Resistance and Tolerance of Young Speckled Trout (Salvelinus fontinalis) to Oxygen Lack, with Special Reference to Low Oxygen Acclimation

Abstract

Samples of trout were exposed to flows of water containing constant low concentrations of oxygen (produced by equilibrating aerated water with nitrogen). At 9°–10 °C. minimum tolerance levels were defined by determining the lowest oxygen level permitting survival of 5%, 50% and 95% of the fish for a period of 5,000 minutes. Median resistance times for samples of fish exposed to lethal levels of oxygen were also determined. Within their first year, most trout reared in aerated water could withstand oxygen concentrations down to 1.9 mg.O2/1. The 50% tolerance level was 1.75 mg.O2/1. Most fish died at 1.5 mg.O2/1. Acclimation to low (but not lethal) oxygen levels occurred; for a drop of 1.0 mg.O2/1. in environmental oxygen concentration, the tolerance level decreased by approximately 0.09 mg.O2/1. and resistance times at given lethal levels increased up to five-fold. By acclimations trout could exist at 1.05 mg.O2/1. without direct lethal effects occurring. Between 20 and 33 hours were required for the fish to acclimate to a change of 1.0 mg. per liter in the oxygen concentration of the environment. Acclimation to low levels of oxygen was accompanied by an apparent increase in the ability of the animals to remove oxygen at low environmental oxygen concentrations, suggesting a physiological mechanism similar to that involved in acclimation of mammals to low oxygen. The tolerance levels of small fish were similar to those of large fish at similar acclimation levels, but small fish died more quickly than large fish when exposed to lethal concentrations.

Surviving winter hypoxia: behavioral adaptations of fishes in a northern Wisconsin winterkill lake

“…These results are consistent with the finding that large fish are more resistant to low oxygen tensions than are smaller fish of the same species at winter temperatures (Moore 1942, Shepard 1955, possibly owing to the generally higher metabolic rates of smaller fishes (Doudoroff & Shumway 1970). Casselman & Harvey (1975) found, however, that northern pike (ESOX l&us) that died during partial winterkills were significantly larger than those that survived, indicating that smaller fish were more resistant to hypoxia.…”

Action Plan for Monitoring, Mitigation and Management of Harmful Algal Blooms in the Coastal Waters of Oman

“…Other possible mitigation practices for HAB causing fish kill include acclimation of fish to decreased oxygen conditions (Shepard, 1995) which elevates the number of erythrocytes in blood.…”

Standard, routine and active oxygen consumption of a freshwater shrimp

“…During the experimental period the rate of flow was adjusted in such a way that the oxygen concentration did not fall much below the air saturation level at that temperature, so that the partial pressure of oxygen in water would not restrict oxygen uptake (cf. Shepard, 1955) . Umnodified Winkler technique, Ellis et al (1946) was used to estimate dissolved oxygen in the samples collected .…”