OXYGEN CONSUMPTION AND ITS INHIBITION IN THE DEVELOPMENT OF FUNDULUS AND VARIOUS PELAGIC FISH EGGS

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Abstract
The rate of O2 consumption of fertilized Fundulus eggs, detd. by the use of Fenn microrespirometers, increases during the first 2\ days of development. No striking fluctuations in rate were seen during this period and no transitory maximum rate followed by a decline shortly after fertilization. The increases found may be correlated with increases in cell number and amt. of material incorporated in the active embryonic mass rather than with any particular embryo-logical stage. The O2 consumption is cyanide-sensitive and the absolute value of the cyanide-stable portion remains relatively constant through 4 days after fertilization. Therefore, increases in O2 consumption during early development occur almost exclusively in the cyanide-sensitive respiratory system. Earlier observations of Loeb on the relative sensitivity of Fundulus and cunner eggs to anaerobiosis were confirmed by the use of NaCN and NaN3 Fundulus eggs before the end of gastrulation are capable of extensive development in high concs. of NaCN and NaN3 which immediately inhibit cunner eggs. Scup and mackerel eggs resemble the cunner eggs in this respect. In lower concs. the pelagic eggs develop at decreased rates. No differences in sensitivity to NaCN or NaN3 were noted in the eggs at the various embryological stages studied.