Dissolved Oxygen Tolerances of Selected Small Stream Fishes of Southwest Missouri: Field vs. Laboratory Measurements

Date of Graduation

Spring 2007


Master of Natural and Applied Science in Biology



Committee Chair

Daniel Beckman


This study sought to determine the critical dissolved oxygen (DO) thresholds for five species of fish: rainbow darter, stippled darter, southern redbelly dace, creek chub, and banded sculpin. Previous studies have used either field-acclimated fish or laboratory-acclimated fish to determine critical DO thresholds. The second goal of this study was to compare the critical DO thresholds between field-acclimated fish and laboratory-acclimated fish to determine if there was any significant difference between the two treatments. Field-acclimated fish were captured and held in small fish pens in the stream until they were used in DO experiments. Laboratory-acclimated fish were housed in aquariums under constant conditions for at least 30 days prior to testing. Fish to be tested were placed in a sealed vessel and allowed to create hypoxic conditions through respiration. When a fish lost equilibrium, a sample of water was taken and the DO concentration measured. The results of the study were mixed. Two of the species showed no differences between field and laboratory-acclimated fish. Three of the species showed a significant difference between the two treatments. An analysis of variance indicated that critical DO was significantly different among species, but that critical DO was not significantly different between the two treatments when all five of the species were looked at as a group.


dissolved oxygen, DO, stippled darter, rainbow darter, southern redbelly dace, creek chub, banded sculpin

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© Curtis B. Klotz