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<br />Study #9 Earlv BioloGV Studies - InvestiGation of effects of flow. <br />temDerature. and other environmental variables on the early bioloGV of <br />selected fishes in the Green River system. <br /> <br />DescriDtion of work <br />This study is under the direction of the LFL. Portions of this <br />study are a new start (RIP new emphasis: Management of Non-native <br />Fishes). The overall goal of this study is to gain an understanding <br />of. the biology and behavior of early life history stages of fishes <br />in the Green River, Utah, and how these attributes interact with <br />their phYSical and biological environments through an integration of <br />laboratory and field studies. This approach relates directly to <br />refinement of the flow recommendations, operation of FGD, and <br />management of the system as a whole. Specific objectives include: <br /> <br />1. Determine relationships between otolith growth and fish growth <br />and assess the utility of otolith-ageing techniques to <br />determine age-growth parameters of age-D Colorado squawfish. <br /> <br />2. Investigate effects of variable environmental factors (e.g., <br />streamflow, water temperature, and food supply) on growth and <br />survival of young Colorado squawfish under laboratory and <br />field conditions. <br /> <br />3. Comparatively describe the early morphological ontogeny of <br />selected fishes, including morphology and development of sense <br />organs and locomotor structures. <br /> <br />4. Evaluate responses of early life stages of selected fishes to <br />manipulated environmental conditions and assess the role of <br />sensory and locomotor systems in various early behaviors <br />(e.g., feeding, predator avoidance, and swimming performance). <br /> <br />Methods <br />Validation studies on .use of otoliths to age young Colorado <br />squawfi sh wi 11 be conducted in the laboratory and wi 11 i nc 1 ude <br />assessment, under laboratory and field conditions, of effects of <br />various environmental factors on fish growth/survival and deposition <br />of daily growth rings in otoliths. General development and behavior <br />of 1 arvae of selected fishes reared in the laboratory wi 11 be <br />documented, and detailed analyses of the early morphological <br />ontogeny of sense organs and locomotor structures will be conducted. <br />Experiments will be conducted subjecting the selected fishes to <br />variable flow, temperature, and water clarity co~ditions to <br />determine the function of sensory organs and locomotor structures <br />relative to behavior (e.g., feeding, predator avoidance, and <br />swimming performance) and to evaluate responses of fish to <br />manipulated environmental conditions. <br /> <br />Rationale <br />Studies such as 8 and 9 are considered important for the management <br />strategies that may result. Through integration of field and <br /> <br />Flaming Gorge Studies <br /> <br />28 <br />