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Juvenile trout appeared to select certain large pool areas offering <br />consistently low water velocity. Such sites appeared to be conducive to <br />energy-conserving "random swimming" activity. In higher velocity areas, <br />the trout were oriented to the current, an activity we referred to as <br />stationary swimming. Swimming speed of fish engaged in stationary <br />swimming activity was a positive function of discharge rate. As <br />discharge increased, it appeared that many trout abandoned the energy <br />conserving random swimming mode, perhaps due to increased water <br />velocities in certain pool areas and, simultaneously, the facing velocity <br />for stationary swimming activity increased. The net effect of increasing <br />discharge, therefore, appeared to be an increase in energy expenditure. <br />This increased activity level would tend to be more taxing for smaller <br />trout. Metabolic rate is considerably higher among smaller fish and <br />swimming efficiency increases with body length. <br />It appeared, therefore, that for the majority of the tailwater, <br />usable area and juvenile trout survival in winter were favored at lower <br />discharge levels. The winter of 1982 was one of relatively high <br />discharge. That winter only juvenile trout near the dam experienced <br />satisfactory survival, based upon pre-winter tagging. Scuba observations <br />suggested the emigration of juvenile trout in 1982 peaked during and <br />immediately after a month-long period of high winter discharges. <br />Fingerling trout stocked in 1980 were subjected to the lowest winter <br />discharges of the study period, which may have contributed to their <br />exceptional survival in the winter of 1981. Angler catch curves <br />suggested that survival of adult trout may have suffered during a year of <br />exceptionally high discharges from June 1983 - May 1984. <br />-5-