101.0 <br />1992 0.487 97.7 <br />1993 0.619 97.6 <br />1994 0.686 98.8 <br />1998 0.966 92.9 <br /> , <br /> . , ., <br />1999 . 0.777 93.5 <br />2000 0.813 92.1 , .', <br /> <br />In the upper reach, where most fish are adults, the population estimates and netting catch <br />rates suggest that, beginning in 1992, adult numbers continued to increase, peaked in <br />1998, and perhaps declined somewhat in 1999. Body condition was relatively stable <br />during the 1991-1994 period but declined significantly by 1998. A preliminary <br />interpretation of declining condition concurrent with increased population size is that <br />food is in short supply and that carrying capacity of the Colorado River may have been <br />exceeded despite the fact that overall population size is small. If subsequent data <br />collection and other studies bear this out, it will have important implications for the <br />potential viability of this population and management activities will need to be directed <br />toward increasing the extent of adult range and the food supply in this river so that this <br />population has the capacity to expand to a more viable population size. <br /> <br />vn. Recommendations: This population should be left alone for three years. In 2004 a new <br />3-year effort should begin. With this schedule, averaged 3-yr population size estimates'! <br />will be spaced 6 years apart. This should be sufficient to adequately monitor this <br />population. Stress associated with sampling is probably hannful to this population and <br />sampling therefore should not be conducted every year. Recommendations for <br />management activities based on findings of this and previous studies include:" <br /> <br />1) Accelerate providing passage at Price-Stubb and Government Highline dams to <br />increase the amount of adult habitat available to this p~pulation. <br /> <br />22-a-2-4 <br />