Effect of Fishway Slope on Performance and Biochemistry of Salmonids

The effect of fishway slope on the performance and biochemical state of salmonids was studied in two experimental \u27endless\u27 fishways with slopes of 1 on 8 and 1 on 16. A locking device in each fishway permitted recycling of fish so that pool-and-overfall fishways of any height could be simulated. Ascents were generally confined to a rise of 104 feet, but a number of fish were permitted to ascend over several hundred feet and one fish was allowed to ascend over 6,000 feet. Principal species tested were chinook salmon (Oncorhynchus tshawytscha), sockeye (Columbia River blueback) salmon (O. nerka), and steelhead trout (Salmo gairdneri). Comparisons of individual passage times, patterns of movement, and biochemical phenomena associated with muscular activity showed no evidence of fatigue of the fish in either fishway when proper hydraulic conditions existed. Data indicated that ascent of a properly designed pool-and-overfall fishway is only a moderate exercise for salmonids and that the rate of ascent will not decline in the upper end of a long fishway. Hydraulic conditions were shown to control rate of ascent and pattern of movement through fishways. Differences in rate of movement and in blood lactate levels were measured between species. The effects of size, sex, maturity, and disease on performance and biochemical state of fish were also examined. Significant relationships were found only for length of male chinook and performance (larger fish were slower), and sex and blood lactate level for chinook (female chinook had higher blood lactate levels)