Temperature-related cleavage rates and mitotic intervals (${ au}_o$) in the far eastern catfish Silurus asotus were studied by averaging the duration of the second and third embryonic divisions to establish effective procedures for chromosome manipulations. At higher temperatures eggs developed faster and underwent more asynchronous development. Mitotic intervals for far eastern catfish were $21.5{pm}1.4$ min at $22^{circ}C$, $18.5{pm}1.2$ min at $24^{circ}C$, and $14.0{pm}2.1$ min at $26^{circ}C$. There was a strong negative correlation between ${ au}_o$ and water temperature (Y=-1.85X+21.9, $R^2=0.9868$, where Y is ${ au}_o$ and X is temperature).