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i 7• <br />METHODS <br />Fish Stomach Contents <br />Stomachs were eviscerated by carefully slitting the fish belly (using <br />sharp nosed scissors) at the vent and cutting towards the isthmus. Each <br />stomach (including esophagus and intestine) was carefully removed with <br />forceps and placed into a 3-dram patent-lip vial conta.ining 70% ethyl <br />alcohol. Several stomachs were removed in one session so that this step <br />would not add time to and interfere with the process of stomach content <br />removal and food item identification. <br />We had planned to use the volumetric syringe measuring device <br />(Myers and Peterka 1974) for estimating volumes of individual macro-food <br />items. Because of the very small, fragile, and fragmented condition of <br />most of the food items, it was necessary to modify the biomass technique. <br />The Myers and Peterka method (1974) had been used earlier on Cutthroat <br />trout (Salmo clarki lewisi) stomach contents (Jacobi 1979) where the food <br />items were whole and larger benthic macroinvertebrates. <br />Before individual food items were removed from each stomach, the <br />following was performed as a check for total stomach content biomass. <br />After carefully removing viscera and other organs from the stomach mass, <br />the stomach was rinsed with water, blotted on a paper towel to remove <br />excess fluid, and then placed into the syringe measuring device. The <br />difference between the initial volume and the displacement volume was <br />roughly equal to the stomach content volume (minimal displacement was <br />attributed to the stomach itself). This value was multiplied by 1.05 <br />(Hynes 1961 and Jacobi 1977) to approximate biomass (weight in mg). The <br />sum of estimated weights of individual food items should not have ex- <br />ceeded the value obtained by this check method.