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fully recover. That fish may appear to be alright at release, but it will eventually die. <br />This point of no return caused by lactic acid build-up is a killing phenomena known as <br />lactic acidosis and was discovered by Black (1958) while conducting hyperactivity studies <br />on fish. Since then it has been reported by other researchers studying fish (Caillouet <br />1968, 1971) and has also been shown to cause death in humans (Huckabee 1961). ' <br />w <br />a <br />U_ <br />C~ <br />O <br />O <br />STRESSOR <br />RESISTANCE <br />ADAPTAT I 0 N <br />OR <br />EXHAUSTION <br />COMPENSATION <br />Figure 4. The potential responses of physiological systems <br />(physiologic state) such as hormones, metabolic <br />rates, and circulatory-respiratory characteristics <br />over time following the application of a stressor - - <br />(Schreck 1976). <br />What I have discussed may be an over-simplification of a complex physiological phenomena. <br />Recently, it has been determined that the cause of death is not the result of acid accumu- <br />lations in the blood, but rather the result of intercellular acidosis. The white muscle <br />cells that produce lactic acid in fish are unable to remove the hydrogen ions from the <br />intercellular spaces at the same rate as that in the blood, and death results (Wood et al. <br />1983, Holeton and Heisler 1983). <br />The point to be made about Figure 4 is that once a stressor has been applied, there is some <br />time period during which the metabolism or physiology of the fish will be affected, and <br />during this time period, the fish will either return to normal or will be pushed out of <br />normality, These stress reactions can occur rapidly and can be influenced by the size of <br />the fish and water temperature or other factors (R. Wydoski, USFWS pers. comm.). In <br />general, electrofishing creates a general stress lasting several hours. <br />Two experiments, one by Schreck et al. (1976) and one by Sternin et al. (1976) have measured <br />the blood lactate and oxygen levels in shocked fish. <br />Schreck et al. (1976) observed changes in lactate levels in the blood of rainbow trout <br />(SaZmo gairdneri) immediately afte'Y~ shocking (dc current) (Figure 5). The lactic acid <br />GAL«N6VA WILpLIFE TRANSAGTTBNS 1984 <br />64 <br />IMMEDIATE REACTION <br />