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<br />VIII. FY 93 Tasks and Deliverables: <br /> <br />. Evaluate microstructure of otoliths from young Colorado squawfish. Analyze <br />otoliths from wild-caught Colorado squawfish (drift-net collections and seine <br />collections in nursery habitats) to derive estimates of growth and relative <br />survival of cohorts. Correlate these estimates with specific environmental <br />parameters (e.g., streamflow and water temperature) to determine how <br />environmental conditions affect growth and survival of young Colorado <br />squawfish in the wild. <br /> <br />. Conduct studies/experiments to evaluate the effects of environmental factors <br />(e.g., streamflow, water temperature, food supply, and diet) on growth, <br />survival, and behavior of eariy life stages of Colorado squawfish and other <br />fishes in. the laboratory and field. <br /> <br />. Conduct studies/experiments on the early development and biology of <br />selected important fishes. <br /> <br />. Analyze data. <br /> <br />. Synthesize and integrate results of the various studies conducted under this <br />project to arrive at a more complete understanding. of the eariy biology of <br />Colorado squawfish and. razorback sucker. Integrate results of these studies <br />with results of other projects concemed with reproduction and eariy life history <br />of Colorado squawfish and razorback sucker conducted under the 5-Year <br />Flaming Gorge Flow Investigations Program. <br /> <br />. Prepare manuscripts on the various studies conducted under thi~ project. <br /> <br />, <br /> <br />IX. Accomplishmenlsllnitial Findings and Shortcomings: <br /> <br />Objective 1: <br /> <br />Otolith microstructure studies <br /> <br />Colorado squawfish embryos obtained from Dexter National Fish <br />Hatchery were hatched and reared. under three fluctuating diel temperature <br />regimes (18,22, and 260C; 50C diel fluctuation) and four constant temperature <br />regimes (18, 22, 26, and 300C). Effects of short-tenn food deprivation, <br />light/dark conditions, and temperature change on otolith and somatic growth, <br />and increment deposition was also assessed. Series of fish were preserved <br />at appropriate intervals in 100% ethanol for analysis. Analyses will include <br />general otolith description and timing of initial formation, determination of <br />increment deposition rate, and otolith and somatic-growth relationships for <br />specimens reared under each of thj:! different temperature regimes. Results <br />of this study will determine the utility of otoliths in growth and age-structure <br />studies and will document the effects of various environmental parameters <br />(e.g., temperature, light, food supply) on otolith microstructure. <br /> <br />4 <br />