Changes in Glycogen and Lactate Levels in Migrating Salmonid Fishes Ascending Experimental "Endless" Fishways

Abstract

Certain aspects of the performance and biochemistry of adult migrating salmonid fishes were investigated during ascents of 116- and l:8-slope experimental fishways which employed locking devices permitting the simulation of fishways of any length. Fish tested were chinook salmon (Oncorhynchus tshawytscha), sockeye salmon (Onerka) and steelhead trout (Salmo gairdneri) diverted from their upstream migration on the Columbia river at the Bonneville dam fishways during the summer of 1959 Blood and muscle lactate, and muscle and liver glycogen levels were determined in control fish, and in fish following three types of activity. Records of individual performance were kept. All species were willing to enter and capable of ascending fishways of either slope up to 1000 ft in height under favourable hydraulic conditions. Blood lactate and muscle glycogen determinations revealed the degree of exercise to be moderate even during prolonged ascents. Moderately high ascents (about 100 ft) in the steeper fishway apparently required the expenditure of some muscle glycogen whereas similar ascents in the 1:16 fishway did not. When muscle glycogen was utilized during prolonged ascents the expenditure appeared to be progressive. All species were apparently able to adapt to prolonged ascents of either fishway. Certain fish of each species tended to stop moving of their own volition in both fish-ways. After a 60-min volitional stop some evidence of recovery from the effects of exercise was observed. Discussion of the above data is presented.