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<br />feeding, surface feeding, and benthic feeding each in of open, flowing <br />sections or stagnant-flow areas. These experiments were repeated with <br />red shiners in the streams to measure potential interspecific <br />competition interactions, including aggressive interactions, scramble <br />competition and exploitation competition. <br /> <br />RESULTS- Bony tail showed significant physiological responses to flow <br />training. Red muscle fibre diameter increased significantly, <br />mitochondrial volume of red fibres increased, and the number of <br />capillaries per red muscle fibre increased. <br /> <br />One-yr old bony tail show strong preferences for high velocity close to <br />substrate. Approximately 90% of the time is spent in these habitats <br />when the bony tails are alone. However, because shiners often are found <br />in the higher velocity areas, bony tail switch to using low-velocity <br />habitats in the presence of red shiners, When alone, bony tail show <br />strong feeding responses for food drifting in downstream directions <br />near the substrate. Behaviorally, bony tail show very similar feeding <br />patterns to those observed for trout, When red shiners are present, <br />bony tail show significant decreases in feeding efficiencies when <br />encounter and capture rates decrease significantly. Perhaps more <br />importantly, feeding position changes significantly when shiners are <br />present, with bony tail spending twice as much time feeding at the water <br />surface and in midchannel as well as exhibiting a four-fold decrease in <br />benthic feeding. <br /> <br />VII, Recommendations: <br /> <br />MANAGEMENT IMPLICATIONS - If we are to successfully reintroduce <br />bony tail in the upper Colorado River basin, we need to strongly <br />consider raising these fish in flowing environments, Their overall <br />physiology and musculature show considerable adaptability for flow <br />training, suggesting that they have evolved in a relatively high <br />velocity environment, <br /> <br />We also should consider reintroducing smaller fish in areas where red <br />shiner abundances are low, Our laboratory data demonstrate that <br />bony tail exhibit considerable changes in habitat selection and feeding <br />efficiency when red shiners are present. <br /> <br />VIII, Project Status: On track and ongoing through FY 95. <br />IX. FY 94 Budget <br /> <br />A. Funds provided: <br />B. Funds expended: <br />C. Difference: <br /> <br />$53,800 <br />$53,800 <br />$ -0- <br /> <br />X. Status of Data Submission: On track, <br /> <br />XI. Signed: Leo Lentsch, December 9, 1994. <br /> <br />2 <br />