Technical Bulletin No. 0078: The Tolerance of Walleyed Pike Eggs to Varied Oxygen Conditions
In addition to the direct effect of environmental conditions on fish themselves, their affect upon the organisms from which they derive sustenance, the eggs and the fry are equally important if a complete understanding of the requirements for fish propagation is to be obtained. In accordance with the Council's policy of pursuing aquatic biology research in a sound manner, studies on the effect of low dissolved oxygen tensions on fish eggs were made and are reported in the attached technical bulletin. These followed the extensive investigations on the effect of low dissolved oxygen tensions upon various species of fish. These studies were made at the Institute of Paper Chemistry under the direction of Dr. Willis M. Van Horn, Biologist. As was observed in studies on fish themselves, it appears that high dissolved oxygen levels are not required for normal egg development since walleyed pike eggs would develop and hatch at dissolved oxygen levels as low as 0.9 ppm. Low oxygen tensions appeared to have little effect on the survival of fry. The only effect of very low oxygen tensions was a slowing of the metabolic rate resulting in a longer incubation period. To an industry concerned with the discharge of effluents- containing organic matter, which tend to depress dissolved oxygen levels in receiving streams, these findings are of considerable importance. It is becoming increasingly obvious that past thinking regarding oxygen requirements need re-examining in the light of not only this research but findings by other investigators reported recently in the literature.