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West Pond was not determined, but observations indicated that <br />macroinvertebrates were extremely plentiful. The abundance of <br />macroinvertebrates in West Pond and their scarcity in Fish Chalet Pond may <br />explain differences in squawfish growth between the two environments. <br />The two ponds were very similar in terms of temperature, conductivity, pH, <br />1 <br />and concentrations of various chemicals (Tables 7 and 8). West Pond had <br />more macrophytes than Fish Chalet, mainly deep beds of Chara sp. West Pond <br />also remained remarkably clear through the season while Fish Chalet Pond was <br />always turbid. In both ponds conductivity was high (5300-5600 umhos), and pH <br />slightly basic (7.8-8.5). Dissolved oxygen varied somewhat between ponds, <br />but was always adequate for fish health (6-13 mg/L). Concentrations of <br />total dissolved solids (TDS) may have been excessive for squawfish (Table 9). <br />Pimentel and Bulkley (1983) performed experiments on Colorado squawfish in <br />12 C water and found that squawfish preferred concentrations of 560-1,150 <br />mg/L and avoided concentrations in excess of 4,400 mg/L. Although the <br />avoidance concentration would be higher at warmer temperatures, Pimentel and <br />Bulkley warned that at lower temperatures TDS avoidance concentrations would <br />be less than those they measured. When pond water was 2.5-3.5 C in <br />December, TDS concentrations were 4,690-5150 mg/L (Table 9). Whether such <br />high TDS concentrations are harmful to Colorado squawfish is not known. <br />13th Hole Pond <br />Because Colorado squawfish were stocked into 13th Hole Pond early in the <br />year, they had a growing season at least four months longer than did fish <br />stocked in Fish Chalet and West ponds. Growth varied greatly among <br />individual fish. The largest caught (216 mm TL) had gained at least 81 mm <br />in length; the smallest gained no more than 23 mm (Table 10). Those fish <br />24