Field Studies on the Oxygen Requirements of Certain Fresh‐Water Fishes

The relations of fishes to the dissolved gases of their habitat, especially the determination of minimum oxygen tensions for various species, are problems of utmost importance and consequently have received considerable attention from biologists. However, since the majority of previous studies have been performed under laboratory conditions, it seemed desirable to supplement this work by field studies. The following report presents a summary of the writer's investigations oin the delimitation of oxygen thresholds for various species of fishes under field conditions.