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<br />o <br />C) <br />"" <br />~;::.:.. <br /> <br />',. , <br /> <br />Upon arrival, each fish was identified by reading its PIT tag and impartially stocked into 757-L <br /> <br />C) <br /> <br />fiberglass circular tanks, Two females and one male were stocked into each of 18 exposure <br /> <br />tanks, with one exception, and four extra fish (two of each sex) were placed in a separate culture <br /> <br />tanle Two males were accidently stocked in one replicate tank of treatment 2 (defined below). <br /> <br />This error occurred because one of these males was misidentified as a female by personnel at <br /> <br />DNFH and was not discovered until the spawning trials were initiated. The tanks were calibrated <br /> <br />to hold 662 L of water using a center-mounted standpipe and sleeve. Prior to stocking, about <br /> <br />two-thirds of the well water in each exposure tank was drained and replaced with water from <br /> <br />tanks on the distribution truck. Water temperature in exposure tanks at the time of stocking <br /> <br />(l3-140C) was within 1-20C of the shipping water (12-130C). <br /> <br />On the day after arrival, the fish were treated with 0,5% salt solution to help them recover <br /> <br />from the handling stress (B. Jensen, U,S. Fish and Wildlife Service, personal communication), <br /> <br />Food-grade NaCI was added directly to each exposure tank and the fish were maintained under <br /> <br />static conditions for about 7 hours. Water flow was then restored to the tanks and the salt <br /> <br />concentration was gradually diluted with well water. None of the fish exhibited any overt signs <br /> <br />of stress (i.e" surfacing or lethargy) during or after the salt treatment. <br /> <br />The fish were held in well water maintained at ambient temperature for 3 weeks before <br /> <br />starting the study, Water flow to the tanks was provided by an intermittent flow-through diluter <br /> <br />system calibrated to deliver 2 L of well water to each tank every 15 minutes, All tanks were <br /> <br />aerated continuously using large air stones supplied with compressed air from an oil-less air <br /> <br />compressor. Mean (SD) characteristics of the holding water were as follows: hardness, 1,065 <br /> <br />(6) mgIL as CaC03; alkalinity, 299 (2) mgIL as CaC03; pH, 7.9 (0, I); conductivity, 2,093 (257) <br /> <br />Ilmhos/cm @250C; un-ionized ammonia, 0.041 (0.022) mgIL as N; and dissolved oxygen (DO), <br /> <br />4 <br />